Selective Photoelectrocatalytic Removal for Group-Targets of Phthalic Esters.

The development of a selective removal method for group-targets of pollutants under the inhibition of nontoxic organic interferents is of great importance in environmental science. A novel TiO2 photoelectrode functionalized with dummy templates (PS-PAE-TiO2) is designed, exhibiting group-targeting selectivity for nine phthalate ester (PAE) analogs. In total, 90-99% of PAEs were removed from 30 μg L-1 in actual wastewater (chemical oxygen demand, 14.5 mg O2 L-1). The selectivity for PAEs originated from preferential enrichment close to the PS-PAE-TiO2 surface result in a twofold improvement in the apparent kinetic constant. The specific sites can be attributed to phenyl rings and o-ester carbonyl groups through the molecular recognition process. The intermediates were analyzed quantitatively, and a degradation pathway with lower toxicity was proposed, excluding ring-hydroxylated phthalates. Almost 100% of the estrogenic activity and acute aquatic toxicity were eliminated and the genotoxicity was reduced by 92.5%, which was about 40% higher than that at the nonselective photoanode. An enhanced removal at the PS-PAE-TiO2 photoanode with better economic benefits was confirmed, saving energy consumption by 2.5 kWh m-3 per order than that at the nonselective anode. The advanced removal method with group-targeting selective capability can provide a propagable strategy for the removal of a class of homologues from complex aqueous systems.