Enhanced adsorption of Ni(ii) using ATP/PPy/SDS composite

Abstract

In this work, sodium dodecyl sulfate was applied to modify ATP/PPy composite to form ATP/PPy/SDS composite due to its large size. Transmission electron microscopy (TEM) and scanning electron microscopy (SEM) demonstrated that the composite has a “core–shell–shell” structure. The aim of this research is to evaluate the sorption characteristic of ATP/PPy/SDS for removing Ni(II) from aqueous solution. The preparation conditions were optimized by orthogonal array experiments, and external factors were investigated. Isotherm data fitted well to the Langmuir isotherm model, the maximum adsorption capacity reached 186.22 mg g⁻¹. The adsorption kinetics was best described by a pseudo-second-order rate model, indicating that chemical sorption might be the limiting-rate step. Desorption was performed using a 0.5 M NaOH solution, and the adsorbent still maintained a high adsorption capacity even for 5 cycles of desorption-adsorption. Furthermore, Ni(II) is easily extracted by ATP/PPy/SDS composite in contrast to Cr(VI).