Formation of multiple trimethylsilyl derivatives in the derivatization of 17α-ethinylestradiol with BSTFA or MSTFA followed by gas chromatography-mass spectrometry determination

N,O-bis(trimethylsily)trifluoroacetamide (BSTFA) and N-methyl-N(trimethylsily) trifluoroacetamide (MSTFA) are common derivatization reagents used in the GC-MS analysis of estrogen steroids such as estrone (E1) and 17(-ethinylestradiol (EE2). In this study, three trimethylsilyl (TMS) steroid derivatives, mono-and di-trimethylsilyl EE2 and mono-trimethylsilyl E1, were observed during the derivatization of EE2 with BSTFA or MSTFA and/or GC separation. Factors influencing the production of multiple TMS derivatives and their relative abundance were examined. It was found that both methanol and bisphenol A competed with estrogenic esteroids when reacting with silylation reagents, and thus affected the formation of TMS derivatives and their relative abundance in the derivatization products. Methanol was found to be more reactive than bisphenol A with the BSTFA reagent. None of the three solvents tested in this study could prevent the generation of multiple TMS derivatives during the derivatization of EE2 with BSTFA, followed by GC analysis. A similar result was observed using MSTFA as the derivative reagent followed by GC analysis. Thus, the suitability of BSTFA or MSTFA as the derivatization reagent for the determination of E1 and EE2 by GC-MS, under the conditions reported here, is questionable. This problem can be solved by adding trimethylsilylimidaz (TMSI) in the BSTFA reagent as recommended, and the performance of the method has been proved in this study.     

Fenton试剂处理油田含聚污水中聚丙烯酰胺的试验研究

通过对我国油田含聚污水污染状况进行分析,提出处理油田含聚污水的关键是去除污水中的聚丙烯酰胺(HPAM).以聚丙烯酰胺污水为处理对象,通过正交试验确定了Fenton试剂各影响因素的影响权重,并深入研究了Fenton试剂中各影响因素的作用机制,同时通过分别试验确定了Fenton试剂处理聚丙烯酰胺污水的最佳操作条件:Fe2 和H2O2浓度分别为400mg/L、1.0mL/L,反应温度40 ℃、反应时间15 min,反应体系的pH为3左右,HPAM的降解率能达到88%以上,COD降解率高达97%.     

Fenton法处理垃圾渗滤液过程中有机物分子质量分布和荧光特性

采用Fenton氧化工艺对上海某垃圾填埋场垃圾渗滤液进行处理. 提取和分离了Fenton氧化前后腐殖酸组分(富里酸、胡敏酸),运用凝胶色谱法和三维荧光光谱技术对Fenton氧化前后各物质的分子质量分布和有机物荧光特性进行了研究. 结果表明:Fenton反应可使ρ(BOD₅)/ρ(COD_Cr)从0.011提高到0.285. 通过分子质量分布和三维荧光特性的测量可知,造成这种可生化性提高的原因是Fenton反应使垃圾渗滤液中有机物的分子质量降低,其中对高分子质量胡敏酸的去除以及对富里酸分子质量的降低起到了关键作用.      

Fenton process for degradation of selected chlorinated aliphatic hydrocarbons exemplified by trichloroethylene, 1,1-dichloroethylene and chloroform

The degradation of selected chlorinated aliphatic hydrocarbons (CAHs) exemplified by trichloroethylene (TCE), 1,1-dichloroethylene (DCE), and chloroform (CF) was investigated with Fenton oxidation process. The results indicate that the degradation rate was primarily affected by the chemical structures of organic contaminants. Hydroxyl radicals (·OH) preferred to attack the organic contaminants with an electron-rich structure such as chlorinated alkenes (i.e., TCE and DCE). The dosing mode of Fenton’s reagent, particularly of Fe²⁺, significantly affected the degradation efficiency of studied organic compound. A new “time-squared” kinetic model, C = C _o exp(−k _obs t ²), was developed to express the degradation kinetics of selected CAHs. This model was applicable to TCE and DCE, but inapplicable to CF due to their varied reaction rate constants towards ?OH. Chloride release was monitored to examine the degree of dechlorination during the oxidation of selected CAHs. TCE was more easily dechlorinated thanDCE and CF.Dichloroacetic acid (DCAA) was identified as the major reaction intermediate in the oxidation of TCE, which could be completely removed as the reaction proceeded. No reaction intermediates or byproducts were identified in the oxidation of DCE and CF. Based on the identified intermediate, the reaction mechanism of TCE with Fenton’s reagent was proposed.     

Optimization of Fenton's oxidation of chemical laboratory wastewaters using the response surface methodology

Establishing a treatment process for practical and economic disposal of laboratory wastewaters has become an urgent environmental concern of the Department of Chemical Engineering of the Universidade Estadual de Maringá (State University of Maringá), Brazil. Fenton and related reactions are potentially useful oxidation processes for destroying toxic organic compounds in water. In these reactions, hydrogen peroxide is combined with ferrous or ferric iron in the presence or absence of light to generate hydroxyl radicals (.OH). The feasibility of Fenton's reagent to treat waste chemicals from an academic research laboratory was investigated in this study. A response surface methodology was applied to optimize the Fenton oxidation process conditions using chemical oxygen demand (COD) removal as the target parameter to optimize, and the reagent concentrations, as related to the initial concentration of organic matter in the effluent, and pH as the control factors to be optimized. Maximal COD removal (92.3%) was achieved when wastewater samples were treated at pH 4 in the presence of hydrogen peroxide and iron in the ratios [COD]:[H2O2]=1:9 and [H2O2]:[Fe2+]=4.5:1. Under these conditions, it was possible to obtain simultaneously maximal COD removal and minimal chemical sludge after treatment, which is a residue that needs further processing.     

Fe(Ⅱ)EDTA/H2O2电催化降解甲基橙模拟废水的研究

在无隔膜电解槽中,采用SPR(Ru-Ir-Ti0₂)为阳极,石墨为阴极,考察了Fe(Ⅱ)EDTA/H₂O₂电催化降解甲基橙(methyl orange)模拟废水的影响,发现EDTA很大程度上促进了类电Fenton试剂对甲基橙模拟废水的降解。实验研究表明,在外加电压为5.0 V,EDTA∶Fe²⁺=2∶1(摩尔比,Fe²⁺=40 mmol/L),H₂O₂=48 mmol/L,电解质Na₂SO₄=40 mmol/L,废水pH值为(6.5±0.1)的条件下,降解260 mg/L的甲基橙模拟废水90 min, EDTA的加入可以使甲基橙模拟废水的脱色率由29.5%上升到78.4%,COD由571.429 mg/L降至80 mg/L,COD的降解率为86%,EDTA在此过程中既是催化剂又是反应物,可有效避免EDTA带来二次环境污染的可能性。     

Fenton试剂与CPAM联合调理对污泥脱水效果的影响研究

含水率是影响污泥处置效果与成本的重要因素,通过泥饼含水率、上清液COD、蛋白质、多糖质量浓度、污泥粒径等指标,研究了阳离子聚丙烯酰胺(CPAM)和Fenton试剂单独及联合调理对污泥脱水效果的影响,初步探讨其调理机制.结果表明,CPAM阳离子度越高,脱水效果越好,且酸性条件有利于改善CPAM的污泥脱水效果.Fenton试剂H2O2投加量越高,污泥脱水效果越好.Fenton试剂与CPAM联合调理时污泥脱水效果更为显著,投加FeSO4=2 g.L-1、H2O2=6 g.L-1,污泥含水率由原泥的85.5%降低至76.7%,再投加CPAM 3 kg.t-1联合调理后污泥含水率降至74.8%.Fenton试剂对胞外聚合物的破解作用使污泥粒径变小,比表面积增大,释放部分的吸附水和内部水;CPAM与Fenton试剂的联合调理,将分散的污泥絮体凝聚,污泥平均粒径由35.16μm增至50.50μm,比表面积由未加入CPAM的0.39 m2.g-1降至0.20 m2.g-1,联合调理对污泥脱水效果的改善作用优于单一絮凝剂调理.     

AN对酸雨伤害蜡梅的防护作用

以１００ｍｇ／Ｌ ＡＮ喷洒蜡梅植株２次，能明显减轻ｐＨ为２．０模拟酸雨对蜡梅植株的伤害。本文认为，此与ＡＮ能提高叶绿素含量，增加光合速率与比叶重，抑制过氧化氢酶活性，减少光合产物损失，降低质膜透性，维持细胞液ｐＨ值稳定性等多重生理效应有关。     

纳氏试剂法测定水中低浓度氨氮的预处理方法的改进

选用纳氏试剂分光光度法测定氨氮时,比较蒸馏法中分别以硼酸和纯水为吸收液时氨氮的检测效果。结果显示,当氨氮质量浓度1.0 mg/L时,用纯水或硼酸作吸收液均可;当氨氮质量浓度1.0 mg/L时,应以纯水为吸收液。     

不同调理剂对厌氧石化污泥脱水性能的影响研究

以厌氧消化后的石化污泥为研究对象,研究聚合硫酸亚铁(PFS)、聚丙烯酰胺(PAM)、聚合氯化铝(PAC)、Fenton试剂对厌氧石化污泥脱水性能的影响,再对调理后的厌氧污泥通过板框压滤机压滤脱水,考察其脱水难易程度。研究结果表明:相比无机絮凝剂PFS、PAC和有机絮凝剂PAM,Fenton试剂(七水合硫酸亚铁加到15,20,25 g/L时,H_2O_2溶液投加量为5 m L/L)的调理效果较好,调理后污泥的毛细吸水时间分别降低至36.82,18.3,27.28 s,污泥比阻分别降低至4.22×1011,1.23×1011,2.45×1011cm/g;采用FPS、PAC、PAM、Fenton(H_2O_2溶液投加量为5 m L/L,Fe SO4·7H2O加到15,20,25 g/L时)调理后的污泥,经过板框脱水后的泥饼含水率分别为68.65%、64.19%、67.21%、57.46%、55.83%、59.36%。由此可见,最优的厌氧石化污泥脱水调理剂为Fenton试剂(Fe SO4·7H2O、H_2O_2投加量分别为20 g/L、5 m L/L),该研究对厌氧石化污泥的高干脱水和减量化具有参考价值。