Heavy Metal Ions in Wastewater Affect the Photodegradation of Phenol‐4‐sulfonic Acid over Biphasic TiO₂/Activated Carbon Fiber Composites

Abstract

The effect mechanism of Cu 2 + , Zn 2 + and Ni 2 + ions in wastewater on photocatalytic activity remained unknown. For phenol-4-sulfonic acid (PSA) photodegradation, we fabricated anatase/rutile/activated carbon fiber composites (A/R/ACFs) by the hydrothermal deposition of rutile TiO 2 nanorods and anatase TiO 2 nanoparticles on ACFs. A/R/ACFs exhibited better photocatalytic activity than both R/ACFs and A/ACFs because anatase/rutile heterojunctions supported electron transfer from rutile to anatase. All Cu 2 + , Zn 2 + and Ni 2 + ions in wastewater improved the chemical stability of PSA by forming PSA-Cu(II), PSA-Zn(II) and PSA-Ni(II) complex compounds, and thus inhibited the PSA photodegradation. Notably, the as-formed photoelectrons over A/R/ACFs were partly consumed due to the reduce reaction of Cu 2 + ions into Cu + /Cu 0 , avoiding electron-hole recombination and improving PSA photodegradation efficiency. No reduce reaction of Zn 2 + and Ni 2 + ions occurred during the PSA photodegradation process. Hence, the A/R/ACFs are an effective photocatalyst for wastewater purification, and low Cu 2 + concentrations facilitated the PSA photodegradation.