Removal of Cadmium and Chromium Ions Using Modified α, β, and γ-cyclodextrin Polymers (original) (raw)
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Eco-Friendly β-cyclodextrin and Linecaps Polymers for the Removal of Heavy Metals
Polymers, 2019
Environment-friendly nanosponges, having a high content of carboxyl groups, were synthesized by crosslinking β-cyclodextrin and linecaps, a highly soluble pea starch derivative, with citric acid in water. Additionally, pyromellitic nanosponges were prepared by reacting β-cyclodextrin and linecaps with pyromellitic dianhydride in dimethyl sulfoxide and used in comparison with the citric nanosponges. After ion-exchange of the carboxyl groups H+ with sodium ions, the ability of the nanosponges to sequester heavy metal cations was investigated. At a metal concentration of 500 ppm, the pyromellitate nanosponges exhibited a higher retention capacity than the citrate nanosponges. At lower metal concentrations (≤50 ppm) both the citrate and the pyromellitate nanosponges showed high retention capacities (up to 94% of the total amount of metal), while, in the presence of interfering sea water salts, the citrate nanosponges were able to selectively adsorb a significantly higher amount of heavy...
Journal of Inclusion Phenomena and Macrocyclic Chemistry, 2010
An insoluble polymeric network containing cyclodextrins (CDs) and amino, hydroxyl and carboxylic groups, was used for the detoxification of multicontaminated wastewaters. The comparison of its sorption capacity with that of a similarly prepared starch material showed superior efficiency towards organic compounds, though maintaining the same efficiency towards inorganic species. The incorporation of cyclodextrin cavity into a solid network provides an easy separation of pollutants from water, after their uptake onto the sorbent surface. In fact, the presence of CDs ensures the formation of inclusion complexes enhancing the sorption properties. The proposed sorbent also shows good sorption capacity for cations and other inorganic compounds, which is mandatory for the treatment of multicontaminated wastewaters.
New hybrid organic–inorganic nanocomposites consist of β-cyclodextrin (β-CD)/epichlorohydrin (ECH), and bentonite clay were prepared by direct intercalation through one step emulsion polymerization. The structure and thermal stability of prepared nanocomposites were investigated by Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), field emission-scanning electron microscopy (FE-SEM), energy dispersive X-ray analysis (EDAX), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), differential of differential scanning calorimetry (DDSC), thermogravimetric analysis (TGA) and differential thermogravimetric (DTG) analyses. The observed results show that the β-CD polymer/clay nanocomposites (β-CD–ECH polymer/clay) with higher thermal stability than β-CD–ECH polymer were successfully prepared. The removal of heavy metals such as Cu(II), Zn(II) and Co(II) ions from drinking water was studied using a batch method at ambient temperature. The re...
Journal of Water Process Engineering , 2021
Hybrid structure from mesoporous silica (MCM-48) and β-cyclodextrin polymer (β-CD/MCM) was prepared for enhanced remediation of As (V) and Hg (II) ions. The β-CD/MCM showed promising uptake affinities for As (V) and Hg (II) ions even in the existence of coexisting anions or metal ions. The maximum capacities are 265.6 mg/g and 207.9 mg/g for the As (V) and Hg (II) ions, respectively. The data followed Pseudo-First order kinetic behavior and Langmuir equilibrium properties declaring homogenous and monolayer adsorption. The values of Gaussian energy (6.45 KJ/mol for As (V) and 3.95 KJ/mol for Hg (II) ions) emphasize the physical nature of their uptake by β-CD/MCM. The thermodynamic studies reflected their adsorption by spontaneous, favorable, and exothermic reactions. Using the β-CD/MCM as a fixed bed in column system achieved total removal percentages of 72.8 % (As (V)) and 60.4 % (Hg (II)) in addition to total adsorbed metals of 879.8 mg (As (V)) and 717.2 mg (Hg (II)) for 8.1 L of polluted water. Therefore, the synthetic β-CD/MCM composite is of promising adsorption properties to be applied in the decontamination of As (V) and Hg (II) ions either in batch studies or fixed bed column studies.
Beilstein Journal of Organic Chemistry, 2016
In this study, a polymer, prepared by crosslinking cyclodextrin (CD) by means of a polycarboxylic acid, was used for the removal of pollutants from spiked solutions and discharge waters from the surface treatment industry. In spiked solutions containing five metals, sixteen polycyclic aromatic hydrocarbons (PAH) and three alkylphenols (AP), the material exhibited high adsorption capacities: >99% of Co2+, Ni2+ and Zn2+ were removed, between 65 and 82% of the PAHs, as well as 69 to 90% of the APs. Due to the structure of the polymer and its specific characteristics, such as the presence of carboxylic groups and CD cavities, the adsorption mechanism involves four main interactions: ion exchange, electrostatic interactions and precipitation for metal removal, and inclusion complexes for organics removal. In industrial discharge waters, competition effects appeared, especially because of the presence of calcium at high concentrations, which competed with other pollutants for the adsor...
Nano γ-alumina (γ-Al2O3) is widely used to adsorb heavy metals due to excellent properties such as high surface area, thermal stability, and high adsorption capacity. Due to poor adsorption of toxic metals on nano γ-Al2O3 surface, coating with β-cyclodextrin improves its adsorption efficiency. The aim of this study was to synthesize nano γ-Al2O3/β-cyclodextrin by co-precipitation method to be used for future study in Cd(II) removal. The Fourier Transmission Infrared (FT-IR) spectroscopy, X- ray powder Diffraction (XRD) and, Scanning Electron Microscope (SEM) were evaluated. The results of XRD and SEM showed nano γ-Al2O3/β-cyclodextrin with 20–30 nm. Also, synthesized nano γ-Al2O3/β-cyclodextrin had suitable structure for cadmium removal as water toxic metal.
Adsorbents based on natural polymers for removal of some heavy metals from aqueous solution
Egyptian Journal of Petroleum, 2017
Heavy metal ions are discharged into water from several industries. They are carcinogenic and they cause severe environmental hazards. In the present work the ability of removal of copper and lead from aqueous solutions has been studied using carboxy methyl b cyclodextrin, poly(ethylene glycol) b cyclodextrin and their magnetic counterparts. Effects of pH, concentration of the metal ion, temperature and contact time have been studied. Equilibrium isotherms for the adsorption of the metals were measured experimentally. Results were analysed at different temperatures and the characteristic parameters for each adsorption isotherm were determined. The adsorption process has been found exothermic in nature and thermodynamic parameters, Gibb's free energy (DG), change in enthalpy (DH) and change in entropy (DS) have been calculated. The paper also includes results on the kinetic measurements of adsorption of the metal on modified b cyclodextrin and their magnetic nano composites at different temperatures. It was found that poly (ethylene glycol) b cyclodextrin showed better performance than carboxy methyl b cyclodextrin.
Treatment of mixed contamination in water using cyclodextrin-based materials
Remediation Journal, 2006
This study investigated the effectiveness of a cyclodextrin-based solid material for the removal of mixed dissolved contaminants. The solid material was prepared by condensation of ␣-cyclodextrin. The removal efficiency was found to be 70 percent for total heavy metals (cadmium, lead, chromium, iron, nickel, cobalt, and mercury) to 98 percent for polychlorinated biphenyls (PCBs). The optimum pH for heavy metal removal was approximately 5 and for PCBs it was in the range of 5-7. All of these heavy metals were successfully recovered from the spent cyclodextrin-based material using nitric acid, allowing the material to be reused for further passes. The results also showed that the presence of alkaline and alkaline earth metals did not have a significant effect on the removal efficiency, indicating that the cyclodextrin-based material could selectively remove the heavy metals of concern without being consumed by alkaline and alkaline-earth metals.
Polymers
Cationic organic pollutants (dyes and pesticides) are mainly hydrosoluble and easily contaminate water and create a serious problem for biotic and abiotic species. The elimination of these dangerous contaminants from water was accomplished by adsorption using cyclodextrin nanosponges. These nanosponges were elaborated by the cross-linking between 1,2,3,4-butanetetracarboxylic acid and β-cyclodextrin in the presence of poly(vinyl alcohol). Their physicochemical characteristics were characterized by gravimetry, acid-base titration, TGA, 13C NMR, ATR-FTIR, Raman, X-ray diffraction, and Stereomicroscopy. The BP5 nanosponges displayed 68.4% yield, 3.31 mmol/g COOH groups, 0.16 mmol/g β-CD content, 54.2% swelling, 97.0% PQ removal, 96.7% SO removal, and 98.3% MG removal for 25 mg/L of initial concentration. The pseudo-second-order model was suitable for kinetics using 180 min of contact time. Langmuir isotherm was suitable for isotherm with the maximum adsorption of 120.5, 92.6, and 64.9 ...