Synthesis of N-Alkyl-N,N-Dimethyl Quaternized Chitosan and its Application as Effective Absorbents towards Reactive Dye KN-R

2016 ◽  
Vol 43 ◽  
pp. 29-37
Author(s):  
Jin Dan Wu ◽  
Guo Qiang Cai ◽  
Ji Ping Wang

Several types of N-alkyl-N,N-dimethyl quaternized chitosan (QC) derivatives with different alkyl chains were prepared as effective adsorbents towards reactive dye KN-R. QC with long dodecanyl chain was insoluble in neutral solution but could self-assembled into spherical nanoparticles. The effects of degree of quaternization and alkyl chain length on the adsorption properties of KN-R onto QC were investigated. The results showed that a higher degree of quaternization of copolymers led to a higher adsorption capacity. At similar degree of quaternization, QC nanoparticles with longer alkyl chains showed better adsorption ability than soluble free QC chain with shorter alkyl chains. Positive charges were accumulated on the surface of nanoparticles, which showed higher charge density than free polymer chain. The adsorption kinetics appeared to followed a well-described by pseudo-second-order model. Meanwhile, all of the obtained quaternized chitosan samples showed a higher adsorption capacity than the commercial adsorbent polyaluminium chloride. This work showed that adsorption ability of the cationic polymer could be improved by self-assembling into nanoparticles and that synthesized quaternized chitosan could be utilized as an efficient adsorbent for dye removal.

2016 ◽  
Vol 75 (5) ◽  
pp. 1051-1058 ◽  
Author(s):  
Qiujin Jia ◽  
Wanting Zhang ◽  
Dongping Li ◽  
Yulong Liu ◽  
Yuju Che ◽  
...  

Hydrazinolyzed cellulose-graft-polymethyl acrylate (Cell-g-PMA-HZ), an efficient adsorbent for removal of Cd(II) and Pb(II) from aqueous solution, has been prepared by ceric salt-initiated graft polymerization of methyl acrylate from microcrystalline cellulose surface and subsequent hydrazinolysis. The influences of initial pH, contact time, and temperature on adsorption capacity of Cell-g-PMA-HZ as well as adsorption equilibrium, kinetic and thermodynamic properties were examined in detail. As for Cd(II) adsorption, kinetic adsorption can be explained by pseudo-second-order, while adsorption isotherm fits well with Langmuir isotherm model, from which maximum equilibrium adsorption capacity can be derived as 235.85 mg g−1 at 28 °C. Further thermodynamic investigation indicated that adsorption of Cd(II) by adsorbent Cell-g-PMA-HZ is endothermic and spontaneous under studied conditions. On the other hand, isotherm of Pb(II) adsorption fits well with Freundlich isotherm model and is more likely to be a physical-adsorption-dominated process. Consecutive adsorption–desorption experiments showed that Cell-g-PMA-HZ is reusable with satisfactory adsorption capacity.


2021 ◽  
Author(s):  
Can Cui ◽  
Yadian Xie ◽  
Jiaojiao Niu ◽  
Hailiang Hu ◽  
Sen Lin

Abstract Heavy metal ions pollution is one of the most dangerous and critical threats to human health and environment. In this work, three different generations of PAMAM dendrimer decorated on magnetic Fe 3 O 4 composites (Fe 3 O 4 @SiO 2 –G1, Fe 3 O 4 @SiO 2 –G3, Fe 3 O 4 @SiO 2 –G5) were fabricated and characterized by FTIR, XRD, TEM, and TGA. The obtained composites were used for Cr(VI) removal. Batch adsorption studies showed that the adsorption reached equilibrium within 60 min, and the optimal pH was 3.0. The result of adsorption kinetics was simulated by the pseudo–second-order model. The adsorption equilibrium isotherm was well fitted with the Langmuir adsorption model. Furthermore, thermodynamics calculations revealed that the adsorption process was endothermic and spontaneous. Importantly, adsorption capacity of Cr(VI) obey the sequence of Fe 3 O 4 @SiO 2 –G1<Fe 3 O 4 @SiO 2 –G5<Fe 3 O 4 @SiO 2 –G3, 3 generation of PAMAM (3G) is the optimal for adsorption capacity of Cr(VI). The maximum theoretical Cr(VI) adsorption capacity ( q m ) of Fe 3 O 4 @SiO 2 –G3 was 334.45 mg/g, and removal ration remained above 89.5% after five cycles of adsorption–desorption. Thus, Fe 3 O 4 @SiO 2 –G3 is predicted to be an efficient adsorbent for the adsorption of Cr(VI) from aqueous solution, and the obtained results can help in the generation optimization during fabrication of dendrimer modified adsorbents.


Author(s):  
Ahmed S. El-Shafie ◽  
Siham S. Hassan ◽  
Nuri Akther ◽  
Marwa El-Azazy

AbstractIn the current investigation, watermelon rinds (WMR) have been utilized as an eco-friendly and cost-efficient adsorbent for acridine orange (AO) from contaminated water samples. Adsorption of AO onto raw (RWM) and thermally treated rinds (TTWM250 and TTWM500) has been studied. The adsorption efficiency of the three adsorbents was evaluated by measuring the % removal (%R) of AO and the adsorption capacity (qe, mg/g). Dependent variables (%R and qe) were optimized as a function of four factors: pH, sorbent dosage (AD), the concentration of AO (DC), and contact time (ST). Box–Behnken (BB) design has been utilized to obtain the optimum adsorption conditions. Prepared adsorbents have been characterized using scanning electron microscopy (SEM), Fourier-transform infrared (FT-IR), and Raman spectroscopies. The surface area of RWM, TTWM250, and TTWM500, as per the Brunauer-Emmett-Teller (BET) analysis, was 2.66, 2.93, and 5.03 m2/g, respectively. Equilibrium investigations suggest that Freundlich model was perfectly fit for adsorption of AO onto TTWM500. Maximum adsorption capacity (qmax) of 69.44 mg/g was obtained using the Langmuir equation. Adsorption kinetics could be best described by the pseudo-second-order (PSO) model. The multi-cycle sorption-desorption study showed that TTWM500 could be regenerated with the adsorption efficiency being preserved up to 87% after six cycles.


2019 ◽  
Vol 107 (6) ◽  
pp. 459-467 ◽  
Author(s):  
Shuting Zhuang ◽  
Jianlong Wang

Abstract In this study, phosphate functionalized bacterial cellulose with micro-fibrous structure was prepared, characterized and applied for U(VI) adsorption. The successful grafting of phosphoric functional groups was proved by the FTIR spectra and EDS analysis (P~4.15 wt%), and the porous structure was confirmed by SEM and BET analyses. Furthermore, the effect of initial pH, contact time, initial concentration, and temperature were studied. The as-prepared adsorbent showed a high adsorption capacity at wide pH range (4.0–8.0) and its maximum adsorption capacity was calculated to be 50.65 mg/g. This endothermic adsorption process conformed to the pseudo second-order kinetic model and the Elovich kinetic models and the Langmuir isothermal models. According to the FTIR and XPS analysis, an adsorption mechanism was tentatively proposed, mainly due to the interaction between U(VI) and phosphoric groups.


Author(s):  
Jiwei Wang ◽  
Lanlan Dai ◽  
Shuangying Hu ◽  
Heli Yin ◽  
Minghui Yang ◽  
...  

Abstract Hg(II) ions in wastewater is highly toxic to the environment and human health, yet many materials exhibit lower adsorption efficiency, and few studies report the reutilization of Hg(II)-loaded waste materials. Here, a cheap and efficient adsorbent was prepared for removal of Hg(II) based on corn bract (CB) loading copper sulfide (CuS), and the Hg(II)-adsorbed material was reused as a photocatalyst. By changing the adsorption variables such as pH, adsorbent dosage, Hg(II) concentration, contact time and coexisted ions, the reasonable adsorption conditions were obtained. The study indicated the adsorption capacity and removal rate of CB/CuS reached 249.58 mg/g and 99.83% at pH 6 with 20 mg CB/CuS, 50 mL Hg(II) concentration (100 mg/L) and 60 min, and coexisting ions did not affect the uptake of Hg(II). The adsorption behavior of CB/CuS toward Hg(II) followed pseudo-second-order and Langmuir model with the theoretical maximum adsorption capacity of 316.46 mg/g. Finally, we have explored an alternative strategy to dispose spent adsorbents by converting the CB/CuS/HgS into a photocatalyst for degradation of rhodamine B with removal rate of 98%. Overall, this work not only develops a promising material for treatment of Hg(II)-containing wastewater, but opens a new approach for the value-added utilization of waste adsorbent.


Author(s):  
Joshua O. Ighalo ◽  
Ibrahim O. Tijani ◽  
Oluwaseun J. Ajala ◽  
Fisayo O. Ayandele ◽  
Omodele A. Eletta ◽  
...  

Background: Modified bio-based adsorbents from plant sources can be used for pollution remediation by adsorption due to their low cost and availability in large quantities. Objective: In this study, the competitive biosorption of Pb(II) and Cu(II) by Micropogonias undulates functionalised fish scales (FFS) was conducted. The functionalisation was done by wet impregnation with Fe2+. Method: The biosorbent was characterised by Fourier Transform Infrared Spectroscopy (FT-IR), Scanning Electron Microscopy with Energy-Dispersive X-ray Spectroscopy (SEM-EDS) and Branueur–Emmett–Teller (BET) analyses. Results: The major constituents in the FFS were calcium and phosphorus from the collagen and apatite on the scales. Optimum removal efficiency for both metals was >99% at 10 g/l dosage. It was observed that the Langmuir isotherm model and the pseudo second order kinetics model were the best fit for the experimental data. The monolayer adsorption capacity of FFS for Pb(II) and Cu(II) was observed to be 96.15 mg/g and 100 mg/g respectively. Conclusion: The study revealed that the competitive biosorption of heavy metals can be achieved (at a good adsorption capacity) using functionalised Micropogonias undulates fish scales.


2016 ◽  
Vol 1133 ◽  
pp. 547-551 ◽  
Author(s):  
Ali E.I. Elkhalifah ◽  
Mohammad Azmi Bustam ◽  
Azmi Mohd Shariff ◽  
Sami Ullah ◽  
Nadia Riaz ◽  
...  

The present work aims at a better understanding of the influences of the intercalated mono-, di- and triethanolamines on the characteristics and CO2 adsorption ability of sodium form of bentonite (Na-bentonite). The results revealed that the molar mass of intercalated amines significantly influenced the structural and surface properties as well as the CO2 adsorption capacity of Na-bentonite. In this respect, a stepwise increase in the d-spacing of Na-bentonite with the molar mass of amine was recorded by XRD technique. However, an inverse effect of the molar mass of amine on the surface area was confirmed by BET method. CO2 adsorption experiments on amine-bentonite hybrid adsorbents showed that the CO2 adsorption capacity inversly related to the molar mass of amine at 25 ͦC and 101 kPa. Accordingly, Na-bentonite modified by monoethanolammonium cations adsorbed as high as 0.475 mmol CO2/g compared to 0.148 and 0.087 mmol CO2/g for that one treated with di- and triethanolammonium cations, respectively.


Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2295
Author(s):  
Marwa El-Azazy ◽  
Ahmed S. El-Shafie ◽  
Hagar Morsy

Biochars (BC) of spent coffee grounds, both pristine (SCBC) and impregnated with titanium oxide (TiO2@SCBC) were exploited as environmentally friendly and economical sorbents for the fluroquinolone antibiotic balofloxacin (BALX). Surface morphology, functional moieties, and thermal stabilities of both adsorbents were scrutinized using SEM, EDS, TEM, BET, FTIR, Raman, and TG/dT analyses. BET analysis indicated that the impregnation with TiO2 has increased the surface area (50.54 m2/g) and decreased the pore size and volume. Batch adsorption experiments were completed in lights of the experimental set-up of Plackett-Burman design (PBD). Two responses were maximized; the % removal (%R) and the adsorption capacity (qe, mg/g) as a function of four variables: pH, adsorbent dosage (AD), BALX concentration ([BALX]), and contact time (CT). %R of 68.34% and 91.78% were accomplished using the pristine and TiO2@SCBC, respectively. Equilibrium isotherms indicated that Freundlich model was of a perfect fit for adsorption of BALX onto both adsorbents. Maximum adsorption capacity (qmax) of 142.55 mg/g for SCBC and 196.73 mg/g for the TiO2@SCBC. Kinetics of the adsorption process were best demonstrated using the pseudo-second order (PSO) model. The adsorption-desorption studies showed that both adsorbents could be restored with the adsorption efficiency being conserved up to 66.32% after the fifth cycles.


2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Jhonatan R. Guarín ◽  
Juan Carlos Moreno-Pirajan ◽  
Liliana Giraldo

Currently, there is a great pollution of water by the dyes; due to this, several studies have been carried out to remove these compounds. However, the total elimination of these pollutants from the aquatic effluents has represented a great challenge for the scientific community, for which it is necessary to carry out investigations that allow the purification of water. In this work, we studied the bioadsorption of methylene blue on the surface of the biomass obtained from the algae D. antarctica. This material was characterized by SEM and FTIR. To the data obtained in the biosorption experiments, different models of biosorption and kinetics were applied, finding that the best fit to the obtained data is given by applying the pseudo-second-order models and the Toth model, respectively. It was also determined that the maximum adsorption capacity of MB on the surface of the biomass is 702.9 mg/g, which shows that this material has great properties as a bioadsorbent.


2012 ◽  
Vol 550-553 ◽  
pp. 2259-2262
Author(s):  
Song Bo Cui ◽  
Hua Yong Zhang ◽  
Lu Yi Zhang

The adsorption behavior of methylene blue (MB) dye from aqueous solutions onto honeycomb-cinder (HC) and its acid-activated product was investigated in a batch system. The results showed the adsorption capacity was decreased for raw HC samples with the increase of pH value, while it was increased for activated samples. The adsorption data were fit with Langmuir isotherm model for MB adsorption by all samples. The MB adsorption capacity on samples was increased from 2.62 mg/g to 7.81 mg/g and 7.00 mg/g after acid-activated by HCl and H2SO4, respectively. The adsorption processes of MB followed pseudo-second-order kinetics with a coefficient of correlation≥0.99. This study demonstrated that acid-activated HC has superior adsorbing ability for MB than raw HC and can be used as alternative adsorbents in dye wastewater treatment.


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