Application Of Electrochemical Microfiltration Reactor In Water Treatment

Electrochemical water treatment technology refers to the process of degrading pollutants in wastewater in a specific electrochemical reactor under the external electric field.The microfiltration membrane separation technology is a kind of precise filtration technology whose membrane is a homogeneous porous membrane with a thickness of 90-150 μm and a particle size of 0.025-10 μm.It’s advantage include uniform membrane pore size,high filtration accuracy,fast filtration speed,low adsorption capacity.In this paper,a type of electrochemical microfiltration reactor was developed and applied to treating waste cutting fluids and simulated electroplating wastewater,and the influencing factors were studied.At the same time,a set of freshwater fresh-keeping system which combined with electrochemical and microfiltration membrane separation was designed and the performance was studied.The waste cutting fluids was treated by an electrochemical microfiltration reactor.The influences of electrode voltage,circulating flow rate,reactor operating time,anode-cathode distance,and filter diameter of the microfiltration filter were studied.The optimum conditions for the study were defined as electrode voltage of 10 V，circulating flow of 0.5 L/min,reactor operating time of 120 min,anode-cathode distance of 10 mm,and pore size as 5 μm.Under the optimal conditions,the COD removal rate of the waste cutting fluid can reach 90.68%，and the oil recovery can reach 5275 mg/L.Biomicroscopy was used to observe the microstructure of the waste liquid before and after the treatment.It was found that after treatment,the particle size of oil droplets increased from 10 μm to 100 μm,which made it easier to collect and separate.The product precipitated after treatment of the waste water was detected by infrared spectrum analysis,and the oil layer material was inferred to be a mineral oil whose main component was n-octane.Up to 5.275 kg of oil recovery would recovered from 1 m3 of waste cutting fluid,while the required power of this process is 6.6 kW·h by theoretical calculation.The simulated electroplating wastewater was treated by an electrochemical microfiltration reactor.The influences of electrode voltage,circulating flow rate,reactor operating time,and anode-cathode distance on the treatment effect were investigated.The optimal conditions for the test were defined as the electrode voltage of 8 V,the circulating flow rate of 0.5 L/min,the reactor operating time of 90 min,and the anode-cathode distance of 10 mm.Under the optimum conditions,theconcentration of Cu2+in the simulated electroplating copper-containing wastewater was reduced from 50 mg/L to 9.09 mg/L,and the removal rate of Cu2+reached 81.82%.The chroma of electroplated copper-containing wastewater changed from blue to colorless after treatment.Through the calculation of energy consumption,the required power is 6.11 kW·h for treating 1 m3 of simulated electroplating copper-bearing wastewater by theoretical calculation.The effects of temperature,polar spacing,and NaCl concentration on the electrolysis of low concentration of NaCl were studied.The optimal reaction conditions of freshwater fresh-keeping system combined with electrochemical and microfiltration membrane separation were as follows:the temperature was set at normal atmospheric temperature,and the anode-cathode distance was 12 mm.The pilot-scale freshwater fresh-keeping system combined with electrochemical and microfiltration membrane separation can produce the residual chlorine rapidly where fresh water can be guaranteed.At 20℃,with an average flow rate of 5.4 m3/h,the chlorine concentration can reach 0.35-0.39 mg/L,and the pH value is stable at about 7.5,which fully up to the chlorine indicators specified in the "Standard for Drinking Water Quality".