Sono-photocatalytic activity of sea sediment@400/ZnO catalyst to remove cationic dyes from wastewater

Abstract

A photocatalyst was generated from sea sediments and ZnO and tested in the sono-photocatalytic removal of methylene blue (MB) and crystal violet (CV).. The results of FTIR, XPS, and XRD analyzes showed that there are different functional groups in the photocatalyst and also the photocatalyst has a crystalline structure. The BET surface area for sea sediment, sea sediment @400 °C, ZnO, and sea sediment @400 °C/ZnO was determined to be 1.787, 4.326, 24.057, and 9.212 m2.g−1, respectively. The maximum removal efficiency of MB (97.85%) and CV (99.14%) has happened at pH 8, contact time of 40 min, hydrogen peroxide dose of 50 µL/100 mL, catalyst dose of 1 g.L−1, and dye content of 10 mg.L−1 under ultrasonic process (180 W, 24 kHz). The effect of scavengers was investigated to determine the type of radicals effective in the removal process. The results showed that the •OH, •O2–, and electron radicals had an effective role in the dye removal process. The pseudo-first-order kinetic model had a good ability to describe data and the reaction rate constant for removing CV and MB dyes was determined to be 0.0671 and 0.052 min−1, respectively. The treatment of industrial wastewater was successfully done by the prepared photocatalyst. The treated aqueous solution had no toxicity for microorganisms, germination, and plant growth. Thus, the resulting water from the process can be used successfully for agricultural purposes.