Design of mesoporous ZnO @ silica fume-derived SiO2 nanocomposite as photocatalyst for efficient crystal violet removal: Effective route to recycle industrial waste

Abstract Recycling sustainable industrial solid waste, such as silica fume, has recently become an important issue. Due to its large amounts, the exploitation of industrial solid waste is a great urgent issue and optimal solution for environmental and water resources protection. Consequently, this manuscript aims to synthesis a novel, low-cost, and efficient photocatalyst to degrade crystal violet and produce crystal violet-free water. The proposed photocatalyst was prepared by combining ZnO nanosheets with silica fume-derived SiO2 to get a novel, mesoporous ZnO@silica fume-derived SiO2 photocatalyst. The influence of pH, time, dose, temperature and initial CV concentration were systematically investigated. The results showed that ZnO@silica fume-derived SiO2 actively removed >98% of the crystal violet dye from synthetic wastewater of 10 ppm concentration within 1 h, at pH 9.0 with a first-order kinetic model. The reaction mechanism between photocatalysts and crystal violet was also discussed. The prepared photocatalyst displayed high stability after five reuse cycles, leading to a decrease in the overall cost of the wastewater remediation process. The as-synthesized ZnO@silica fume-derived SiO2 nanocomposite shows promising potential for ecological safety, demonstrating that ZnO@silica fume-derived SiO2 has a large removal performance.