Degradation And Toxicity Change Of Naphthol By Contact Glow Discharge Plasma

Naphthol is the basic materials of multitudinous chemical products synthetic dyes, pesticide, rubber stabilizer, is a kind of highly toxic organic compounds. The annual production of naphthol in our country accounts for about half of the world, contains large amounts of naphthalene phenolic wastewater emission aggravate the water pollution,cause serious harm to the ecological environment and human health, so the naphthol wastewater treatment get high attention by people. In the treating process, as a result of the existence of a large number of intermediate product, the toxicity of pollutants may not reduce, even may increase,cause more serious environmental pollution. So, to explore the change of biological toxicity in the process of naphthol degradation and its effect on the toxicity of the ecological environment have more practical significance.Contact glow discharge plasma as a kind of advanced oxidation technology, was widely used in the degradation of organic pollutants in recent years, and achieved a good effect. In this paper, furthermore with scenedesmus obliquus, daphnia magna, luminous bacteria as testing organisms, determination the change of biological toxicity in the process of degradation, in order to provide basic data support for actual wastewater treatment.This paper first investigated the biological toxicity of naphthol on different testing organisms. Experiments were determined half inhibitory concentration of 1-naphthol to scenedesmus obliquus, daphnia magna and luminescent bacteria, results show that the EC50 of 1-naphthol to scenedesmus obliquus, daphnia magna, luminescent bacteria were 33.0, 6.26, 5.1 mg/L, so1-naphthol has a strong biological toxicity. The EC50 of 2-naphthol to luminescent bacteria is 3.5 mg/L, showed that more toxic than 1-naphthol.Moreover, this paper investigates the change of 1-naphthol toxicity in the process of CGDP degradation. In the process of CDGP degradation, biological toxicity presents a trend of rising firstly and then reducing. After 120 min degradation,the degradation liquid did no longer inhibit the growth of scenedesmus obliquus, even would accelerate the growth of scenedesmus obliquus; The inhibition rate to daphnia magna and luminescent bacteria was reducing to around 10%,and the toxicity reducing was more pronounced when Na Cl as the electrolyte than Na2SO4.Finally, the experiment with luminous bacteria as testing organisms, studied the impact of the experiment respectively forl initial concentration, electrode number of 1-naphthol, 2-naphthol: the smaller the initial concentration, the more number of electrodes, the faster degradation process of naphthol degradation speed, the easier biological toxicity was lower. Na Cl as electrolyte, the initial concentration of 10 mg/L, the number of electrodes of 3, after 120 min degradation, had no obvious inhibition to luminous bacteria.