Polyaniline doping induced abundant active sites in orange peel as an efficient adsorbent material for water treatment

Abstract

The study of the physicochemical properties of water and the removal of water contaminants using an active adsorbent material is a vital approach today. The purpose of this study is to modify orange peel (OP) using polyaniline (PANI) via in situ oxidative polymerization method and characterize it for wastewater treatment applications. The properties of water were analyzed according to the standard guideline published by APH before the adsorption study. The proposed materials were characterized by SEM, FTIR, and UV–VIS spectroscopy. The modification of orange peel using polyaniline was confirmed by electronic transition and stretching vibration peaks obtained from FT-IR and UV–Vis spectroscopies and its morphologies from SEM. The results of most of the physicochemical properties, nutrients, and heavy metals were above the acceptable range for wastewater discharge limits set by FAO, WHO, and EEPA. The Cu and Zn adsorption performance of as-synthesized materials was studied and depicted a high adsorption capacity for copper (176.9 mg/g) and zinc (151.3 mg/g) in wastewater solutions. When all parameters were optimized (pH at 6, contact time at 40 min, temperature at 300 K, and 1 gr of PANI-OP), 90.03% removal of copper and 85% (pH at 4, contact time at 60 min, temperature at 300 K, and 1 gr of PANI-OP) removal of zinc were observed. The adsorption equilibriums of both copper and zinc were best described by the Freundlich isotherm model. Therefore, the synthesized novel material PANI-OP is a promising candidate for the removal of Cu and Zn from wastewater.