Hexavalent chromium reduction by ZnO, SnO2 and ZnO-SnO2 synthesized using biosurfactants from extract of Solanum macrocarpon

In this study, ZnO, SnO2 and their composite (ZnO-SnO2) were synthesized by green route using aqueous extract of Solanum macrocarpon fruit used for the photo-reduction hexavalent chromium. The synthetic involved a two-step procedure, induced temperature via calcination at 350 600 °C. was prepared treatment mixture precursor compounds to up 800 °C, extension 1000 resulted in emergence ZnO-SnO2-Zn2SnO4 (ZTO). nanoparticles characterized X-ray diffraction (XRD), transmission electron microscopy (TEM), UV–vis spectroscopy. XRD studies binary oxides confirmed hexagonal wurtzite structure ZnO tetragonal phase SnO2, without any change patterns or supplementary peaks. morphology indicated fairly spherical shapes that tend agglomerate with increase temperature. showed rectangular both temperatures reaction, while ZnO-SnO2 presence morphologies component oxides. photo-enhanced degradation under ultra-violet light, effect pH (2–8), concentration chromium(VI) (2 – 8 ppm), photocatalyst dosage (25 - 150 mg/L) on reduction Cr(VI) Cr(III) investigated. higher efficiency acidic environment than alkaline environment, also dosage. exhibited highest photoreduction efficiency, above 90%, optimum condition 2, mg/L photocatalyst, 2 ppm chromium solution after 90 min. These low-cost nontoxic metal oxide have great potentials pollution clean-up from waste water.