电絮凝-过硫酸盐氧化协同工艺处理页岩气压裂返排废水

2018年第38卷第3期化工环保ENVIRONMENTALPROTECTIONOFCHEMICALINDUSTRY·317·电絮凝-过硫酸盐氧化协同工艺处理页岩气压裂返排废水冯岐，刘德蓉，何芳，任勇，袁涛，熊伟（重庆科技学院化学化工学院，重庆401331）［摘要］采用电絮凝-过硫酸盐氧化协同工艺处理页岩气压裂返排废水，通过电解过程产生的Fe2+活化过硫酸盐产生强氧化性的硫酸根自由基氧化废水中的有机物，同时Fe2+被氧化成Fe3+进而水解起到絮凝作用。实验结果表明，在电解时间25min、电流密度41.7mA/cm2、电极间距4cm、搅拌转速100r/min、废水pH7.0、过硫酸盐添加量0.006mol/L的条件下，COD去除率达94.5%，出水BOD5/COD从0.13增至0.56，电导率从104mS/m降至71mS/m，矿化度从16704mg/L降至4065mg/L，不可滤残渣含量从554mg/L降至59mg/L。电絮凝-过硫酸盐氧化协同处理的效果明显优于单独电絮凝和硫酸亚铁活化过硫酸盐氧化工艺，循环伏安测试结果表明其原因是硫酸根自由基的产生，同时溶液的导电性增强，强化了絮凝效果。［关键词］电絮凝；过硫酸盐；页岩气压裂返排废水；硫酸根自由基［中图分类号］X741［文献标志码］A［文章编号］1006-1878（2018）03-0317-06［DOI］10.3969/j.issn.1006-1878.2018.03.012Treatmentofshalegasfracturingflow-backwastewaterbyelectrocoagulation-persulfateoxidationsynergeticprocessFENGQi，LIUDerong，HEFang，RENYong，YUANTao，XIONGWei（CollegeofChemistryandChemicalEngineering，ChongqingUniversityofScienceandTechnology，Chongqing401331，China）Abstract：Theshalegasfracturingflow-backwastewaterwastreatedbyelectrocoagulation-persulfateoxidationsynergeticprocess.TheFe2+producedbytheelectrolysisprocessactivatedpersulfateandproducedstrongoxidizingsulfateradicaltodegradetheorganiccompoundsinwastewater，whentheFe2+wasoxidizedtoFe3+andthenhydrolyzedtoformflocculation.Theexperimentalresultshowedthatundertheconditionsofelectrolysistime25min，currentdensity41.7mA/cm2，electrodegap4cm，stirringrate100r/min，wastewaterpH7.0andpersulfateamount0.006mol/L，theremovalrateofCODreached94.5%，theBOD5/CODvalueincreasedfrom0.13to0.56，theconductivitydecreasedfrom104mS/mto71mS/m，thesalinitydecreasedfrom16704mg/Lto4065mg/Landtheresiduecontentreducedfrom554mg/Lto59mg/L.Thetreatmenteffectoftheelectrocoagulation-persulfateoxidationsynergisticprocesswassignificantlybetterthanthatofthesingleelectrocoagulationprocessandtheferroussulfate-activatedpersulfateoxidationprocess.Thereason（asindicatedbycyclicvoltammetrytest）wasthattheflocculationeffectwasenhancedwiththeproductionofsulfateradicalandtheincreaseofsolutionconductivity.Keywords：electrocoagulation；persulfate；shalegasfracturingfl