Catalysis

Adsorption

Engineering

Water treatment

Telecommunications

Computer science

Chemical engineering

Environmental engineering

Organic chemistry

Ultrapure water

Degradation (telecommunications)

Environmental chemistry

Aqueous solution

Persulfate

Zerovalent iron

Chemistry

Benzophenone

The Science of The Total Environment

2,4-Dihydroxybenzophenone (BP-1), a typically known derivative of the benzophenone-type UV filter, has been frequently detected in aqueous environments and poses a potential risk to human health and the entire ecosystem. In this study, an effective advanced oxidation technique using zero-valent iron powder (Fe0)-activated persulfate (PS) was used for the degradation of BP-1. The effects of several experimental parameters, including Fe0 dosages, PS dosages, pH, and common natural water constituents, were systematically investigated. The BP-1 degradation efficiency was enhanced by increasing the Fe0 and PS dosages and decreasing the solution pH. The presence of different concentrations of humic acid (HA) could inhibit BP-1 removal, while the addition of various cations and anions had different effects on the degradation. Moreover, the degradation of BP-1 in five water matrices was also compared, and the removal rates followed the order of ultrapure water > tap water > secondary clarifier effluent > river water > synthetic water. Thirteen oxidation products were identified by liquid chromatography-time-of-flight-mass spectrometry (LC-TOF-MS) analysis, and five possible degradation pathways were proposed. The addition reactions initiated by HO and SO4−, as well as single-electron coupling reactions and ring-closing reactions, were further supported by density functional theory (DFT) calculations. Assessment of toxicity of intermediates of the oxidation of BP-1 suggested decreased toxicity from the parent contaminant. The present work illustrates that BP-1 could be efficiently degraded in the Fe0/PS system, which may provide new insights into the removal of benzophenones in water and wastewater.

Effective degradation of 2,4-dihydroxybenzophenone by zero–valent iron powder (Fe0)-activated persulfate in aqueous solution: Kinetic study, product identification and theoretical calculations