Hydroxytyrosol, the phenolic compound of olive oil protects human PBMC against oxidative stress and DNA damage mediated by 2,3,7,8-TCDD

The protective effect of hydroxytyrosol (HT), a strong antioxidant compound from extra virgin olive oil, against TCDD induced toxicity was investigated in human peripheral blood mononuclear cells (PBMC). PBMC (1 × 10⁶ cells mL⁻¹) were divided into four groups and were incubated in a CO₂ incubator (5% CO₂) for 12 h with vehicle, TCDD (10 nM), TCDD + HT (10 nM + 100 μM) and HT alone (100 μM) respectively. To clarify the role of HT against TCDD induced cytotoxicity, oxidative stress and the levels of antioxidant enzymes were assessed. Incubation of PBMC with TCDD significantly decreased cell viability, catalase (CAT) and glutathione peroxidase (GPx) and increased the levels of superoxide dismutase (SOD), glutathione reductase (GR) and oxidative stress markers such as lipid peroxidation products (LPO), protein carbonyl content (PCC) and reactive oxygen species (ROS). Whereas, HT had an effective antioxidant property as observed by the increased cell viability, normalization of antioxidant enzymes and decreased levels of LPO, PCC and ROS in PBMC co-treated with HT and TCDD. Apoptosis detection and comet assay results shows that HT, by acting as an antioxidant, prevents the damage to DNA induced by TCDD. In addition light microscopic and histopathological observations revealed that the cells are apoptotic and degenerated during TCDD treatment, whereas cells showed intact morphology during co-treatment with HT. On the whole, the results reveal that HT exerts a promising antioxidant potential in protecting the PBMC against TCDD induced oxidative stress, which might be due to the presence of catechol moiety in its structure.     

Elimination of diclofenac from water using irradiation technology

The effluents of wastewater treatment plants, usually directly emitted to the environment, often contain the anti-inflammatory drug diclofenac (DCF). The paper investigates DCF elimination using irradiation technology. Hydroxyl radical and hydrated electron reactive intermediates resulting from water radiolysis effectively degrade DCF and strongly reduce the toxicity of the solutions. OH attaches to one of the rings of DCF, and hydroxylated molecules, 2,6-dichloroaniline and quinoid type compounds are the products. Hydrated electron adds to the chlorine atom containing ring, in the reaction quinoid type compounds and 4-chloroacridine form. At a 0.1 mM DCF concentration, a ∼1 kGy absorbed dose is needed for the degradation of DCF molecules, but for mineralization of the products (in presence of O₂) an order of magnitude higher dose is required.For irradiation of wastewater after biological treatment a ∼1 kGy dose is suggested. At this dose DCF and other drugs or metabolites present at μg L⁻¹ level are eliminated together with microorganism deactivation.     

Phenol depletion by thermally activated peroxydisulfate at 70°C

The ability of thermal activated peroxydisulfate (PS) of mineralizing phenol at 70 °C from contaminated waters is investigated. Phenol in concentrations of 10⁻⁴ to 5 × 10⁻⁴ M is quantitatively depleted by 5 × 10⁻³ to 10⁻² M activated PS in 15 min of reaction. However, mineralization of the organic carbon is not observed. Instead, an insoluble phenol polymer-type product is formed. A reaction mechanism including the formation of phenoxyl radicals and validated by computer simulations is proposed. High molecular weight phenolic products are formed by phenoxyl radical H-abstraction reactions. This is not the case for the room temperature degradation of phenol by sulfate radicals where sulfate addition to the aromatic ring mainly leads to the generation of hydroxycyclohexadienyl radicals leading to hydroxybenzenes and oxidized open chain products. Therefore, a change in the reaction mechanism is observed with increasing temperature, and thermal activation of PS at 70 °C does not lead to the mineralization of phenol. Thus PS activation at 70 °C may be considered a potential method to reduce the load of phenol in polluted waters by polymerization.     

臭氧氧化处理页岩气钻井废水的机理与动力学

采用臭氧氧化法处理页岩气钻井废水经混凝沉淀后的出水(COD=759.63 mg/L),重点研究了废水中有机污染物的去除机理与反应动力学。实验结果表明:在废水pH为11.2、臭氧通入量为8 mg/min、反应时间为50 min的最佳工艺条件下,废水的COD去除率为42.51%;羟基自由基抑制剂CO_3~(2-)、HCO_3~-和叔丁醇的引入抑制了废水COD的臭氧氧化去除,尤其是叔丁醇的加入使COD去除率显著下降,说明废水中有机物的臭氧氧化去除过程遵循羟基自由基机理;臭氧氧化法对钻井废水中有机物的氧化去除过程符合表观二级反应动力学规律。     

气浮-·OH强氧化组合工艺处理高藻水的研究

以库区天然水培养的二形栅藻(Scenedesmus dimorphus)为研究对象,利用大气压强电场电离放电产生羟基自由基(·OH),结合压力溶气气浮前处理工艺处理高藻水.实验结果表明,对于藻密度为65.6×10~4 cells/mL,浊度为10.8NTU,COD_(Mn)为6.74mg/L的高藻水,在总氧化剂TRO浓度为1.03 mg/L时,藻类去除效率达到100%;总细菌,总大肠菌群和大肠埃希氏菌均未检出;出水COD_(Mn)由1.43 mg/L降至1.25mg/L,降低了10%;浊度由0.66NTU降至0.54NTU,降低了12.59在排放高藻水的主管路中·OH杀藻的接触反应时间仅为6s.因此汽浮-·OH强氧化组合工艺可高效快速地处理高藻水,为保障水源水的供水安全探索了一种新的思路.     

新型锰氧化菌株Pseudoxanthomonas mexicana S5-3-5X的分离及锰氧化机理研究

锰氧化微生物能催化氧化Mn^II生成锰氧化物（Mn^IV&III）,而生成的锰氧化物可强化水处理体系（如锰砂滤池、湿地）中的微量有机污染物降解及底泥中甲烷的厌氧氧化,因而受到广泛研究.从环境中分离出更多种属和生态位的锰氧化菌是生物强化环境中锰氧化过程的重要基础.依据锰氧化菌株对低浓度营养物的潜在偏好,本研究梯度稀释常用的锰氧化菌培养基（PYG培养基）,配置出5级营养物梯度浓度的培养基.相对于原培养基,从较低浓度的4级培养基中多分离出6个菌属的锰氧化菌株,提高了锰氧化菌株的分离效率.分离出的Pseudoxanthomonas（假黄色单胞菌属）菌属的锰氧化菌株（Pseudoxanthomonas mexicana S5-3_-5X）,属中文文献首次报道.研究发现该菌株能在环境常见条件（pH 6.0~7.8、低营养物浓度（如稀释5~625倍PYG培养基）、50 μmol·L^-1 ~1.6 mmol·L^-1的Mn^II浓度）生长并产生锰氧化活性;可以产生胞外超氧化物和锰氧化蛋白等锰氧化活性物质;基因组具有编码锰氧化模式菌株Pseudomonas putida GB-1的3个Mn^II氧化蛋白的同源基因,并且具有降解一些有机污染物的代谢通路.因此,该菌株具有较好的工程应用潜力.     

The Effect of Hydroxyl Radical Generation on Free-Radical Activation of TMP Fibers

The purpose of this work was to study the mechanisms involved in free radical activation of thermal mechanical pulp (TMP) fibers with the ultimate goal of developing methods for bonding wood fiber without the use of traditional adhesives. The generation of hydroxyl radicals in a mediated Fenton system was studied using electron spin resonance (ESR) spin-trapping techniques and indirectly through chemiluminescence measurement. The activation of TMP fibers was also evaluated by ESR measurement of free phenoxy radical generation on solid fibers. The results indicate that low molecular weight chelators can improve Fenton reactions, thus in turn stimulating the free radical activation of TMP fibers. However, it was also shown that excessive and prolonged free radical treatment may cause the destruction of fiber phenoxy radicals. In conclusion, this study demonstrates the potential for application, but also the complexity of free radical chemistry in biological materials, especially with regard to the chelation of transition metals and the interaction between free radicals.     

Fe(Ⅱ)活化过硫酸钠深度处理工业园区污水处理厂出水

采用Fe(Ⅱ)活化过硫酸钠(PS)技术对工业园区污水处理厂出水进行深度处理,通过响应曲面法考察了PS/COD、Fe(Ⅱ)/PS和pH对COD和TOC去除率的单独和联合效应.利用紫外-可见扫描、凝胶色谱及三维荧光等手段表征深度处理前后的有机物特性变化.结果表明,PS/COD和Fe(Ⅱ)/PS对COD去除影响极显著;而PS/COD、Fe(Ⅱ)/PS和pH对TOC去除均有显著影响.PS/COD和pH联合效应对COD去除影响显著.最优工艺条件PS/COD比3.47、Fe(Ⅱ)/PS比3.32、pH 6.5时,COD和TOC去除率为50.7%和60.6%.Fe(Ⅱ)-PS氧化能将大分子有机物转化为小分子,削减类蛋白质、类富里酸和类腐殖酸的含量.     

溶解性有机质对罗红霉素光降解的影响研究

近年来,罗红霉素(ROX)因其用量大、检出频率高和生态风险大引起了广泛关注.本文主要研究了环境pH条件下不同的溶解性有机质(DOM),包括富里酸(PLFA)、腐殖酸(SRHA)和天然有机质(SRNOM)对罗红霉素光降解的影响及主要活性物种对其光降解的贡献.结果表明:纯水中罗红霉素可发生自敏化光降解,在pH 6～8条件下,罗红霉素光降解的一级反应速率常数为0.0033～0.0049 h~(-1).DOM促进了罗红霉素光降解,其促进效果从大到小为PLFASRNOMSRHA.DOM共存时罗红霉素光降解的反应速率常数随pH增加而增加,在pH 6时为0.0145～0.0266 h~(-1),在pH 8时为0.0273～0.0577 h~(-1).通过异丙醇淬灭实验发现,羟基自由基(·OH)对罗红霉素光降解起主要贡献,其贡献率在pH 6时为83.45%～98.70%,在pH 8时降低至76.76%～78.02%;3种DOM体系中产生的单态氧(~1O_2)的稳态浓度在(5.15～7.86)×10~(-14) mol·L~(-1)范围内;在pH 6、7和8的条件下,~1O_2与罗红霉素的二级反应速率常数分别为2.27×10~5、1.96×10~6和1.51×10~7 L·mol~(-1)·s~(-1).~1O_2对罗红霉素的光降解的贡献随pH升高而升高,在pH 6时为0.21%～0.43%,在pH 8时为4.85%～11.33%.