Nonylphenol deca-ethoxylate removal from wastewater by UV/H2O2: Degradation kinetics and toxicity effects

Nonylphenol ethoxylated (NPEOs) nonionic surfactants have been increasingly used in different industrial, commercial and domestic applications. Unfortunately, they are classified as endocrine disrupting chemicals (and also considered as contaminants of emerging concern) having adverse effects on animal and human reproduction. The treatment of nonylphenol-decaethoxylated (NP-10) via H2O2/UV-C process at different reaction times (5, 10, 20, 40, 80 min) and H2O2 concentrations was investigated. After 80 min treatment the removal rates of NP-10 solution (initial concentration 100 mg/L) in deionized water were 88%, 97% and 98% for 10, 20 and 100 mg/L of H2O2 respectively. The same experimental conditions were applied to real wastewater spiked with 100 mg/L of NP-10 showing the following removal rates: 84%, 98% and 99%, respectively. The possible contribution of different radicals to NP-10 degradation by H2O2/UV-C treatment was investigated by evaluating the effect of different radical scavengers (namely NO3−, NaCl, Na2SO4, Na2CO3, KH2PO4 and phatalate). Toxicity data (Aliivibrio fischeri, Raphidocelis subcapitata and Daphnia magna) on treated solutions and wastewater highlighted the presence of residual toxicity in all samples evidencing that no complete mineralization occurred.