To understand the degradation of endocrine disrupting chemicals (EDCs) in natural environment with existence of iron oxides and carboxylic acids, the dependence of bisphenol A (BPA) photodegradation on the initial concentration of oxalate (COX) in lepidocrocite (?酌-FeOOH) aqueous suspension was investigated under both UV and visible lights in this study. Lepidocrocite powder was home-pr epared by a hydrothermal process. It was found that BPA degradation was promoted greatly in the presence of oxalate owing to the formation of lepidocrocite-oxal ate complex. And there was an optimal COX, which was 2.0 and 2.4 mmol/L, under U V and visible lights, respectively. The first-order kinetic constant, k value in creased 38 times from 0.17 ×10-2 min-1 in the absence of oxalate to 6.39 × 10- 2 min-1 in the presence of oxalate with an optimal COX (2.0 mmol/L) under UV irr adiation, and almost 306 times from 0.02 ×10-2 min-1 in the absence of oxalate to 6.11 × 10-2 min-1 in the presence of oxalate with an optimal COX (2.4 mmol/L ) under visible irradiation. The BPA degradation rate increased and the first-or der kinetic constants decreased with the increase in BPA initial concentration. The dependence of the variation of pH value, total-Fe and Fe2+ during the photor eaction on COX was also investigated. The pH value increased obviously with the reaction time. Total-Fe increased dramatically at the first 5 min and then decre ased quickly under UV irradiation and slowly under visible irradiation. The init ial concentration of oxalate is a main factor to affect BPA photodegradation in aqueous suspension under both UV and visible lights.
