scholarly journals Contribution of Cross-Linker and Silica Morphology on Cr(VI) Sorption Performances of Organic Anion Exchangers Embedded into Silica Pores

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1249 ◽  
Author(s):  
Ecaterina Stela Dragan ◽  
Doina Humelnicu
Keyword(s):  
Sorption Capacity ◽  
Organic Anion ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Anion Exchangers ◽  
Fast Kinetics ◽  
Strong Base ◽  
Maximum Sorption Capacity ◽  
Composite Sorbents ◽  
Cross Linker

Removal of Cr(VI) from the environment represents a stringent issue because of its tremendous effects on living organisms. In this context, design of sorbents with high sorption capacity for Cr(VI) is getting a strong need. For this purpose, poly(vinylbenzyl chloride), impregnated into porous silica (PSi), was cross-linked with either N,N,N’,N’-tetramethyl-1,2-ethylenediamine (TEMED) or N,N,N’,N’-tetramethyl-1,3-propanediamine, followed by the reaction of the free -CH2Cl groups with N,N-diethyl-2-hydroxyethylamine to generate strong base anion exchangers (ANEX) inside the pores. The PSi/ANEX composite sorbents were deeply characterized by FTIR spectroscopy, SEM-energy dispersive X-ray spectroscopy (EDX), thermogravimetric analysis (TGA), and water uptake. The sorption performances of composites against Cr(VI) were investigated as a function of pH, contact time, initial concentration of Cr(VI), and temperature. It was found that the cross-linker structure and the silica morphology are the key factors controlling the sorption capacity. The adsorption process was spontaneous and endothermic and well described by pseudo-second-order kinetic and Sips isotherm models. The maximum sorption capacity of 311.2 mg Cr(VI)/g sorbent was found for the composite prepared with mesoporous silica using TEMED as cross-linker. The PSi/ANEX composite sorbents represent an excellent alternative for the removal of Cr(VI) oxyanions, being endowed with fast kinetics, equilibrium in about 60 min, and a high level of reusability in successive sorption/desorption cycles.

scholarly journals Chromium (VI) removal from aqueous solutions by purolite base anion-exchange resins with gel structure

2013 ◽  
Vol 19 (4) ◽  
pp. 615-628 ◽  
Author(s):  
Catalin Balan ◽  
Irina Volf ◽  
Doina Bilba
Keyword(s):  
Sorption Process ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Gel Structure ◽  
Solution Ph ◽  
Sorption Data ◽  
Strong Base ◽  
Maximum Sorption Capacity ◽  
Chromium Vi ◽  
Exchange Resins

The removal of Cr (VI) from aqueous solution using two strong base anionic resins with gel structure, Purolite A-400 (styrene-divinylbenzene matrix) and Purolite A-850 (acrylic matrix) was investigated in batch technique. The sorption efficiency was determined as a function of phases contact time, solution pH, resin dose, temperature and initial Cr (VI) concentration. The percentage of Cr (VI) removed reaches maximum values (up to 99 %) in the pH range 4 - 5.3 under a resin dose of 6 g/L and of Cr (VI) concentration up to 100 mg/L. An increase in temperature has a positive effect on the Cr (VI) sorption process. The equilibrium sorption data were fitted with the Freundlich, Langmuir and Dubinin-Radushkevich isotherm models, using both linear and nonlinear regression method. The Langmuir model very well verifies the experimental data and gives the maximum sorption capacity of 120.55 mg Cr (VI)/g and 95.82 mg Cr (VI)/g for A-400 and A-850 resins, respectively. The thermodynamic study and mean free energy of sorption values calculated using Dubinin-Radushkevich equation indicated the sorption is a chemical endothermic process. The kinetic data were well described by pseudo-second order kinetic equation and the sorption process is controlled by external (film) diffusion and intraparticle diffusion.

scholarly journals Kinetic, isotherm and thermodynamic investigations of nitrite (NO2–) removal from water by anion exchange resins

2018 ◽  
Vol 20 (2) ◽  
pp. 368-372 ◽  
Keyword(s):  
Anion Exchange ◽  
Freundlich Isotherm ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Weak Base ◽  
Strong Base ◽  
Anion Exchange Resins ◽  
Base Resin ◽  
Equilibrium Data ◽  
Exchange Resins

This study presents the evaluation of a strong base (Purolite A200) and weak base (Purolite PFA847) polymeric anion exchange resins for nitrite removal. The different parameters on the removal of NO2– were investigated in batch sorption mode. Common isotherm models; Langmuir and Freundlich, were used in order to present a description of the equilibrium data. Experimental results showed that the equilibrium data tend to follow Freundlich isotherm model for weak base resin and Langmuir model for strong base resin. The sorption of NO2– on anion exchange resins was found to follow the pseudo-second order kinetic model. The values of thermodynamic parameters proved that ion exchange reaction of NO2– onto such resins are endothermic (ΔH > 0).

scholarly journals Comparative study between activated carbon and biochar for phenol removal from aqueous solution

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 6781-6790
Author(s):  
Moammar Elbidi ◽  
Agab Hewas ◽  
Rajab Asar ◽  
Mohamad Amran Mohd Salleh
Keyword(s):  
Experimental Data ◽  
Activated Carbon ◽  
Freundlich Isotherm ◽  
Sorption Process ◽  
Isotherm Models ◽  
Phenol Removal ◽  
Order Kinetic ◽  
Fast Kinetics ◽  
Pseudo Second Order ◽  
Maximum Removal

Removal of phenol from wastewater using local biochar (BC) was investigated, while using activated carbon (AC) as a reference material. The main parameters affecting the sorption process were initial concentration, contact time, pH, and temperature. Statistical analysis of the results showed that the maximum removal percent when using AC and BC were 95% and 55%, respectively. Experimental data showed that the removal of phenol has fast kinetics and reached equilibrium within 5 minutes. The Langmuir and Freundlich isotherm models were applied to fit the adsorption experimental data. Pseudo-first order and pseudo-second order kinetic models were employed.

scholarly journals Synthesis, Characterization and Sorption Capacity Examination for a Novel Hydrogel Composite Based on Gellan Gum and Graphene Oxide (GG/GO)

Polymers ◽  
2020 ◽  
Vol 12 (5) ◽  
pp. 1182 ◽  
Author(s):  
Cristina Modrogan ◽  
Andreea Mădălina Pandele ◽  
Constantin Bobirică ◽  
Dan Dobrotǎ ◽  
Annette Madelene Dăncilă ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Ion Exchange ◽  
Sorption Capacity ◽  
Sorption Isotherms ◽  
Gellan Gum ◽  
Order Kinetic ◽  
Maximum Sorption Capacity ◽  
Hydrogel Composite ◽  
Rate Determining Step ◽  
Acidic Conditions

A novel hydrogel composite based on gellan gum and graphene oxide (GG/GO) was synthesized, characterized and tested for sorption capacity in this work. The microstructural, thermogravimetric and spectroscopic analysis confirmed the formation of the GG/GO composite. Comparative batch sorption experiments revealed a sorption capacity of the GG/GO composite for Zn (II) ions of approximately 2.3 higher than that of pure GG. The GG/GO composite exhibits a maximum sorption capacity of 272.57 mg/g at a pH of Zn (II) initial solution of 6. Generally, the sorption capacity of the sorbents is approximately 1.5 higher in slightly acidic conditions (pH 6) comparative with that for strong acidic conditions (pH 3). The sorption isotherms revealed that the sorption followed a monolayer/homogenous behavior. The sorption kinetic data were well fitted by the pseudo-second-order kinetic model, and were consistent with those derived from sorption isotherms. The intraparticle diffusion was considered to be the rate-determining step. Two main sorption mechanisms for Zn (II) were identified namely, ion exchange at low pH values, and both ion exchange and chemisorption in weekly acidic conditions.

scholarly journals Uranium (VI) Recovery from Black Shale Leaching Solutions Using Ion Exchange: Kinetics and Equilibrium Studies

Minerals ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 689
Author(s):  
Omirserik Baigenzhenov ◽  
Alibek Khabiyev ◽  
Brajendra Mishra ◽  
M. Deniz Turan ◽  
Merey Akbarov ◽  
...  
Keyword(s):  
Kinetic Model ◽  
Sorption Isotherm ◽  
Room Temperature ◽  
Sorption Kinetics ◽  
Second Order ◽  
Order Kinetic ◽  
Strong Base ◽  
Maximum Sorption Capacity ◽  
Order Kinetic Model ◽  
Pseudo Second Order

This work studies the removal of uranium ions from chemically leached solutions by sorption using two weak and two strong base anionites. Batch sorption experiments were performed to evaluate the optimum conditions at pH 1.2–2.2, 1.0 g resin dose for 1–12 h contact time at room temperature. These experiments addressed sorption kinetics and sorption isotherm. The maximum sorption capacity reached 55.8 mg/g at room temperature. The kinetics data are well described by the pseudo-second-order kinetic model at initial uranium concentration of 0.62 mg·L−1. To describe sorption kinetics pseudo-first-order, pseudo-second-order and intraparticle diffusion models were proposed. Studies indicated that the sorption of uranium can be fitted by a pseudo-second-order kinetic model very well. Equilibria were described by Langmuir, Freundlich, and Dubinin–Radushkevich equations. The experimental sorption isotherm is successfully described by the Langmuir model.

Phosphate removal from aqueous solutions using (vinylbenzyl)trimethylammonium chloride grafted onto polyester fibers

2015 ◽  
Vol 71 (12) ◽  
pp. 1875-1883 ◽  
Author(s):  
HyunJu Park ◽  
Duc Canh Nguyen ◽  
Choo-Ki Na
Keyword(s):  
Free Energy ◽  
Ion Exchange ◽  
Aqueous Solutions ◽  
Sorption Capacity ◽  
Phosphate Removal ◽  
Trimethylammonium Chloride ◽  
Order Kinetic ◽  
Phosphate Sorption ◽  
Maximum Sorption Capacity ◽  
Competing Anions

In this study, we investigated the removal of phosphate from aqueous solutions using (vinylbenzyl)-trimethylammonium chloride (VBTAC) grafted onto poly(ethylene terephthalate) (PET) fibers (PET-g-VBTAC). Batch-mode experiments were conducted using various contact times, initial phosphate concentrations, temperatures, pH values, and competing anions, to understand phosphate sorption onto PET-g-VBTAC. The phosphate sorption capacity of PET-g-VBTAC increased with increasing solution pH and was highest near pH 7. The equilibrium data fitted the Langmuir isotherm model well. The maximum sorption capacity (qm) of PET-g-VBTAC for phosphate was 55.6–56.0 mg/g at 25–45 °C. The sorption process followed a pseudo-second-order kinetic model. The obtained values of the mean free energy indicated that sorption of phosphate on PET-g-VBTAC occurs via ion exchange. Thermodynamic parameters, enthalpy change, entropy change, and Gibb's free energy, confirmed that phosphate sorption was spontaneous and endothermic. The adverse effects of competing anions on phosphate removal by PET-g-VBTAC were insignificant. These results demonstrate that PET-g-VBTAC effectively removes phosphate from aqueous solutions by ion exchange.

scholarly journals Functionalized macroporous copolymer of glycidyl methacrylate: The type of ligand and porosity parameters influence on Cu(II) ion sorption from aqueous solutions

2009 ◽  
Vol 63 (3) ◽  
pp. 269-273 ◽  
Author(s):  
Zvjezdana Sandic ◽  
Aleksandra Nastasovic
Keyword(s):  
Heavy Metals ◽  
Aqueous Solutions ◽  
Metal Ions ◽  
Sorption Capacity ◽  
Glycidyl Methacrylate ◽  
Mechanical Stability ◽  
Fast Kinetics ◽  
Maximum Sorption Capacity ◽  
Maximum Sorption ◽  
Chelating Polymers

The removal of heavy metals from hydro-metallurgical and other industries' wastewaters, their safe storage and possible recovery from waste- water streams is one of the greater ecological problems of modern society. Conventional methods, like precipitation, adsorption and biosorption, electrowinning, membrane separation, solvent extraction and ion exchange are often ineffective, expensive and can generate secondary pollution. On the other hand, chelating polymers, consisting of crosslinked copolymers as a solid support and functional group (ligand), are capable of selectively loading different metal ions from aqueous solutions. In the relatively simple process, the chelating copolymer is contacted with the contaminated solution, loaded with metal ions, and stripped with the appropriate eluent. Important properties of chelating polymers are high capacity, high selectivity and fast kinetics combined with mechanical stability and chemical inertness. Macroporous hydrophilic copolymers of glycidyl methacrylate and ethylene glycol dimethacrylate modified by different amines show outstanding efficiency and selectivity for the sorption of precious and heavy metals from aqueous solutions. In this study poly(GMA-co-EGDMA) copolymers were synthesized with different porosity parameters and functionalized in reactions with ethylene diamine (EDA), diethylene triamine (DETA) and triethylene tetramine (TETA). Under non-competitive conditions, in batch experiments at room temperature, the rate of sorption of Cu(II) ions from aqueous solutions and the influence of pH on it was determined for four samples of amino-functionalized poly(GMA-co-EGDMA). The sorption of Cu(II) for both amino-functionalized samples was found to be very rapid. The sorption half time, t1/2, defined as the time required to reach 50% of the total sorption capacity, was between 1 and 2 min. The maximum sorption capacity for copper (2.80 mmol/g) was obtained on SGE-10/12-deta sample. The sorption capacity of Cu(II) ions increases with increasing pH and has maximum at pH ~5. In the experimental pH range, the maximum sorption capacity of Cu(II) ions again is reached on SGE-10/12-deta. By comparing literature data and obtained results it is possible to conclude that amino-functionalized macroporous copolymers based on glycidyl methacrylate are efficient for sorption of Cu(II) ions from aqueous solutions and sorption capacity for copper mostly depends on type of amine with which the basic copolymer is functionalized.

Kinetics, mechanism and thermodynamics involved in sorption of meso-tetrakis(4-sulfonatophenyl)porphyrin onto chitosan in aqueous medium

2014 ◽  
Vol 18 (03) ◽  
pp. 240-250 ◽  
Author(s):  
Tapan K. Saha ◽  
Subarna Karmaker ◽  
Md F. Alam
Keyword(s):  
Free Energy ◽  
Aqueous Medium ◽  
Second Order ◽  
Isotherm Models ◽  
Order Kinetic ◽  
Diffusion Kinetic ◽  
Sorption Data ◽  
Film Diffusion ◽  
Initial Concentration ◽  
Maximum Sorption Capacity

Sorption of meso-tetrakis(4-sulfonatophenyl)porphyrin ( H 2 tpps ) onto chitosan has been investigated in aqueous medium. Kinetic and isotherm studies were carried out by considering the effects of various parameters, such as pH, initial concentration of H 2 tpps solution, and temperature. The kinetic data obtained from different batch experiments were analyzed using pseudo first-, second-order, intraparticle, and film diffusion kinetic models. The equilibrium sorption data was analyzed by using Tempkin, Langmuir and Freundlich models. The best results were achieved with the pseudo second-order kinetic, Langmuir and Freundlich isotherm models. The intraparticle diffusion and film diffusion are the rate limiting steps. The amount of sorbate adsorbed at equilibrium (qe) increased with increasing the initial concentration of H 2 tpps solution, showing maximum sorption capacity of 445.21 μmol.g-1. The activation energy (Ea) of sorption kinetics was found to be 19.47 kJ.mol-1. Thermodynamic parameters such as change in free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) were evaluated by applying the Van't Hoff equation. Thermodynamic activation parameters such as change in enthalpy of activation (ΔH‡), entropy of activation (ΔS‡), and free energy of activation (ΔG‡) were also calculated. The thermodynamics of H 2 tpps sorption onto chitosan in aqueous medium indicates its spontaneous and endothermic nature.

scholarly journals Synthesis of Mesoporous γ-Alumina Support for Water Composite Sorbents for Low Temperature Sorption Heat Storage

Energies ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 7809
Author(s):  
Manca Ocvirk ◽  
Alenka Ristić ◽  
Nataša Zabukovec Logar
Keyword(s):  
Hydrothermal Synthesis ◽  
Structural Properties ◽  
Sorption Capacity ◽  
Heat Storage ◽  
Alumina Support ◽  
Fast Kinetics ◽  
Storage Density ◽  
Storage Performance ◽  
Composite Sorbents ◽  
Sorption Heat

The efficiency of thermochemical heat storage is crucially determined by the performance of the sorbent used, which includes a high sorption capacity and a low regeneration temperature. The thermochemical salt hydrate– γ-alumina composite sorbents are promising materials for this application but lack systematic study of the influence of γ-alumina structural properties on the final storage performance. In this study, mesoporous γ-Al2O3 supports were prepared by solvothermal and hydrothermal synthesis containing a block copolymer (F-127) surfactant to design thermochemical CaCl2 and LiCl composite water sorbents. Altering the solvent in the synthesis has a significant effect on the structural properties of the γ-Al2O3 mesostructure, which was monitored by powder XRD, nitrogen physisorption, and SEM. Solvothermal synthesis led to a formation of mesoporous γ-Al2O3 with higher specific surface area (213 m2/g) and pore volume (0.542 g/cm3) than hydrothermal synthesis (147 m2/g; 0.414 g/cm3). The highest maximal water sorption capacity (2.87 g/g) and heat storage density (5.17 GJ/m3) was determined for W-46-LiCl containing 15 wt% LiCl for space heating, while the best storage performance in the sense of fast kinetics of sorption, without sorption hysteresis, low desorption temperature, very good cycling stability, and energy storage density of 1.26 GJ/m3 was achieved by W-46-CaCl2.

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