强化过硫酸钠降解含吐温-80溶液中的三氯乙烯

Degradation of Trichloroethylene in Solutions Containing Tween-80 by Enhanced Sodium Persulfate

文章采用铁刨花(IS)协同柠檬酸(CA)强化Fe(Ⅱ)活化过硫酸钠(PS)体系降解含吐温-80(TW-80)水溶液中的三氯乙烯(TCE),探究了IS协同CA对PS/Fe(Ⅱ)体系的强化作用效果,考察了药剂投加量、TW-80浓度、溶液初始pH值和无机阴离子对TCE(含TW-80)降解效果的影响,并确定了TCE(含TW-80)降解的主导活性氧物种类别。结果表明,IS协同CA可有效强化TCE的降解,在TCE和TW-80初始浓度分别为0.15 mmol/L和1.0 g/L的溶液中,PS、Fe(Ⅱ)-CA和IS投加量分别为4.5 mmol/L、0.6 mmol/L和2.5 g/L时,180 min内TCE降解率为92.4%;TW-80的存在会抑制TCE的降解,且其浓度越高,抑制作用越强;自由基清扫和电子顺磁共振仪检测表明,HO·和SO_(4)^(-)·在含TW-80水溶液中TCE的降解过程中均起到了重要作用,其中SO_(4)^(-)·的作用更大;当初始pH值小于9时,PS/Fe(Ⅱ)/CA/IS体系对TCE(含TW-80)具有良好的降解效果;溶液中Cl-的存在对TCE降解的影响不明显,而HCO3-的抑制效果显著;实际地下水中受复杂水质的影响抑制了TCE的降解,但通过提高药剂投加量可克服实际地下水的不利影响,仍可达到较高的TCE去除率。

Trichloroethylene(TCE)degradation in aqueous solution containing Tween-80(TW-80)was carried out using iron scraps(IS)coupled with citric acid(CA)to enhance Fe(Ⅱ)-activated sodium persulfate(PS)system.The effects of IS synergized with CA on the enhancement of PS/Fe(Ⅱ)system were explored,and the influences of chemical dosage,TW-80 concentration,initial solution pH,and inorganic anions on TCE degradation(with TW-80)were investigated.The main reactive oxygen species responsible for TCE degradation were confirmed.The results showed that IS synergized with CA can effectively enhance the TCE removal,and when the initial concentrations of TCE and TW-80 were 0.15 mmol/L and 1.0 g/L,respectively,TCE degradation reached 92.4%with the dosages of 4.5 mmol/L,0.6 mmol/L,and 2.5 g/L of PS,Fe(Ⅱ)-CA,and IS,respectively.The presence of TW-80 inhibited the TCE degradation,and the higher its concentration,the stronger the inhibition.Free radical scavenging tests and electron paramagnetic resonance analysis showed that both HO·and SO_(4)^(-)·played important roles in TCE degradation with SO_(4)^(-)·more important than HO·.In PS/Fe(Ⅱ)/CA/IS system,a desired TCE removal performance was obtained at the initial solution pH<9.The presence of Cl-in the solution did not have a significant effect on TCE degradation,while the inhibition caused by HCO3-was obvious.TCE removal was inhibited in the simulated actual groundwater experiment due to the complex solution matriexs,and the adverse effect can be overcome by increasing the chemical dosage,thus achieving higher TCE removal efficiency.