Physiochemical analysis of clay and polyoxometallate composite used for sorptive detoxification of mutagenic Brilliant Green dye.

Water pollution is a grave risk to mankind. Water pollutants including organic toxins, dyes effluents, and heavy metals have posed great stress on water quality in recent years. This has necessitated the search for an affordable, eco-friendly, inexpensive, stable, and effective strategy for wastewater remediation. In this work, a pollyoxometallate K₆[H₂AlBW₁₁O₄₀].9H₂O (KAB) was impregnated on kaolin clay to synthesize a clay-based nanocomposite KAB-K which was then evaluated for adsorptive removal of brilliant green dye (BG) from wastewater. The prepared composite was characterized by different techniques such as FTIR, SEM, and EDX analysis. The characterization results indicated the fine distribution of KAB on kaolin's surface. The adsorption studies of BG involved evaluation of optimum parameters such as time contact (30 min), quantity of adsorbent (20 mg), pH (5), temperature (40 °C), and agitation speed (125 rpm). 99.5% of BG was removed by KAB-K within 30 min. The assessment of kinetic data was performed via Langmuir, Freundlich, and Temkin models. The experimental data was found to be in good agreement with the Langmuir model (R² > 0.9965) as compared to other models. Q_max value of KAB-K (144.92 ± 0.005 mg/g) was much higher than simple kaolin (33.22 ± 0.01 mg/g). The applicability of the pseudo-second-order kinetic model suggested that the process was predominately chemisorption. KAB-K was easier to recycle and efficiently removed up to 68.7% dye in 3 subsequent cycles. Thus rapid adsorption rate, high adsorption capacity, efficient recovery, and reusability of KAB-K endorses that the synthesized composite is an effective adsorbent for wastewater pollutants. [ABSTRACT FROM AUTHOR]