电子束深度氧化烟气净化技术

介绍电子束烟气净化技术的特点 ,对传统电子束法与深度氧化法的反应原理、工艺流程进行了比较及分析 ,实验结果表明 ,电子束深度氧化烟气净化技术能耗低、可靠性高 ,是一种具有广阔工业应用前景的环保新技术。     

混合电子供体对好氧非光合微生物菌群固碳效率影响的析因实验分析

通过混合电子供体析因实验,定量描述了Na2S、NaNO2、Na2S2O3 3种无机物的用量和比例与非光合微生物固碳量之间的关系,并分析了3种电子供体之间的两两交互作用.最后,通过16S rDNA V3区DGGE图谱分析,研究了不同混合电子供体对固碳微生物群落结构的影响.结果表明,电子供体析因实验的模型具有较好的拟合度,...     

Adsorption behavior of condensed phosphate on aluminum hydroxide

Sodium pyrophosphate （pyro-P, Na4P2OT）, sodium tripolyphosphate （tripoly-P, Na3P3O10）, and sodium hexametaphosphate （meta-P, （NaPO3）6） were selected as the model compounds of condensed phosphate to investigate the adsorption behavior of condensed phosphate on aluminum hydroxide. The adsorption was found to be endothermic and divisible into two stages： （1） fast adsorption within 1 h; and （2） slow adsorption between 1 and 24 h. The modified Freundlich model simulated the fast adsorption stage well; the slow adsorption stage was described well by the first-order kinetics. The activation energies of pyro-P, tripoly-P, and meta-P adsorption on aluminum hydroxide were determined to be 20.2, 22.8 and 10.9 kJ/mol P adsorbed, respectively, in the fast adsorption stage and to be 66.3, 53.5 and 72.5 kJ/mol P adsorbed, respectively, in the slow adsorption stage. The adsorption increased the negative charge of the aluminum hydroxide surface. Transmission electron microscopy and energy dispersive X-ray analysis analyses provided evidence that the adsorption was not uniform on the surface and that the small crystals contributed more to the fast adsorption than the normal sites did. The results from X-ray fluorescence spectrometry and X-ray photoelectron spectroscopy tests also revealed the uneven adsorption of condensed phosphate as a function of the penetration depth. More condensed phosphates were adsorbed on the outer surface of aluminum hydroxide than in its inner parts.     

蒽醌类有机质对针铁矿异化还原解离特征影响

基于希瓦氏金属还原菌(Shewanella decolorationis S12)和针铁矿相互作用,讨论了蒽醌类有机质(AQS)对该针铁矿异化还原过程的调控机制.结果表明:AQS作为电子运移载体,使得还原解离态铁总量(Fetot)和可溶态铁含量(Fedis)均快速增加;不同含量的AQS加入前后,针铁矿还原平均速率得到显著上升,速率比在2.4~4.0之间,且该比值和AQS含量呈显著的线性关系,可决系数为0.9947.Fedis/Fetot比值随AQS含量升高而降低,当AQS含量由0.05 mmol·L-1增加至0.3 mmol·L-1时,Fedis/Fetot比值由0.935减小至0.705.Feads含量随AQS含量增加而增加,当体系中无AQS时,Feads含量维持在较低的水平(0.05 mmol·L-1).AQS参与下的铁异化还原过程实际上是由两个独立的子过程组成,即微生物呼吸作用驱动了AQS和还原态蒽二酚(AH2QS)的循环转变过程以及AH2QS进一步还原解离针铁矿的非生物过程.     

重构土壤垂直剖面重金属Cd赋存形态及影响因素

针对矿业废弃地高背景值-历史矿业源相叠加区下土壤重金属Cd污染问题,以西南地区某历史硫磺矿业废弃地重构土壤为研究对象,采集剖面土壤共30个样品,分析测试土壤样品中镉(Cd)、铬(Cr)、镍(Ni)、砷(As)和汞(Hg),利用电镜扫描-能谱分析(SEM-EDS)和重金属形态连续提取的BCR方法,分析不同土层厚度下Cd的赋存形式,运用风险评价编码法(RAC)和次生相与原生相分布比值法(RSP)对其进行有效性评价,以及对不同理化性质下Cd各形态的变化规律进行了初步探讨.结果表明,研究区5种重金属中Cd全量的富集系数最高,达4以上;通过形貌特征可以发现,样品中存在较多的次棱角状、棱角状颗粒,不同深度下的能谱特征显示结果相似,均含有Cd、Fe、S和As等元素,Cd元素是以类质同象形式存在;对Cd进行潜在风险评价,RAC结果显示为中等风险及以下,RSP结果主要为重度污染;重金属全量是影响Cd各形态含量分布的最主要因素,其次pH、有机质和CEC,对垂直深度的土壤Cd赋存形态也表现出不同程度的影响.该研究结果可为进一步了解Cd在剖面土壤的活性、迁移规律、生物毒性和赋存形式提供科学依据.     

武汉城市污水中微塑料的分离、鉴定及其微观特征分析

为研究武汉城市污水中微塑料的分布特点及其表面形貌特征,采用以连续浮选分离装置为基础进行改进设计的微塑料提取装置对污水中微塑料进行分离,通过用65%硝酸和30%过氧化氢混合液（体积比为1:3）对污水样品进行消解,并采用筛网（300、600、1 000目）（100目=0.147 mm）和滤膜（1 μm玻璃纤维滤膜和20 nm氧化铝滤膜）分离技术建立起对水体微塑料和纳米塑料的分离富集方法.通过傅里叶变换红外光谱（FTIR）、扫描电镜-X射能谱分析联用（SEM-EDS）等方法对所提取微塑料颗粒的组成成分、赋存特征、表面形貌特征进行分析.结果表明:①提取装置的平均回收率在92%以上.②污水中微塑料类型主要为碎片类、泡沫类、薄膜类和纤维类.③FTIR结果证实,该方法所提取的微塑料颗粒中有聚乙烯、聚丙烯等成分,且发现了羰基、聚酯类物质存在,说明提取到的微塑料中可能有可降解塑料颗粒.④SEM-EDS结果显示,各类微塑料表面粗糙、撕裂程度不同,存在不同程度的风化痕迹,并在其表面发现Si、Cu、O、Al、Na、Ca、Ba等元素的富集.研究显示:改进的微塑料分离方法能够实现对污水中微塑料的高效提取;同时,明确了武汉城市污水微塑料的表面形貌特征及赋存特征,为未来武汉城市污水中微塑料污染的针对性治理提供理论依据.      

Effect of elevated tropospheric ozone on methane and nitrous oxide emission from rice soil in north India

Physiological changes in crop plants in response to the elevated tropospheric ozone (O₃) may alter N and C cycles in soil. This may also affect the atmosphere-biosphere exchange of radiatively important greenhouse gases (GHGs), e.g. methane (CH₄) and nitrous oxide (N₂O) from soil. A study was carried out during July to November of 2007 and 2008 in the experimental farm of Indian Agricultural Research Institute, New Delhi to assess the effects of elevated tropospheric ozone on methane and nitrous oxide emissions from rice (Oryza sativa L.) soil. Rice crop was grown in open top chambers (OTC) under elevated ozone (EO), non-filtered air (NF), charcoal filtered air (CF) and ambient air (AA). Seasonal mean concentrations of O₃ were 4.3 ± 0.9, 26.2 ± 1.9, 59.1 ± 4.2 and 27.5 ± 2.3 ppb during year 2007 and 5.9 ± 1.1, 37.2 ± 2.5, 69.7 ± 3.9 and 39.2 ± 1.8 ppb during year 2008 for treatments CF, NF, EO and AA, respectively. Cumulative seasonal CH₄ emission reduced by 29.7% and 40.4% under the elevated ozone (EO) compared to the non-filtered air (NF), whereas the emission increased by 21.5% and 16.7% in the charcoal filtered air (CF) in 2007 and 2008, respectively. Cumulative seasonal emission of N₂O ranged from 47.8 mg m⁻² in elevated ozone to 54.6 mg m⁻² in charcoal filtered air in 2007 and from 46.4 to 62.1 mg m⁻² in 2008. Elevated ozone reduced grain yield by 11.3% and 12.4% in 2007 and 2008, respectively. Global warming potential (GWP) per unit of rice yield was the least under elevated ozone levels. Dissolved organic C content of soil was lowest under the elevated ozone treatment. Decrease in availability of substrate i.e., dissolved organic C under elevated ozone resulted in a decline in GHG emissions. Filtration of ozone from ambient air increased grain yield and growth parameters of rice and emission of GHGs.     

串联微生物燃料电池的电压反转行为

微生物燃料电池是一种处理废水同时产电的具有广阔应用前景的新型水处理技术,其串联是产生更高电压的有效方法之一,但是会产生电压反转现象降低串联微生物燃料电池的性能.文章将二极管引入串联微生物燃料电池中以考察电压反转的行为.结果表明,不同的串联微生物燃料电池中均会发生电压反转.串联正向二极管的微生物燃料电池的电压反转行为与没...     

铁钛共掺杂氧化铝诱发表面双反应中心催化臭氧化去除水中污染物

多相催化臭氧化技术因能有效去除水中有机污染物而受到广泛关注.然而,基于单一位点氧化还原的金属氧化物催化臭氧化过程存在速率限制步骤,使活性受到抑制,极大地限制了多相催化臭氧化技术的实际应用.为解决这一瓶颈,以过渡金属物种Fe和Ti对金属氧化物y-Al2O3基底进行晶格掺杂制备出新型双反应中心催化剂FT-A-1 DRCs....     

Mitochondrial electron transport chain is involved in microcystin-RR induced tobacco BY-2 cells apoptosis

Microcystin-RR （MC-RR） has been suggested to induce apoptosis in tobacco BY-2 cells through mitochondrial dysfunction including the loss of mitochondrial membrane potential . TO further elucidate the mechanisms involved in MC-RR induced apoptosis in tobacco BY-2 cells, we have investigated the role of mitochondrial electron transport chain （ETC） as a potential source for reactive oxygen species （ROS）. Tobacco BY-2 cells after exposure to MC-RR （60 mg/L） displayed apoptotic changes in association with an increased production of ROS and loss of Am. All of these adverse effects were significantly attenuated by ETC inhibitors including Rotenone （2 μmol/L, complex I inhibitor） and antimycin A （0.01 μmol/L, complex III inhibitor）, but not by thenoyltrifluoroacetone （S μmol/L, complex Ⅱinhibitor）. These results suggest that rnitochondrial ETC plays a key role in mediating MC-RR induced apoptosis in tobacco BY-2 cells through an increased mitochondrial production of ROS.