Cornstalk biochar-TiO 2 composites as alternative photocatalyst for degrading methyl orange.

Dye wastewater is one of the most harmful wastewater types generated during industrial processes. Effectively treating dye wastewater is essential. This study used TiO 2 and cornstalk biochar to prepare biochar-TiO 2 composites in order to treat methyl orange (MO) in the water. It is found that composites prepared using biochar generated at 700 ℃ and TiO 2 /biochar mass ratio values of 0.75/1 showed the best performance on decolorization efficiency and mineralization efficiency of MO while low pH, low initial MO concentration, and 1 g/L of composite amount added can enhance MO degradation efficiency. Additionally, it is also noted that biochar-TiO 2 composites were easier to separate from water compared to pure TiO 2 . This benefits the recycling of biochar-TiO 2 composites after application. Furthermore, the study indicated that the biochar-TiO 2 composites degrade MO by a combination of adsorption and photocatalysis while photoelectron (e - ) and ·O 2 - are the key species participating in photocatalytic degradation of MO. These research outcomes suggest that cornstalk biochar and TiO 2 can be used to prepare composites, which can be seen as an alternative photocatalyst for dye wastewater treatment. However, further investigations related to their long-term applications and in real scale projects are recommended.