Formation of persistent chlorinated aromatic compounds in simulated and real fly ash from iron ore sintering

Effects of carbon concentration and Cu additive in simulated fly ash (SFA) and real fly ash (RFA) on the formation of polychlorinated dibenzofurans (PCDFs), polychlorinated dibenzo-p-dioxins (PCDDs), chlorobenzenes, and polychlorinated biphenyls which were all regarded as persistent chlorinated aromatics in iron ore sintering were investigated. In the annealing process of SFA with various carbon contents, the yield of chlorinated aromatics and the I-TEQ obtained their maximum at 10 wt% carbon content. Active carbon in SFA acted as the carbon source as well as an adsorbent which led to higher production of PCDD/F in solid phase at 10 wt% carbon content. The increase of carbon content will be beneficial on the formation of 2,3,7,8-Chloro-substituted PCDF compared with 2,3,7,8-Chloro-substituted PCDD. In addition, the CuCl₂·2H₂O was a much more powerful catalyst in the formation of chlorinated aromatic compounds compared with elementary Cu, since it served as both a catalyst and a chlorine donor. However, the RFA behaved similarly with SFA with elementary Cu in the formation of chlorinated aromatic compounds. The effect of carbon content and copper additives on formation of 2,3,7,8-chloro-substituted congeners displayed similar characteristics with the tetra- to octa-PCDD/F isomers and even the total PCDD/Fs.     

Preparation of biochar catalyst with saccharide and lignocellulose residues of corncob degradation for corncob hydrolysis into furfural

This paper presented a novel process for production of furfural by hydrothermal degradation of corncob over biochar catalyst, in which it was prepared with the recycling degradation solution and lignocellulosic solid residues. The biochar catalyst was papered by lignocellulose residues and concentrated saccharide solution, and then impregnated in 0.5 mol/L sulphuric acid at room temperature for 24 h assisted by the ultrasonic vibration. In the system of recycling, 8.8 % lignocellulose residues and 100 % concentrated saccharide solution from corncob hydrolysis have been recycled. Hydrolysis of corncob was carried out at 180 °C for duration of 170 min over the biochar catalyst. The experimental results have shown that the furfural yield of up to 37.75 % and overall corncob conversion rate of 62.00 % could be achieved under optimum operating conditions for the catalysts preparation and the corncob hydrolysis. It is believed that the acid density of 4.27 mmol/g of biochar catalyst makes the SO₃H groups cleave β-1,4 glycosidic linkages effectively and hydrolyze the cellulose and hemicellulose to water-soluble sugars, as well as to facilitate dehydration of xylose to give the product of furfural.     

Demonstrating Contaminant Degradation at an MGP Site With Metabolic Gas Flux and Radio Carbon Dating

Obtaining lines of evidence indicating that contamination in sediment environments is degrading and being transformed to less toxic forms is an important component of building support for a monitored natural recovery remedy for contaminated sediments. This project was a field demonstration of manufactured gas plant contaminant degradation in river sediments using metabolic gas flux and was performed in an urban area section of a river in northeastern Indiana. CO₂ sorbent traps were deployed to measure CO₂ flux from the river sediments. Sediment samples were collected and analyzed for polycyclic aromatic hydrocarbon (PAH) concentrations and for microbial community composition using molecular techniques. The results showed that the deployment was successful, measuring CO₂ flux at all sediment locations and demonstrating that microbial contaminant degrading activity was occurring in the sediments. Radio carbon dating showed a significant portion of the CO₂ being generated (approximately 19–27 percent) was the result of fossil fuel degradation. Molecular results showed that the microbial community consisted of phylotypes known to be associated with monocyclic aromatic and PAH degradation. ©2017 Wiley Periodicals, Inc.     

High CO2 adsorption on improved ZSM-5 zeolite porous structure modified with ethylenediamine and desorption characteristics with microwave

Journal of Material Cycles and Waste Management - Synthesized zeolite Socony Mobil-5 (ZSM-5) with large pore surface structures and modified with ethylenediamine were used to achieve high CO2...     

羟基乙叉二膦酸镀铜废液的处理及Cu~(2+)的高附加值资源化回收

采用Na BH4还原法将羟基乙叉二膦酸(HEDP)镀铜废液中的Cu~(2+)制备成纳米铜粉,并采用聚丙烯酰胺(PAM)对还原反应后的废液进行絮凝处理。研究了n(Cu~(2+))∶n(Na BH4)、还原反应温度、还原反应时间及PAM添加量对废液中剩余Cu~(2+)质量浓度的影响,并对回收的纳米铜粉进行了XRD和TEM表征。实验结果表明:当n(Cu~(2+))∶n(Na BH4)=4∶6、还原反应温度为50℃、还原反应时间为2 h时,废液中剩余Cu~(2+)质量浓度降低至1.1 mg/L,Cu~(2+)还原率达99.99%;可获得粒径为20~45 nm的近球型、高纯度、由多晶组成的纳米铜粉;当PAM添加量为10 mg/L时,废液中剩余Cu~(2+)质量浓度降至0.35 mg/L以下,达到GB 21900—2008《电镀污染物排放标准》(小于0.5 mg/L)的要求。     

3种杀菌剂及其复配剂对斑马鱼的急性毒性

采用"半静态法"测定了3种农药及其复配剂对斑马鱼的24 h、48 h、72 h和96 h急性毒性,根据我国《化学农药环境安全评价实验准则》中毒性等级划分标准来划分它们对斑马鱼的毒性等级,发现35%精甲霜灵悬浮种衣剂的24 h、48 h、72 h和96 h-LC_(50)均超过10 a.i.mg·L~(-1),属"低毒"级,而25 g·L~(-1)咯菌腈悬浮种衣剂的24 h、48 h、72 h和96 h-LC_(50)分别为0.704 mg·L~(-1)、0.514 mg·L~(-1)、0.424 mg·L~(-1)、0.262 mg·L~(-1),根据0.100 a.i.mg·L~(-1)LC_(50)(96 h)≤1.00 a.i.mg·L~(-1)划分,属"高毒"级,80%嘧菌酯水分散粒剂的24 h、48 h、72 h和96 h-LC_(50)分别为9.803 mg·L~(-1)、5.175 mg·L~(-1)、4.328 mg·L~(-1)、2.326 mg·L~(-1),根据1.00 a.i.mg·L~(-1)LC_(50)(96 h)≤10.00 a.i.mg·L~(-1)划分,属于"中毒"级。11%精甲霜灵-咯菌腈-嘧菌酯悬浮种衣剂的24 h、48 h、72 h和96 h-LC_(50)分别为2.267 mg·L~(-1)、2.073 mg·L~(-1)、1.620 mg·L~(-1)、1.280 mg·L~(-1),根据1.00 a.i.mg·L~(-1)LC_(50)(96 h)≤10.00 a.i.mg·L~(-1)划分,属于"中毒",虽然11%精甲霜灵-咯菌腈-嘧菌酯悬浮种衣剂和80%嘧菌酯水分散粒剂同属"中毒",但比较具体数值,发现11%精甲霜灵-咯菌腈-嘧菌酯悬浮种衣剂毒性相对更大,原因是其中含有"高毒"的咯菌腈。     

三氯卡班可以影响肾小管上皮细胞的屏障功能

三氯卡班(TCC)是一种被广泛应用于个人护理用品中的广谱型亲脂性杀菌剂,已在多种环境介质和生物体中检出。因其潜在的环境蓄积、生物累积和生物毒性效应,日益受到学者们的关注。借助TCC对NRK-52E(大鼠肾小管上皮细胞)的毒性暴露实验,通过检测细胞活力、以及与跨膜电阻和紧密连接相关的连接黏附分子1(JAM~(-1),junctional adhesion molecule 1)的蛋白表达水平,研究了TCC潜在的肾脏毒性效应。结果显示,10μmol·L~(-1)TCC处理48 h时培养细胞呈现不规则的集落;10μmol·L~(-1)和20μmol·L~(-1)TCC处理NRK-52E 24 h、48 h和72 h后可以显著抑制细胞生长;3.57μmol·L~(-1)TCC(生长抑制的48 hIC20)处理NRK-52E 48 h可以显著抑制细胞间紧密连接蛋白JAM~(-1)的表达量,并降低跨膜电阻,影响肾脏的屏障功能。本研究的结果能够为进一步揭示TCC对动物的毒害机制、评估其对动物的健康风险提供数据支持。     

双酚A及其类似物对斑马鱼胚胎及幼鱼的毒性效应

为探讨双酚A及其类似物对鱼类早期生长发育的毒性效应,研究了双酚A及其7种类似物对斑马鱼胚胎及仔鱼的毒性效应。通过对胚胎的孵化率、心率、仔鱼体长等指标进行测定分析,结果显示:(1)双酚A及其7种类似物都可使斑马鱼胚胎出现心包水肿、卵黄囊肿、脊柱弯曲和尾部弯曲等症状。(2)综合考虑斑马鱼78 hpf胚胎心率、120 hpf胚胎孵化率及7 dpf仔鱼体长抑制率等指标,8种受试物中双酚P(BPP)的毒性最大,其次是双酚AP(BPAP)、双酚AF(BPAF)、双酚Z(BPZ),然后是双酚A(BPA)、双酚B(BPB)、双酚F(BPF),双酚S(BPS)的毒性最小,每种受试物的浓度与受精卵的孵化率、仔鱼心率呈明显负相关关系,与体长抑制率呈明显正相关关系。8种受试物毒性与辛醇-水分配系数(log K_(OW))呈正相关关系,log K_(OW)越大毒性则越大。     

BP-4的模拟生物降解特性研究

为研究紫外吸收剂2-羟基-4-甲氧基二苯甲酮-5-磺酸(BP-4)的最大生物降解能力,采用欧洲经济合作与发展组织(OECD)生物降解测试标准方法——303A模拟试验-污水好氧处理:活性污泥单元法,建立并进行了城市污水处理厂曝气池环境模拟试验。研究结果表明:在单一新鲜活性污泥作为接种物条件下,BP-4在第47天达到降解稳定期,溶解性有机碳(DOC)去除率平均值为36.90%±5.68%(n=18)。在以10种不同来源混合接种物条件下,BP-4在第41天达到降解稳定期,去除率平均值为33.11%±4.87%(n=17)。研究结果表明BP-4在环境中的降解能力有限,在本模拟方法试验条件下只能部分降解。     

黄、渤海滨海带大气颗粒物时空分布与来源特征

PM10作为大气污染物监测的主要指标之一,探究大气PM10浓度对大气环境质量和人体健康评价具有重要意义。黄、渤海滨海带包括京、津和辽、冀、鲁、苏等工、农业大省,区域大气PM10污染的时空分布和来源特征具有复杂性和典型性。在锦州、北京、天津、烟台、青岛、连云港和盐城7个城市布设10个采样点,含7个城市点和3个农村点,开展为期一年的大气颗粒物的采样;同时,于冬季1月和夏季7月在锦州、天津和烟台进行合计60 d的加密采样,藉以确定研究区域大气PM10的时空分布和来源特征。结果表明,黄、渤海滨海带大气年均PM10总浓度为(129’18)"g·m~(-3),单月最低值出现在2015年7月盐城农村样点15"g·m~(-3),最高值为2015年3月北京城市点307"g·m~(-3)。盐城大气PM10浓度(城市点(85’27)"g·m~(-3)和农村点(66’35)"g·m~(-3))显著低于其他样点大气PM10浓度。渤海滨海带中西部的京(140’68"g·m~(-3))、津(169’60"g·m~(-3))两市大气PM10年均浓度显著高于东部的锦州(125’41"g·m~(-3))和烟台(109’31"g·m~(-3));而且黄海滨海带大气PM10年均浓度(114"g·m~(-3))显著低于渤海滨海带年均浓度(136"g·m~(-3)),总体上表现出西高东低、北高南低的特征。黄、渤海滨海带城市点和农村点年均浓度分别为(129’18)"g·m~(-3)和(112’30)"g·m~(-3);农村点春冬季大气PM10浓度和城市点浓度相当,无显著差异,夏秋季大气PM10浓度略低于城市浓度,表明农村地区大气颗粒物污染情况也较为严重,需受到关注。区域内PM10浓度季节变化整体表现为春冬高、夏秋低。利用多元回归分析初步判断黄、渤海滨海带PM10属于复合来源,大气PM10浓度约30%的变化与降水、人均能耗和沙尘天气相关。黄、渤海滨海带大气PM10浓度的昼夜变化不大,大气PM10浓度与气温呈现正相关,与风速和降水呈现负相关,表现为受各种气象因素综合作用的影响。