Preparation of Chitosan-Coated Silica from Rice Husk and Its Application on Chromium Adsorption

Chromium is a premier heavy metal that has versatile applications in different industrial purposes. It is essential to remediate Cr(VI) from its polluted aqueous solution due to its high toxicity and bioaccumulation. A waste product rice husk (RH), contained 15-20% silica which can be extracted by incineration at muffle furnace. Shrimp shell is another waste material and uses as the raw material of chitosan preparation. Here, chitosan was used as a coating material to increase the adsorption performance of prepared silica. The prepared chitosan-coated silica (CCS) was characterized by ATR-FTIR and TGA analysis. In the adsorption study of CCS, the adsorption capacity of Cr(VI) increases with contact time and an acidic pH (3–6). The maximum adsorption capacity was found at 7.14 mg/g and from the adsorption isotherm. The R2 value 0.701 supports Langmuir model of monolayer adsorption.