The Study Of Two Phenolic Organic Oxidated By Ozone And The Acute Toxicity

In the present work,the degradation efficiency of 2-naphthol and phenol with ozone in aqueous solution were investigated in laboratory–scale experiments in which pH, initial concentration, ozone dose, temperature were varied. In order to know the possible environmental risk caused by 2-naphthol, phenol and their intermediates oxidated by ozone in aqueous solution, the acute toxicity assessment with zebrafish embryos was conducted before and after the treated solution by ozone.2-Naphthol, which originates widely from various industrial activities, is toxic and thus harmful to marine life and human. It is of great importance for the water environment to remove it. The experiments of ozonation showed that: the degradation and mineralization of 2-naphthol followed pseudo-first-order kinetic. At the same time, It was influenced by ozone dose and the initial concentration of 2-naphthol. The degradation and mineralization efficiency of 2-naphthol by ozone rised as the initial concentration of 2-naphthol decreased, and an increasing O3 dose clearly exerted a positive in?uence on degradation and mineralization of 2-naphthol. At initial pH 6.31, initial concentration of 2-naphthol 50mg/L, and ozone dose 94.3 mg/hour, the efficiency of 2-naphthol removal was more than 93% after 12 min, and the TOC was more than 62% after 180 min. The related anions(oxalic acid, acetic acid and formic acid ) during the reaction process was ascertained by ion chromatography (IC), and the concentration increased with the reaction time. The major intermediates detected by liquid chromatography/mass spectrometry (LC/MS) were naphthalene-1,2-dio,naphthalene-1,2-dione,3-phenylpropanoic acid,(E)-3-(2-hydroxyphenyl)acrylic acid and so on. The zebrafish embryo was a very good model to evaluate the toxicity of 2-naphthol, and the LC50 of 2-naphthol by Zebrafish embryos exposed 24 hour,48 hour,72 hour was 7.39±0.65mg/L,6.49±0.48 mg/L,6.27±0.52 mg/L respectively. Besides it can make Zebrafish embryos lethal, under the inverted microscope we can observe deformity of Zebrafish embryos and the inhibition of Embryonic hatch in the developmental process. The acute toxicity of the reaction solution to zebrafish embryo (Danio rerio) were estimated, and it was decreased with the reaction time. O3 is a powerful tool to reduce the toxicity of 2-naphthol. The removal of 2-naphthol was more quick than the toxicity, and the decrease of toxicity was more quick than the TOC. This indicated that some of intermediates were also toxic, which needs further research.Phenol is a very important chemical intermediate,which brings serious harm for humans and animals because of the existence in the environment. The experiments of ozonation showed that: O3 was a powerful tool for phenol degradation, But for TOC the removal was powerless. An increasing O3 dose, pH, temperature clearly exerted a positive in?uence on degradation of phenol. And the increase of the initial concentration was unfavorable to the degradation of phenol. The ozonation of phenol followed pseudo-first-order kinetic. The experiments of the acute toxicity of zebrafish embryos showed that the deformity of Zebrafish embryos and the inhibition of Embryonic hatch appeared after the exposure of 72 hour in the phenol solution.The EC50 of phenol solution to Zebrafish embryos was 75±2.5mg/L. In the phenol oxidation process,the acute toxicity increased in the beginning stage, and began to decline when reaching the maximum.The possible reason why the acute toxicity increased in the beginning stage, was the synergy between phenol and its Intermediate products. The specific mechanism was needed further research.