Absorption Behavior of a Modified Cellulose Hydrogel for both Fluoride and Arsenic

2013 ◽  
Vol 726-731 ◽  
pp. 733-738 ◽  
Author(s):  
Ling Die Meng ◽  
Min Wu ◽  
Ye Tian ◽  
Shigenori Kuga ◽  
Yong Huang

This work reports a cationic modified cellulose hydrogel for fluoride and arsenic adsorption. This adsorbent had a high efficiency in removal of F-, AsO2- and AsO43- simultaneously from aqueous solutions, even at low initial concentrations. Adsorption kinetics showed the relatively rapid rate to reach equilibrium, as could be explained by the pseudo-second-order model and the intraparticle diffusion model within 20 min before the equilibrium. Freundlich model could fit the adsorption process best, and the results showed the improved arsenic adsorption performances especially for AsO43-, much larger than other reported absorbents.

Water ◽  
2021 ◽  
Vol 13 (17) ◽  
pp. 2394
Author(s):  
Rosa Devesa-Rey ◽  
Jesús del Val ◽  
Jorge Feijoo ◽  
José González-Coma ◽  
Gonzalo Castiñeira ◽  
...  

The main objective of this study consists in the synthesis of a layered double hydroxide (LDH) clay doped with magnesium and aluminum in order to test the removal of phosphates and ibuprofen in water. Two different LDH composites are assessed: oven-dried (LDHD) and calcined (LDHC). Single adsorptions of phosphate and ibuprofen showed up to 70% and 58% removal in water, when LDHC was used. A poorer performance was observed for LDHD, which presented adsorption efficiencies of 52% and 35%, respectively. The simultaneous removal of phosphate and ibuprofen in water showed that LDHC allows a greater reduction in the concentration of both compounds than LDHD. Phosphate adsorption showed a close agreement between the experimental and theoretical capacities predicted by the pseudo-second-order model, whereas ibuprofen fitted to a first-order model. In addition, phosphate adsorption showed a good fit to an intraparticle diffusion model and to Bangham model suggesting that diffusion into pores controls the adsorption process. No other mechanisms may be involved in ibuprofen adsorption, apart from intraparticle diffusion. Finally, phosphate desorption could recover up to 59% of the initial concentration, showing the feasibility of the recuperation of this compound in the LDH.


2016 ◽  
Vol 17 (3) ◽  
pp. 698-706
Author(s):  
Chunnuan Ji ◽  
Suwen Sun ◽  
Shenghua Chi ◽  
Rongjun Qu ◽  
Changmei Sun ◽  
...  

A highly selective polymeric ligand exchanger was developed for the removal of trace As(V) from aqueous solution. This adsorbent was prepared by loading Fe(III) onto porous amidoximated polyacrynitrile (AN)/itaconic acid (IA) copolymers (Fe(III)-AO AN/IA). Negligible ferric ion dissolution was observed from Fe(III)-AO AN/IA in solution of acidic pHs up to 2. As(V) adsorption by Fe(III)-AO AN/IA is a pH-dependent process with maximum capacity of 1.32 mg/g at pH 2–3. The adsorption process was found to be governed by pseudo-second-order kinetics, and could be described by the Freundlich model. Fe(III)-AO AN/IA had higher adsorption selectivity for As(V) than other anions in a simulated groundwater body such as Cl−, SO42−, PO43−, SiO32−. Fixed-bed adsorption indicated that As(V) in simulated groundwater could be effectively captured from 400 μg/L to <10 μg/L within 190 bed volumes (BV). The As(V) adsorbed on Fe(III)-AO AN/IA could be efficiently eluted with 10 BV of 5% NaCl solution (at pH = 9.0).


Author(s):  
Dorota Kołodyńska ◽  
Aleksandra Łyko ◽  
Marzena Gęca ◽  
Zbigniew Hubicki

<p>Lately there has been observed the increased presence of chlorates(VII) in the natural environment which can affect human health negatively. Therefore the removal of chlorate(VII) ions using the gel type resin functionalized with the tri-n-butyl ammonium (Dowex<sup>™</sup>PSR-2) from waters was studied. The main aim was to evaluate the effects of experimental conditions including contact time, initial solution concentration, pH and temperature on chlorate(VII) ions removal as well as the anion exchanger properties on chlorate(VII) ions sorption. It was found that only the pseudo second order model described the experimental data well and the intraparticle diffusion was not the rate-limiting step. According to the Freundlich model, the q<sub>e</sub> value was to be 69.26 mg/g at optimum conditions (pH 7.0 at 25 <sup>o</sup>C).<strong></strong></p>


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Faranak Pishgar ◽  
Homayon Ahmad Panahi ◽  
Ali Akbar Khodaparast Haghi ◽  
Vahid Motaghitalab ◽  
Amir Hesam Hasani

Diazinon and chlorpyrifos are two common organophosphorus poisons to fight the pests in Iran. The removal of these poisons from water by thermosensitive nanosphere polymer (TNP), synthesized from the copolymerization of N-isopropylacrylamide and 3-allyloxy-1,2-propanediol, was investigated. The effect of pH, contact time, and the initial concentration on the removal amount was studied. The highest removal amount of these poisons by TNP occurred at pH 7. The contact time increase improves the removal amount and the equilibrium contact time for diazinon and chlorpyrifos was 10 and 18 min, respectively. For low concentration of less than 50 mgL−1it was shown that removal capacity remains above 95%. The initial concentration above 50 mgL−1decreased the removal amount, in which chlorpyrifos showed a greater decrease. The kinetic data has been checked using pseudo first-order, pseudo second-order, and intraparticle diffusion equations. The intraparticle diffusion model had the best conformability for the adsorption process.


2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Yuan Lu ◽  
Dankui Liao ◽  
Xuezhen Feng ◽  
Hualin Meng ◽  
Yuting Lu ◽  
...  

A metal affinity-immobilized magnetic liposome (MA-IML) was prepared in this research, which was with lipid and Ni2+ content of 143.25 μg/mg and 32 μmol/mg, respectively. The antihypertensive peptides Ile-Pro-Pro (IPP) and Val-Pro-Pro (VPP) could be adsorbed onto MA-IML under specific conditions, and the adsorption kinetics was explored. The pseudo-second-order kinetics (R2 value>0.98) was more suitable to describe the adsorption process of IPP and VPP than the intraparticle diffusion model and pseudo-first-order kinetic model. The results indicated that MA-IML could be used as an adsorbent for screening antihypertensive peptides from natural products.


2019 ◽  
Vol 2019 ◽  
pp. 1-10 ◽  
Author(s):  
Yunfei Hu ◽  
Yue Zhang ◽  
Yuqun Hu ◽  
Chen-Yao Chu ◽  
Jinke Lin ◽  
...  

Tea powder, a biosorbent prepared from wasted oolong tea, was collected as a prospective adsorbent for the adsorption of methylene blue (MB) from aqueous solution. The effect of factors on adsorption efficiency, isotherms, kinetics, and potential mechanism was carried out. Adsorption capacity of MB onto wasted tea powder increased with the MB concentration and contact time, whereas the increase in pH value and ion strength appeared to have a negative effect for the adsorption process. The adsorption efficiency increased rapidly and reached a stable state within 120 min. The optimal tea powder loading weight is suggested to be at 0.1 to 0.2 g, and the highest efficiency of 94.8% is achieved at 333 K. There were no significant changes in adsorption efficiency when the effect of temperature is considered. The Langmuir isotherm model was found to be the best isotherm models to elucidate the adsorption mechanism in this study. The maximum adsorption capacities calculated at different temperatures by the Langmuir model ranging from 312.5 to 333.3 mg·g−1 were much close to the experimental results. From the kinetic analysis, the pseudo--second-order model was found to be the best model to describe the adsorption behavior. The calculated adsorption capacities at different initial MB concentrations by the pseudo-second-order model ranging from 92.34 to 400 mg·g−1 were well close to the experimental data. The fitting results obtained from the intraparticle diffusion model suggested that the intraparticle diffusion was not the only rate-controlling step and some other mechanisms along with the intraparticle diffusion were probably involved. The intraparticle diffusion of MB molecules into pore structures of wasted tea powder is the rate-limiting step for the adsorption process in this study. The repetitive cycle experiments indicated that the wasted oolong tea powder was efficiently regenerated using NaOH and thus be used for many times.


2019 ◽  
Vol 9 (5) ◽  
pp. 4394-4400 ◽  

Dyes wastewater is listed as one of the largest water polluter in this world and cause problems to the environment as well as human health. The present study aims to investigate the adsorption of methylene blue, a cationic dye commonly used in industries by activated carbon derived from the water hyacinth stem (Eichhornia crassipes (Mart.) Solms). The removal of MB solution was affected by some parameters such as dosage, contact time, pH, and initial dye concentration. The present study showed that the optimum condition for the adsorption process was pH 7, the adsorbent dosage at 0.8 g with the equilibrium was reached at 100 minutes. However, there is no significant adsorption in the effect of pH. It was found that the best correlation of kinetic with the MB adsorption was the pseudo-second-order model, while the isotherm study was well represented with the Freundlich model. The porosity of adsorbent was enhanced after carbonization process. The functional group presence on the surface of adsorbent including alcohols, carboxyl and carbonyl were also contributed to the effectiveness of adsorption process.


Author(s):  
Farid Abu Shammala ◽  
Barry Chiswell

This article describes a novel and efficient MCTS/GO nanocomposite for the accumulation and removal of a hazardous azo dye (Chrysoidine Y) from its aqueous solutions. Magnetic Chitosan /graphene oxide (MCTS/GO) nanocomposite adsorbent was prepared by wet-spinning technique, was used as accumulation and removal of Chrysoidine Y from aqueous solution. The structure and morphology of MCTS/GO nanocomposites were investigated using transmission electron microscope (TEM) and Fourier transform infrared (FTIR) spectroscopy were carried out on the MCTS/GO before the Chrysoidine Y (CY) accumulation experiments. The adsorption kinetics and isotherm studies were conducted under different conditions (pH = 3-7 and CY concentration = 100-400 mg/L) to examine the accumultion efficiency of the MCTS/GO towards CY in aqueous solution. The kinetics data of the adsorption process were analyzed using different kinetic models in order to investigate the adsorption behavior of CY on MCTS/GO. The results showed that the maximum adsorption capacity of the MCTS/GO nanocomposites towards CY can achieve up to ~700 mg/g for the adsorption at 300 mg/L CY. Kinetic data of adsorption process were found to fit pseudo-second order model as compared with pseudo-first-order model. The intraparticle diffusion model suggested that the adsorption process of MCTS/GO towards CY was dominated by the external mass transfer of CY molecules to the surface of MCTS/GO.


2019 ◽  
Vol 9 (1) ◽  
pp. 37-44
Author(s):  
Amira AM ◽  
Fatima Ouzidan ◽  
Tarik Ainane ◽  
Mohamed Talbi ◽  
M'hammed El Kouali

This paper evaluates the ability of a natural rock found in Morocco to remove the pollutant properties of methylene blue (MB) dye. In this regard, the experiments were conceived to test the hypothesis that the rock native of the country’s region of Khenifra can be used as a new abundant adsorbent to remove cationic dyes from water through the adsorption technique in order to avoid extra cost and contribute to the valorization of this material. For this, several factors such as pH of the solution, granulometry, mass of adsorbent, initial dye concentration and stirring rate were tested. The adsorption kinetics process was tested through three models, namely, the pseudo-first-order model, pseudo-second-order model and the intraparticle diffusion model, to predict which type of adsorption is best suited in the removal of dye pollution. The batch study proves that only the granulometry (G ≤ 63µm = 91%, G ≤ 80µm = 88.4% and G ≤ 100µm=70.7%) and the adsorbent mass (the more the mass of the adsorbent increases the more the elimination is achieved) can influence the elimination rate of our rock. Meanwhile, the data of the adsorption kinetics test show that the experimental adsorption could be described by the mechanism of the pseudo-second-order model (correlation coefficients near the unit ‘R 2 = 0.99’ ), confirming chemical sorption as a rate-limiting step of the intraparticle diffusion mechanism. According to the results of this study, the rock collected from the area of Khenifra can be used as a new and efficient adsorbent in the field of wastewater treatment.


2014 ◽  
Vol 809-810 ◽  
pp. 907-911
Author(s):  
Jun Long Wang ◽  
Jie Hou ◽  
Ting Jiang ◽  
Yong Jun He ◽  
Yao Dong Liang

Dry waters with an average diameter of 82 μm were prepared by a high speed mixed route. The formaldehyde absorption kinetics of dry waters was investigated by simulating indoor formaldehyde pollution in glass chamber. The results showed that pseudo-second order model could be used to simulate the adsorption process; the adsorption rate was highest in the initial 60 minutes; when the adsorption lasted for 180 minutes, the adsorption reached equilibrium.


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