Adsorption Characteristics of Pb2+ from Aqueous Solution on the Corn Stalk/montmorillonite Nanocomposite

2013 ◽  
Vol 295-298 ◽  
pp. 438-442
Author(s):  
Xiao Li Wang ◽  
Lixiang Wang ◽  
Huijuan Wang

The corn stalk/montmorillonite(CS/MMT) nanocomposite was prepared by a solution intercalation technique. The effects of the initial pH value of Pb2+ solution, contact time and the dosage of adsorbent on the adsorption capacitiy of CS/MMT nanocomposite for Pb2+ were investigated. The adsorption kinetics and isotherms of nanocomposite were also studied. The results indicated that with the initial pH value increasing, the adsorption capacity of the CS/MMT nanocomposite increased. Compared with the adsorption capacity of CS (6.32 mg/g), the nanocomposite exhibited the higher adsorption capacity (31.95 mg/g). The adsorption behaviors of CS/MMT nanocomposite showed that the adsorption kinetics was in accorded with pseudo-second-order equation and the adsorption isotherms followed the Langmuir and Freundlich equation.

2012 ◽  
Vol 450-451 ◽  
pp. 769-772 ◽  
Author(s):  
Ya Hong Zhao ◽  
Li Wang

The carboxymethylcellulose/montmorillonite (CMC/MMT) nanocomposite was prepared by a solution intercalation technique. The effects of contact temperature, the initial pH value of dye solution, contact time and the initial dye concentration on the adsorption capacitiy of CMC/MMT nanocomposite for Congo red (CR) were investigated. The adsorption kinetics and isotherms of nanocomposite were also studied. The results indicated that with the contact temperature increasing and the initial pH value decreasing, the adsorption capacity of the CMC/MMT nanocomposite increased. Compared with the adsorption capacity of CMC (62.42 mg/g), the nanocomposite exhibited the higher adsorption capacity (161.08 mg/g). The adsorption behaviors of CMC/MMT nanocomposite showed that the adsorption kinetics and isotherms were in good agreement with pseudo-second-order equation and the Langmuir equation.


2012 ◽  
Vol 189 ◽  
pp. 69-74
Author(s):  
Wei Hu ◽  
Zhen Zhang ◽  
Hui Yun Liu ◽  
Ru Wang

The adsorption behaviors of V(V) and Mo(VI) on the collagen fiber immobilized bayberry tannin (IBT), a new kind of adsorption, were investigated. It was found that at 323K, pH=2.0, the adsorption capacities of V(V) on 0.100g adsorbent was 1.03mmol/g in 100ml of 1.960mmol/L V(V) solution, and that of Mo(VI) was 0.86mmol/g at 323K, pH=4.0, with 100ml of 1.042 mmol/L Mo(VI) solution. The effect of pH on the adsorption capacity of V(V) and Mo(VI) was conspicuous. The adsorption capacity of Mo(VI) decreased with pH increasing, and the maximal adsorption capacity of V(V) was observed at pH4.0. Langmuir equation was used for the description of adsorption isotherms of V(V), while Freundlich equation could be well described that of Mo(VI). The adsorption kinetics of V(V) and Mo(VI) can be well described by the pseudo-second-order-rate model and the adsorption capacities calculated by this model are very close to those experimentally determined. The adsorbent can be regenerated by using 0.1mol/L HCl and 0.02mol/L EDTA in tune as desorption agent after the adsorption of V(V) and Mo(VI). In the desorption process V(V) and Mo(VI) were utilized respectively. These facts implies that the adsorbent can be used for the separation of V(V) and Mo(VI) in aqueous.


2021 ◽  
Vol 13 (8) ◽  
pp. 1512-1520
Author(s):  
MiaoSen Zhang ◽  
SiYang Wang ◽  
Zheng Hu ◽  
RunZe Zhang ◽  
XiaoLi Wang

China is a big coal producing country, there are a lot of coal gangue piled up. The zeolite X was synthesized by alkali melting and hydrothermal method based on the coal gangue from Chifeng city, Inner Mongolia. The obtained zeolite X sample is characterized by X-ray diffraction, SEM, EDS spectrum and IR which showed the X zeolite is an octahedral structure with complete crystal shape and uniform grain size. The results of BET showed the specific surface area of zeolite X is 354.8 m2/g and the minimum pore size is 3.8 nm which indicated that the zeolite X belongs to mesoporous materials. The adsorption conditions of the zeolite X adsorbent on copper ions were optimized. A solution containing Cu2+ ions with an initial concentration of 300 mg/L was added to the zeolite X with a dosage of 0.1 g and the initial pH value of the solution was adjusted to 6. Then the solution was oscillated for 120 min at 225 r/min. The maximum adsorption capacity and removal rate were 148.6 mg/g and 99.1%, respectively. The adsorption mechanism was discussed by adsorption kinetics and thermodynamics. The quasi-second order kinetic equation can be well used to describe the adsorption kinetics of zeolite X to Cu2+ (R2 = 0.9994) and Langmuir can well describe the adsorption behavior of zeolite X to Cu2+ (R2 = 0.9995) which showed the adsorption is a monolayer of chemical adsorption. The adsorption capacity of zeolite X to Cu2+ is about 4.0 times that of coal gangue, indicating that the zeolite X has good adsorption capacity.


2014 ◽  
Vol 522-524 ◽  
pp. 552-559
Author(s):  
Min Zhang ◽  
Ben Zhi Ju ◽  
Shu Fen Zhang ◽  
Xue Zhang ◽  
Zhi Hua Cui

This paper presents a study on the adsorption of structurally different C.I. Acid Red 1(AR-1) and C.I. Acid Yellow 4(AY-4) from aqueous solution by a series water-insoluble crosslinked cationic starches with different degrees of substitution (DS) synthesized by a dry process. The adsorption quickly establish equilibrium within 15 min. The effective adsorption took place at the initial pH of 2-10 and pH of 2-8 for AR-1 and AY-4, respectively. The adsorption capacity of the two acid dyes increased with the increasing of DS of the crosslinked cationic starches. The adsorption capacity of AY-4 was almost two times higher than that of AR-1 under the present conditions. It was found that the adsorption kinetics of the two acid dyes on the crosslinked cationic starch was well described with the pseudo-second-order model (R2>0.99). Further, the Langmuir isotherm agreed well with the experimental data (R2>0.99). Besides, the thermodynamic parameters are shown.


2011 ◽  
Vol 335-336 ◽  
pp. 111-115
Author(s):  
Jie Wu ◽  
Juan Zhang ◽  
Hai Jiang Zhang ◽  
Yi Jing

The chitosan/palygorskite resins with tannic acid (TA) as template molecules (CPRT) were prepared by emulsion cross-linking technology. Palygorskite (PAL), a kind of natural one-dimensional clay, worked as perfect filler in this study to enhance the adsorptive properties and acid resistance of chitosan resin (CR). The effect of PAL and imprinted molecules on pore parameters of the CPRT, such as swelling degree, porosity, and ratio of weight loss, were investigated, and the effects of the initial pH value of the TA solution, contact time and temperature on adsorption capacity of the CPRT were also discussed. The results revealed that the adsorption process was found to be pH dependant with an optimum activity at pH 8.0. In comparison with CR, the adsorptive ability of CPRT increased from 225 to 410 mg/g, and the ratio of weight loss decreased from 18.8 to 6.2 %. The study of adsorption kinetics and isotherms showed that the sorption processes were better fitted by pseudo-second-order equation and the Langmuir equation, respectively.


2012 ◽  
Vol 66 (9) ◽  
pp. 2027-2032 ◽  
Author(s):  
C. X. Wang ◽  
Q. P. Song

N-carboxymethyl chitosan (NCMC) was synthesized by reacting chitosan with chloroacetic acid in water under triethylamine (Et3N) as catalyst. The chemical structures of NCMC were characterized by Fourier transform infrared (FT-IR) and hydrogen-1 nuclear magnetic resonance (1H-NMR) spectroscopy and confirmed that carboxymethylation occurred on the amino groups. Samples of NCMC were used for removal of Cu(II) from aqueous solution. The effects of degree of substitution of NCMC, initial pH value and adsorption kinetics on the adsorption were studied. Adsorption experiments showed that NCMC has a high adsorption speed and high adsorption capacity for remove Cu(II) from aqueous solution. The adsorption kinetics data were best fitted with the pseudo-second-order model. The experimental equilibrium data of Cu(II) on the NCMC were both fitted to the Langmuir model and Freundlich model, which revealed that the maximum capacity for monolayer saturation was 147.93 mg/g.


2018 ◽  
Vol 77 (11) ◽  
pp. 2699-2708 ◽  
Author(s):  
Yixi Wang ◽  
Linyan Zhao ◽  
Juan Hou ◽  
Huili Peng ◽  
Jianning Wu ◽  
...  

Abstract In this study, a highly efficient and eco-friendly porous cellulose-based aerogel was synthesized by grafting polyethyleneimine onto quaternized cellulose (PQC) to remove the anionic dye Congo Red (CR). The prepared aerogel had a good flexibility and formability. The adsorbents were characterized by scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy and elemental analysis. The results showed that there were many amino groups on CE/PQC aerogel and the structure was porous, which increased the adsorption capacity. The effects of initial concentration, adsorbent dose, contact time, temperature, and pH on the dye sorption were all investigated. The adsorption mechanism was also explored, including adsorption kinetics, adsorption isotherms and thermodynamic studies of adsorption. The results showed that the adsorption kinetics and isotherms fitted the pseudo-second-order kinetic model and Langmuir isotherm, respectively. The Langmuir isotherm revealed that the maximum theoretical adsorption capacity of the aerogels for CR was 518.403 mg g−1. The thermodynamic parameters including Gibbs free energy change (ΔG0), enthalpy change (ΔH0) and entropy change (ΔS0), showed the adsorption process was exothermic and spontaneous. These results imply that this new absorbent can be universally and effectively used for the removal of dyes from industrial textile wastewater.


2021 ◽  
Vol 21 (3) ◽  
pp. 1462-1473
Author(s):  
Wen-Juan Zhang ◽  
Bo-Bo Zhang ◽  
Xue-Yan Du ◽  
You-Liang Wang ◽  
Yu-Long Fei ◽  
...  

In this work, a novel N-doped magnetic mesoporous carbon (NMC) composite (Fe3O4/NMC) was synthesized by a two-step process. First, NMC was prepared by a template method using a melamine formaldehyde resin as nitrogen and carbon sources, and then, Fe3O4 nanoparticles were loaded into the as-prepared NMC via in-situ coprecipitation process. The morphology, structure, and magnetic properties of Fe3O4/NMC were characterized and its adsorption properties were investigated. It can be found that Fe3O4/NMC with saturation magnetization of 20 emu · g−1 features a mesoporous structure, and its specific surface area reaches 513 m2 · g−1. These two excellent specificities are propitious to the adsorption and separation of Ag(I) from aqueous solution. The adsorption behavior of Fe3O4/NMC nanocomposite has been investigated by adsorption kinetics and isotherms adsorption analyses as well. The adsorption isotherm and the adsorption kinetics of Ag(I) onto Fe3O4/NMC agrees well with Langmuir model and pseudo-second-order model, respectively. Moreover, the Fe3O4/NMC was easily to recovery by applied magnetic field, the adsorption capacity of Fe3O4/NMC was about 90.3% of the initial saturation adsorption capacity after five continuous uses.


Water ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 1141 ◽  
Author(s):  
Joanna Lach

The aim of the study was to evaluate the possibility of applying commercial activated carbons currently used in water treatment plants and modified carbon at 400 and 800 °C in the atmosphere of air, water vapour and carbon dioxide to remove chloramphenicol. Adsorption kinetics was examined for solutions with pH of 2–10. Adsorption kinetics were determined for the initial concentration of chloramphenicol of 161 mg/dm3 and the adsorption isotherm was determined for the concentrations of 161 to 1615 mg/dm3. Of the analysed activated carbons (F-300, F-100, WG-12, ROW 08 Supra and Picabiol), the highest adsorption capacity was obtained for the use of Picabiol (214 mg/g), characterized by the highest specific surface area and pore volume. The pH value of the solution has little effect on the adsorption of chloramphenicol (the highest adsorption was found for pH = 10, qm = 190 mg/g, whereas the lowest—for pH = 6, qm = 208 mg/g). Modification of activated carbon WG-12 at 800 °C caused an increase in adsorption capacity from 195 mg/g (unmodified carbon) to 343 mg/g. A high correlation coefficient was found between the capacity of activated carbons and the total volume of micropores and mesopores. Among the examined adsorption kinetics equations (pseudo-first order, pseudo-second order, Elovich, intraparticle diffusion), the lowest values of the R2 correlation coefficient were obtained for the pseudo-first order equation. Other models with high correlation coefficient values described the adsorption kinetics. The adsorption results were modelled by means of the Freundlich, Langmuir, Temkin and Dubibin–Radushkevich adsorption isotherms. For all activated carbons and process conditions, the best match to the test results was obtained using the Langmuir model, whereas the lowest was found for the Dubibin–Radushkevich model.


2017 ◽  
Vol 13 (4) ◽  
pp. 778-783
Author(s):  
Azreen Ibrahim ◽  
Lija Yusof ◽  
Abu Zahrim Yaser

Ammonia nitrogen (NH3 - N) is one of the common and toxic species of nitrogen and excess of it in waterway causes eutrophication, decreased in dissolved oxygen and toxic to aquatic organisms. This study aims to investigate the isotherm and kinetic modeling of adsorption of ammonia nitrogen from aqueous solution by using jackfruit (Artocarpus heterophyllus) seed. Batch equilibrium experiments were carried out at 60 minute of contact time with initial pH value of 7. The adsorption isotherm data fitted well with Langmuir model with correlation (R2) of 0.9809 and maximum monolayer adsorption capacitiy (Qe) of 3.94 mg/g. Meanwhile, the adsorption of NH3 - N follows pseudo second order with correlation (R2) values ranges from 0.62 to 0.96 for various concentrations. Besides, the adsorption capacity obtained from experiment also has the smallest difference with calculated adsorption capacity. This suggest that the adsorption is mainly governed by chemical process involving cations sharing or exchange between the adsorbent and NH3 - N in the solution. In conclusion, jackfruit seed can be used as adsorbent materials for ammonia nitrogen removal from aqueous solution. 


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