Modification of kenaf fibers by single step radiation functionalization of 2-hydroxyl methacrylate phosphoric acid (2-HMPA)

Abstract

Phosphorylated adsorbent is commonly used in the extraction of rare earth metals and radioactive waste because of its high affinity in acidic condition. In this study, adsorbent containing phosphoric acid groups was synthesized by one-step radiation-induced grafting of 2-hydroxyl methacrylate phosphoric acid monomer (2-HMPA) onto kenaf fibers. The kenaf fibers were pre-treated with sodium chlorite prior grafting process. The incorporation of poly (2-HMPA) in the bleached kenaf fibers was confirmed by Fourier transform infrared spectroscopy (FTIR), FT-IR chemical imaging and scanning electron microscopy (SEM). The structural property was investigated using X-ray diffraction (XRD). The result revealed optimum grafting yield of 91.3% with 10% 2-HMPA and 50 kGy at 40 °C for 3 h. The performance of the synthesized adsorbent showed almost complete thorium adsorption. The removal efficiency of 99.9% thorium from aqueous solution was achieved using fibrous adsorbent at an initial thorium concentration of 10 mg/L, a reaction time of 3 h, and pH of 3 at room temperature. This single step combining grafting and functionalization to modify kenaf fibers showed sufficient property for application of natural fibers as adsorbent.