Polyaniline-coated biochar : synthesis, characterization, and Cr(VI) adsorption studies

Abstract

Polyaniline (PANI) is a promising adsorbent for heavy metal removal due to its high conductivity, large surface area, cost-effective synthesis, and environmental stability. Biochar, derived from organic waste, also shows potential for pollutant removal. In this study, a polyaniline-biochar composite (PANI-NSA/BC) was synthesized and assessed for Cr(VI) removal from aqueous solutions. SEM analysis showed rod-like polyaniline structures distributed within the biochar matrix. Batch adsorption studies were performed to evaluate the effects of adsorbent dosage, polyaniline-to-biochar ratio, and solution pH. Cr(VI) removal efficiency decreased with biochar fraction (maximum at 25% biochar) and increased with composite dosage, (maximum at 40 mg). The process was highly pH-dependent, achieving maximum removal at pH 2. These results demonstrate the potential of PANI-NSA/BC for Cr(VI) remediation in water treatment. Future work will focus on scaling up the synthesis, optimizing operational parameters, and exploring the composite’s regeneration and reuse performance under continuous flow conditions.