2017
A review on waste-derived adsorbents from sugar industry for pollutant
removal in water and wastewater
Anastopoulos Ioannis
Elsevier BV
info:eu-repo/semantics/article
info:eu-repo/semantics/acceptedVersion
© Elsevier B.V
CC BY-NC-ND https://creativecommons.org/licenses/by-nc-nd/4.0/
http://dx.doi.org/10.1016/j.molliq.2017.05.063
https://erepo.uef.fi/handle/123456789/4384
Downloaded from University of Eastern Finland's eRepository
A review on waste-derived adsorbents from sugar industry for pollutant removal in water and wastewater
Ioannis Anastopoulos, Amit Bhatnagar, Bassim H. Hameed, Yong Sik Ok, Michalis Omirou
PII: S0167-7322(17)31331-4
DOI: doi:10.1016/j.molliq.2017.05.063
Reference: MOLLIQ 7355
To appear in: Journal of Molecular Liquids Received date: 28 March 2017
Revised date: 14 May 2017 Accepted date: 15 May 2017
Please cite this article as: Ioannis Anastopoulos, Amit Bhatnagar, Bassim H. Hameed, Yong Sik Ok, Michalis Omirou , A review on waste-derived adsorbents from sugar industry for pollutant removal in water and wastewater, Journal of Molecular Liquids (2017), doi:10.1016/j.molliq.2017.05.063
This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain.
ACCEPTED MANUSCRIPT
1
A review on waste-derived adsorbents from sugar industry for pollutant removal in water and wastewater
Ioannis Anastopoulosa, Amit Bhatnagarb, Bassim H. Hameedc, Yong Sik Okd,
Michalis Omiroua
a Department of Agrobiotechnology, Agricultural Research Institute, P.O. Box 22016, 1516, Nicosia, Cyprus
b Department of Environmental and Biological Sciences, University of Eastern Finland, P.O. Box 1627, FI-70211, Kuopio, Finland
c School of Chemical Engineering, Engineering Campus, Universiti Sains Malaysia, 14300 Nibong Tebal, Penang, Malaysia
d School of Natural Resources and Environmental Science & Korea Biochar Research Center, Kangwon National University, 24341 Chuncheon, Korea
Corresponding author. Tel.: +357-22403151
Email address: anastopoulos_ioannis@windowslive.com, ianastopoulos@ari.gov.cy(I. Anastopoulos)
ACCEPTED MANUSCRIPT
2 Abstract
Sugar industry generates a significant amount of by-products (such as sugar beet pulp (SBP), sugar bagasse (SB)) and their handling and management is a matter of great concern. Among their uses such as fuel and fertilizer, the valorization of biowastes from sugar industry as adsorbents for the removal of various aquatic pollutants presents promising features in terms of cost reduction for waste disposal and environmental protection. This review article deals with the use of sugar waste based materials used as adsorbents in water treatment. For this purpose, isotherms, kinetics, desorption and thermodynamic information are thoroughly presented. Moreover, many parameters which control the adsorption process, such as the effect of initial concentration, initial solution pH, contact time, temperature and adsorbent's dose, are also discussed in detailed. The performance of the adsorbents largely depends on the type of pollutants and experimental conditions. Surface modification with chemicals greatly enhance the removal efficiency with favorable kinetics and adsorption mechanism.
Keywords: Heavy metals, dyes, aquatic pollutants, adsorption, sugar wastes.
ACCEPTED MANUSCRIPT
3 Content:
Page
1. Introduction ………5
2. Sugar waste for heavy metals removal ………...6
2.1 Raw sugar wastes ………..7
2.2 Chemically modified sugar wastes ……….9
2.3 Sugar waste based adsorbents ………11
3. Sugar wastes for dyes removal ………13
3.1 Raw sugar wastes ………..13
3.2 Chemically modified sugar wastes ……… 15
3.3 Sugar waste based adsorbents ………18
4. Sugar wastes for miscellaneous pollutants ……….19
5. Thermodynamic studies ………...22
6. Conclusions and future directions.……….. 24
References ……….36
ACCEPTED MANUSCRIPT
4 Abbreviation list
MB Methylene blue
EB Erythrosin B
MG Malachite green
AO7 Acid orange 7
CPBr Cetylpyridinium bromide
OR2 Orange II
CR Congo red
ACCEPTED MANUSCRIPT
5 1. Introduction
Water pollution due to industrial, agricultural and domestic activities has caused a significant threat to human as well as surrounding environment [1]. Various water treatment technologies have been developed during the last few decades [2]. Among them, adsorption still remains the most favorable process for removing pollutants
MR Methyl red
RBB Remazol black B
BB3 Basic blue 3
RO16 Reactive orange 16
CRR195 Chemazol reactive red 195 BV16 Basic violet 16
RR2 Reactive red 2
AR1 Acid red 1
SA Safranin
DW Distilled water
SBP Sugar beet pulp
SCB Sugarcane bagasse
COD Chemical oxygen demand
FTIR Fourier transform infrared spectroscopy BET Brunauer,Emmett and Teller
Ea Activation energy
C-SCB Carbonaceous bagasse CPBr Cetylpyridinium bromide
F-SCB) Formaldehyde- Sugarcane bagasse S-SCB Sulphuric acid-SCB
PAC Commercial activated carbon QSCB Quartenized sugarcane bagasse DSBPC Dehydrated sugar beet pulp carbon
ΔGo Gibbs free energy
ΔHo Enthalpy change
ΔSo Entropy change
L Langmuir
F Freundlich
Ps1 Pseudo-first-order
Ps2 Pseudo-second-order
ACCEPTED MANUSCRIPT
6
from water and wastewater due to its simplicity to design, easiness to operate and low cost [3].
Activated carbon has been used for this purpose since long, but focus has been shifted towards developing low-cost adsorbents using agro-industrial wastes such as rice husk, wheat straw, coffee waste, coconut wastes, peanut hull, fruits and vegetable peels, sludges, steel slag, red mud, sugarcane bagasse etc. [4-13].
Various industries produce huge amounts of wastes which create disposal problems as well as environmental pollution in many ways (air, soil and water). Sugar industry is one such industries generating large amounts of wastes [14, 15]. Around 160 million tons of sugar are produced annually from more than 123 sugar-producing countries with Brazil, India, China, Thailand and Pakistan as top five producers. A significant amount of wastes is generated during the production of sugar which consists elevated levels of suspended solids, organic matter, effluent, sludge, press mud, and bagasse [16].
Bagasse and filter cake are two main types of solid wastes generated by sugarcane industry [17, 18]. The solid residual material, left after the juice is extracted from the sugarcane, is termed as bagasse. It is estimated that bagasse contributes to 33% residue of the total cane crushed [17, 18]. It has a calorific value of about 1920 kcal/kg [17, 18] and is mainly used as fuel in boilers for steam generation. For each 10 tons of sugarcane crushed, a sugar factory produces nearly 3 tons of wet bagasse.
Bagasse fly ash is produced when bagasse is burned to generate energy and steam for power. The precipitate in the form of sludge slurry after filtration is termed as filter cake or press mud cake.
Press mud is a residue of sugarcane juice filtration process [19]. It contains all non-sucrose impurities along with CaCO3 precipitate and sulphate. Press mud from
ACCEPTED MANUSCRIPT
7
double sulphitation process contains valuable nutrients such as nitrogen, phosphorous, potassium, etc., and therefore used as a fertilizer. The press mud from double carbonation process is used for land filling [20]. Molasses is a by-product left over from the process of crystallization of sugar from the sugarcane juice [21].
Sugar mills significantly contribute towards environmental pollution by generating wastewater, emissions and solid wastes. The massive quantities of plant matter and sludge washed from mills are decomposed in freshwater bodies, absorbing available oxygen and leading to massive fish kills [22]. In addition, mills release flue gases, soot, ash, ammonia and other substances during processing. If all the by-products of sugar industry can be used for converting into value-added products, it will minimize the pollution load to a large extent. Sugar industry wastes are, therefore, a promising resource for environmental technology if applied in the treatment of water and wastewater. This paper presents the recent advances in the utilization of sugar industry wastes as adsorbents and their performance in the removal of different aquatic pollutants.
2. Sugar waste for heavy metals removal
Heavy metals are recognized as one of the most toxic groups which reach in food chain through the disposal of wastes to water receptors or land. Heavy metals are taxed in causing toxic effects, cancer and diseases because they cannot be degraded [23-25]. The most important factors which affect their mobility are pH, sorbent nature, presence and concentration of organic and inorganic ligands [26]. The maximum adsorption monolayer capacity, best isotherm and kinetic models are tabulated in Table 1.
2.1 Raw sugar wastes
ACCEPTED MANUSCRIPT
8
The adsorption of Mn2+ by sugar beet pulp (SBP) and sugarcane bagasse (SCB) from aqueous solution was examined by Ahmed et al. [27]. Optimum adsorption conditions for SCB was obtained at pH 6, 1.5 g and equilibrium was reached after 150 min, while for BP optimum adsorption conditions were recorded at pH 6 and 1 g and the equilibrium time was attained after 90 min. FTIR spectra before and after Mn2+
adsorption were used to determine the functional groups which participated in adsorption process. For both SCB and SBP, it was found that oxygen containing functional groups vis, methoxy –OCH3, carboxy–COOH and phenolic –OH groups were affected after removal process. Intra particle diffusion was found to involve in uptake process but it was not the only rate limiting step.
Moubarik et al. [28] examined the use of SCB for the uptake of Cd2+. Highest removal was noticed at pH 7 and at 25 oC and the equilibrium was reached in 25 min.
Arrhenius activation energy (EA) was estimated to be 4.6 kJ mol-1 suggested physisorption. The adsorption percentage was found to increase from 87 to 96% as the concentration increase from 10 to 30 mg L-1.
SCB was also used as adsorbent for the removal of Cd2+ from aqueous solutions [29]. Maximum adsorption was achieved at 150 rpm of agitation rate and at pH 5 – 7.
Adsorption was noticed to be fast and equilibrium was reached after about 90 min of contact time. Kinetic studies showed that pore diffusion was not the only rate-limiting step. Rosmi et al. [30] also concluded that maximum adsorption percentage (55%) of Cd2+ by SCB was achieved at pH 7, with 120 min of contact time and 1 g of adsorbent dosage.
Pehlivan et al. [31] studied the adsorption of Pb2+ and Cd2+ by SBP. The pH was found to control the uptake process and maximum adsorption was found at pH 5.3 and 5, for Cd2+ and Pb2+, respectively. Equilibrium time was attained after 70 min
ACCEPTED MANUSCRIPT
9
for both metals and the increase of adsorbent dose from 0.1 g to 1 g caused an increment of removal efficiency from 57 to 72% for Cd2+ and from 65 to 71% for Pb2+, respectively. The presence of 0.1 M NaNO3 had no significant effect on Pb2+
and Cd2+ removal, while increasing the ionic strength over 0.1 M NaNO3, a reduction in the adsorbed amount for both metals was noticed.
Batch equilibrium studies were carried out in order to test the uptake of Cu2+ by dried SBP [32]. The increase in pH from 2 to 4 was found to positively affect the adsorption process and the removal efficiency was raised from to 10.8 to 24.6 mg g-1. At higher pH values such as 4.5 and 5, a significant decrease of Cu2+ uptake was noticed due to the plausible precipitation of Cu2+ as insoluble Cu(OH)2. The increase in temperature from 25 to 45 oC had negative effect on Cu2+ adsorption that resulted in the decrease of the amount adsorbed from 24.6 to 12.3 mg g-1. The external mass transfer, intra particle diffusion and sorption process were potential rate controlling- steps indicated the complexity of the adsorption mechanism. The activation energy of adsorption (EA) was estimated to be -58.47 kJ mol-1 and thermodynamic studies suggested that the adsorption was spontaneous, exothermic with a decrease in the randomness at the solid/solution interface.
SCB and its modified forms (NaOH-SCB and HCl-SCB) were used as promising adsorbents for the removal of Hg1+ from aqueous solution [33]. Raw biomass appeared to have higher maximum adsorption capacity than modified adsorbents. The highest removal of 97.58% was noticed at pH 4, while for pH values higher than 4, a decrease was observed due to the potential precipitation of mercury ions. The raise of temperature from 30 to 50 oC caused an increment of the uptake efficiency in the first minutes but at equilibrium time negligible changes were performed.
ACCEPTED MANUSCRIPT
10 2.2 Chemically modified sugar wastes
SCB was treated with 0.1 M oxalic acid in order to use as adsorbent for the removal of Cu2+ from water [34]. Optimum adsorption conditions were obtained at pH 2.0 and at 100 min of contact time. Compared to raw SCB, the modified adsorbent appeared to have higher maximum adsorption capacity at optimum conditions (1.854 mg g-1 vs 0.556 mg g-1). Thermodynamic parameters showed the spontaneity and endothermicity of adsorption process as well as the positive values of entropy change indicated the high degree of randomness at the solid/solution interface.
SBP treated with NaOH and citric acid was also examined for Cu2+ removal [35]. Compared with untreated sugar beet pulp, the modified adsorbent had higher cation exchange capacity (3.21 meq g-1 vs 0.86 meq g-1), suggested higher cation uptake capability. The pretreatment lead to stabilization of adsorbent due to lower swelling capacity and COD values than the untreated SPB. The mean free energy of adsorption estimated from Dubinin-Radushkevich and the Polanyi potential was in the range 10.91 – 11.95 kJ mol-1 of 25 – 55 oC, suggesting that the ion exchange mechanism controlled the adsorption process. Negative values of ΔG0 and ΔH0 indicated that the adsorption was spontaneous and exothermic.
Jiang et al. [36] tested the use of SCB treated with acrylonitrile and hydroxylamine with the aim to enhance the ability to adsorb Cu2+ from wastewater.
The increase of pH (from 3 to 6) and initial concentration (from 76 to 600 mg L-1) affected positively the Cu2+ uptake while the raise of temperature from 30 to 60 oC had negative effect on adsorption capacity (decrease from 101.01 to 59.28 mg g-1).
SCB was pretreated by sulphuric acid and it investigated to adsorb Pb2+ [37].
Potentiometric titrations showed two different types of sites present on adsorbent that
ACCEPTED MANUSCRIPT
11
may be correspond to carboxyl and amine groups. Equilibrium sorption data were better fitted to Langmuir model than the Freundlich model. Compared to untreated material, the modified adsorbent had higher adsorption capacity (7.297 mg g-1 vs 6.366 and mg g-1) at 25 °C and pH 5.
Batch adsorption experiments were carried out in order to investigate the adsorption capability of chromium (Cr3+ and Cr6+) by immobilized SCB (SCBRB- sugarcane bagasse rind beads and SCBPB-sugarcane bagasse pith beads) [38].
Compared to native adsorbents (SCBR-sugarcane bagasse rind, SCBP-sugarcane bagasse pith), immobilized adsorbents showed higher adsorption capability. The pH was found to control the adsorption process and that maximum adsorption for Cr3+
and Cr6+ was marked at pH 2 and 5, respectively. Highest uptake capacity was noticed at 0.1 g of adsorbent dose, while a decreasing trend was appeared at higher adsorbent dose due to overlapping or aggregation of adsorption sites. The application of above adsorbents in tannery wastewaters was evaluated and the results showed that at conditions: pH 2, 0.1 adsorbent dose and 240 min of contact time. The maximum chromium adsorption was found as: SCBR (384 mg g-1, 68%), SCBRB (393 mg g-1, 70.5%), SCBP (404 mg g-1, 72%) and SCBPB (411 mg g-1, 73.5%).
Biodegradable adsorbent from hydrogel prepared by the free radical graft polymerization of SCB with acrylic acid and acrylamide using N, N-methylene-bis- acrylamide as a crosslinker was examined for the removal of Cu2+, Pb2+ and Cd2+
from aqueous solutions [39]. FTIR spectra before and after adsorption showed that – COO– and –NH2 participate in adsorption process. The adsorption equilibrium was reached in 60 min, 90 min and 180 min for Pb2+, Cd2+ and Cu2+, respectively. The increase of pH from 1 to 6 led to an increment of uptake efficiency from 19 to 213 mg g-1 for Cu2+, 1 to 232 mg g-1 for Cd2+ and from 36 to 246 mg g-1 for Pb2+. Desorption
ACCEPTED MANUSCRIPT
12
studies were achieved by using 1 M HCl and after five adsorption/desorption cycles, the desorption rates were 95%, 96% and 92% for Pb2+, Cd2+ and Cu2+, respectively.
2.3 Sugar waste based adsorbents
Iron (III)-impregnated sorbent prepared from SCB was tested for Cr6+ removal by Zhu et al. [40]. At an adsorbent dose of 300 mg/50 mL, an increase of initial chromium (VI) concentration from 25 to 130 mg/L enhanced the amount adsorbed from 4.15 to 12.20 mg g-1, from 4.16 to 12.50 mg g-1, and from 4.16 to 13.72 mg g-1 at 20 °C, 30 °C and 40 °C, respectively. Whereas, a negative effect on adsorption capacity was obtained by the raise of pH from 1 to 10 in which the correspondence removal decreased from 99.89 to 93.68%. The estimated thermodynamic parameters indicated the spontaneous and endothermic nature of adsorption with an increase in randomness at the solid/solution interface.
Activated carbon fabricated from SCB was also examined for the removal of Cr6+ [41]. The adsorption was found to decrease from 89.41 to 45.82% with the raise of pH from 2 to 10 while the increase of temperature from 25 to 45 oC positively affect the uptake efficiency (from 61.4 to 89.4%). Based on the thermodynamic parameters, the adsorption was found to be spontaneous and endothermic.
Activated carbons obtained from SBP impregnated with phosphoric acid were synthesized and examined for Cd2+ uptake [42]. The carbonization process was carried out by heating the phosphoric acid-treated samples in a fixed bed at different temperatures (300, 400 and 500 oC). The maximum adsorption percentage was 90.6%, 93.4% and 95.8% at initial pH 6.3 for activated carbons obtained at 300, 400 and 500
oC, respectively. Adsorption equilibrium was reached after 60 min for all tested
ACCEPTED MANUSCRIPT
13
activated carbons. The adsorption was found to be spontaneous, exothermic with positive entropy changes values.
Ozer and Tumen [43] also examined the use of carbons from SBP which was carbonized at different temperatures (300, 400 and 500 oC) for the Cu2+ removal. The optimum pH was observed at pH 5.5 and the equilibrium time was achieved in 120 min whereas increase in adsorbent dosage lead to the increment of the removal up to maximum value and then declined. An optimum dosage of 5 g L-1 was obtained with maximum adsorption capacities of 9.06, 10.48 and 12.20 mg g-1 for carbons carbonized at 300, 400 and 500 oC, respectively.
Biochar fabricated from SCB was used to adsorb Pb2+ from aqueous solutions [44]. The biochar has BET surface area of 92.30 m2 g-1, 12.21% ash content and pH 9.63, probably due to high content of alkali metals such as Ca2+ and Mg2+. The maximum removal was observed at pH 5 and 25 oC. The uptake of Pb2+ resemble to have endothermic nature as the adsorption was not favored at low temperatures. The desorption rate after 5 adsorption/desorption cycles was exceed to 94% suggesting that 1 M HNO3 was ample to regenerate the biochar but the removal efficiency was decreased due to the fact that a loss of biomass was noticed by using 1 M HNO3.
Pectin extracted from SBP was prepared by Ma et al. [45] for the removal of Hg2+. The adsorption was quick in the first 10 min and attaining equilibrium within 40 min. With increase in pH from 2 to 4, the capacity increased whereas increased in pH up to 12, the amount of Hg2+ removal decreased. In addition, there was a negligible effect on the adsorption capacity with change in temperature from 30 to 70 oC.
Palin et al. [46] utilized SCB, in natural (Nat), colonized by Pleurotus ostreatus (U2-11), colonized by Lentinula edodes (U6-1), colonized by Pleurotus ostreatus (U12-4), and colonized by Ganoderma lucidum (U12-6) for Pb2+ removal. The points
ACCEPTED MANUSCRIPT
14
of zero charge was found to be 4.6 for residue only with the bagasse, 4.0 for the residues colonized by P. ostreatus U2-11 and P. ostreatus U12-4, 3.8 for the residue colonized by G. lucidum, and 3.6 for the residue colonized by L. edodes. For all the adsorbents, maximum adsorption was found at pH 5 (pH studied range 2 – 5). The equilibrium was reached in 20 min and the residues colonized with P. ostreatus U2- 11, P. ostreatus U12-4, and G. lucidum showed higher adsorptive capacities than (Nat). The value of Gibbs free energy was found to be negative indicating the spontaneity of adsorption.
3. Sugar wastes for dyes removal
Dyes are an important class of pollutants which came are large amounts from textile, dyeing, paper and pulp, tannery and paint industries [47] . The main use of dyes is to modify the color characteristics of different substrates such paper, fabric, leather and others [48]. It is already demonstrated that dyes largely affect the photosynthetic activity [49]. Moreover, many dyes are toxic and even carcinogenic thus affecting the aquatic biota and human health [50]. The maximum adsorption monolayer capacity, best isotherm and kinetic models are tabulated in Table 2.
3.1 Raw sugar wastes
SCB washed with tap water at least 4 to 5 times, soaked in distilled water for 48 h, dried for 24 h at 100 oC and was examined for Erythrosin B (EB) and methylene blue (MB) removal using batch mode [51]. Adsorption was maximum at pH 9 and 7- 9, for MB and EB, respectively. Regarding contact time (studied range 10 – 180 min), the highest removal was achieved at equilibration time of 1 h. The raise of temperature from 35 to 55 oC was found to affect differently the uptake of dyes; the
ACCEPTED MANUSCRIPT
15
EB removal was increased while MB adsorption increased up to 45 oC and then declined. Based on thermodynamic parameters estimation, the adsorption process of EB and MB was spontaneous and endothermic with physical nature. The adsorption ability of SCB to sequestrate MB from aqueous solution was assessed [52]. The maximum dye uptake capacity for SCB was obtained as 108.67 mg g-1.
Malekbala et al. [53] examined the removal of MB and safranin (SA) by SBP from aqueous solution. The increase of adsorbent dose from 0.05 to 0.5 g led to an increment of adsorption capacity from 34% to 88% and from 26% to 89%, for MB and SA, respectively. Highest adsorption was occurred at pH 10 for both dyes due to the fact that at low pH values there are repulsive forces between the positively charged adsorbent surface and positively charged dyes. Adsorption equilibrium was reached after 210 min. Desorption studies were carried out using different HCl concentrations (0.1, 0.5 and 1 N) and the best desorption amount was observed with 0.1 N HCl (desorption amount SA=74.98 mg g-1, desorption amount MB=29.39 mg g-1).
The adsorption of congo red (CR) by ball-milled SCB was studied [54]. The pHpzc (point of zero charge) was estimated to be 5 and the raise of pH from 5 to 10 affected negatively the adsorbed amount (93.4% at pH 5, 84.7% at pH 10). The CR removal was increased from 11.3% to 98.3% with the increment of adsorbent dosage from 1 g L-1 to 20 g L-1. FTIR spectra before and after adsorption demonstrated the interaction between the carboxyl and hydroxyl groups of the adsorbent and CR functional groups. Thermodynamic analysis suggested the spontaneity and exothermicity of the process with a decrease in randomness at the solid/solution interface.
ACCEPTED MANUSCRIPT
16
The use of SCB to remove malachite green (MG) dye was examined by Sharma and Nandi [55]. External mass transfer (earlier stages) and intraparticle diffusion (later stages) were found to control the uptake of dye. The adsorption process was spontaneous and exothermic in nature with a decrease in randomness at solid/solute interface. Based on Boyd model, the external mass transfer was the slowest step which participated in the sorption process.
The ability of SBP to capture basic violet 16 (BV16) dye was assessed by Harifi-Mood et al. [56]. Batch experiments were carried out and the results showed that the increase of pH from 2 to 13 had negligible effect in the amount removed (only a smooth increase was noticed after pH 6). Maximum removal of 85.2% was noticed using 10 g L-1 of adsorbent dosage. The surface adsorption, bulk diffusion and intra particle diffusion were determined as possible adsorption mechanisms. The removal process proved to be non-spontaneous, exothermic with physical nature.
3.2 Chemically modified sugar wastes
Poly(methacrylic acid)-modified SCB were synthesized and explored for the adsorption of MG [57]. The adsorption was minimum at pH 2, with increased from 2 to 6, the adsorption of MG increased, but thereafter, there was no significant change in the amount adsorbed. The Gibbs free energy was estimated to be negative confirming the spontaneity of adsorption process. Fast uptake efficiency was achieved during initial stage of the removal process and equilibrium was attained in at approximately 3 h. Modified SB appeared to have better adsorptive properties than raw SB.
SCB was modified with formaldehyde and sulfuric acid to produce carbonaceous bagasse (C-SCB) and used to remove MG [58]. Among tested
ACCEPTED MANUSCRIPT
17
isotherms (Langmuir, Freundlich and Dubinin–Radushkevich), Langmuir isotherm gave the best fit. Compared to raw SCB, the C-SCB showed about 89% dye removal, possibly due its higher surface area. The adsorption was spontaneous, exothermic with positive ΔSo values.
Modified SCB was also examined for MG adsorption [59]. Maximum removal of 81% was notice at pH 8 (pH studied range 3 – 9) and after 30 min of contact time, respectively while optimum adsorption was obtained at 0.6 g adsorbent dose. The estimated mean adsorption energy was < 8 kJ mol-1 indicated the physical nature of the process.
The adsorption of acid orange 7 (AO7) dye from aqueous solution by SCB and cetylpyridinium bromide (CPBr) modified SCB was tested [60]. The pretreated SCB was modified with three different concentrations of CPBr i.e. 0.1, 1.0, and 4.0 mM, giving SCBC1, SCBC2 and SCBC3 adsorbents. The maximum adsorption capacity followed the sequence in the order: SCBC3 > SCBC2 > SCBC1 > SCB. The pH was found to control the removal process and the highest removal occurred at pH 2 and 7 for raw and modified adsorbents, respectively.
Raw SCB treated with propionic acid and examined for the removal of MB and orange II (OR2) [61]. Maximum adsorption occurred at pH 3-11 and 2, for MB and OR2 respectively. The increase of adsorbent dose from 0.2 g/50 mL to 2 g/50 mL was found to increase the removal percentage. In case of OR2 the effect of particle size (0.25 – 1 mm particle size range) had negative uptake results. Compared to OR2, MB adsorbed faster and for both dyes the equilibrium time was achieved after 60 min.
The removal of MB by raw and treated via CaCl2 and NaOH SCB was also examined [62]. In case of raw SCB, at higher tested concentration, adsorption was reached plateau in 15 min, while at lowest tested concentration of 0.833 g L-1, 30 min
ACCEPTED MANUSCRIPT
18
was needed to equilibrate. At the intermediate pH, approximately 4 < pH < 8, the NaOH-SCB gave the highest uptake efficiency. One possible explanation was explained that a delignification might be occurred, resulted in an increment of adsorptive properties of NaOH-SCB. At alkaline pH, all the adsorbents showed similar removal capacities.
Modified SCB (formaldehyde-SCB abbreviated as F-SCB) and sulphuric acid- SCB (abbreviated as S-SCB) were fabricated and used to adsorb methyl red [63]. For comparison reason, a commercial activated carbon (PAC) was also tested for the same purpose. The pH between 7 to 10 was found to favor the MR removal for modified SCBs while using activated carbon the adsorption was constant for all the pH range.
The adsorption efficiency followed the order: PAC>S-SCB>F-SCB.
Quartenized sugarcane bagasse (QSCB) was used to sequestrate basic blue 3 (BB3) and reactive orange 16 (RO16) in single and double dye solution [64]. The adsorption of BB3 and RO16 was found to enhance at basic (optimum at pH=10) and at acid pH values (optimum at pH=2), respectively. Kinetics and isotherm studies indicated that pseudo-second-order kinetic model and Freundlich isotherm model had the best fit to the experimental data. The uptake of BBE was enhanced by raising the temperature from 26 to 80 oC revealing the endothermic nature of the process whereas the adsorption of RO16 was found to be exothermic in nature.
SBP pretreated with quaternary ammonium salt in order to investigate its adsorptive ability to remove reactive red 2 (RR2) [65]. Compared to raw SBP, the modified SBP exhibited better removal efficiency in the studied pH range (2 – 10) suggesting the success of modification. The equilibrium was established within 60 min and Weber-Morris model showed that intra particle diffusion was involved in adsorption mechanism but it was not the only rate-limiting step. The mean energy of
ACCEPTED MANUSCRIPT
19
biosorption was estimated to be between 28.01 and 22.74 kJ mol-1 suggesting chemisorption. Thermodynamic parameters were calculated and revealed the spontaneity and endothermicity of removal process. Subsequently, they [66]
examined the adsorption of acid red 1 (AR1) by quaternary ammonium SBP. At the optimum pH 2, the equilibrium was attained within 30 min. The raise of temperature from 10 to 50 oC resulted to in enhanced adsorption capacity from 84.68 to 100.46 mg g-1, respectively. The adsorptive ability of modified SPB in real wastewater (spiked with 100 mg L-1 AR1) lead to 93.45% biosorption efficiency demonstrating that there was no matrix effect. Activation energy (Ea) was estimated to be 22.82 kJ mol-1 entailed chemisorption mechanism.
3.3 Sugar waste based adsorbents
Reticulated formic lignin (RFL) from SCB was used for the uptake of MB [67].
Maximum adsorption (34.30 mg g-1) was achieved at pH 5.8 (acetic acid-sodium acetate aqueous buffer), 50 oC and 0.1 ionic strength and 12 h of equilibrium time.
Dursun et al. [68] prepared carbon from SBP to adsorb the remazol black B dye.
A reduction of maximum adsorption capacity from 83.33 to 59.88 mg g-1 was obtained as the temperature increased from 25 to 50 oC. Large amount of dye was removed in 60 min and the equilibrium time was established in 180 min. The adsorption was maximum at pH 1 (tested pH range 1 – 10). The external mass transfer, intraparticle diffusion and sorption process seemed to constitute the adsorption mechanism. Thermodynamic study demonstrated the feasibility and spontaneity of the removal of dye.
In addition, activated carbon was also produced from SBP to sequestrate MB [69]. The optimal conditions to fabricate the activated carbon were: liquid-to-solid
ACCEPTED MANUSCRIPT
20
ratio of 5, temperature of 450 °C and phosphoric acid concentration of 3 mol L-1. BET surface area was estimated to be 1029.31 m2 g-1 and 100 min were found sufficient to achieve the equilibrium phase. Film diffusion was found to govern the adsorption process and the intraparticle diffusion was not only the rate-limiting step.
Dehydrated sugar beet pulp carbon (DSBPC) was produced in order to explore its efficiency to remove Chemazol reactive red 195 CRR195 dye [70]. The pH was found to control the adsorption process and maximum removal of CRR195 was noticed at pH 1. The raise of temperate from 25 to 50 oC enhanced the adsorption capacity due to increase in the number of active sites, porosity and total pore volume of the adsorbent. Regarding the mechanism of adsorption, both external mass transfer and intra-particle diffusion participated in removal process. Thermodynamic study showed that adsorption of CRR195 on DSBPC was spontaneous and endothermic in nature.
4. Sugar wastes for miscellaneous pollutants
Sugar wastes were also applied for the removal of other pollutants such as nitrate, phosphate, fluoride, phenol and COD. Τhe presence of phosphate and nitrate in the aquatic environment can lead to eutrophication [71]. Eutrophication promotes proliferation of algae and aquatic plants, resulting in a reduction of dissolved oxygen [72]. Furthermore, high nitrate concentration in drinking water can lead a potential risk to animal and human health. Excessive level of nitrate in drinking water can cause methemoglobinemia (blue baby syndrome), various types of cancers, adverse reproductive outcomes (especially neural tube defects), diabetes, and thyroid conditions [73]. Modified SCB was also used to adsorb phosphate ions from aqueous media [74, 75]. Hena et al. [74] reported that the adsorption was found to increase
ACCEPTED MANUSCRIPT
21
significantly from 54.1% to 95.2% when the adsorbent dosage raised from 0.5 to 2 g L-1. A decline of phosphate uptake occurred at higher temperatures of 40 oC and 60
oC. Optimum adsorption was noticed at 20 oC and at 2 g L-1 of adsorbent dosage.
Carvalho et al. [75] compared the ability of raw SCB fibres, SCB fibres doped with Fe2+ ions, carboxymethylated SCB fibres, carboxymethylated SCB fibres doped with Fe2+ ions, to adsorb phosphate. They concluded that carboxymethylated SCB fibres doped with Fe2+ ions exhibited the highest adsorption capability. The adsorption of nitrate ions from modified SCB was examined [76]. The increase of initial nitrate concentration from 5 to 40 mg L-1 lead to a raise of adsorption capacity from 0.5 to 1.57 mg g-1. The temperature was found to affect the adsorption efficiency. More specifically, the removal was enhanced at low temperature (25 oC), whereas with further increase of temperature up to 55 oC, a reduction of nitrate uptake was noticed.
Fluoride is another toxic contaminant which is found in excess in surface or groundwater because of geochemical reactions or anthropogenic activities such as the disposal of industrial wastewaters. Fluoride is mainly consumed in drinking water with 1.5 mg/L as the maximum permissible limit as recommended by World Health Organization (WHO) [77]. Continuous consumption of fluoride at high concentration can be toxic causing dental fluorosis, teeth mottling, skeletal fluorosis and deformation of bones in children as well as in adults [78, 79]. Singh et al. [80] used the SCB to remove fluoride ion from water. Optimum adsorption conditions were found as 1 g L-1 of adsorbent dosage and pH 5.4. The adsorption capacity was improved by raising the temperature from 20 oC to 50 oC. Desorption studies were carried out by changing the pH levels (2 – 12) and the results showed low desorption potential (3 – 4 %).
ACCEPTED MANUSCRIPT
22
Phenolic compounds are generated from petroleum and petrochemical, coal conversion, and Phenol-producing industries are common contaminants in wastewater and incriminated for their toxic and carcinogenic effects for aquatic and human being, respectively. Phenol is very soluble in water, oils, carbon disulfide and numerous organic solvents [81]. For the aforementioned reasons, the removal of phenol from wastewater before discharge into water bodied is necessary [82].The toxicity level for fish is around 9 to 25 mg/l while that for human being ranges 10-24 mg/l. lethal blood concentration of phenol is around 150-mg/100 mL [83].The Environmental Protection Agency (EPA) calls for lowering phenol content in the wastewater to less than 1 mg mL-1 [84]. Activated carbon prepared by SCB [85] and carbonized SBP [86] were used to sequestrate phenol ions from aqueous solution. Dursun et al. [86] mentioned that maximum adsorption was at pH 6 and at 60 oC. Equilibrium was attained in 120 min for all studied temperatures. Akl et al. [85] concluded that highest adsorption was observed at pH 7.5 – 8 and more than 90% of phenol was removed within 15 min. An increment of uptake capacity was occurred with the raise of temperature from 17 to 55
oC. Kinetic results showed that intra particle diffusion was not the only rate controlling step.
The industry generates strong wastewaters which are characterized by high biological oxygen demand (BOD) and chemical oxygen demand (COD) concentrations. COD and BOD reflect the high organic content of wastewater [87].
COD is a measure of the oxygen equivalent of the organic matter in a water sample that is susceptible to oxidation by a strong chemical oxidant, such as dichromate [88].
Higher COD levels mean that there is a greater amount of oxidizable organic material in wastewater, which will reduce dissolved oxygen levels [89]. A reduction in dissolved oxygen can lead to anaerobic conditions, which are harmful to higher
ACCEPTED MANUSCRIPT
23
aquatic organisms [90]. Lakdawala and Patel [91] studied the use of bagasse fly ash to remove COD from wastewater. The bagasse fly ash specific surface area was estimated to be 0.26 m2 g-1. The adsorption results showed that the COD removal was up to 24% and the experimental result followed the Langmuir and Freundlich isotherms.
The best isotherm, kinetic models and the maximum adsorption capacity was tabulated in Table 3.
5. Thermodynamic studies
Most often, thermodynamic parameters such as Gibbs free energy (ΔG0) (Eqn.
1), enthalpy change (ΔH0) (Eqn. 2) and entropy change (ΔS0) (Eqn. 3) are used in order to address the adsorption process as (non)-spontaneous, endo - or exo-thermic and to provide information about the potential increase or decrease of randomness at the solid/liquid interface. There are many ways to estimate the aforementioned parameters and in most cases, there is need to use necessary experimental data at three or more temperatures to estimate them. The ΔH0 and ΔS0 are obtained from the slope and intercept of different plots like ln(bL) vs 1/T (in (L mol-1) from Langmuir model) or ln(K0) vs 1/T (Ko can be evaluated by plotting ln(qe/Ce) versus qe by extrapolating to qe=0), or ln(K) vs 1/T (K=qmXbL calculated from Langmuir constant (qm), is the maximum adsorption capacity in mg g-1 and bL units in L mg-1) and ln(qe/ce) vs 1/T (qe/ce is the ratio where qe is adsorbed adsorbate at concentration (mg L-1) and ce is the residual adsorbate concentration in the solution (mg L-1)). The reason to choose one for the above methods is not explained (appeared) clearly in the works and with the combination with the lack of a protocol, make the thermodynamic calculation a complicated issue. Anastopoulos and Kyzas [92], authors provided different
ACCEPTED MANUSCRIPT
24
approaches recommended by many authors about the appropriate units of K (Eqn. 1) and they also obtained a linearity when a plot of ΔS0 vs ΔH0 (Eqn. 3) is drawn where thermodynamic data was applied from different adsorption systems.
(1)
0 0 0
ΔG = ΔΗ ΤΔS (2)
0 0
0 G
S
(3)
In Table 4, the thermodynamic parameters are tabulated for the adsorption of different aquatic pollutants by sugar industry wastes based adsorbents. As can be seen (Table 4), sorption data, ranged from three to five temperatures (278–338 K) were used. Thermodynamic studies showed that in most cases, the adsorption was spontaneous or non-spontaneous (ΔG0 < 0, ΔG0 > 0, absolute value 0.32 to 33.31 kJ mol-1), endothermic or exothermic (ΔH0 < 0, ΔH0 > 0, absolute values 0.091 to 66.3 kJ mol-1) with positive or negative entropy values (absolute value 0.001 to 0.22 kJ mol-1 K-1).
Based on the Eq. 3 and on the thermodynamic data obtained from Table 4, a plot of ΔHo versus ΔSo shows a strong linear relationship (R2>0.82) (Fig. 1) which is known as enthalpy-entropy compensation [48, 92-97]. This phenomenon sounds strange and it is not justifiable to observe a universal correlation among corresponding ΔHo and ΔSo following adsorption due to the fact that the calculated thermodynamics parameters the came from different studies with various experimental conditions [98].
0 ln
G RT K
ACCEPTED MANUSCRIPT
25
One possible explanation is that both ΔH0 and ΔS0 calculated from the same equation.
Finally, it can be concluded that in order to avoid misunderstandings, the thermodynamic parameters estimation should be done with deeper analysis and a thermodynamic protocol seems to be necessary.
6. Conclusions and future directions
This paper presents the recent advances in the use of waste materials from sugar industry as adsorbents and their performance in the removal of various aquatic pollutants. The study revealed that surface modification with chemicals greatly enhanced the removal efficiency of sugar wastes based adsorbents with favorable kinetics and adsorption efficiency. The performance of the adsorbents largely depends on the type of pollutants and experimental conditions. Most of the studies aimed at estimating the maximum adsorption capacities using batch mode experiments using single synthetic pollutant solution. The adsorption process was found to be affected significantly by different parameters such as initial pollutant concentration, contact time, solution pH, adsorbent dosage, temperature etc. Langmuir isotherm and pseudo- second kinetic model were found to show the best fit to the experimental data.
Columns studies and experiments with real wastewaters should be conducted in future in order to evaluate the potential of sugar waste based adsorbents for real applications.
To understand in depth the mechanism of adsorption, except from well-known and most applied isotherms and kinetic models, three parameters isotherm models and diffusion kinetic models are highly recommended. There is also the need to further utilize the SBP, SCB and their derivatives for the removal of other emerging
ACCEPTED MANUSCRIPT
26
pollutants such as pharmaceuticals, endocrine disruptors and radionuclides, apart from dyes and heavy metals. Most studies paid no attention on the reusability of sugar wastes based adsorbents. In order to make the adsorption process more economically feasible, regeneration studies are also required. Based on the fact that adsorption process produces large amount of pollutant-loaded waste, its disposal is an important environmental concern. Future work should also focus on a cost analysis of application of sugar waste as adsorbents.
Fig. 1: The enthalpy-entropy compensation plot for the works reviewed in the present review article
ACCEPTED MANUSCRIPT
27
Table 1. The maximum monolayer adsorption capacity and the best-fitting isotherm and kinetic models for the adsorption of metals by sugar wastes based adsorbents.
Adsorbents Metals Isotherm
models
Kinetic models
Maximum monolayer adsorption capacity (mg g-1)
Ref.
Sugar beet pulp Mn2+ - Ps2 0.869a [27]
Sugarcane bagasse Mn2+ - Ps2 0.423a [27]
Sugar beet pulp Cd2+ F - 46.1b [31]
Sugarcane bagasse Cd2+ - Ps2 0.955c [28]
Sugarcane bagasse Cd2+ L Ps2 6.79 [29]
Sugarcane bagasse Cd2+ L Ps2 0.1865 [30]
Acrylic-modified sugarcane bagasse Cd2+ L Ps2 304.878 [39]
Activated carbons obtained from sugar beet pulp impregnated with phosphoric acid (carbonized at 300 oC)
Cd2+ L Ps2 68.03 [42]
Activated carbons obtained from sugar beet pulp Cd2+ L Ps2 71.99 [42]
ACCEPTED MANUSCRIPT
28 impregnated with phosphoric acid (carbonized at 400 C)
Activated carbons obtained from sugar beet pulp impregnated with phosphoric acid (carbonized at 500 oC)
Cd2+ L Ps2 79.99 [42]
Sugar beet pulp Pb2+ F - 43.5b [31]
Sugarcane bagasse was modified by sulphuric acid Pb2+ L - 7.297 [37]
Acrylic-modified sugar cane bagasse Pb2+ L Ps2 704.225 [39]
Biochar fabricated from sugar cane bagasse Pb2+ L Ps2 86.96 [44]
Sugarcane bagasse in natura Pb2+ L Ps2 30.71 [46]
Sugarcane bagasse colonized by Pleurotus ostreatus (U2- 11)
Pb2+ L Ps2 47.89 [46]
Sugarcane bagasse colonized by Lentinula edodes (U6-1) Pb2+ L Ps2 42.67 [46]
Sugarcane bagasse colonized by Pleurotus ostreatus (U12-4)
Pb2+ L Ps2 44.76 [46]
Sugarcane bagasse colonized by Ganoderma lucidum (U12-6)
Pb2+ L Ps2 43.27 [46]
Dried sugar beet pulp Cu2+ L Ps1, Ps2 31.4 [32]
ACCEPTED MANUSCRIPT
29
Raw sugar cane bagasse Cu L,F Ps2 7.813 [34]
Sugar beet pulp treated with NaOH and citric acid Cu2+ L Ps2 119.43 [35]
Carbons obtained from sugar beet pulp (carbonized at 300
oC)
Cu2+ L Ps1 12.24 [43]
Carbons obtained from sugar beet pulp (carbonized at 400
oC)
Cu2+ L Ps1 13.44 [43]
Carbons obtained from sugar beet pulp (carbonized at 500
oC)
Cu2+ L Ps1 14.81 [43]
Modified sugar cane bagasse with 0.1 M oxalic acid Cu2+ L,F Ps2 9.260c [34]
Treated sugar cane bagasse with acrylonitrile and hydroxylamine
Cu2+ L Ps2 101.01 [36]
Acrylic-modified sugarcane bagasse Cu2+ L Ps2 265.252 [39]
Raw sugarcane bagasse Hg1+ L, F Ps2 35.71 [33]
Pectin extracted from sugar beet pulp Hg2+ L - 19.8 [45]
SCBR-sugarcane bagasse rind Cr3+ L Ps2 296.21 [38]
SCBRB-sugarcane bagasse rind beads Cr3+ L Ps2 303.11 [38]
ACCEPTED MANUSCRIPT
30
SCBP-sugarcane bagasse pith Cr L Ps2 381.05 [38]
SCBPB-sugarcane bagasse pith beads Cr3+ L Ps2 449.23 [38]
SCBR-sugarcane bagasse rind Cr6+ L Ps2 495.56 [38]
SCBRB-sugarcane bagasse rind beads Cr6+ L Ps2 491.24 [38]
SCBP-sugarcane bagasse pith Cr6+ L Ps2 767.25 [38]
SCBPB-sugarcane bagasse pith beads Cr6+ L Ps2 832.13 [38]
Iron (III)-impregnated sorbent prepared from sugarcane bagasse
Cr6+ L Ps2 12.22 [40]
Activated carbon fabricated from acid modified sugarcane bagasse
Cr6+ - Ps1 15.42d [41]
aQm obtained from kinetic studies.
bQm obtained from batch studies.
C Qm obtained from Ps2 model.
d Qm obtained from Ps1 model.
ACCEPTED MANUSCRIPT
31
Table 2. The maximum monolayer adsorption capacity and best-fitting isotherm and kinetic models for the adsorption of dyes by sugar wastes based adsorbents.
Adsorbents Dyes Isotherm
models
Kinetic models
Maximum monolayer adsorption capacity (mg g-1)
Ref.
Sugarcane bagasse MB L,F - 1,000.00 [51]
Reticulated formic lignin (RFL) from sugarcane bagasse (unbuffered, pH=5.9)
MB L - 14.57 [67]
Reticulated formic lignin (RFL) from sugar cane bagasse (buffered, pH=5.8)
MB L - 15.72 [67]
Reticulated formic lignin (RFL) from sugarcane bagasse (buffered, pH=4.5)
MB L - 16.50 [67]
ACCEPTED MANUSCRIPT
32
Sugarcane bagasse treated with propionic acid MB L Ps2 59.5 [61]
Sugarcane bagasse MB L - 84.85 [62]
Sugarcane bagasse treated with 0.0248 M CaCl2 MB L - 35.21 [62]
Sugarcane bagasse MB L - 108.69 [52]
Sugar beet pulp MB L Ps2 211b [53]
Sugarcane bagasse treated with propionic acid OR2 F Ps2 25.5a [61]
Sugarcane bagasse EB L,F - 333.3 [51]
Sugarcane bagasse MG L Ps2 190 [55]
Sugarcane bagasse MG L Ps2 23.41 [57]
Poly(methacrylic acid)‐ modified sugarcane bagasse MG L Ps2 103.2 [57]
Sugar cane bagasse MG F Ps2 5.71
[59]
Sugarcane bagasse AO7 L,F - 9.901 [60]
Sugarcane bagasse pretreated with 0.1 mM CPBr AO7 L,F - 14.599 [60]
Sugarcane bagasse pretreated with 1 mM CPBr AO7 L,F - 102.041 [60]
Sugarcane bagasse pretreated with 4 mM CPBr AO7 L,F - 144.928 [60]
Balli-milled sugarcane bagasse CR F Ps2 39.8 [54]
ACCEPTED MANUSCRIPT
33
Carbon from sugar beet pulp RBB L Ps2 83.33 [68]
Dehydrated beet pulp carbon CRR195 F Ps1 45.24 [70]
Sugar beet pulp BV16 L,F Ps1,Ps2 192.3 [56]
Quaternary ammonium modified-sugar beet pulp RR2 L Ps2 2.08 x 10-3
mol g-1
[65]
Quaternary ammonium modified-sugar beet pulp AR1 L Ps2 1.92 x 10-4
mol g-1
[66]
Sugar beet pulp SA L Ps2 147b [53]
a Adsorbed dye at equilibrium
b Obtained from kinetic study
ACCEPTED MANUSCRIPT
34
Table 3. The maximum monolayer adsorption capacity and the best-fitting isotherm and kinetic models for the adsorption of miscellaneous pollutants by sugar wastes based adsorbents.
Adsorbents Pollutants Isotherm
models
Kinetic models
Maximum monolayer Adsorption capacity (mg g-1)
Ref.
Physicochemically modified sugarcane bagasse Nitrate F Ps2 0.5302* [76]
Chemically modified sugarcane bagasse Phosphate L - 1.05 mmol g-1 [74]
Carboxymethylated sugarcane bagasse fibres Phosphate L - 67.5 [75]
Carboxymethylated sugarcane bagasse fibres incorporating with Fe2+ ions
Phosphate L - 152 [75]
Sugarcane bagasse Fluoride F Ps2 2.168 [80]
Activated carbon from sugarcane bagasse Phenol L Ps2 47.92 [85]
Chemically activated carbon from sugarcane bagasse Phenol L - 121.36 [85]
Carbonised beet pulp Phenol F Ps2 89.96 [86]
Sugarcane bagasse fly ash COD L,F - 118.1631 [91]
ACCEPTED MANUSCRIPT
35
a Obtained from kinetic study
ACCEPTED MANUSCRIPT
36
Τable 4. List of models for the adsorption isotherms and kinetics for adsorption of different pollutants on sugar waste based adsorbents.
Adsorbents Pollutants T (K) ΔGo
(kJ mol-1)
ΔΗo (kJ mol-1)
ΔSo
(kJ mol-1 K-1) Ref.
Sugar beet pulp treated with NaOH and citric acid Cu2+ 298 -19.40 -14.80 0.015 [35]
313 -19.40 328 -19.83
Raw sugar cane bagasse with 0.1 M oxalic acid Cu2+ 298 -1.73 26.42 0.094 [34]
303 -2.32 308 -2.68 313 -3.16 318 -3.68
Modified sugar cane bagasse with 0.1 M oxalic acid Cu2+ 298 -4.12 17.45 0.072 [34]
303 -4.38 308 -5.07 313 -5.17 318 -5.53
Dried sugar beet pulp Cu2+ 298 -0.74 -66.3 -0.22 [32]
Sugarcane bagasse EB 308 -0.38 0.091 0.002 [51]
318 -0.39 328 -0.41
Balli-milled sugarcane bagasse CR 303 -5.50 -24.25 -0.062 [54]
313 -5.13 323 -4.26
Sugarcane bagasse MG 293 -3.86 -23.41 -0.067 [55]
303 -3.19 313 -2.52 323 -1.86
Sugar beet pulp BV16 298 12.23 -18.70 -0.104 [56]
ACCEPTED MANUSCRIPT
37
308 13.35 318 14.30
Carbonaceous sugarcane baggase MG 303 -0.323 -6.92 0.001 [58]
308 -0.328 313 -0.332 318 -0.336
Sugar beet pulp RBB 298 -26.43 -16.39 0.034 [68]
313 -27.51 -16.39 0.036
323 -27.18 -16.39 0.033
Dehydrated beet pulp carbon CRR195 298 -29.46 16.019 0.099 [70]
313 -31.46 0.152
323 -33.31 0.153
Chemically modified sugarcane bagasse Phosphate 293 -10.87 -17.63 -0.016 [74]
313 -10.33 333 -10.21
Sugarcane bagasse Fluoride 293 to
323
-24.70 to -
28.06 8.12 0.111 [80]
Chemically activated carbon from SCB Phenol 290.15 -18.76 -1.796 0.058 [85]
313.15 -20.11 328.15 -20.98
Steam activated carbon from SCB Phenol 290.15 -22.05 5.928 0.096 [85]
313.15 -24.31 328.15 -25.71
Carbonised beet pulp Phenol 298 -21.57 6.35 0.095 [86]
313 -23.36 333 -25.04
ACCEPTED MANUSCRIPT
38 References
[1] R.P. Schwarzenbach, T. Egli, T.B. Hofstetter, U. von Gunten, B. Wehrli, Global water pollution and human health, Annual Review of Environment and Resources 35 (2010) 109-136.
[2] N.P. Cheremisinoff, Handbook of water and wastewater treatment technologies, Butterworth-Heinemann2001.
[3] A. Abdolali, H.H. Ngo, W. Guo, J.L. Zhou, J. Zhang, S. Liang, S.W. Chang, D.D.
Nguyen, Y. Liu, Application of a breakthrough biosorbent for removing heavy metalsfrom synthetic and real wastewaters in a lab− scale continuous fixed− bed column, Bioresource Technology 229 (2017) 78–87.
[4] Y. Chen, F. Wang, L. Duan, H. Yang, J. Gao, Tetracycline adsorption onto rice husk ash, an agricultural waste: Its kinetic and thermodynamic studies, Journal of Molecular Liquids 222 (2016) 487-494.
[5] Q. Lin, K. Wang, M. Gao, Y. Bai, L. Chen, H. Ma, Effectively removal of cationic and anionic dyes by pH-sensitive amphoteric adsorbent derived from agricultural waste-wheat straw, Journal of the Taiwan Institute of Chemical Engineers (2017).
[6] I. Anastopoulos, M. Karamesouti, A.C. Mitropoulos, G.Z. Kyzas, A review for coffee adsorbents, Journal of Molecular Liquids 229 (2017) 555–565.
[7] A. Bhatnagar, V.J. Vilar, C.M. Botelho, R.A. Boaventura, Coconut-based
biosorbents for water treatment—a review of the recent literature, Advances in colloid and interface science 160 (2010) 1-15.
[8] L.D. Hafshejani, A. Hooshmand, A.A. Naseri, A.S. Mohammadi, F. Abbasi, A.
Bhatnagar, Removal of nitrate from aqueous solution by modified sugarcane bagasse biochar, Ecological Engineering 95 (2016) 101-111.
[9] A. Bhatnagar, V.J. Vilar, C.M. Botelho, R.A. Boaventura, A review of the use of red mud as adsorbent for the removal of toxic pollutants from water and wastewater, Environmental technology 32 (2011) 231-249.
[10] M.S.M. Zahar, F.M. Kusin, S.N. Muhammad, Adsorption of manganese in aqueous solution by steel slag, Procedia Environmental Sciences 30 (2015) 145-150.
[11] P. Devi, A.K. Saroha, Utilization of sludge based adsorbents for the removal of various pollutants: A review, Science of The Total Environment 578 (2017) 16–33.
[12] A. Bhatnagar, M. Sillanpää, A. Witek-Krowiak, Agricultural waste peels as versatile biomass for water purification–A review, Chemical Engineering Journal 270 (2015) 244-271.
[13] C.-S. Zhu, L.-P. Wang, W.-b. Chen, Removal of Cu (II) from aqueous solution by agricultural by-product: peanut hull, Journal of hazardous materials 168 (2009) 739-746.
[14] M. Balakrishnan, V. Batra, Valorization of solid waste in sugar factories with possible applications in India: a review, Journal of environmental management 92 (2011) 2886-2891.
[15] A. Bhatnagar, K.K. Kesari, N. Shurpali, Multidisciplinary approaches to handling wastes in sugar industries, Water, Air, & Soil Pollution 227 (2016) 11.
[16] P. Muthusamy, S. Murugan, S. Manothi, Removal of Nickel ion from industrial waste water using Maize cob, ISCA Journal of Biological Sciences 1 (2012) 7-11.
[17] A.D. Patwardhan, Industrial Solid Wastes, TERI press, ISBN: 9788179935026 (2013).
[18] A.D. Patwardhan, Industrial Waste Water Treatment, Prentice-Hall of India, New Delhi (2008).
ACCEPTED MANUSCRIPT
39
[19] A. Petit, Application of vacuum belt press filters for cane mud filtration and performance comparison with rotary filters, Sugar Industry-Zuckerindustrie 139 (2014) 298-301.
[20] S. Kaul, P. Pathe, T. Nandy, Overview of waste management in sugar industry, Journal of the Indian Association for Environmental Management 17 (1990) 55-78.
[21] A.R. Gopal, D.M. Kammen, Molasses for ethanol: the economic and
environmental impacts of a new pathway for the lifecycle greenhouse gas analysis of sugarcane ethanol, Environmental Research Letters 4 (2009) 044005.
[22] J. Clay, World Agriculture and the Environment: A Commodity-By-Commodity Guide To Impacts And Practices, Island Press (2013).
[23] J.T. Petrović, M.D. Stojanović, J.V. Milojković, M.S. Petrović, T.D. Šoštarić, M.D. Laušević, M.L. Mihajlović, Alkali modified hydrochar of grape pomace as a perspective adsorbent of Pb 2+ from aqueous solution, Journal of environmental management 182 (2016) 292-300.
[24] J. Milojković, L. Pezo, M. Stojanović, M. Mihajlović, Z. Lopičić, J. Petrović, M.
Stanojević, M. Kragović, Selected heavy metal biosorption by compost of Myriophyllum spicatum—A chemometric approach, Ecological Engineering 93 (2016) 112-119.
[25] J.V. Milojković, M.L. Mihajlović, M.D. Stojanović, Z.R. Lopičić, M.S. Petrović, T.D. Šoštarić, M.Đ. Ristić, Pb (II) removal from aqueous solution by Myriophyllum spicatum and its compost: equilibrium, kinetic and thermodynamic study, Journal of Chemical Technology and Biotechnology 89 (2014) 662-670.
[26] A. Violante, V. Cozzolino, L. Perelomov, A. Caporale, M. Pigna, Mobility and bioavailability of heavy metals and metalloids in soil environments, Journal of soil science and plant nutrition 10 (2010) 268-292.
[27] S.A. Ahmed, A.M. El-Roudi, A.A. Salem, Removal of Mn (II) from ground water by solid wastes of sugar industry, Journal of Environmental Science and Technology 8 (2015) 338-351.
[28] A. Moubarik, N. Grimi, Valorization of olive stone and sugar cane bagasse by- products as biosorbents for the removal of cadmium from aqueous solution, Food Research International 73 (2015) 169-175.
[29] S. Ibrahim, M. Hanafiah, M. Yahya, Removal of cadmium from aqueous
solutions by adsorption onto Sugarcane Bagasse, Am. Eurasian J. Agric. Environ. Sci 1 (2006) 179-184.
[30] M. Rosmi, S. Azhari, R. Ahmad, Adsorption of Cadmium from Aqueous
Solution by Biomass: Comparison of Solid Pineapple Waste, Sugarcane Bagasse and Activated Carbon, Advanced Materials
Research 832 (2014) 810-815.
[31] E. Pehlivan, B. Yanık, G. Ahmetli, M. Pehlivan, Equilibrium isotherm studies for the uptake of cadmium and lead ions onto sugar beet pulp, Bioresource technology 99 (2008) 3520-3527.
[32] Z. Aksu, İ.A. İşoğlu, Removal of copper (II) ions from aqueous solution by biosorption onto agricultural waste sugar beet pulp, Process Biochemistry 40 (2005) 3031-3044.
[33] E. Khoramzadeh, B. Nasernejad, R. Halladj, Mercury biosorption from aqueous solutions by sugarcane bagasse, Journal of the Taiwan Institute of Chemical
Engineers 44 (2013) 266-269.
[34] O. Akiode, M. Idowu, S. Omeike, F. Akinwunmi, ADSORPTION AND
KINETICS STUDIES OF Cu (II) IONS REMOVAL FROM AQUEOUS SOLUTION
