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.