Application of Magnetically Recoverable Biochar Amended Zirconium Adsorbent Composite for Enhanced As(III, V) Removal from Aqueous Solutions

The occurrence of elevated levels of arsenic in water sources is a global health concern and necessitates implementing sustainable removal technologies. The utilization of biochar composite for treating arsenic contaminated water has been reported as a promising technique in recent years. In the present study, corncob biochar was magnetically modified and amended with zirconium (CCB@Fe₃O₄-Zr with Zr to Fe₃O₄ molar ratio of 1:1, and 1:5) for the purposively removal of As(III) and As(V) from aqueous solutions. Characterization analyses and factors affecting the adsorption, such as adsorbent dose, initial As(III) and As(V) concentration, pH, temperature, contact time, and co-existing anions were investigated. Results demonstrated that the removal of As(III) and As(V) were about 81 and 99%, respectively with the initial concentration of 80 mg/L. Lower solution pH favored As(V) removal and it slightly affected As(III) adsorption in pH range (5.0 to 9.0) due to the presence of neutral As(III) form. Also, increased solution temperature promoted As(V) removal performance demonstrating of an endothermic nature of the adsorption process. Characterization analyses confirmed of the successful magnetization of biochar and zirconium amendment with 7.8 Am²/kg saturation magnetization potential and thermally super stable (> 60% residual mass). The weight percentage of Fe and Zr were 12.23 and 7.54% in CCB@Fe₃O₄-Zr, which revealed the sufficient agglomeration of the surface modified components on biochar and the post-adsorption tests revealed arsenic adsorption. Findings from the present study suggested that the adsorbent composite could be a precise and promising alternative for enhanced As(III) and As(V) removal from contaminated water.