PbO2 electrode modified by graphene oxide to boost electrodegradation of 4-hydroxybenzophenone.

Abstract

4-Hydroxybenzophenone (4-OH-BP), a highly toxic and widely used pharmaceutical and personal care products (PPCPs), has been obtained growing concern recently. Electrochemical anodic oxidation technology has been confirmed efficient in eliminating organics from aqueous solution. In this work, we constructed two novel PbO2 electrodes by modifying the middle or active layer with graphene oxide (GO) to degrade aquatic 4-OH-BP. Compared with the pristine PbO2 electrode, the modification by GO could enhance the anchor of the active layer (PbO2 particles) onto the middle layer and improve the isolation of the titanium matrix from the active layer and solution. Therefore, we might obtain the better performance of PbO2 electrodes after modification. Under the experimental conditions optimized by the Box-Behnken design model, as we expected, two novel electrodes (with modified middle layer: 99.85%; with modified active layer: 100%) outperformed the pristine electrode (95.46%) for 4-OH-BP degradation. We proposed the catalytic mechanism of GO-modified electrodes for 4-OH-BP and the degradation pathway of 4-OH-BP and evaluated the toxicity of intermediates based on the quantitative structure-activity relationship model. Furthermore, two GO-modified PbO2 electrodes consumed less energy than commercial boron-doped diamond electrode, reflecting the prominent practicability of GO-modified PbO2 electrode.