Synthesis of TiO₂ nanoparticles loaded on magnetite nanoparticles modified kaolinite clay (KC) and their efficiency for As(III) adsorption

Arsenic pollution is one of important environmental issues in the world. In this study, kaolinite clay coated with titanium oxide-magnetic iron oxide nanoparticles (KC/TiO₂-Fe₃O₄) was synthesized as a new and effective adsorbent by simple precipitation method for influential adsorption of As(III) from the aquatic system. The factorial design method was employed for determining the significance level of the optimized batch experimental parameters. The optimum levels of the parameters in the factorial designing were validated by response surface methodology (RSM) analysis. The isotherm modelling investigations showed that the developed KC/TiO₂-Fe₃O₄ composite had a high monolayer adsorption capacity of 462.0 mg g⁻¹ at optimized conditions, pH 5, sorbent dose (300 mg L⁻¹), initial As(III) concentration (10 mg L⁻¹) and contact time (40 min). Adsorption mechanism based on kinetic evaluations well followed the pseudo-second-order model with higher regression values (>0.99). Adsorption/recovery performance at first, 3rd, 6th and 10th cycles were found to be 92/90 %, 80/77 %, 60/52 % and 20/12 %. All results revealed that the synthesized composite would be promising sorbent for As(III) adsorption from aquatic media due to its beneficial characteristics such as cost-effectiveness, stability, reusable performance and high adsorption capacity.