scholarly journals Biosorption Characteristics of Hg(II) from Aqueous Solution by the Biopolymer from Waste Activated Sludge

Author(s):  
Jiao Zhang ◽  
Pan Wang ◽  
Zhiqiang Zhang ◽  
Pengyu Xiang ◽  
Siqing Xia

The divalent mercury ion (Hg(II)) is one of the most hazardous toxic heavy-metal ions, and an important industrial material as well. It is essential to remove and recover Hg(II) from wastewater before it is released into the environment. In this study, the biosorption characteristics of Hg(II) from aqueous solution by the biopolymer from waste activated sludge (WAS) are investigated. The major components of the biopolymer consisted of proteins, carbohydrates, and nucleic acids. The adsorption kinetics fit for the pseudo-second-order kinetic model, and the adsorption isotherms were well described by Langmuir equation. The adsorption capacity of the biopolymer increased along with rising temperature, and the maximal adsorption capacity was up to 477.0 mg Hg(II)/g biopolymer at 308 K. The infrared spectroscopy analyses showed that the complexation of Hg(II) by the biopolymer was achieved by the functional groups in the biopolymer, including hydroxyl (–OH), amino (–NH2), and carboxylic (–COOH). From the surface morphology, the special reticulate structure enabled the biopolymer to easily capture the metal ions. From the elemental components analyses, a part of Hg(II) ions was removed due to ion exchange with the Na+, K+, and Ca2+, in the biopolymer. Both complexation and ion exchange played key roles in the adsorption of Hg(II) by the biopolymer. These results are of major significance for removal and recovery of Hg(II) from wastewater.

2021 ◽  
Author(s):  
Duy Hoai-Phuong Nguyen ◽  
Quang Thanh Le ◽  
Tung Cao Thanh Pham ◽  
Thanh Tu Le

Abstract Heavy metal and radioactive ions can cause serious environmental problems if they are not completely removed from wastewater as well as in groundwater. In this study, large pore LTL and MOR zeolites were successfully synthesized and used as adsorbent to remove Pb2+, Cu2+, Zn2+, Cd2+, Cs+ and Sr2+ ions in aqueous solution. At low initial concentration (10 ppm), LTL and MOR zeolites effectively removed above metal ions with removal efficiency in the range of 95–99%. Both zeolites showed high affinity to Cs+ and Pb2+ ions with the adsorption capacity of LTL zeolite to Cs+ and Pb2+ were 278.8 mg/g and 141.4 mg/g, and that of MOR zeolite were 238.8 mg/g and 178.9 mg/g, respectively. The EDS results showed that Pb2+ ions from the aqueous solution were exchanged with exchangeable Na+ ions in MOR zeolite and K+ ions in LTL zeolite. The pseudo-second-order kinetic model and Langmuir isotherm model fitted better to experiment data on the adsorption of metal ions on both LTL and MOR zeolite. This result revealed that the adsorption of these metal ions on LTL and MOR zeolite was monolayer chemisorption. The equilibrium adsorption results showed that the microstructure of zeolite significantly affected the adsorption capacity of LTL and MOR zeolite on removal of tested metal ions.


2021 ◽  
Vol 10 (1) ◽  
pp. 59-66
Author(s):  
Son Le Lam ◽  
Phu Nguyen Vinh ◽  
Hieu Le Trung ◽  
Tan Le Thua ◽  
Nhan Dang Thi Thanh ◽  
...  

Glucomannan/graphene oxide (GM/GO) hydrogel was synthesized by using calcium hydroxide as the crosslinker. The synthesized material was characterized by using IR, XRD, SEM, EDX and RAMAN technology. The composite hydrogel was used for removal of organic dyes from aqueous solution. The results showed that the GM/GO hydrogel had a porous structure and a high adsorption capacity toward methylene blue (MB). The pseudo-second-order kinetic model could fit the rate equation of MB adsorption onto the GM/GO hydrogel. The adsorption of MB onto GM/GO hydrogel was a spontaneous process. In addition, the equilibrium adsorption isotherm data indicated that equilibrium data were fitted to the Langmuir isotherm and the maximum dye adsorption capacity was 198,69 mg.g-1. Moreover, the hydrogel was stable and easily recovered and adsorption capacity was around 97% of the initial saturation adsorption capacity after being used five times.


2016 ◽  
Vol 18 (4) ◽  
pp. 96-103 ◽  
Author(s):  
Wojciech Konicki ◽  
Rafał Pelka ◽  
Walerian Arabczyk

Abstract The removal of Ni2+ from aqueous solution by iron nanoparticles encapsulated by graphitic layers (Fe@G) was investigated. Nanoparticles Fe@G were prepared by chemical vapor deposition CVD process using methane as a carbon source and nanocrystalline iron. The properties of Fe@G were characterized by X-ray Diffraction method (XRD), High-Resolution Transmission Electron Microscopy (HRTEM), Fourier Transform-Infrared Spectroscopy (FTIR), BET surface area and zeta potential measurements. The effects of initial Ni2+ concentration (1–20 mg L−1), pH (4–11) and temperature (20–60°C) on adsorption capacity were studied. The adsorption capacity at equilibrium increased from 2.96 to 8.78 mg g−1, with the increase in the initial concentration of Ni2+ from 1 to 20 mg L−1 at pH 7.0 and 20oC. The experimental results indicated that the maximum Ni2+ removal could be attained at a solution pH of 8.2 and the adsorption capacity obtained was 9.33 mg g−1. The experimental data fitted well with the Langmuir model with a monolayer adsorption capacity of 9.20 mg g−1. The adsorption kinetics was found to follow pseudo-second-order kinetic model. Thermodynamics parameters, ΔHO, ΔGO and ΔSO, were calculated, indicating that the adsorption of Ni2+ onto Fe@G was spontaneous and endothermic in nature.


2013 ◽  
Vol 9 (1) ◽  
pp. 1822-1836
Author(s):  
Keon Sang Ryoo ◽  
Jong-Ha Choi ◽  
Yong Pyo Hong

The present study is to explore the possibility of utilizing granular activated charcoal (GAC) for the removal of total phosphorous (T-P) and total nitrogen (T-N) in aqueous solution. Batch adsorption studies were carried out to determine the influences of various factors like initial concentration, contact time and temperature. The adsorption data showed that GAC has a similar adsorption capacity for both T-N and T-P. The adsorption degree of T-N and T-P on GAC was highly concentration dependent. It was found that the adsorption capacity of GAC is quite favorable at a low concentration. At concentrations of 1.0 mg L-1 of T-P and 2.0 mg L-1 of T-N, approximately 97 % of adsorption was achieved by GAC. The equilibrium data were fitted well to the Langmuir isotherm model. The pseudo-second-order kinetic model appeared to be the better-fitting model because it has higher R2 compared with the pseudo-first-order and intra-particle kinetic model. The theoretical adsorption equilibrium qe,cal from pseudo-second-order kinetic model were relatively similar to the experimental adsorption equilibrium qe,exp. To evaluate the effect of thermodynamic parameters at different temperatures, the change in free energy ΔG, the enthalpy ΔH and the entropy ΔS were estimated. Except for adsorption of T-P at 278 K, the ΔG values obtained were all negative at the investigated temperatures. It indicates that the present adsorption system occurs spontaneously. The adsorption process of T-N by GAC was exothermic in nature, whereas T-P showed endothermic behavior. In addition, the positive values of ΔS imply that there was the increase in the randomness of adsorption of T-N and T-P at GAC-solution interface.  


Author(s):  
Ernesto Jr. S. Cajucom ◽  
◽  
Lolibeth V. Figueroa ◽  

This study was carried out to investigate the efficiency of raw pili shell (RPS) and the surface modified pili shell using EDTA (EMPS) and oxalic acid (OMPS). A comparative study on the adsorption capacity of the adsorbents was performed against lead (Pb2+) from aqueous solution. The adsorbents were characterized by FTIR, which showed higher peak of adsorption bands of carboxylic groups on the acid modified pili shells. Scanning electron microscope orSEM was also used to describe the surface morphology of the adsorbents. The linear form of Langmuir and Freundlich models were applied to represent adsorption data. The calculated equilibrium data of Pb (II) best fitted to Langmuir compare to Freundlich isotherm model with maximum adsorption capacity (qmax) of 27.03 mg/g and 45.45 mg/g using EMPS and OMPS, respectively. Kinetic sorption models were used to determine the adsorption mechanism and the kinetic data of all the adsorbents correlated (R2=1) wellwith the pseudo second order kinetic model. Among the three adsorbents, OMPS shown higher percent removal of lead compared to RPS and EMPS. The large adsorption capacity rate indicated that chemically modified pili shell in present study has great potential to be used as a cost-effective adsorbent for the removal of lead ions from the water.


2013 ◽  
Vol 361-363 ◽  
pp. 760-763 ◽  
Author(s):  
Wei Fang Dong ◽  
Li Hua Zang ◽  
Hao Li

The adsorption capacity was compared for the dye wastewater onto adsorbent MnO2. The effects of contact time and dosage of adsorbent were studied. The adsorption kinetics was analyzed. The results showed that MnO2 possessed higher adsorption capacity to Methylene blue than Methyl orange which the removal efficiency could reached 94.82%and 78.63% respectively under the conditions (the dosage1.2g/L, time 60min, initial dye concentration 50mg/L, pH7). The dynamical data fit well with the pseudo second order kinetic model. The MnO2 has higher Methylene blue adsorption capacity in short equilibrium times and are good alternative in wastewater treatment.


2014 ◽  
Vol 675-677 ◽  
pp. 647-653
Author(s):  
Hong Bin Lv ◽  
Yao Li ◽  
Wan You Zhang ◽  
Li Juan Xi

Mg-Fe hydrotalcite-like compounds (Mg-Fe-HTLCs) were synthesized via hydrothermal method, and characterized by XRD and FT-IR. The roasted products were used to remove sulfate ions by the adsorptive ability from aqueous solution. The effects of adsorbent dosage, initial pH and temperature on the sulfate ions removal were fully investigated, and the adsorption kinetics and adsorption isotherms were also studied. Results showed that the synthesized materials with CO32- as the interlayer anions had fine crystallinity. The materials of Mg-Fe hydrotalcite-like compounds had a very good adsorption capacity for aqueous solution with the initial sulfate ions concentration was 500mg/L, pH range from 4 to 8 and temperature of 35°C. Moreover, the adsorption equilibrium was about 90 min under the optical condition. The experimental data showed a good compliance with the pseudo-second-order kinetic model, and the adsorption isotherm data met Langmuir models well. It was found that the maximal adsorption capacity reached 151.51mg/g.


2017 ◽  
Vol 19 (4) ◽  
pp. 65-74 ◽  
Author(s):  
Wojciech Konicki ◽  
Daniel Siber ◽  
Urszula Narkiewicz

Abstract Magnetic ZnFe2O4 nanocomposite (ZnFe-NC) was used as an adsorbent for the removal of Rhodamine B (RB) from aqueous solution. The synthesized nanocomposite was characterized by XRD, SEM, HRTEM, BET and FTIR. The effects of various parameters such as initial RB concentration (5–25 mg L−1), pH (3.4–11.1) and temperature (20–60°C) were investigated. The adsorption capacity at equilibrium increased from 5.02 to 9.83 mg g−1, with the increase in the initial concentration of RB from 5 to 25 mg L−1 at pH 7.0 and at 20°C. The experimental results indicated that the maximum RB removal could be attained at a solution pH of 4.4 and the adsorption capacity obtained was 6.02 mg g−1. Kinetic adsorption data were analyzed using the pseudo-first-order kinetic model, the pseudo-second-order model and the intraparticle diffusion model. The adsorption kinetics well fitted using a pseudo-second-order kinetic model. The experimental isotherm data were analyzed using two isotherm models, namely, Langmuir and Freundlich. The results revealed that the adsorption behavior of the RB onto ZnFe-NC fitted well with the Langmuir isotherm model. In addition, various thermodynamic parameters, such as standard Gibbs free energy (ΔG°), enthalpy (ΔH°) and entropy (ΔS°) have been calculated.


2013 ◽  
Vol 13 (1) ◽  
pp. 101-106 ◽  
Author(s):  
Jagjit Kour ◽  
Puspa Lal Homagai ◽  
Megh Raj Pokhrel ◽  
Kedar Nath Ghimire

The biomass of Desmostachy bipannata (Kush, a religious plant of Hindus) was modified for the better adsorption of metal ions from aqueous solution. The FTIR and SEM images were used for the characterization of biomass. The adsorptive separation of metal ions from aqueous solution was studied with equilibrium isotherm and kinetic model. Langmuir adsorption isotherm and pseudo second order kinetic model showed better explanation for the adsorption process. The experimental results suggest that biomass from Kush can be used as an effective biosorbent for the removal of metal ions from aqueous solution. Nepal Journal of Science and Technology Vol. 13, No. 1 (2012) 101-106 DOI: http://dx.doi.org/10.3126/njst.v13i1.7448


2016 ◽  
Vol 78 (5-3) ◽  
Author(s):  
Borano Te ◽  
Boonchai Wichitsathian ◽  
Chatpet Yossapol

Broken mesoporous ceramic filter was reutilized by coating with ferric solution through a simple loading method enhanced with heating at a moderate temperature for arsenate uptake from aqueous solution. BET, XRF, XRD, and SEM methods were applied for the adsorbent characterization. The adsorption study was conducted in a batch mode to investigate kinetics, isotherms, and the effect of solution pH and co-existing anions. The pseudo-second order kinetic model well fitted the experimental data (R2 = 0.9997). The maximum arsenate adsorption capacity (2.27 mg/g) was derived from the better described Langmuir isotherm model (R2 = 0.9992). The adsorbent expressed high arsenate adsorption capacity over a pH range of 4-10. The uptake behavior is a favorable and physical adsorption process based on the value of separation factor and mean sorption energy.  The presence of co-existing anions decreased the arsenate adsorption capacity in the following order: NO3-< SO42- < PO43-. The new ferric-coated mesoporous ceramic adsorbent could be an effective and low-cost adsorbent for arsenate removal from water. 


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