In this study, we have investigated the degradation and primary radiolytic degradation mechanism of 4-tert-octylphenol (4-t-OP) by using of electron beam (EB) -irradiation. The results show that at an absorbed dose of 10 kGy and an initial concentration of 25 mg·L -1 , the degradation of 4-t-OP in a methanol/water reduction system is higher than in a acetonitrile/water oxidation system by 19.4% and higher than in an acetone/water system by 26.8%, which is due to both of ·OH and e aq - playing an important role in the decomposition of 4-t-OP, although the latter is more effective. The degradation rate of 4-t-OP will decrease with increment of absorbed dose in a methanol/water solution, and increase with decrement of initial concentration at a constant absorbed dose. The degradation efficiency will also decrease with the addition of anions and H 2 O 2 into the solution. A system saturated with N 2 will make an increment in the degradation of 4-t-OP. The pH value of solution has been also found to affect the degradation efficiency, while the degradation is more efficient in alkaline conditions. Finally, the initial products involved in degradation reaction have been determined to be ethylbenzene, styrene, bicyclo[4.2.0]octa-1,3,5-triene, 2,2,4-trimethylpentane and p-tert-butyl-phenol, which may arise from e aq - attack at the position of the alkyl side chain of 4-t-OP molecule. The results have been revealed that EB irradiation is a promising method for degradation of 4-t-OP, and e aq - may be main reactive species to attack at the position of the alkyl side chain of 4-t-OP.
WANG Liang WU Minghong XU Gang LIN Ning BU Tingting ZHENG Jisan TANG Liang
E-beam degradation of bisphenol A(BPA) was carried out,under reductive condition of ethanol-water solution and oxidative condition of acetonitrile-water solution.The degradation efficiency is higher in oxidative condition than that in reductive condition,and increases with the dose but decreased with increasing initial concentration.The BPA radiolysis follows the pseudo-first-order kinetics.Adding H_2O_2,or neutral condition,does not benefit BPA degradation in oxidative conditions.Pulsed radiolysis was used to investigate mechanism of the BPA radiolysis.The rate constant for BPA reaction with OH(1.85×10^(10) L·mor^(-1)·s^(-1)) is about an order of magnitude higher than that with e_(aq)^-(1.80×l0~9 L·mor^(-1)·s^(-1)).The degradation products were analyzed by ion chromatograph.Smaller molecules such as formic acid and acetic acid were detected,indicating that ^-OH attacks the BPA molecule.The work is of significance for the practical E-beam treatment of waste water containing BPA.
XU Gang REN Hua WU Ming-Hong LIU Ning YUAN Qing TANG Liang WANG Liang
