关键词: 页岩气采出水, 小分子, 臭氧催化氧化, 吸附

Abstract:

The treatment of small molecular organic matter in shale gas produced water by reverse osmosis membrane is often difficult to reach the standard. In order to solve this problem, three processes of ozone catalytic oxidation, activated carbon adsorption and catalytic ozonation coupled activated carbon adsorption were studied and compared in terms of the treatment effect of shale gas production water. The influencing factors in the first two processes on the advanced treatment of small molecular organic matter in shale gas produced water and the treatment effects of the coupling process were investigated. The results showed that using the ozone catalytic oxidation process under the optimal reaction conditions of pH 8, reaction time 120min and ozone dosage 0.8g/L, the ozone consumption m(O₃)∶m(COD_Cr) is 3.58, the COD_Cr decreased from 143mg/L to 68.6mg/L, and the removal rate was 52.03%. Using the activated carbon adsorption process under the optimal reaction conditions of pH 8, reaction time 90min and filling ratio of activated carbon 30%, the COD_Cr decreased from 143mg/L to 103.2mg/L, and the removal rate was only 27.83%. Using catalytic ozonation coupled activated carbon adsorption process under the optimal reaction conditions, the ozone consumption m(O₃)∶m(COD_Cr) was 2.78—2.88,the COD_Cr decreased steadily from 143mg/L to 25—34mg/L, and the removal rate was between 76.2% and 82.5%. It could be seen that the catalytic ozonation coupled activated carbon adsorption process had the best treatment effect on small molecular organic matter.

Key words: shale gas produced water, small molecule, ozone catalytic oxidation, adsorption