To investigate the influence of radiolysis on kinetics and factors of dimethyl phthalate(DMP),the aqueous DMP solution is degraded by 1.8 MeV E-beam,following pseudo-first-order kinetics.The rate constant of DMP degradation decreased exponentially with increasing initial DMP concentration.The DMP is favorably degraded by radical scavengers under its low concentration and alkaline condition.At high doses,the DMP is attacked by eaq-and ·OH,producing monomethyl phthalate,phthalate acid,and a series of aliphatic carboxylic acids,which are completelymineralized into H2O and CO2.
LIU Ning XU Gang MA Jing TANG Liang YUAN Qing WANG Liang BAI Yulei WU Minghong
Polybrominated diphenyl ethers (PBDEs) spread widely in the environment are mainly removed by photochemical and anaerobic microbial degradation. In this paper, the decomposition of 4-bromodiphenyl ether (BDE -3), the PBDEs homologues, is investigated by electron beam irradiation of its ethanol/water solution (reduction system) and acetonitrile/water solution (oxidation system). The radiolytic products were determined by GC coupled with electron capture detector, and the reaction rate constant of esol– in the reduction system was measured at 2.7×1010 L·mol–1·s–1 by pulsed radiolysis. The results show that the BDE-3 concentration affects strongly the decomposition ratio in the alkali solution, and the reduction system has a higher BDE-3 decomposition rate than the oxidation system. This indicates that the BDE-3 was reduced by effectively capturing esol– in radiolytic process.
TANG Liang XU Gang WU Wenjing SHI Wenyan LIU Ning BAI Yulei WU Minghong
Thiamphenicol(THA) and florfenicol(FLO) aqueous solutions were irradiated to different doses by 1 MeV electron beams,and redox reactions of THA/FLO and radicals of OH,e_(eq)^- and ~·H were investigated under various conditions.The results showed that at 8 kGy,the decomposition rate of THA and FLO was 97.2%and 98.5%, respectively.Quantitative and qualitative analysis indicated that OH played a key role in E-beam degradation of the THA and FLO in aqueous solutions,and e_(eq)^- and ~·H radicals could initiate the degradation,too.Seven primary products of the THA and FLO degradation were identified.These indicate that E-beam radiation is an effective method to reduce THA and FLO in aqueous solutions.
Zhou JiaxinWu MinghongXu GangMa JingWang LiangLiu Ning
N,N-diethylhydroxylamine (DEHA) is a novel salt-free reducing agent used in separating Pu and Np from U in the reprocessing of spent nuclear fuel.In this paper,we report the study on γ-radiolysis of DEHA in water and its radiolytic liquid organics by gas chromatography.The radiolysis rate of DEHA increases with the absorbed dose,but decreases with the primary DEHA concentration at 0.1-0.5 mol?L-1 irradiated to 10-1000 kGy.The main organics produced in radiolysis of DEHA are acetaldehyde,acetic acid and ethanol.The concentration of acetaldehyde increases with the primary DEHA concentration and the absorbed dose at ≤500 kGy,but over 500 kGy it decreases with increasing dose.The dependence of the concentration of acetic acid on the absorbed dose is similar to that of acetaldehyde,with a lower turning point of the dose,though.The ethanol concentration changes differently among the irradiated samples of different primary DEHA concentrations,and this is discussed.The maximum concentrations of acetaldehyde,acetic acid and ethanol are 0.029,0.014 and 0.028 mol·L-1,respectively.
WANG JinhuaZHANG JieWU MinghongXU GangBAO BorongSUN XilianZHENG WeifangHE HuiZHANG Shengdong
