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991.
经急性毒性实验,得到萘对成体斑马鱼96 h的半数致死浓度(LC50)为11.8 mg·L-1.在此基础上,设置5个浓度梯度:0、 1/6 LC50、 1/4 LC50、 1/3 LC50、 1/2 LC50,研究了在不同的暴露时间下(0.5、 1、 2、 4、 、 14d),萘对斑马鱼抗氧化防御系统的影响.结果表明,还原型谷胱甘肽(glutathione, GSH)、谷胱甘肽过氧化物酶(glutathione peroxidase, GPx)和谷胱甘肽硫转移酶(glutathione S-transferase, GST)对萘非常敏感,在暴露0.5 d时就受到抑制或诱导.0.5 d后GPx活性整体上被诱导,只在第14 d时高浓度组(1/3 LC50和1/2 LC50浓度组)GPx活性被抑制;GST和GSH则总体上是低于对照的.超氧化物岐化酶(superoxide dismutase, SOD)活性在2d后呈现先诱导后抑制;过氧化氢酶(catalase, CAT)活性在1 d后整体上受抑制.萘对斑马鱼内脏团抗氧化防御系统能产生影响,其变化可作为生物标志物,来评价暴露于多环芳烃有机污染的鱼类的生物学效应. 相似文献
992.
MAHMOOD Tariq CHEN Chuncheng LIU Lili ZHAO Dan MA Wanghong LIN Jun ZHAO Jincai 《环境科学学报(英文版)》2009,21(2):263-267
The photocatalytic degradation of dyes (Acid Chrome Blue K (ACBK) and Alizarin Red (AR)) with strong complexation ability was investigated in the presence of metal ions under visible light irradiation.It was found that, at low dye-metal ratio, the photodegradation of ACBK was markedly inhibited by the addition of high oxidative potential Cu2+.However, at high dye-metal ratio, the presence of Cu2+ enhanced the photodegradation of ACBK.The negtive effect of Cu2+ on the photodegradation of AR was observed for all dye-metal ratios.The relative chemical inert Zn2+ tended to enhance the photodegradation of both anionic dyes.The mechanism underlying the different effect of Cu2+ is discussed from the different roles of surface-adsorbed and dye-coordinated Cu2+ in the photodegradation of dyes. 相似文献
993.
Microwave photocatalytic degradation of Rhodamine B using TiO2 supported on activated carbon: Mechanism implication 总被引:1,自引:0,他引:1
The photocatalytic degradation of Rhodamine B (RhB) was carried out using TiO2 supported on activated carbon (TiO2-AC) under
microwave irradiation. Composite catalyst TiO2-AC was prepared and characterized using X-ray di raction (XRD), transmission
electron microscopy (TEM) and Brunauer-Emmett-Teller (BET). In the process of microwave-enhanced photocatalysis (MPC), RhB
(30 mg/L) was almost completely decoloured in 10 min, and the mineralization e ciency was 96.0% in 20 min. The reaction rate
constant of RhB in MPC using TiO2-AC by pseudo first-order reaction kinetics was 4.16 times of that using Degussa P25. Additionally,
according to gas chromatography/mass spectrometry (GC/MS) and liquid chromatography/mass spectrometry (LC/MS) identification,
the major intermediates of RhB in MPC included two kinds of N-de-ethylation intermediates (N,N-diethyl-N’-ethyl-rhodamine (DER)),
oxalic acid, malonic acid, succinic acid, and phthalic acid, maleic acid, 3-nitrobenzoic acid, and so on. The degradation of RhB in MPC
was mainly attributed to the destruction of the conjugated structure, and then the intermediates transformed to acid molecules which
were mineralized to water and carbon dioxide. 相似文献
994.
Parameters effect on heterogeneous photocatalysed degradation of phenol in aqueous dispersion of TiO_2 总被引:2,自引:0,他引:2
KASHIF Naeem 《环境科学学报(英文版)》2009,21(4)
In this study, photocatalytic degradation of phenol selected as model compound of organic pollutant had been investigated in aqueous titanium dioxide (TiO2) dispersion under UV irradiation. The effects of various parameters such as pH, catalyst concentration, phenol concentration, anions, metal ions, electron acceptors, and surfactants on the photocatalytic degradation of phenol were investigated. The degradation kinetics was determined by the change in phenol concentration employing UV-Vis spectrometry as a function of irradiation time. The degradation kinetics of phenol follows pseudo first-order kinetics. The results showed a significant dependence of the photocatalytic degradation of phenol on the functional parameters. The probable promising roles of the additives on the degradation process were discussed. 相似文献
995.
Effects of temperature and surfactants on naphthalene and phenanthrene
sorption by soil 总被引:1,自引:0,他引:1
Adsorption experiments were carried out to investigate the sorption behaviors of naphthalene and phenanthrene in six different soils and to determine the effects of temperature, linear alkylbenzene sulfonate (LAS) and cetylrimethyl ammonium bromide (CTAB) on sorption. The results show that for a given sorbent phenanthrene exhibited greater nonlinear and stronger sorption than naphthalene. There was a strong negative correlation for the Koc values with organic carbon content (foc). The increase of temperature was not favorable to sorption. Sorption decreased along with the increasing aqueous LAS concentration from 0 to 1000 mg/L. At low CTAB concentration (< 100 mg/L), the adsorption increased as CTAB hemimicelles formed on the soil surface. At high concentration, CTAB decreased the adsorption by occupying active hydrophobic adsorption sites and solubilization of naphthalene and phenanthrene. 相似文献
996.
P450酶系对污染物的生物指示和催化降解机制 总被引:2,自引:1,他引:1
细胞色素P450酶系是广泛存在于不同生物体内的含有多种超家族CYP450血红素蛋白或相同结构域的一系列酶,是多组分电子传递链的终端氧化还原酶。最新研究发现,利用P450在生物体内的含量/活性与污染物浓度的定量响应关系可实现环境污染的早期预警和诊断,对环境污染的监测和预报具有重要意义。更重要的是,P450酶系被认为是生物对内源或外生污染物代谢途径的启动催化因子。P450的脱卤化、羧基化、脱烷基化、环氧化等催化作用在诱导污染物的分解代谢过程中起核心作用。本文综述了P450酶系的结构、催化过程和诱导抑制机理,分析了其在环境污染物的生物指示和催化降解中的应用进展,以便为利用P450进行环境预警和生物修复提供系统的理论和技术支持。 相似文献
997.
一株假单胞菌对高粘原油的乳化降解作用 总被引:1,自引:0,他引:1
从油田原油污染土壤中筛选出一株以原油为最佳碳源产表面活性剂的假单包菌SY-3。该菌在以原油烃为唯一碳源的无机盐培养基中,除降粘外还能产生甲酸和乙酸。通过单因素试验,确定了降低原油粘度最适条件:初始原油浓度12g/L,氮源为4g/L的混合氮源[硝酸钠和硝酸铵(1:1)],培养温度37℃,接种量5%,初始pH值7.0,培养时间5d。GC谱图分析经SY-3菌降解前后原油组分的变化,可知原油的重质组分含量明显降低,轻质组分含量明显增加,降粘率达56%。表明该菌株对原油有良好的乳化降解能力。 相似文献
998.
非平衡等离子体降解两种不同VOCs的研究 总被引:1,自引:1,他引:0
实验以甲醛和苯乙烯为研究对象,采用介质阻挡放电,考察了放电电压、初始浓度和停留时间对他们降解率的影响,并对两者的能耗进行了分析。研究发现甲醛和苯乙烯的降解率随放电电压、初始浓度和停留时间的增大均呈现不同的变化趋势:随着放电电压和停留时间的增大,甲醛的降解率较苯乙烯增加得慢,且达到一定值后有趋于平缓的趋势;而当初始浓度增大时,甲醛的降解率先增大后减小,出现一个最佳降解浓度区域,苯乙烯的降解率则直接快速减小;在输入的能量较高时,苯乙烯的能量利用率更高。 相似文献
999.
1000.