Enhanced removal of hydrocarbons BTX by light-driven Aspergillus niger ZnS nanobiohybrids

Benzene, toluene, and xylene (BTX) are volatile aromatic compounds used in industries, however, they are hazardous when released into the environment. BTX degradation by Aspergillus niger cells combined with semiconducting zinc sulfide (ZnS) nanoparticles was explored in batch systems. Experiments were conducted individually for benzene, toluene, and xylene as well as in binary and trinary mixtures using A. niger cells-ZnS nanobiohybrids. The mechanism governing the removal of BTX by both A. niger cells and A. niger cells-ZnS nanobiohybrids were elucidated. Complete BTX degradation was achieved in 75 min and 60 min, respectively, by nanobiohybrids composed of chemical and biological ZnS nanoparticles in the presence of UV-A light at 1.83 * 10¹⁸ photons/second and 1.68 * 10¹⁸ photons/second, respectively. The removal efficiency was in the order of the molecular weight for A. niger cells, whereas for the light-driven A. niger-ZnS nanobiohybrids, the removal efficiency was according to the methyl group number. Further, the respiratory coefficient and volumetric mass transfer coefficient (Ka) values are higher for A. niger cells compared to the light-driven A. niger-ZnS nanobiohybrids.