Enhanced photocatalytic dye detoxification by banana peel derived enzyme inherited ZnO/g-CN nanocomposite: Validation by soil health and seed germination analyses.

Development of bio-supported photocatalysts has become a pressing need in the field of environmental remediation. This work reports the synthesis of bio-enzyme (from banana peels) inherited (ZnO/g-CN) nanocomposite by simple soft chemical method and its photocatalytic degradation ability against the mixed dye (Methylene blue (MB) + Rhodamine-B (RhB)) under UV irradiation. Synthesized nanoparticles were characterized using experimental techniques XRD, FESEM, TEM, EDAX, XPS, UV-vis-NIR spectroscopy and FTIR. The degradation efficiency of the (ZnO/g-CN) is 98 % against MB component and 93 % against the RhB component within the irradiation time of 75 min which is superior to bare ZnO, enzyme activated ZnO and g-CN. The presence of enzymes peroxidase, protease, cellulase, lipase and amylase in the nanocomposite is confirmed by enzyme quantitative study. The dye detoxification was confirmed by supplying the treated water to two different soils (sandy loam and clay) and investigating the soil health. The detoxification was further confirmed by applying the treated water to fenugreek (Trigonella foenum-graecum L., Fabaceae) seeds and analysing the seed germination. The observed complete detoxification of the mixed dye solution showed that the banana peel derived bio-enzyme inherited (ZnO/g-CN) nanocomposite can be considered as a desirable candidate for industrial dye waste water treatment.