Fabrication of novel Z-scheme BaFe2O4/BiOCl nanocomposite with promoted visible light photocatalytic palm oil mill effluent treatment and pathogens destruction

In recent years, organic pollution and biological hazards have become indisputable considerable environmental issues. Semiconductor-based photocatalysis has been regarded as a promising and sustainable solution in minimizing the negative impacts of these issues. Herein, a two-step precipitation-hydrothermal method was employed to fabricate novel Z-scheme BaFe2O4/BiOCl nanocomposites as efficient visible light-driven photo -catalysts. The physicochemical properties and morphological characteristics of the fabricated nanocomposites were investigated via multiple characterization methods. The BiOCl nanosheets loaded with 5 wt% BaFe2O4 particles (5 wt% BaFe2O4/BiOCl) demonstrated the best visible light photoactivity with a palm oil mill effluent (POME) degradation efficiency of 61 % and a reaction rate constant of 0.0045 min(-1) within 210 min. The photocatalytic enhancement benefited from the formation of Z-scheme heterojunction between BaFe2O4 and BiOCl, hence accelerating the interfacial charge transfer and maintaining strong redox potential for active radical generation. Moreover, by regulating the pH value of photoreaction system, more superior POME degradation efficiency was attained and reached 85 % at the same duration. Interestingly, the 5 wt% BaFe2O4/BiOCl nanocomposite also possessed a convenient catalyst separation along with good recyclability with only 7 % loss in efficiency after four successive runs. Based on the active species scavenging experiment, superoxide radical was found as the eminent active species during the POME treatment. In addition to the investigation of POME treatment, the fabricated 5 wt% BaFe2O4/BiOCl nanocomposite was also successfully employed to inactivate the E. coli and B. cereus. This study revealed that the as-fabricated BaFe2O4/BiOCl nanocomposite had great potential applications to degrade various organics and to inactivate bacteria from wastewater.

Automated summary

Organic pollution and biological hazards have become significant environmental issues. Semiconductor-based photocatalysis is a promising solution to minimize their negative impacts. In this study, novel Z-scheme BaFe2O4/BiOCl nanocomposites were fabricated as efficient visible light-driven photocatalysts. The nanocomposites showed improved photocatalytic activity due to the formation of a Z-scheme heterojunction, leading to enhanced charge transfer and active radical generation. The nanocomposites also exhibited good recyclability and the ability to degrade various organics and inactivate bacteria from wastewater.