Preparation and characterization of oyster shell powder-treated rice husk ash adsorbent pellet for As(III) removal

Abstract

The adsorbent pellet for As(III) removal was prepared from ground oyster shell and rice husk ash. The effects of particle size of oyster shell powder (OS) and the ratio between the OS and Treated rice husk ash (TRHA) on the stability of the adsorbent pellet were studied. The adsorbent pellet was characterized by XRD, XRF and SEM. The solubility and As(III) adsorption tests were performed. The results showed that the adsorbent pellet prepared from OS size <106 μm with OS:TRHA ratio of 0.7:0.3 could provide As(III) maximum adsorption capacity of approximately 26.20 mg/g. Furthermore, the XRD and SEM results indicated that the adsorbent pellet could consist of two parts i.e. CaO that could adsorb As(III) in the form of Ca-As-O and the CaSiO 3 and C-S-H compounds which behaved as a binder to bind the precursor powders to be stable adsorbent pellet without cracking.