Sun-light driven photo degradation of organic dyes from wastewater on precipitation Ag₂CrO₄ over SiO₂-aerogel and nano silica

In this study, Ag₂CrO₄/SiO₂ nanostructure was synthesized by the precipitation method to ameliorate the low specific surface area of Ag₂CrO₄ with nano-Silica (NS) and Silica Aerogel (SA). The coupled nanophotocatalysts with various weighted contents of Ag₂CrO₄ and Nano Silica were characterized with PXRD, FESEM, UV–Vis, FTIR and BET-BJH analyses. In order to find the optimal amount, different percentages of Nano Silica 10%, 20% and 30% were investigated. It was observed from BET-BJH that adding Nano Silica lead to an increase the catalyst surface area and crystallinity of synthesis samples. Then, in order to investigate the impact of specific surface area on optimal catalyst activity (Ag₂CrO₄/Nano Silica (20%)), Silica Aerogel, which has a higher surface area than Nano silica, was used instead of Nano silica. It was observed that increasing the surface area has a direct effect on the activity of the Ag₂CrO₄. The photocatalytic activity of various nanocomposites was evaluated in the remediation of the organic dyes after 120 min visible light irradiation. The tremendous enhanced photocatalytic activity under the simulated solar light with 95.4% removal of AO7 was observed over Ag₂CrO₄/Nano Silica (20%) sample. In addition, to illustrate how the influence of various parameters such as various organic dyes, pH, catalyst loading and reusability on the photodegradation efficiency, were conducted over Ag₂CrO₄/Nano Silica (20). The high activity was obtained in the medium with pH = 7, catalyst loading = 1 g/L and AO7 concentration = 20 mg/L.