Synergistic effect of aeration-assisted photocatalysis: Two parallel mechanism pathways for TXP-10 surfactant removal

TXP-10 is a commercial member of alkylphenol polyethoxylate surfactant family that is widely adopted as emulsifier, detergent and dispersing agent in agriculture and industry. However, it has adverse effects on environmental and public health due to the risk of eutrophication, oestrogenic activities and anti-precipitation properties. Here, we evaluated critical parameters and addressed the mechanism of aeration-assisted photo degradation of TXP-10 by using TiO2 particulates as model photocatalysts. It was found that O-2 aeration could significantly enhance photocatalytic degradation efficiencies with a high synergetic index of 3.30 at an optimum rutile composition of 90 wt.%. Trapping experiments and superoxide radical quantification suggest two parallel mechanism pathways (O-2-sensitive and-insensitive) dependent on phase composition of photocatalyst and irradiation intensity. Furthermore, the anti-precipitation property of TXP-10 solution during photocatalysis was evaluated and correlated to transformation of hydrophobic groups to hydrophilic derivatives. This work would gain important enlightenment into the mechanism of synergistic effect of aeration-assisted photocatalysis and its essential role in the environmental remediation.