硼强化铁离子活化过硫酸盐高效降解荧蒽的研究

Boron-Enhanced Degradation of Fluoranthene Using Persulfate Activated by Iron Ions

采用硼(B)强化铁离子活化过硫酸盐(PS)降解荧蒽(FLT),阐明了B的强化机理,从FLT的降解效果和PS利用率角度研究了B强化三价铁(Fe^(3+))活化PS的优越性,探究了水质条件对FLT降解的影响,验证了PS/Fe^(3+)/B体系在实际地下水中降解FLT和其他多环芳烃的可行性。结果表明:PS/Fe^(3+)/B体系中FLT降解的拟一级反应动力学常数k_(obs)为0.043 9 min^(-1),PS/Fe^(2+)/B体系中k_(obs)在30 min后从0.044 7 min^(-1)降低至0.009 6 min^(-1),证明PS/Fe^(3+)/B体系可实现FLT的持续高效降解。当Fe^(3+)浓度在0.02~0.08 mmol/L之间时,PS/Fe^(3+)/B体系均可高效降解FLT,表现出更强的可操作性。结合X射线光电子能谱仪的分析结果、Fe^(2+)和PS的浓度变化,证明Fe^(3+)的持续释放和B的持续还原性可以保障体系中活性氧物种(ROS)的高效利用。水质条件影响试验结果表明,酸性条件有利于FLT的高效降解,碳酸根离子和高浓度的腐殖酸不利于FLT的降解。实际地下水的复杂环境对FLT的降解有一定的抑制作用,但是通过预调酸pH=4.0后FLT去除率达到99.9%,同时PS/Fe^(3+)/B体系对萘和菲也具有良好的去除效果。

Boron (B) was applied to enhance the degradation of fluoranthene (FLT) using persulfate (PS) activated by iron ions.The strengthening mechanisms of B were investigated and the superiority of Fe~(3+)coupled with B was studied through the degradation performance of FLT and utilization of PS.The effects of water matrixes on FLT were studied.The application potential of the PS/Fe~(3+)/B process in actual groundwater contaminated by FLT and other polycyclic aromatic hydrocarbons was verified.Experimental results revealed that the pseudo-first-order kinetic constant (k_(obs)) of FLT in the PS/Fe~(3+)/B system was 0.043 9 min~(-1),while after 30 min k_(obs) in the PS/Fe~(2+)/B system decreased from 0.044 7 min~(-1) to 0.009 6 min~(-1),proving long-lasting and high efficient FLT degradation in PS/Fe~(3+)/B system.When the concentration of Fe~(3+)was within 0.02~0.08 mmol/L,the PS/Fe~(3+)/B system could degrade FLT efficiently,exhibiting better application in implementation.Combining the analytical results from X-ray photoelectron spectroscopy,Fe~(2+)and PS variations,it was concluded that long-lasting release of Fe~(3+)and fast reduction of Fe~(3+)to Fe~(2+)by B could ensure the effective utilization of ROS and degradation of FLT.The test results in investigating the effects of groundwater conditions suggested that FLT could be effectively removed in PS/Fe~(3+)/B system at acidic conditions,but would be inhibited by HCO_3~-and high content of humic acid.Although the complex environment in the actual groundwater might cause a negative effect on FLT degradation to some extent,99.9%of FLT could be removed completely after pre-adjusting the pH of groundwater to 4.0.Meanwhile,naphthalene and phenanthrene could also be degraded effectively by the PS/Fe~(3+)/B process.