Removal of Cr(VI) from aqueous solution by rice husk derived magnetic sorbents

Abstract

A novel magnetic porous sorbent obtained from agricultural waste rice husk was successfully synthesized through a simple carbon-thermal method. The sorbent was characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, vibrating sample magnetometer, N2 sorption analysis, and X-ray photoelectron spectroscopy. The removal efficiency of the sorbent for Cr(VI) was also investigated. Chromium adsorption was fitted by the pseudo-second-order and Langmuir models. The maximum chromium adsorption capacity, Brunauer-Emmett-Teller surface area, and average Barrett-Joyner-Halenda pore size of the magnetic sorbent were 157. 7mg·g−1, 134. 1m2·g−1, and 4. 99 nm, respectively. The saturated magnetization of the novel adsorbent was 77. 8 emu·g−1, indicating that the material can facilitate separation and recovery from aqueous systems. The removal mechanisms of Cr(VI) were also discussed. The result illustrates that rice husk-derived magnetic carbonaceous materials are a potential adsorbent for Cr(VI) pollution treatment and provide a suitable method for the effective conversion of biomass waste, which may solve the problem of waste disposal and widen the applications of the materials.