Simultaneous adsorption of dye and toxic metal ions using an interfacially polymerized silica/polyamide nanocomposite: Kinetic and thermodynamic studies

A silica/aromatic polyamide (SiPA) nanocomposite was synthesized by the interfacial copolymerization of a trimesoyl chloride (TMC) monomer and m-phenylene diamine (MPD) in silica. The obtained SiPA nanocomposite was investigated with a Fourier transform infrared spectrometer, a scanning electron microscope, and Brunauer-Emmett-Teller (BET) nitrogen adsorption/desorption. Adsorption of methylene blue (MB) on SiPA was evaluated for various factors influencing the process. The MB adsorption experimental data were fitted to Kinetic and thermodynamic models. The analysis indicates that adsorption of MB on SiPA fitted well with the Langmuir isotherm model, as well as to the pseudo-second-order model. The removal rate was rapid and equilibrium was attained in a short time. From a thermodynamic viewpoint, the adsorption was spontaneous and endothermic Delta H degrees = 12.6 KJ/mol, in addition to being favorable with q(m) = 44.6 mg/g. The prepared adsorbent showed good applicability to remove MB from real wastewater samples. The influence of the interference on adsorption was investigated in the presence of metal ions including Pb, Ni, Hg, Cd, As, Cu, Cr, and Mn. Interestingly, with approximate to 100% removal of the dye, the SiPA nanocomposite also exhibited a rapid simultaneous uptake of the toxic metals. (C) 2020 Elsevier B.V. All rights reserved.