| Currently,the machining industry is growing,the cutting fluid with cooling,lubrication,cleaning,rust and other functions is widely used,and bringing a lot of cutting fluid wastewater emissions and pollution problems.The cutting fluid wastewater is complex and stable,and contains a large number of refractory organic compounds and toxic and hazardous substances,which brings great difficulties to the treatment and threatens the human living environment seriously.Therefore,it must be dealt with strictly before they can discharge.In this study,Heterogeneous Fenton/ultrasound was used to treat the organic wastewater in a precision processing plant in Shenzhen,and the chemical coagulation was used as the pretreatment process.The catalytic performance of the catalyst,the degradation mechanism of the system,degradation efficiency and optimization conditions were discussed in detail.The chemical coagulation method was used to demineralize the cutting fluid wastewater to reduce the load of the subsequent depth treatment.The best coagulation conditions are room temperature,pH value is not adjusted(7.0?8.0),coagulant 3.Og/L PAC and 0.2g/L PAM compound use,250r/min rapid agitation 2min,50r/min slow stirring 8min.At this time,the settling fast,high efficiency,and the demulsification effect is the best.But when dealing with the higher concentration of the cutting fluid wastewater,it can be acid heating first to reduce the subsequent coagulation breaking and improve coagulation effect,so that the treatment is more economical and feasible.Preparation of supported catalysts CuO/CeO2 and H2O2 constitute heterogeneous Fenton system to degrade cutting fluid wastewater.Transition metal oxide CuO was chosen as the active component of the catalyst.Through SEM,BET and XRD and other characterization studies and degradation removal effect,screening CeO2 as catalyst carrier,and optimize the preparation conditions of catalyst CuO/CeO2.The loading capacity is 5%,the baking atmosphere is dry air,the calcination temperature is 400 ?,and the calcination time is 3h,the catalyst has the highest catalytic performance.The catalyst of CuO/CeO2 dissolution of copper content is low,and the reuse rate is high,has a very important significance for engineering application.The CuO/CeO2 catalyst under the optimal preparation conditions with H2O2 to degrade cutting fluid together.Compared with using H2O2 alone,CuO/CeO2/H2O2 heterogeneous Fenton system a better catalytic performance.In normal light,room temperature,pH value is not adjusted,H2O2 dosage is 3mol/L,catalyst CuO/CeO2 dosage is 0.6g/L,reaction 120min,cutting liquid wastewater COD can reach more than 40%,chroma removal rate can reach more than 75%.Construction of heterogeneous Fenton/ultrasound combined system for synergetic degradation of organic wastewater from cutting fluid.In room temperature,pH value is not adjusted,H2O2 dosage was 0.4mol/L,The addition of H2O2 is a constant speed,catalyst dosage of CuO/CeO2 was 0.6g/L,the reaction of ultrasonic frequency under the condition of 800kHz,COD degradation effect obviously and effluent clarification.Compared with the traditional homogeneous Fenton system,the reaction rate and degradation rate were improved to a great extent.Under the same experimental conditions,three kinds of different reaction systems were used to separate and degrade the cutting fluid wastewater by using single ultrasonic system,single heterogeneous Fenton system and heterogeneous Fenton/ultrasound combined system The results showed that the removal of COD and chroma from organic wastewater in cutting solution by US-CuO/CeO2-H2O system was the best,which could reach 90%and 80%above.The addition of ultrasound system,promoting the H2O2 decomposition to produce more · OH,weakening the agglomeration of catalyst,thereby increasing the demand for H2O2,while improving the system efficiency of catalytic oxidation treatment for organic wastewater,and provides a reference value for high concentration cutting fluid organic wastewater treatment. |
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