Polyaniline/reduced graphene oxide doping induced abundant active sites in enset fiber as an efficient adsorbent material for wastewater treatment

Abstract

Analysis of physicochemical properties and water treatment is vital for the environment and societal living standards. In this study, polyaniline (PANI)/enset fiber (EF), reduced graphene oxide/EF, and PANI/rGO/EF composites as adsorbent materials were prepared via facile in-situ chemical oxidative polymerization techniques. The as-synthesized materials were characterized using XRD, FTIR, UV-VIS, TGA, and SEM spectroscopy. Physical characterization revealed the deposition of PANI and rGO on the surface of EF, confirmed by the cloudy and wrinkled fibrous morphology observed in the SEM images. After physical characterization, the adsorption performance of the proposed materials was tested using the batch method. The results showed a maximum adsorption capacity (q_max) of Cu²⁺ and Pb²⁺ ions by PANI/rGO-coated EF was 10.11 mg/g and 13.4 mg/g, respectively, which is higher than that of pristine EF, PANI/EF, and rGO/EF. When all parameters were optimized, the adsorptive removal efficiency of PANI/rGO/EF composite material towards Pb²⁺ and Cu²⁺ ions was 99% and 97.77%, respectively. The Freundlich isotherm data for Cu²⁺ and Pb²⁺ showed a good fit with the experimental data (R² = 0.99 and 0.98), and Langmuir isotherm data for Cu²⁺ and Pb²⁺ (RL = 0.18 and 0.19), respectively. The pseudo-second-order kinetic isotherm was a better fit for physisorption, with R² = 0.99 for Cu2 + and R² = 1 for Pb²⁺. Therefore, the synthesized novel material PANI/rGO/EF shows remarkable adsorption performance compared to EF, PANI/EF, and rGO/EF, due to the doping-induced abundant active sites of the composite material, making it a promising candidate for wastewater treatment techniques.