Magnetic quaternized alumina nanotube with fast and enhanced lead (II) and malachite green adsorption: multivariate optimization, kinetic and isotherm study

Abstract

This research aimed to prepare quaternized magnetic alumina nanotube by anchoring hexamethylenetetramine onto chlorinated Fe₃O₄@alumina surface. The prepared materials were characterized by XRD, EDX, VSM, FTIR and FESEM techniques. In view of an environmental application of ionomers, the prepared composite was used for uptake of Pb (II) and malachite green (MG) from aqueous solution, and results were compared by the Fe₃O₄@alumina. The optimum value of four main factors on the removal efficiency including adsorbent dosage, pH, contact time and ionic strength was obtained by response surface method (RSM) based on Box–Behnken design (BBD). Kinetic and isotherm studies revealed that pseudo-second-order model and Freundlich model are dominant in adsorption by magnetic alumina besides the Langmuir model better described the removal by magnetic ionomer. Results revealed that modifying the magnetic alumina with a quaternized fragment improved its performances for Pb and MG adsorption as the adsorption capacity of Pb (II) and dye is 312 and 151 mg g⁻¹ by ionomer, respectively.