The Removal of Copper Ions from Aqueous Solutions Using Silica Supports Immobilized with 2-Hydroxy-5-nonylacetophenoneoxime

Abstract

Silica supports immobilized with 2-hydroxy-5-nonylacetophenoneoxime (LIX 84) were prepared after surface modification by γ-aminopropyltriethoxysilane. Three types of silica beads and a silica powder were used as supports. Batch and packed-column tests were conducted to investigate the capabilities of the prepared adsorbents to remove copper ions. A comparison of the different silica supports was performed with respect to copper adsorption capacity, copper adsorption rate, and nitrogen content. In addition, studies were carried out for the modified silica beads that showed highest copper ion removal capability among the three silica beads (SB2-L). The extraction rate of the SB2-L increases with solution pH in the range between pH 2 and 4. Stability tests show that the SB2-L is stable under acidic conditions. From regeneration experiments it was found that copper ions which are adsorbed at the surface of the SB2-L were recovered by washing with 0.1 M HNO₃ and that the regenerated beads are reversible. The recovery ratios were between 80 and 90%. A breakthrough curve was obtained using modified silica powder (SP-L). The copper recovery ratio for SP-L was 74%. The results show that the SP-L prepared is feasible for the extraction of copper ions from aqueous solutions using a fixed-bed reactor.