Optimizing Magnetic Carbon Nanotube/Polyaniline Nanocomposite for Sequestering Harmful Organic Contaminants
摘要
Water contamination with hazardous chemicals poses significant risks to human health and the environment. Benzene and Reactive Black 5 dye are particularly harmful water contaminants, necessitating immediate and effective removal from aquatic bodies. Herein, a ternary nanocomposite consisting of amphoteric, multi-walled carbon nanotubes, polyaniline, and magnetite (MWCNTs/PANI/Fe3O4) was successfully synthesized via co-precipitation of magnetite (Fe3O4) onto the surface of a pre-existing binary composite of MWCNTs/PANI. The adsorption capacity of MWCNTs/PANI/Fe3O4 for RB5 and benzene was thoroughly investigated under various operational parameters. The sorption processes were found to be pH-dependent and conformed to the Langmuir adsorption model, indicating monolayer adsorption on a homogenous surface. The sorption kinetics were well-described by the pseudo-second-order kinetic model, suggesting that chemisorption was the rate-limiting step. Effectively, the nanocomposite displayed high sorption capacities of ≈ 796 mg g−1 for RB5 and ≈ 300 mg g−1 for benzene at an initial solution pH of 3.0 and 10.0 for RB5 and benzene, respectively. Benzene exhibited a negative ΔH° (-15.479 kJ mol−1), indicating an exothermic process, whilst the sorption of RB5 was endothermic and entropy-driven process with ΔH° of 19.061 kJ mol−1. The dye-loaded adsorbent can be easily regenerated using a mixture of 0.1 M NaOH and 1.0 M NaCl. While, the application of microwave irradiation enabled the effective desorption of benzene, confirming its renewability for at least four successive sorption/desorption cycles. The use of MWCNTs/PANI/Fe3O4 nanocomposite in the removal of RB5 and benzene from wastewater appears highly promising.