Purified Bentonite and Aliquat 336-Bentonite for Removal of Lead and Cadmium Ions from Aqueous Solutions

The presence of multiple contaminants often complicates treatment processes due to possible interactions and competition for binding sites. Focusing on a binary system allows researchers to explore these complexities and develop more effective treatment strategies. The modified bentonite may exhibit selective adsorption towards lead and cadmium ions in binary mixtures, effectively removing these pollutants from contaminated water or solutions. This study investigates the adsorption potential of Cd (II) and Pb (II) ions from aqueous solutions using purified bentonite and modified Algerian bentonite with Aliquat 336. The characterization of the bentonite surface, before and after modification, was conducted using BET, IR, and XRD analysis techniques. The experimental parameters influencing the adsorption process were examined. Results revealed that the specific surface area of natural bentonite, purified bentonite, and B336 Aliquat 336-bentonite was 47.20 m2/g, 91 m2/g, and 29.71 m2/g, respectively. The advantage of manufacturing 336 bentonite over purified bentonite is the increased distance between the layers, which led to enhanced maximum absorption capacity (31.04 mg/g for lead (II) and 25.03 mg/g for cadmium (II) using an aliquot of 336 bentonite. At the same time, it was 29.35 mg/g for lead (II) and 17.66 mg/g for cadmium (II) using purified bentonite). The equilibrium isotherms were best described by the Langmuir adsorption isotherm model. Furthermore, the modified bentonites exhibited effective desorption performance for cadmium using various stripping eluents (HNO3, HCl, H2SO4, and CH3COOH) while retaining Pb (II) ions. This demonstrates their potential as efficient adsorbents for heavy metals removal from contaminated environments, also, the combination of Algerian bentonite and Aliquat 336 likely creates a synergistic effect, leading to improved adsorption performance compared to unmodified bentonite or other sorbents.