Recent progress of arsenic adsorption on TiO2 in the presence of coexisting ions: A review.

Arsenic (As)-contaminated wastewater and groundwater pose a pressing environmental issue and worldwide concern. Adsorption of As using TiO2 materials, in combination with filtration, introduces a promising technology for the treatment of As-contaminated water. This review presents an overview on the recent progress of the application of TiO2 for removal of As from wastewater and groundwater. The main focus is on the following three pressing issues that limit the field applications of TiO2 for As removal: coexisting ions, simulation of breakthrough curves, and regeneration and reuse of spent TiO2 materials. We first examined how the coexisting ions in water, especially high concentrations of cations in industrial wastewater, affect the efficacy of As removal using the TiO2 materials. We then discussed As breakthrough curves and the effect of compounded ions on the breakthrough curves. We successfully simulated the breakthrough curves by PHREEQC after integrating the CD-MUSIC model. We further discussed challenges facing the regeneration and reuse of TiO2 media for practical applications. We offer our perspectives on remaining issues and future research needs.