Novel montmorillonite/jute composites functionalized with polyethyleneimine and cetyltrimethylammonium bromide for Cr(VI) adsorption

Abstract

Industrial wastewater containing heavy metal ions of Cr(VI) has drawn increasing attention because of extreme toxicity and detrimental effects on human health. This paper reported a novel nanocomposite adsorbent for Cr(VI) removal from water, consisting of montmorillonite (Mt), jute and the functional modifiers of polyethyleneimine (PEI) and cetyltrimethylammonium bromide (CTAB), i.e., Mt/Jute-PEI-CTAB. The Mt/Jute-PEI-CTAB adsorbent was synthesized via a synergistic method of ultrasonic treatment and sand milling. Various methods were used to characterize the Mt/Jute-PEI-CTAB adsorbent, and the effects of different components on Cr(VI) adsorption behaviors were systematically investigated. The adsorption experiments indicated that Mt/Jute-PEI-CTAB exhibits an excellent Cr(VI) adsorption performance, with a maximum adsorption amount of 59.3 mg/g, 4 times higher that of the Mt/Jute adsorbent without PEI or CTAB. A high Cr(VI) removal efficiency of 99% was achieved, and it is superior to most of clay/biomass-based adsorbents reported. The significantly improved Cr(VI) adsorption capacity can be attributed to the amino functional groups in Mt/Jute-PEI-CTAB through the modification of biomass, CTAB and PEI. The Cr(VI) adsorption process on Mt/Jute-PEI-CTAB can well be described using the pseudo-second order kinetic model and the Langmuir isotherm model. This work provides a novel and environmentally friendly method to design high-performance Cr(VI) adsorbents using clay minerals and biomass for environmental remediation.