Abstract:Heavy metal pollution in wastewater poses a significant threat to the ecological environment of surface water and represents a major environmental challenge. To develop an efficient and stable adsorbent for the removal of Cr(Ⅵ) and Cu2+ from industrial wastewater, this study modified activated boron nitride with a 5% mass concentration of polyaniline and synthesized a novel polyaniline-modified activated boron nitride composite material (a-BN@5%Pani) via in situ chemical oxidation a-BN@5%Pani. The resulting a-BN@5%Pani demonstrated remarkable efficacy in the adsorption of Cr(Ⅵ) and Cu2+ from aqueous solutions. Comprehensive characterization using SEM, FTIR, BET, and XPS techniques revealed a mesoporous structure with excellent thermal stability. Crucially, the integration of polyaniline introduced imine groups, substantially enhancing the surface charges and providing abundant active sites for efficient heavy metal binding. This resulted in exceptional adsorption capacities: a maximum of 589.32 mg/g for Cr(Ⅵ) and 185.30 mg/g for Cu2+. However, the adsorption process exhibited a strong pH dependence, with Cr(Ⅵ) adsorption reaching a maximum of 306.10 mg/g at pH 6. Isotherm studies indicated that the Langmuir model provided a better fit (higher R2 value) to the experimental data compared to the Freundlich model, suggesting monolayer adsorption onto a homogenous surface. Kinetic analysis revealed that the pseudo-second-order model best described the adsorption process, indicating chemisorption as the dominant mechanism. The adsorption process was rapid, achieving equilibrium within approximately 30 minutes. Interestingly, competitive adsorption experiments in a mixed solution of Cr(Ⅵ) and Cu2+ revealed a significant enhancement in Cr(Ⅵ) adsorption in the presence of Cu2+. The maximum Cr(Ⅵ) adsorption capacity increased by a factor of 3-4 compared to the single-metal system, while Cu2+ adsorption remained significantly lower (4-5 times less than Cr(Ⅵ)), highlighting the selective adsorption of Cr(Ⅵ) by a-BN@5%Pani. Furthermore, the composite demonstrated excellent reusability, maintaining approximately 80% of its initial adsorption efficiency after five regeneration cycles, showcasing its robust stability and potential for practical applications. In conclusion, this research presents a-BN@5%Pani as a highly effective and reusable adsorbent for the removal of Cr(Ⅵ) from industrial wastewater, offering a promising solution for mitigating heavy metal pollution. The selective adsorption capacity and ease of regeneration further enhance its practical appeal. The findings of this study have provided a novel adsorbent material for the removal of heavy metal pollutants from industrial wastewater. Close-