Ph-triggered interfacial interaction of kaolinite/chitosan nanocomposites with anionic azo dye

Abstract

Advanced engineering of naturally occurring materials opens new doors in nanoscience and nanotechnology for the separation and/or removal of environmental hazards. Here, a series of nanocomposites containing kaolinite and chitosan varying in the range of 20 to 80% (w/w) kaolinite were used for the adsorptive removal of a reactive textile dye, Remazol Red, from an aqueous solution. Batch experiments were carried out to investigate the effects of pH, contact time, and initial dye concentration on the adsorption capacity. Nanocomposites containing 80% kaolinite (w/w) and 20% chitosan (w/w), i.e., NK80C20, showed an equilibrium adsorption capacity of 371.8 mg/g at pH 2.5, which was 5.2 times higher than that of commercial activated charcoal. Moreover, NK80C20 was regenerated instantly up to 99.9% at pH 10. Therefore, NK80C20 can be effectively utilized as a potential adsorbent for the separation of Remazol Red and homologous azo dyes from industrial effluents. We expect that the findings from this study will play a vital role in environmental research leading to advanced applications in water purification.