Radiation synthesis of crown ether functionalized microcrystalline cellulose as bifunctional adsorbent: A preliminary investigation on its application for removal of ReO4- as analogue for TcO4-

Abstract

Supramolecular host immobilized cellulose-based adsorbent for TcO4- recognition from groundwater was developed. A novel bifunctional adsorbent composed of amine and crown ether group was newly synthesized by radiation grafting supramolecular host 2-aminomethyl-18-crown-6 (AM18C6) onto microcrystalline cellulose microsphere (MCC). The optimized condition for grafting reaction of glycidyl methacrylate (GMA) onto MCC was 30% GMA emulsion at dose of 20 kGy and the maximum conversion rate of ring opening reaction was 34.8%. 13C-NMR, XPS, FTIR and TGA were applied to characterize the bifunctional adsorbent and verified AM18C6 was successfully bonded to cellulose. Adsorption behaviors towards ReO4- as analogue for TcO4- were also investigated as function of contact time, solution pH, ReO4- concentration and competing anion. It was found that there were synergistic effects of amine and crown ether on ReO4- removal. Contributions of bifunctional adsorbent for ReO4- uptake were mainly dependent on amines under acidic condition while dependent on crown ether under neutral or weak alkaline conditions. The adsorption isotherm was well fitted by the Langmuir model with adsorption capacities of 114.2 mg/g at pH 2.36 and 8.199 mg/g at pH 7.00. This work provided a new way to immobilize crown ether onto microcrystalline cellulose and a new bifunctional adsorbent for separation of ReO4- and TcO4-.