Cross-linked polyaniline/graphene-MWCNT nanocomposite as an adsorbent for removing organic dye from environmental water samples: kinetic, isotherm, and thermodynamic studies

Abstract

This study elucidates a fast, uncomplicated, convenient, and environmentally friendly technique for removing hazardous dyes such as acid red (AR1) and methylene blue (MB) from aquatic solutions. The process of adsorption was employed to eliminate AR1 and MB dyes by utilizing nanocomposite (NCs) consisting of cross-linked polyaniline (ClPani) combined with variety carbon nanomaterials (CNMs). ClPani was synthesized using aniline (ANI) and p-phenylenediamine (PPDA) were chemically oxidatively copolymerized with triphenylamine (TPA) at the existence of carbon nanomaterials (CNMs), namely, Graphene (Gr), multi-walled carbon nanotube (MW), and graphene-multi-walled carbon nanotube (Gr-MW). The characteristics of the NCs, including their shape, structure, and thermal properties, were analyzed using various techniques. When compared to other nanocomposites, the adsorption analysis demonstrated that ClPani/Gr-Mw exhibited the highest removal effectiveness for AR1 and MB dyes. Different factors that impact adsorption efficacy, including pH solution, adsorbent mass, temperature, the duration of shaking, and KNO₃ concentration. The efficiency of AR1 and MB dyes' adsorption on ClPani/Gr-Mw was studied kinetically, and the obtained data showed the processes followed a pseudo-second-order system. The Langmuir model was determined to be appropriate for telling the isotherm behavior of dye removal by ClPani/Gr-Mw, under optimal conditions. The maximal adsorption capacity was found to be 153.8 mg g⁻¹ for AR1 and 46.1 mg g⁻¹ for MB. Furthermore, the thermodynamic study suggests that the elimination of AR1 and MB dyes is a process that absorbs heat, while the attachment of dyes is a procedure that involves chemical bonding and occurs naturally. Ultimately, the removal effectiveness of AR1 and MB dyes was tested on three distinct actual samples using ClPani/Gr-Mw, resulting in a (E%) exceeding 94%. In summary, ClPani/Gr-Mw was found to be a cost-effective and environmentally acceptable chemical for effectively eliminating the hazardous dyes AR1 and MB.