Application of nano–MnO2 modified lignin – based adsorbent for removal of dichromate ions and diclofenac from water

Abstract

The aim of this paper is to investigate the application of modified lignin-based adsorbent for successful removal of dichromate ions and sodium diclofenac (DCF) from aqueous solutions by adsorption. Modification of lignin-based adsorbent (LBA) was performed by inverse suspension copolymerization with branched poly (ethylene-imine) using epichlorohydrin as a crosslinker. After that, the functionalization of LBA was performed by chemical binding of amino modified nanoparticles of manganese (IV) oxide, in order to improve the adsorption properties. Characterization of LBA-MnO2 microspheres was performed using FT-IR spectrometer, Scanning electron microscopy, BET/BJH analysis. The adsorption process was performed in a batch adsorption system. The results were obtained with the help of kinetic and corresponding equilibrium adsorption isotherms. The maximum adsorption capacity for the removal of Cr2O7 2- ions and DCF was obtained using the Langmuir model and amounts to 88.4 mg g-1 and 52.8 mg g-1 at 45 °C, respectively. Adsorption kinetics was described using a second-order pseudo model. Based on thermodynamic parameters, it was concluded that the adsorption process is an endothermic and spontaneous. Based on the obtained results, LBA-MnO2 material possess very good adsorption properties.