Biosorption of Acid Dyes Using Modified Chitosan: Effect of Dye Structure, Hydrogen Bonding and PH

2011 ◽  
Vol 236-238 ◽  
pp. 464-469 ◽  
Author(s):  
Zuo Hua Wang ◽  
Bo Xiang ◽  
Zheng Zhai ◽  
Yi Jiu Li

This work investigated sorption properties of diethylenetriamine derivative of chitosan (CTSN) for removal of acid dyes (Acid Green 25 (AG25), Acid Red 18 (AR18) and Acid Orange 10 (AO10)) from aqueous solutions. Sorption kinetics was firstly evaluated. It was found that pseudo-second-order model fits well with these dyes adsorbed on CTSN. Compared with normal chitosan, CTSN has higher capacity for AR18 and AO10, but a lower value for AG25. Mechanisms and interactions of dyes with CTSN were also discussed by study the effect of pH, influence of hydrogen-bonding and comparing the sorption capacities.

2021 ◽  
Vol 60 (1) ◽  
pp. 365-376
Author(s):  
Xiaoxing Zhang ◽  
Hui Liu ◽  
Jin Yang ◽  
Li Zhang ◽  
Binxia Cao ◽  
...  

Abstract Iron phosphate-modified pollen microspheres (pollen@FePO4) were prepared and applied as sorbents for the removal of heavy metals (Cd2+ and Pb2+) from the aqueous solution. Batch sorption studies were conducted to investigate the effects of solution pH, contact time, sorbent dosage, and metal concentration on the adsorption process. The sorption of Cd2+ and Pb2+ ions on pollen@FePO4 corresponds to the pseudo-second-order model and Langmuir isotherm, which is similar to the unmodified pollen. At pH 5.92, pollen@FePO4 offers maximum adsorption capacities of 4.623 and 61.35 mg·g−1 for Cd2+ and Pb2+, respectively. The faster sorption kinetics and higher adsorption capacities of Cd2+ and Pb2+ ions onto pollen@FePO4 than pollen indicates that it might be a promising material for the removal of heavy metal ions in aqueous solutions. The possible adsorption mechanism involves electrostatic and chemisorption for Cd2+ and mainly complexion for Pb2+.


Molecules ◽  
2021 ◽  
Vol 26 (5) ◽  
pp. 1437
Author(s):  
Chih Ming Ma ◽  
Bo-Yuan Yang ◽  
Gui-Bing Hong

Hydrogel beads based on the husk of agarwood fruit (HAF)/sodium alginate (SA), and based on the HAF/chitosan (CS) were developed for the removal of the dyes, crystal violet (CV) and reactive blue 4 (RB4), in aqueous solutions, respectively. The effects of the initial pH (2–10) of the dye solution, the adsorbent dosage (0.5–3.5 g/L), and contact time (0–540 min) were investigated in a batch system. The dynamic adsorption behavior of CV and RB4 can be represented well by the pseudo-second-order model and pseudo-first-order model, respectively. In addition, the adsorption isotherm data can be explained by the Langmuir isotherm model. Both hydrogel beads have acceptable adsorption selectivity and reusability for the study of selective adsorption and regeneration. Based on the effectiveness, selectivity, and reusability of these hydrogel beads, they can be treated as potential adsorbents for the removal of dyes in aqueous solutions.


2012 ◽  
Vol 66 (8) ◽  
pp. 1699-1707 ◽  
Author(s):  
A. K. Giri ◽  
R. K. Patel ◽  
P. C. Mishra

In this work, the biosorption of As(V) from aqueous solutions by living cells of Bacillus cereus has been reported. The batch biosorption experiments were conducted with respect to biosorbent dosage 0.5 to 15 g/L, pH 2 to 9, contact time 5 to 90 min, initial concentration 1 to 10 mg/L and temperature 10 to 40 °C. The maximum biosorption capacity of B. cereus for As(V) was found to be 30.04 at pH 7.0, at optimum conditions of contact time of 30 min, biomass dosage of 6 g/L, and temperature of 30 ± 2 °C. Biosorption data were fitted to linearly transformed Langmuir isotherms with R2 (correlation coefficient) >0.99. Bacillus cereus cell surface was characterized using AFM and FTIR. The metal ions were desorbed from B. cereus using both 1 M HCl and 1 M HNO3. The pseudo-second-order model was successfully applied to predict the rate constant of biosorption.


2012 ◽  
Vol 14 (2) ◽  
pp. 1-8 ◽  
Author(s):  
S. Ghadiri ◽  
R. Nabizadeh ◽  
A. Mahvi ◽  
S. Nasseri ◽  
A. Mesdaghinia ◽  
...  

Potential of granulated modified nanozeolites Y for MTBE removal from aqueous solutions: Kinetic and isotherm studies Adsorption of methyl tert-butyl ether (MTBE) from aqueous solutions by granulated modified nanozeolites Y was investigated. Nanozeolite Y powders were converted into granulated zeolites and subsequently modified with two cationic surfactants (20 mmol/dm3), to be used as adsorbent. Granulated nanozeolites were characterized by BET surface area analysis, elemental analysis and X-ray diffractometer. -Hexade-cyltrimethylammonium (HDTMA-Cl) modified granulated zeolite had more effective performance than N-cetylpyridinium bromide (CPB) modified granulated zeolite. The most conventional adsorption isotherms and kinetic models were applied to describe MTBE adsorption and reaction dynamic, respectively. The equilibrium sorption data fitted the Langmuir 2 isotherm model and the kinetic study was followed the pseudo-second-order model. The maximum adsorption capacities for HDTMA-Cl modified zeolite and CPB modified granulated zeolite were 333.33 and 142.8 mg/g, respectively as calculated by the Langmuir model. This study demonstrated that the removal of mtbe by granulated modified nanozeolites Y is a promising technique.


2013 ◽  
Vol 726-731 ◽  
pp. 2380-2383
Author(s):  
Li Xia Li ◽  
Xin Dong Zhai

Modified bentonite was used as adsorbent for the methylene blue adsorption in a batch process. Experimental results show that the adsorption kinetics is well described by pseudo-second-order model and the equilibrium data was better represented by the Freundlich isotherm model. The results revealed that the modified bentonite has the potential to be used as a good adsorbent for the removal of methylene blue from aqueous solutions.


2017 ◽  
Vol 13 ◽  
pp. 323-329 ◽  
Author(s):  
Anastasiya E. Kucherova ◽  
Irina V. Romantsova ◽  
Alexandr E. Burakov ◽  
Nariman R. Memetov ◽  
Mikhail N. Krasnyansky

The present paper describes an investigation of the adsorption of lead ions (Pb2+) on graphene-based nanocomposites obtained via exfoliation of hydrolyzed expanded graphite intercalation compound. Three types of these nanocomposites - suspension of graphene nanoplatelets (SGN), paste of multi-layered oxidized graphene (PMOG), and paste of few-layered oxidized graphene (PFOG) - were used to extract Pb2+ from 1,040 mg L-1 aqueous solutions of Pb (NO3)2, and the kinetic of the Pb2+ adsorption was studied. It was found that the kinetic data are best fitted by the pseudo-second-order model. The adsorption equilibrium was achieved within 30 min under normal conditions. The maximum Pb2+ adsorption capacity of SGN, PMOG and PFOG was found to be 457, 103 and 38 mg g-1, respectively. Considering the obtained results, it can be assumed that the phenolic and hydroxyl oxygen-containing functional groups located at the surface of the adsorption materials under study play an important role in the Pb2+ removal process.


2014 ◽  
Vol 70 (1) ◽  
pp. 102-107 ◽  
Author(s):  
Caroline Trevisan Weber ◽  
Gabriela Carvalho Collazzo ◽  
Marcio Antonio Mazutti ◽  
Edson Luiz Foletto ◽  
Guilherme Luiz Dotto

Papaya (Carica papaya L.) seeds were used as adsorbent to remove toxic pharmaceutical dyes (tartrazine and amaranth) from aqueous solutions, in order to extend application range. The effects of pH, initial dye concentration, contact time and temperature were investigated. The kinetic data were evaluated by the pseudo first-order, pseudo second-order and Elovich models. The equilibrium was evaluated by the Langmuir, Freundlich and Temkin isotherm models. It was found that adsorption favored a pH of 2.5, temperature of 298 K and equilibrium was attained at 180–200 min. The adsorption kinetics followed the pseudo second-order model, and the equilibrium was well represented by the Langmuir model. The maximum adsorption capacities were 51.0 and 37.4 mg g−1 for tartrazine and amaranth, respectively. These results revealed that papaya seeds can be used as an alternative adsorbent to remove pharmaceutical dyes from aqueous solutions.


2012 ◽  
Vol 463-464 ◽  
pp. 7-11 ◽  
Author(s):  
Ming Yan Dang ◽  
Hong Min Guo ◽  
Yan Kun Tan

Chitosan was crosslinked using epichlorohydrin as crosslinking agent to prepare crosslinked chitosan which was used as an adsorbent for the removal of Zn(II) from aqueous solutions. The adsorption prosperities of Zn(II) on crosslinked chitosan were studied, including the influence of pH value and the adsorption kinetics. The kinetics of adsorption was discussed using two kinetic models, the pseudo first-order and the pseudo second-order model. Results reveal that the crosslinked chitosan is suitable as adsorbent to remove Zn(II) from dilute solution. The rate parameters for the Zn(II) by crosslinked chitosan were also determined. It was shown that the adsorption kinetics of Zn(II) could be best described by the pseudo second-order model and the adsorption process may involve a physical adsorption.


2017 ◽  
Vol 68 (1) ◽  
pp. 1-5
Author(s):  
Rodica Elena Patescu ◽  
Claudia Maria Simonescu ◽  
Cristian Onose ◽  
Teodor Laurentiu Busuioc ◽  
Daiana Elena Pasarica ◽  
...  

This research study deals with lead and nickel simultaneous removal from aqueous solutions by the use of chitosan coated cobalt ferrite as adsorbent. Batch removal tests were performed in order to establish the main parameters that influence the sorption capacity, removal efficiency and the selectivity of this adsorbent. The values of sorption capacity for lead and nickel experimentally determined are: 56.23 mg/g and respectively 45.11 mg/g. Langmuir and Freundlich adsorption isotherms were used to interpret the sorption experimental data. The kinetic data were explored by pseudo-first order, pseudo-second order and intraparticle diffusion kinetic models. The experimental data were well fitted with the pseudo-second order model for both heavy metals. The main conclusion that can be drawn from this research is that this material can be successfully used for the removal of lead and nickel from binary aqueous solutions and wastewater.


2013 ◽  
Vol 683 ◽  
pp. 530-533
Author(s):  
Yan Zhang ◽  
Xian Jun Lv ◽  
Xiao Yan Kou

The potential of AlCl3 modified palygorskite was assessed for adsorption of phosphate from aqueous solutions. The Langmuir isotherm adequately described adsorption with an R2 goodness of fit of 0.9683. The process kinetics was found to follow the pseudo-second-order model. Positive △H and △S values indicated that the adsorption of phosphate onto AlCl3 modified palygorskite was endothermic. Negative △G showed that the adsorption of phosphate onto this sorbent is feasible and spontaneous.


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