BiOBr nanoparticle-modified TiCT MXenes for photocatalytic degradation of organic arsenic in wastewater.

Arsenic (As) contamination in water remains a serious concern due to its high toxicity and harmful effects on human health and the environment. Herein, we successfully synthesized a novel photocatalyst (BiOBr/TiC) by inserting BiOBr nanoparticles into TiCT MXenes for the photocatalytic degradation of organic arsenic roxarsone (3-nitro-4-hydroxyphenylarsonic acid) in wastewater. BiOBr/TiC exhibited a unique morphology characterized by uniform BiOBr nanoparticles within more dispersed TiCT layers. Heterojunctions were formed between TiCT and BiOBr, which were conducive to photogenerated charge separation and electron transfer in TiCT layers. An optimal BiOBr/TiC photocatalyst achieved a removal efficiency of 1.27 mg g h for 2 mg L of roxarsone wastewater within 0.5 h and a higher removal rate (about 1.5 times at 3 h) than pure TiCT . In addition, BiOBr/TiC exhibited an apparent quantum yield (AQY) of 29.5% and good reusability for 4 cycles. The enhanced photocatalytic performance was mainly attributed to the intercalation of BiOBr nanoparticles within TiCT layers, which increased reaction space and improved the separation and transport of photocarriers. Holes (h) and ˙OH in the valence band (VB) of BiOBr/TiC were involved in the main route of roxarsone oxidative mineralization. The present BiOBr/TiC system provides fundamentals for the sustainable photocatalytic treatment of wastewater containing organic arsenic.