Optimized chemical preconditioning of Philippine natural zeolites

Abstract

AbstractNatural zeolites in the Aksitero sedimentary formation of the western Luzon area of the Philippines were evaluated. The natural washed zeolite (NW-Z) was preconditioned with acid to purify it and increase its surface area. Acid treatment with 3 M HCl for 12 h yielded optimum acid treatment of the NW-Z, causing increases in the Si/Al ratio, the specific surface area by 32.5% and the porosity of the acid-treated zeolite (HC-Z). The HC-Z was washed with 4 M NaCl for 3, 6, 12, 18, 24, 48 and 72 h to improve its cation-exchange capacity for copper. The sodium-treated zeolite (Na-Z) was immersed in 100 ppm CuSO4 solution to test the copper-uptake capacity. Pretreatment of HC-Z with 4 M NaCl for 24 h is optimal for sodium treatment of the preconditioned HC-Z. The preconditioning techniques did not significantly alter the structure and morphology of the zeolite samples. It is suggested that the preconditioned Philippine natural zeolite samples are readily available for further functionalization that will enhance their antibacterial, catalytic and adsorption properties, with various useful applications in the field of catalysis, biomedicine, environmental mitigation and wastewater treatment.