Enhanced remediation of As (V) and Hg (II) ions from aqueous environments using β-cyclodextrin/MCM-48 composite: Batch and column studies

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.