| In recent years, oil pollution in water has become increasingly serious, seriously affecting environmental safety and human health. Traditional oil removal methods in water are complex process, high cost, easy to produce twice pollution. This study by hydrodynamic cavitation(HC) and electrocatalytic membrane(ECM) enhanced catalytic oxidation technology to remove the oil pollutants in water, the impact factors on the removal of oil contaminants in HC and ECM technology, study on the stability of the ECM treatment of oil wastewater, discussed the degradation mechanism of cavitation and electrocatalysis on oil pollutant.The results of HC treatment of oil wastewater show that HC has good solubility about oil pollutants in water and also has some degradation. In the initial oil concentration was 90mg/L and the inlet pressure is 0.30MPa, the temperature is 35?, the cavitation time is 2h, the initial concentration of oil in water increased from 90mg/L to 215mg/L, reached the maximum; cavitation time is 5h, the oil removal rate reached 52.70%; GC-MS analysis of water samples before and after HC . The number of peaks in the chromatogram of HC decreases, the peak intensity decreased, the number of peaks from raw water 62 to 42, the peak area of alkane peaks decreased by the total peak area of 49.36% to 35.49%. On the one hand is the use of cavitation bubbles increase oil solubility in water, on the other hand high temperature, high pressure and hydroxyl radicals of after the collapse to degrade oil pollutants and removal effect.The maximum amount of dissolved oil in water after cavitation is 215mg/L as raw water of ECM to treat oil wastewater. Research shows that, when the current density is 2.0mA/cm2, the pH value is 6, the residence time is 3.8min, the electrode spacing is 40mm,the temperature is 30?, the best oil catalytic degradation of pollutants in water, oil removal rate reached 98.81%, the removal rate of COD reached 94.77%. GC-MS analysis showed that the peak intensity of degradation not only decreased after ECM, but also the number of peaks decreased, reduced from 57 to 10, the peak area of alkane peak by the total peak area of 44.36% to 23.49%. ECM is to produce free radicals or substances by electrocatalysis to degrade oil contaminants in water, and use membrane to separate them.The response surface model analysis and the cleaning results show that the ECM has a good stability in the treatment of oil wastewater. The theoretical value of COD removal rate is 94.78% and the COD removal rate of the 5 times repeated experiments is basically consistent, indicating that the ECM in the removal of oil wastewater COD stability is better.The ECM after cleaning the water flux, the oil removal rate and COD removal rate were recovered, the water flux by cleaning before 75L/(m2 h) recovery to 72.8L/(m2·h), the removal rates of oil recovery from 99.02% to 98.72%, the removal rate of COD get from 94.52% back to 93.73%. In addition, the energy consumption and catalytic efficiency of the ECM were 0.797kW h/m3 and 2.445kW·h/kg.HC and ECM catalytic oxidation technology can effectively remove oil contaminants in water. As a new water treatment technology, it has broad application prospects in the removal of refractory organics. |
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