| Nowadays,with the rapid development of the machining industry,cutting fluids are widely used and used in large quantities with lubrication,rust prevention,cooling,degreasing cleaning and anti-corrosion properties,which brings about an increase in the discharge of waste water from the cuttings,serious environmental pollution and other issues.Therefore,it must be treated effectively by a suitable process before it can be discharged.This experiment is aimed at the wastewater generated in the actual production process of a precision instrument machinery processing plant in Shenzhen,the electro-flocculation method is used for the demulsification pretreatment,the multi-phase Fenton-loaded catalyst CuO/CeO2 is used and the multiphase Fenton/ultrasound is used to treat the electrocoagulated effluent water in depth,then studing the catalytic performance of the catalyst,the degradation effect of the process and optimized the reaction conditions.The high-concentration cutting fluid wastewater was pretreated by electrocoagulation to reduce the difficulty of degradation of subsequent treatment processes.When the cathode is made of 316 stainless steel,the anode is made of aluminum plate,the plate spacing is 4cm,the initial pH is 8,the reaction time is 70min and the current density is 20mA/cm2,the CODCr removal rate of the cutting fluid wastewater can be 97.4%,the effect is good and the reaction rate is high.Then the orthogonal experiment of 3 levels and 4 factors are carried out,and the effect of each factor on the removal rate of CODCr is as follows:reaction time<pH<plate spacing<current density.The removal effect of CODCr on the supported catalyst prepared by different carriers and methods is investigated,and the catalyst samples are characterized by SEM,XRD and BET,the results show that the supported catalyst CuO/CeO2 with CeO2 as carrier is prepared by sedimentation precipitation method,the surface oxide has regular shape,uniform distribution and specific surface area of 150m2/g.Moreover,through further experimental research,it is found that the prepared catalyst CuO/CeO2 can have a removal rate of 34%CODCr when calcination temperature of 400?,CuO loading of 7%and a calcination time of 3 h.When the reaction time is 240 min,the copper ion elution amount is 1.212 mg,the dissolution ratio is only 1.29%and the catalyst stability is good.After five times of recovery,the recovery rate of the catalyst is still 95%and there is still a good CODCr removal rate.The multi-phase Fenton system consisting of CuO/CeO2 prepared under optimal conditions and H2O2 catalysts is used to treat the clectroflocculation effluent,it is found that the treatment effect of the system on wastewater is significantly better than that of CeO2/H2O2 system and H2O2 system alone.When the initial pH value is 8,the stirring speed is 400r/min,the initial temperature is room temperature(25?),the H,O2 dosing method is uniform feeding,the reaction time is 240min,the dosage of the catalyst is 2g/L and the dosage of H2O2 is 0.6 mol/L,the multiphase Fenton system can have a 50%CODcr removal rate and a 70%chroma removal rate.The multiphase Fenton/ultrasound system constructed by multiphase Fenton system and ultrasonic technology further processes the electroflocculation effluent and found that the system has better treatment effect than the multiphase Fenton system and the ultrasonic system.When the reaction time is 180 min,the initial temperature is room temperature(25?),the H2O2 dosing method is uniform dosing,the initial pH value is 8,the catalyst dosage is 1.6 g/L,the ultrasonic frequency is 800 KHz and the H2O2 dosage is 0.5 mol/L,the multiphase Fenton/ultrasound system can have a 65%CODCr removal rate and the chroma removal rate can reach 80%.This study found that the use of electroflocculation-multiphase Fenton/ultrasound system technology to treat the high concentration of cutting fluid wastewater produced in the actual production process,the CODcr removal rate can reach 99.09%,the treatment effect is good,for processing high concentration cutting liquid wastewater provides a fast and efficient method. |
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