Polyamide-baghouse dust nanocomposite for removal of methylene blue and metals: Characterization, kinetic, thermodynamic and regeneration

In this research, polyamide modified baghouse dust nanocomposite (PMBHD) was synthesized from steel industry waste using the interfacial polymerization technique. Adsorption capacities of the PMBHD were examined for the uptake of cadmium Cd (II), lead Pb (II), and methylene blue MB from simulated solutions. The effects of different operational factors of the adsorption, including contact time, pH, adsorbent dosage, initial concentration, and temperature, were investigated. The obtained results revealed that the equilibrium data of MB, Pb (II), and Cd (II) were best fitted to Dubinin-Radushkevich, Langmuir, and Freundlich isotherm. Maximum removal uptake was found to be 6.08, 119, and 234 mg.g(-1), whereas maximum removal efficiencies of 90%, 99.8%, and 98% were achieved for MB, Pb (II), and Cd (II). Adsorption kinetics of MB and metals well-fitted to the pseudo-second-order kinetic. The characterization results showed the presence of polymeric chain on the surface of the PMBHD. The thermodynamic study revealed that the values of the free energy DG for Pb (II) and Cd (II) were found to be negative, which indicates spontaneous, energetic, and favorable adsorption. While for MB removal, positive values of (DG) were noticed, which implies that the adsorption was unfavorable. The proposed mechanism for the adsorption of MB and metals on the PMBHD showed that the dominating mechanism is physisorption. The adsorption/desorption results verified the high reusability of the PMBHD for adsorption of MB and metals. (C) 2020 The Chemical Industry and Engineering Society of China, and Chemical Industry Press Co., Ltd. All rights reserved.

Automated summary

The research focused on synthesizing PMBHD from steel industry waste and examining its adsorption capacities for Cd(II), Pb(II), and MB. The results showed high removal efficiencies for all three contaminants and the adsorption kinetics fitting well with pseudo-second-order kinetics. The presence of polymeric chains on the PMBHD surface and the favorable thermodynamic attributes for Pb(II) and Cd(II) adsorption were also highlighted. Adsorption mechanism studies suggested physisorption as the dominating mechanism, with high reusability of PMBHD confirmed through adsorption/desorption results.