Performance of polyaniline doping induced active surface area of Moringa olifera for heavy metal removal from wastewater

Abstract

Analysis of physicochemical properties and treatment of water via modified natural adsorbent material is vital to the ecosystem. The purpose of this study is to analyze physicochemical parameters and synthesize polyaniline (PANI)/moringa oliefera (MO) nano-composite adsorbent material via in situ polymerization techniques. Physicochemical parameters of the sample show, a strong and moderate correlation between all parameters while a weak correlation of turbidity. The synthesized materials were also characterized using powder XRD, FT-IR, UV-VIS spectroscopy, SEM, and conductometer. The physical characterization shows the amorphous nature of MO and the crystallinity of polyaniline and composite material. The existence of skeletal interaction, electronic transition, and porous and granular morphology was confirmed using FT-IR, UV-VIS spectroscopy, and SEM, respectively. After physical characterization, the adsorption performance of as-synthesized material was tested using the batch method. The maximum adsorption capacity (q_max) of Cu²⁺ and Pb²⁺ ions by PANI/MO was 10.01 mg/g and 23.01 mg/g, respectively. When all parameters were optimized (pH at 5, contact time at 30 min, temperature at 25⁰C, and 2 grams of PANI/MO) adsorption efficiency for Pb²⁺ is 99%, and Cu²⁺ ions is 97.77%. The Freundlich isotherm data for Cu²⁺ and Pb²⁺ have a good fit with the experimental data (R² = 0.99 and 0.98), and Langmuir isotherm data for Cu²⁺ and Pb²⁺ is R_L=0.18 & 0.19, respectively. The pseudo-second-order kinetic isothermal was more fit with physisorption at R² = 0.99 for Cu²⁺ and R² = 1 for Pb²⁺. Therefore, the novel PANI/MO composite remarkably outperformed MO and can be a promising candidate to adsorb Cu²⁺ and Pb²⁺ from wastewater.