不同生物反应器中基因工程菌生物强化处理阿特拉津研究

在膜-生物反应器(MBR)和复合生物反应器中,考察基因工程菌生物强化处理阿特拉津去除效果,并对基因工程菌浓度和降解基因atzA基因丰度变化进行检测.结果表明,阿特拉津对COD和氨氮的生物去除活性具有一定的抑制作用;基因工程菌生物强化后,COD及氨氮的去除效率得到恢复.MBR对COD和氨氮的去除效果优于复合生物反应器.基...     

原位红外光谱法研究CdS-TiO_2/MWCNTs可见光光催化降解气相甲苯

通过原位红外光谱技术研究了可见光下甲苯在CdS-TiO2/MWCNTs（多壁碳纳米管）和CdS-TiO2光催化剂表面的吸附、光催化降解过程,并考察了水汽对光催化反应的影响.结果表明,在吸附过程中甲苯在CdS-TiO2和CdS-TiO2/MWCNTs光催化剂表面就能被氧化成苯甲醛、苯甲酸等中间产物,水汽的存在有利于提高光...     

宁南山区两种灌木林土壤矿化过程中PLFA指纹季节变化特征

研究土壤矿化过程中土壤微生物群落结构的变化特征,对深入理解土壤中物质转化和养分迁移机理、提高土壤质量具有重要意义.因此,本文以宁南山区典型的两种人工灌木林-柠条和山桃林地土壤为研究对象,采用PVC顶盖埋管法进行1年的原位矿化实验,每隔2个月采样测定土壤基本理化性质和磷脂脂肪酸(Phospholipid fatty acid,PLFA)含量,探讨土壤在矿化过程中微生物群落结构的变化特征.结果显示:土壤矿化过程中,柠条林地土壤有机碳、全氮、硝态氮、铵态氮和土壤含水率显著高于山桃林地(p0.05);两种灌木林地有机碳含量在矿化240 d和360 d时较低,显著小于其他矿化时期(p0.05),硝态氮、铵态氮含量均在矿化240 d时最低,全氮和土壤pH随时间变化不显著.柠条林土壤各菌群PLFA含量高于山桃林土壤;两种土壤各菌群PLFA随矿化时间大体呈现出夏季春、秋季冬季的趋势,且差异显著(p0.05);土壤细菌与真菌、革兰氏阳性(GP)和阴性菌(GN)的PLFA比值差异显著(p0.05),柠条林土壤细菌与真菌PLFA比值随矿化时间呈现出夏、秋季春、冬季的趋势,而山桃林土壤细菌与真菌PLFA比值在冬季最低,两种土壤革兰氏阳性和阴性菌PLFA比值在春季最大.PLFA主成分分析表明,柠条和山桃林土壤微生物群落结构不同,并且土壤微生物群落结构随矿化时间逐步发生变异,微生物结构的变化主要由以16∶0、16∶1ω9c、16∶1ω9t、17∶0、10Me18∶0和cy19∶0所代表的细菌及以18∶2ω9,12c所代表的真菌的变化引起.土壤微生物PLFA与土壤有机碳、硝态氮和土壤含水率显著相关,与土壤pH值不相关,说明土壤微生物PLFA与土壤理化性质联系紧密.     

氯乙烯在地下水和土壤中的厌氧脱氯还原降解

主要介绍了通过原位生物修复技术还原脱氯降解氯乙烯的污染。通过注射井向氯乙烯污染区域注射有机物基质作为电子供体,再加入通过富集培养的强化微生物,通过微生物的作用对污染物降解,从而达到对污染地区修复的目的。并列举了一个实例说明此修复技术目前的研究进展水平。     

荧光原位杂交法检测反应器中聚磷菌实验条件优化及应用

文章简要介绍了荧光原位杂交（FISH）技术的基本原理和操作步骤。通过正交试验筛检荧光原位杂交（FISH）技术在检测反应器中聚磷菌时的最佳及适合的实验条件。结果显示,样品预处理较优的条件为：样品在固定前应先经过1×PBS清洗两次,37℃热固定3h,乙醇脱水3min;FISH技术检测反应器中聚磷菌的最佳实验条件为：杂交温度46℃,杂交时间2h,清洗缓冲液中NaCl浓度70 mmol/L。FISH技术检测反应器样品中聚磷菌与传统检测方法相比具有快捷、简便、淮确的优点,在研究环境微生物方面有较好的应用前景。     

CeO2 doping boosted low-temperature NH3-SCR activity of FeTiOx catalyst: A microstructure analysis and reaction mechanistic study

• CeO₂ doping significantly improved low-temperature NH₃-SCR activity on FeTiO_x. • The crystallinity of FeTiO_x was decreased dramatically after CeO₂ doping. • Unique Ce-O-Fe structure in FeCe_0.2TiO_x accounted for its superior redox property. • Facile activation of NH₃ to-NH₂ on FeCe_0.2TiO_x promoted the DeNO_x efficiency. FeTiO_x has been recognized as an environmental-friendly and cost-effective catalyst for selective catalytic reduction (SCR) of NO_x with NH₃. Aimed at further improving the low-temperature DeNO_x efficiency of FeTiO_x catalyst, a simple strategy of CeO₂ doping was proposed. The low-temperature (<250℃) NH₃-SCR activity of FeTiO_x catalyst could be dramatically enhanced by CeO₂ doping, and the optimal composition of the catalyst was confirmed as FeCe_0.2TiO_x, which performed a NO_x conversion of 90% at ca. 200℃. According to X-ray diffraction (XRD), Raman spectra and X-ray absorption fine structure spectroscopy (XAFS) analysis, FeCe_0.2TiO_x showed low crystallinity, with Fe and Ce species well mixed with each other. Based on the fitting results of extended X-ray absorption fine structure (EXAFS), a unique Ce-O-Fe structure was formed in FeCe_0.2TiO_x catalyst. The well improved specific surface area and the newly formed Ce-O-Fe structure dramatically contributed to the improvement of the redox property of FeCe_0.2TiO_x catalyst, which was well confirmed by H₂-temperature-programmed reduction (H₂-TPR) and in situ XAFS experiments. Such enhanced redox capability could benefit the activation of NO and NH₃ at low temperatures for NO_x removal. The detailed reaction mechanism study further suggested that the facile oxidative dehydrogenation of NH₃ to highly reactive-NH₂ played a key role in enhancing the low-temperature NH₃-SCR performance of FeCe_0.2TiO_x catalyst.     

基于VOCs浓度反演的地下水中含油物质泄漏原位在线监测方法的建立及应用

石油石化企业的含油物质泄漏进入地下水,会对生态环境造成负面影响。通过构建地下水井模型,比选不同原理的挥发性有机物(VOCs)检测传感器,建立了基于VOCs浓度反演的地下水中含油物质泄漏原位实时在线监测方法。研究发现,常规水质六参数传感器对含油物质泄漏的响应会产生滞后现象,在实时预警监测地下水井中含油物质时可不安装常规水质六参数传感器,节约企业污染防控监测成本。将该方法应用于企业现场进行原位实时监测,当实时监测值超过数据监控平台预警阈值时,系统会发出警报,实现了地下水井中含油物质泄漏实时预警监测。该监测方法具有响应速度快、准确性高、成本低、监测过程简单等优势,将帮助企业实时掌握地下水污染状况,提高地下水污染防控预警效率。     

退役工业固废填埋场地再利用的全寿命环境风险特征

通过现场采样和过程模型模拟等方法研究了典型退役工业固废填埋场地（DISWL）原位开发条件下的健康风险及长期演化规律.结果表明,经过近20a的浸出和降解,86%的废物浸出浓度依然处于有害水平,70%的废物不宜直接作为建设用地土壤.直接作为建筑用地开发利用条件下,由于DISWL的性能退化会导致有害组分的浸出和渗漏增加,由此导致地下水水质超标概率经历从无（短期）到有（中期,个别物质如总氰化物T-CN和易释放氰化物F-CN）,再到后期的较大概率超标（T-CN和F-CN）的渐变过程;同时,场地利用过程的健康风险也逐步增加,来自于As的致癌风险和自于T-CN的非致癌风险,分别超过风险可接受水平的81~179倍和55.32~224.3倍.上述结果提示DISWL场地开发再利用的风险评估和管控策略应重点考虑长期风险.对于长期风险不可接受的场地,通过降低废物中毒性物质的浸出浓度可实现长期风险可接受,并提出了相应浸出浓度限值的计算框架和方法.     

Mechanism for the destruction of carbon tetrachloride and chloroform DNAPLs by modified Fenton's reagent

The destruction of a carbon tetrachloride DNAPL and a chloroform DNAPL was investigated in reactions containing 0.5 mL of DNAPL and a solution of modified Fenton's reagent (2M H2O2 and 5mM iron(III)-chelate). Carbon tetrachloride and chloroform masses were followed in the DNAPLs, the aqueous phases, and the off gasses. In addition, the rate of DNAPL destruction was compared to the rate of gas-purge dissolution. Carbon tetrachloride DNAPLs were rapidly destroyed by modified Fenton's reagent at 6.5 times the rate of gas purge dissolution, with 74% of the DNAPL destroyed within 24h. Use of reactions in which a single reactive oxygen species (hydroxyl radical, hydroperoxide anion, or superoxide radical anion) was generated showed that superoxide is the reactive species in modified Fenton's reagent responsible for carbon tetrachloride DNAPL destruction. Chloroform DNAPLs were also destroyed by modified Fenton's reagent, but at a rate slower than the rate of gas purge dissolution. Reactions generating a single reactive oxygen species demonstrated that chloroform destruction was the result of both superoxide and hydroxyl radical activity. Such a mechanism of chloroform DNAPL destruction is in agreement with the slow but relatively equal reactivity of chloroform with both superoxide and hydroxyl radical. The results of this research demonstrate that modified Fenton's reagent can rapidly and effectively destroy DNAPLs of contaminants characterized by minimal reactivity with hydroxyl radical, and should receive more consideration as a DNAPL cleanup technology.     

Longitudinal monitoring of neutral and adaptive genomic diversity in a reintroduction

Restoration programs in the form of ex-situ breeding combined with reintroductions are becoming critical to counteract demographic declines and species losses. Such programs are increasingly using genetic management to improve conservation outcomes. However, the lack of long-term monitoring of genetic indicators following reintroduction prevents assessments of the trajectory and persistence of reintroduced populations. We carried out an extensive monitoring program in the wild for a threatened small-bodied fish (southern pygmy perch, Nannoperca australis) to assess the long-term genomic effects of its captive breeding and reintroduction. The species was rescued prior to its extirpation from the terminal lakes of Australia's Murray-Darling Basin, and then used for genetically informed captive breeding and reintroductions. Subsequent annual or biannual monitoring of abundance, fitness, and occupancy over a period of 11 years, combined with postreintroduction genetic sampling, revealed survival and recruitment of reintroduced fish. Genomic analyses based on data from the original wild rescued, captive born, and reintroduced cohorts revealed low inbreeding and strong maintenance of neutral and candidate adaptive genomic diversity across multiple generations. An increasing trend in the effective population size of the reintroduced population was consistent with field monitoring data in demonstrating successful re-establishment of the species. This provides a rare empirical example that the adaptive potential of a locally extinct population can be maintained during genetically informed ex-situ conservation breeding and reintroduction into the wild. Strategies to improve biodiversity restoration via ex-situ conservation should include genetic-based captive breeding and longitudinal monitoring of standing genomic variation in reintroduced populations.