Ultrasonic And Ozone Pretreatment The Polyether Wastewater And Applied Research

Polyether polyol,also known as polyether,is an important chemical raw materials.It is with a low molecular weight polyols,amines or active hydrogen-containing compound as the initiator,and olefin oxide in the catalyst ring-opening polymerization.It would produce high concentrations polyether polyether waste water during the production process.High degree of polymerization of polyether alcohol wastewater,difficult to biodegradation,are difficult to degradation of organic matter.When the polyether alcohol is added into the water,it requires large amounts of oxygen in the aerobic biodegradation process,causing serious water hypoxia,and eventually polluted the water.As the conventional treatment techniques,polyether wastewater treatment susceptible to water quality and quantity fluctuations and other shocks,resulting in reduced processing efficiency.Therefore,urgent need to develop an new processing technology and equipment to enhance the degradation of organic matter in the polyether wastewater.In this work,the most widely used polyether alcohol polyethylene glycol as an example,the use of ozone oxidation technology ultrasonic synergistic treatment of the wastewater.The experimental wastewater treatment plant was established by using the ozone generator,ultrasonic generator and self-made organic glass reactor.The simulated wastewater was dispose according to the wastewater of a chemical enterprise.The ozone was oxidized separately,and the ozone was oxidized in two different ways.The initial COD concentration,the ozone flow rate,the ultrasonic power and the ultrasonic frequency on the degradation efficiency of COD in the wastewater were studied.The effects of ultrasonic synergistic ozone on the degradation of COD in the wastewater were also discussed.The reaction kinetics of the wastewater was studied and the application of ultrasonic/ozone technology in polyether alcohol wastewater was studied.The polyether witha high degree of polymerization is belong to refractory organics wastewater.Under the ozone treatment system,the degradation rate of COD of polyether increased with the decrease of pH value and increase of ozone flow rate,but the change of degradation rate tended to be insignificant when pH>7.The increase of the initial concentration of polyether was not helpful to the degradation efficiency,but the mass of organic of polyether being decomposed form the unit volume of solution was increased.The degradation rate was very low by solely using ultrasound,which can however enhance the COD of polyether degradation by ozone.Under the system of ultrasound and ozone,degradation efficiency was increased with the decrease pH value and initial concentration of polyether.It also increased at higher ozone flow rate and ultrasonic intensity and reduce the ultrasonic frequency.Synergetic effect was observed in the US/O3 system for COD of polyether.This may be explained by the two ways:(1)atomic oxygen was produce by sonochemical O3 thermolysis,atomic oxygen then reacted with vapor in cavitation bubbles and hydroxyl radical produced.(2)the solubility of O3 in water was increased because of sonication.Determining the fluorescence intensity of terephthalic acid indicated that COD of polyether was mainly oxidized by hydroxyl radical in the system of O3and US/O3.More hydroxyl radicals were produced in US/03 system than in ultrasound or O3 systems.Three different approaches to the degradation of COD of polyether wastewater and different initial concentration of COD of polyether wastewater under the US/O3 system both abided basic laws,the degradation kinetics accordingpseudo first order,that the COD remove rate was directly proportional with the reaction time.A large number of experimental data are summarized that the first order kinetics equation of using US/O3 to degrade COD of the polyether is:C= C0e-kt.The following conclusions are drawn:The relationship between In(CO/C)and the reaction time of COD degradation of polyether alcohol wastewater was discussed,which indicated that the degradation of polyether alcohol COD was consistent with macroscopic first order reaction.The COD removal rate of polyether alcohol wastewater degraded by the ultrasonic/ozone method is higher when the initial COD concentration is the same,the bigger the apparent rate constant is.The COD degradation of polyether alcohol wastewater under different ultrasonic conditions was in accordance with the first-order reaction kinetics.The total reaction formula was:C = C-0 e(-kt).The COD removal rate of wastewater was 86%and the COD of effluent was lower than 500img/L,which reached the standard of the enterprise to take over the wastewater(COD<500mg/L)after 120min of treatment with ultrasonic/ozone treatment.The feasibility of the application of ultrasonic/ozone treatment technology in practical production was verified.