聚氨酯型固沙剂改性土室内试验研究

对自主研发的PUA、PUB和PUC 3种聚氨酯型固沙剂改性土的强度、抗冲刷性、抗风蚀性等性能进行了室内试验研究,并结合聚氨酯分子结构和功能对固沙剂改良原理进行了分析。试验结果表明:3种聚氨酯型固沙剂改性土的无侧限抗压强度、内聚力得到了提高,抗冲刷和抗风蚀性能得到了明显增强;3种固沙剂改性土的无侧限抗压强度和内聚力均随着固沙剂浓度的增加而增大;PUA、PUB和PUC浓度为3g/cm3的改性土试样的冲刷率分别只有4.4%、14.7%和0.6%,而参照样高达79.5%;PUA、PUB和PUC浓度达到1g/cm3以上的改性土风蚀后表面保持完整,没有风蚀破坏痕迹。因此,聚氨酯型固沙剂可以很好地增强土体粘聚力、促进表层固化、减少水土流失,可用于坡面防护、水土保持、防尘固沙、沙漠化治理等领域。     

螯合剂对铜毒性的影响

研究了螯合剂EDTA和DTPA对海州香薷蓄铜能力和铜毒性的影响.结果显示,EDTA和DTPA能抑制植物的生长,使其生物量降低,叶绿素含量下降,同时降低了植物的根系活力.EDTA和DTPA都可引起植物SOD、POD活性上升,在与Cu²⁺共同作用下,EDTA对Cu²⁺毒性影响较小,表现在SOD、POD活性仍按Cu²⁺独立作用下的变化规律而变化,且数值上变化不大.而DTPA则降低了Cu²⁺作用下SOD、POD活性的变化.EDTA使海州香薷地上部分铜浓度增加,DTPA则明显降低了海州香薷的铜含量.     

取代脲类除草剂光催化降解动力学比较

为研究取代脲类除草剂在TiO₂光催化降解过程中的动力学规律,以非草隆、异丙隆和利谷隆3种取代脲类除草剂为研究对象,通过Langmuir-Hinshelwood动力学模型对其TiO₂光催化降解动力学进行模拟,并系统探讨了催化剂用量、C₀(取代脲类除草剂的初始浓度)、溶液pH、温度、ROSs(活性氧物种)和电子捕获剂等的影响. 结果表明:非草隆、异丙隆和利谷隆的TiO₂光催化降解均符合假一级动力学模型,其动力学常数分别为0.082 8、0.068 7和0.095 4 min-1;取代脲类除草剂分子中的芳香环和脲桥上的取代基对降解速率常数的大小有明显的影响. ROSs试验表明,非草隆、异丙隆和利谷隆光催化降解过程中分别有91.6%、95.5%和86.8%的贡献来自·OH;而光生空穴和其他ROSs的贡献相对较小,并且电子捕获剂BrO₃-和S₂O₈2-对取代脲类除草剂的降解动力学有显著的促进作用.      

Ozonation of the 5-fluorouracil anticancer drug and its prodrug capecitabine: Reaction kinetics,oxidation mechanisms,and residual toxicity

Specific second-order rate constants were determined for 5-FU and CAP with ozone. Reaction sites were confirmed by kinetics, Fukui analysis, and products. The olefin moiety was the main ozone reaction site for 5-FU and CAP. Carboxylic acids comprised most of the residual TOC for 5-FU. Ozonation removed the toxicity associated with 5-FU and products but not CAP. Anticancer drugs (ADs) have been detected in the environment and represent a risk to aquatic organisms, necessitating AD removal in drinking water and wastewater treatment. In this study, ozonation of the most commonly used antimetabolite ADs, namely 5-fluorouracil (5-FU) and its prodrug capecitabine (CAP), was investigated to determine reaction kinetics, oxidation mechanisms, and residual toxicity. The specific second-order rate constants between aqueous ozone and 5-FU, 5-FU⁻, 5-FU²⁻, CAP, and CAP⁻ were determined to be 7.07(±0.11)×10⁴ M⁻¹·s⁻¹, 1.36(±0.06)×10⁶ M⁻¹·s⁻¹, 2.62(±0.17)×10⁷ M⁻¹·s⁻¹, 9.69(±0.08)×10³ M⁻¹·s⁻¹, and 4.28(±0.07)×10⁵ M⁻¹·s⁻¹, respectively; furthermore, the second-order rate constants for ^•OH reaction with 5-FU and CAP at pH 7 were determined to be 1.85(±0.20)×10⁹ M⁻¹·s⁻¹ and 9.95(±0.26)×10⁹ M⁻¹·s⁻¹, respectively. Density functional theory was used to predict the main ozone reaction sites of 5-FU (olefin) and CAP (olefin and deprotonated secondary amine), and these mechanisms were supported by the identified transformation products. Carboxylic acids constituted a majority of the residual organic matter for 5-FU ozonation; however, carboxylic acids and aldehydes were important components of the residual organic matter generated by CAP. Ozone removed the toxicity of 5-FU to Vibrio fischeri, but the residual toxicity of ozonated CAP solutions exhibited an initial increase before subsequent removal. Ultimately, these results suggest that ozone is a suitable technology for treatment of 5-FU and CAP, although the residual toxicity of transformation products must be carefully considered.     

高浓度豆制品废水预处理实验研究

豆制品是中国的传统食品,在生产过程中产生高浓度废水,如果对高浓度有机废水进行预处理,采用回收蛋白质以及化学混凝处理方法可以大大降低废水浓度,一定程度上可以减轻后续处理的难度、降低处理成本。针对豆制品生产废水问题,对高浓度豆制品废水的预处理方法作了实验研究。采用调节等电点酸沉降的方法回收蛋白质,然后用聚合硫酸铁化学混凝处理上清液以降低COD的含量。实验证明了方法的可行性并得出了最佳实验条件。     

Oxidation of diesel soot on binary oxide CuCr(Co)-based monoliths

Binary oxide systems (CuCr₂O₄, CuCo₂O₄), deposited onto cordierite monoliths of honeycomb structure with a second support (finely dispersed Al₂O₃), were prepared as filters for catalytic combustion of diesel soot using internal combustion engine's gas exhausts (O₂, NO_x, H₂O, CO₂) and O³ as oxidizing agents. It is shown that the second support increases soot capacity of aforementioned filters, and causes dispersion of the particles of spinel phases as active components enhancing thereby catalyst activity and selectivity of soot combustion to CO₂. Oxidants used can be arranged with reference to decreasing their activity in a following series: O₃ >> NO₂ > H₂O > NO > O₂ > CO₂. Ozone proved to be the most efficient oxidizing agent: the diesel soot combustion by O₃ occurs intensively (in the presence of copper chromite based catalyst) even at closing to ambient temperatures. Results obtained give a basis for the conclusion that using a catalytic coating on soot filters in the form of aforementioned binary oxide systems and ozone as the initiator of the oxidation processes is a promising approach in solving the problem of comprehensive purification of automotive exhaust gases at relatively low temperatures, known as the "cold start" problem.     

Determination of chemical warfare agents

Ethylarsine dichloride was used during WW I as a chemical warfare agent. Residues of this chemical warfare agent and its metabolites are still present today and continue to contaminate soil and water. A gas Chromatographic method for the detection and determination of ethylarsine dichloride is shown. Six dithiols were tested as possible derivatization reagents for ethylarsine dichloride. With selection of the dithiol, matrix interferences can be eliminated because of the different retention times of the derivatives.     

Destruction of diphenylarsine chloride (CLARK I) with activated ozone

The new technology of Plasmazon® uses the extremely strong oxidation of radicals to break up the compocunds of organic connections, e.g. chemical warfare agents like Clark I. In making a comparison of oxidation to normal ozone, the factor of the Plasmazon® -technology is available up to 10³. The investigation in an experimental test shows that it is possible to destroy the warfare agent character of Clark I. As the possibility of a large-lot application this technology is the method of choice for other chemical or biological warfare agents.     

废水生物处理出水中溶解性微生物产物的形成机制与特征

废水生物处理出水中的溶解性微生物产物(SMP)主要产生于基质降解和微生物的内源呼吸过程,它的存在是影响生物处理出水水质和有机物去除率的一个重要因素,已引起人们的普遍关注.简单阐述了SMP的定义,详细探讨了废水生物处理出水中溶解性微生物产物的形成机制与特征.     

强力霉素生产废水资源化技术研究

根据强力霉素生产废水的特殊性,选用三烷基胺为络合剂、正辛醇和磺化煤油为稀释剂、氢氧化钠为反萃取剂,进行萃取-反萃取实验研究.确定了最佳的工艺条件.结果表明,通过三级萃取后,磺基水杨酸(SSA)、对甲基苯磺酸(PTSA)、COD和BOD5去除率分别达到99.8%、95.4%、92.8%和77.4%,一次反萃取率接近100%,并且萃取剂可以循环使用.采用该工艺不但有明显的环境效益,而且还可以回收磺酸类原料资源.具有良好的经济效益.