Assessment of adsorption efficiency of Kaoline-Chitosan composite beads for removal of Ca and As from aqueous solution in lab-scale

Abstract

Abstract In this study, Kaoline (CK) and Chitosan (CTS) including water-soluble CTS (WCTS) and acid-soluble CTS (ACTS), were synthesized from commercial materials to produce composite beads which were then employed as adsorbents to investigate the removal of Ca and As from aqueous solutions. Results showed that the adhesion and granular properties of CK-WCTS and CK-ACTS were different, which affected the adsorption efficiency. Specifically, when 0.3 g of adsorbent (i.e., CK-WCTS and CK-ACTS) was used to test with 30 ml aqueous solution containing 380 ± 50 mg/L Ca(II) during 2 hours, the CK-ACTS showed more effective (i.e., Ca(II) removal of 34.73%) as compared to CK-WCTS (i.e., only 2.08%). In the case of As(III) removal, 0.5 g of adsorbent (i.e., pure ACTS and CK-ACTS composite) was applied to test with 50 ml artificial aqueous As (III) solution of 500 ± 50 μg/L during 90 mins of operation. The CK-ACTS composite also showed better performance since the highest removal As efficiency of 72% could be obtained after a contacting time of 45 mins, as compared to that produced by pure ACTS (i.e. As removal of 42.42%). The SEM analysis was also conducted to compare the difference in morphology of pure ACTS and CK-ACTS composite.