Performance and mechanism of NiO/La-KTaO3 composite photocatalysts for UV degradation of isoamyl xanthate in synthetic flotation wastewater

Abstract

The study employed a direct hydrothermal method to synthesize NiO/La-KTaO₃ heterojunction photocatalysts. The photocatalytic efficiency of the composites was assessed by their ability to destroy isoamyl xanthate in the presence of Ultraviolet light, mimicking the conditions seen in flotation wastewater. The results showed a significantly greater photocatalytic activity when comparing the composite catalyst to KTaO₃. A photocatalytic reaction was performed utilizing a 40 mg NiO/K_1−xLa_xTaO₃ (x = 0.04) photocatalyst at pH = 3. The reaction was carried out using 50 mL of isoamyl xanthate synthesis wastewater, which had a concentration of 20 mg/L. The degradation rate achieved after 30 min was 87.28%. The addition of nickel oxide (NiO) and the introduction of La into the K lattice position were thought to facilitate charge separation, migration, and the generation of additional active sites, hence augmenting the catalytic impact. The findings from radical capture tests indicated that the ·O²⁻ (superoxide ion) served as the principal active species in the photocatalytic process, playing a substantial role. The process of photodegradation of isoamyl xanthate was determined through the utilization of different analytical and testing methods. This work introduces a direct and effective approach for the eco-friendly decomposition of xanthate flotation wastewater.