Bentonite polymer composite for water purification

Abstract

A polyethylene glycol (PEG)-bentonite (BT) composite was prepared by direct polymerization of PEG in suspensions of BT. Based on detailed analyses using field-effect scanning electron microscopy, X-ray diffraction, surface area measurements and chemical methods, the obtained product was mainly composed of Ca-BT with a specific surface area of 4.13 m 2 g −1. The optimal conditions for adsorption of Pb 2+ and Cd 2+ ions were found to be a PEG content of 0.1% and a contact time of 60 min. The sorption experiments were performed under various operating variables, including polymer concentration, pH and temperature. For both Pb 2+ and Cd 2+ , the adsorption equilibrium was described by the Freundlich model, which confirmed the presence of a heterogeneous system with irregular filling of the active centres. The maximum sorption capacities of BT-PEG for removal of Pb 2+ and Cd 2+ were found to be 22 and 18 mg g −1 , respectively. The rate constants calculated for the sorption of Pb 2+ and Cd 2+ were 6.29 and 6.67 g mg −1 min −1 , respectively, at 25 • C. This study shows that the obtained sorbents based on BT may be used for treatment of waste water and could help resolve environmental protection issues.

Adsorption of Hexavalent Chromium from Aqueous Solution by a Chitosan/Bentonite Composite: Isotherm, Kinetics, and Thermodynamics Studies

“…Nowadays, the modification of bentonite by natural or synthetic polymers has gained critical research attention, such as polyethylene glycol, polystyrene, polysiloxane, carboxymethyl cellulose, chitin, and chitosan. − The preparation methods of polymer/bentonite composites can be classified into three categories: (i) intercalation polymerization, (ii) polymer intercalation by the melt method, and (iii) polymer intercalation by the solution method . A competitive advantage of the solution method is that it can better control the homogeneity of the constituents compared to the first two methods, which is helpful to comprehend the intercalation process and composites’ morphology.…”

Mesoporous Carbonaceous Material From Expanded Polystyrene and Bentonite for Instantaneous Degradation of Mixture of Dyes

“…For EPS the initial weight loss can be due to the removal of adsorbed moisture and solvent molecules. Chain scission starts at 350 o C and degradation is completed at 459.1 o C. The thermo gram of BT indicates two dehydration steps extending up to 450 o C. The final weight loss of 5% in the range of 420-700 o C might be due to the condensation reaction between adjacent hydroxyl groups present in the inorganic polymer network [24].…”

“…Silver doped nano metal oxides, clay/ activated carbon [23] semiconductor composites, biowastes etc have been reported to be used for the removal of synthetic dyes individually [24,25]. As industrial effluents contain a mixture of synthetic dyes and organic pollutants it would be beneficial to develop a single photo catalyst that can remove all these pollutants simultaneously [26].…”

The influence of technological conditions and molecular weight of PEG on basal spacing of Vietnamese bentonite

“…Research on modification of bentonite with PEG for application as an adsorbent for treating water contaminated with organic solvents such as benzene, toluene, ethylbenzene, xylene [10,11] or contaminated with heavy metal ions such as Pb 2+ , Cd 2+ . [12] Bentonite is also modified with PEG for application as reactive clays inhibitor additive in water-based drilling fluids. [13] A number of studies related to the influence of PEG on the rheological behavior [5,[14][15][16][17][18] and electrokinetic property [5,15,16] of bentonite have also been published.…”