伊朗南部克尔曼省6.4级地震

2005年2月22日伊朗东南部克尔曼省发生里氏6．4级地震,造成几个村庄房屋被毁,500多人死亡,1000多人受伤。     

石油污染对海洋生态环境的影响与防治对策

分析了石油污染对海洋生态环境的影响,提出了预防泄漏措施.     

高氨氮渗滤液处理的ANAMMOX A2/O工艺研究

通过好氧出水回流到厌氧流化床可以实现厌氧氨氧化过程.对于高浓度氨氮渗滤液,ANAMMOX反应可使ANAMMOX A²/O工艺比普通A²/O工艺的TN去除率提高15%～20%,达32%以上;好氧出水NO-2-N浓度有较大幅度地降低,改善了出水水质.ANAMMOX反应总反应级数为3级,对NH₄⁺-N、NO₃^--N和NO₂^--N的反应级数均为1级,反应速率常数为-3.43E-5 L²·(mmol²·h)^-1.     

Low-temperature CO oxidation over Au-doped 13X-type zeolite catalysts: preparation and catalytic activity

Au-supported 13X-type zeolite (Au/13X) was synthesized using a common deposition–precipitation (DP) method with a solution of sodium carbonate as a precipitate agent. Further testing was conducted to test for catalytic oxidation of CO. A study was conducted on the effects of different preparation conditions (i.e., chloroauric acid concentration, solution temperature, pH of solution, and calcinations temperature) on Au/13X for CO oxidation. In respect to the catalytic activity, the relationship between different the preparation conditions and gold particles in 13X zeolite was analyzed using X-ray diffraction, TEM and XPS. The activity of Au/13X catalysts in CO oxidation was dependent on the chloroauric acid concentration. From XRD results, a higher chloroauric acid concentration induced larger gold nanoparticles, which resulted in lower catalytic activity. Results revealed that higher temperatures induced higher Au loading, homogeneous deposit, and smaller gold clusters on the support of 13X, resulting in higher CO activity. Furthermore, a pH of 5 or 6 generated greater amounts of Au loading and smaller Au particles on 13X than at a pH of 8 or 9. This may be a result of an effective exchange between Au(OH)2Cl2- and Au(OH)₃Cl^- on specific surface sites of zeolite under the pH’s 5 and 6. The sample calcined at 300°C showed the highest activity, which may be due to the sample’s calcined at 200°C inability to decompose completely to metallic gold while the sample calcined at 400°C had larger particles of gold deposited on the support. It can be concluded from this study that Au/13X prepared from a gold solution with an initial chloroauric acid solution concentration of 1.5 × 10^-3 mol·L^-1 gold solution pH of 6, solution temperature of around 90°C, and a calcination temperature of 300°C provides optimum catalytic activity for CO oxidation.     

Nitrifying population dynamics in a redox stratified membrane biofilm reactor (RSMBR) for treating ammonium-rich wastewater

Nitrogen removal performance and nitrifying population dynamics were investigated in a redox stratified membrane biofilm reactor (RSMBR) under oxygen limited condition to treat ammonium-rich wastewater. When the NH4+-N loading rate increased from 11.1±1.0 to 37.2±3.2 gNH4+-N·m-2·d-1, the nitrogen removal in the RSMBR system increased from 18.0±9.6 mgN·d^-1 to 128.9±61.7 mgN·d^-1. Shortcut nitrogen removal was achieved with nitrite accumulation of about 22.3±5.3 mgNO2--N·L-1. Confocal micrographs showed the stratified distributions of nitrifiers and denitrifiers in the membrane aerated biofilms (MABs) at day 120, i.e., ammonia and nitrite oxidizing bacteria (AOB and NOB) were dominant in the region adjacent to the membrane, while heterotrophic bacteria propagated at the top of the biofilm. Real-time qPCR results showed that the abundance of amoA gene was two orders of magnitude higher than the abundance of nxrA gene in the MABs. However, the nxrA gene was always detected during the operation time, which indicates the difficulty of complete washout of NOB in MABs. The growth of heterotrophic bacteria compromised the dominance of nitrifiers in biofilm communities, but it enhanced the denitrification performance of the RSMBR system. Applying a high ammonia loading together with oxygen limitation was found to be an effective way to start nitrite accumulation in MABs, but other approaches were needed to sustain or improve the extent of nitritation in nitrogen conversion in MABs.     

三维电极电催化氧化法处理废水的研究进展

综述了近几年国内外在三维电极电化学反应器方面的最新研究进展,分析了电源的输出形式、阴阳极板的布置方式、粒子电极的填充方式等因素对废水处理效果的影响,探讨了碳纳米材料等新材料在粒子电极载体上的应用,最后介绍了三维电极法与其他技术联用的最新研究,并指出了三维电极法存在的问题及今后的研究方向。     

Enhancing soil aggregation and acetamiprid adsorption by ecofriendly polysaccharides hydrogel based on Ca2+- amphiphilic sodium alginate

Soil aggregation plays an important role in agricultural production activities. However, the structure of soil aggregation is destroyed by the natural environment and unreasonable farming management, resulting in the loss of water, fertilizers and pesticides in soil. At present, hydrogels have been widely reported to promote the formation of soil aggregation. In this paper, amphiphilic calcium alginate (ASA/Ca²⁺) was applied to promote the formation of soil aggregation and enhance pesticide retention. Initially, an ASA was obtained through the one-pot Ugi condensation (a four-component green chemical reaction). Then, ASA/Ca²⁺ hydrogel is prepared by Ca²⁺ cross-linking. The formation of soil aggregation was determined through the Turbiscan Lab Expert stability analyzer, Confocal Laser Scanning Microscope (CLSM), and Transmission Electron Microscope (TEM). And the effect of soil aggregation on acetamiprid environmental behavior was investigated by adsorption kinetics, adsorption isotherms, and leaching. The results shown that the three-dimensional network structure of ASA/Ca²⁺ hydrogel can promote the formation of soil aggregation. Aggregate durability index (ADI) was 0.55 in the presence of ASA/Ca²⁺ hydrogel, indicating that amphiphilic hydrogel can enhance the stability of soil aggregation. The adsorbing capacity of acetamiprid was 1.58 times higher than pure soil, and the release of acetamiprid only about 20% in the presence of ASA/Ca²⁺ hydrogel. These results would be helpful for the formation of soil aggregation and pesticides adsorption on soil aggregation. Thus, ASA/Ca²⁺ hydrogel is likely to improve soil quality, simultaneously it can minimize the mobility of pesticides in the agricultural system.     

Thermal and Mechanical Properties of Polyurethane Rigid Foam Based on Epoxidized Soybean Oil

A soypolyol based on epoxidized soybean oil (ESO) was prepared in the presence of HBF₄ and diethanolamine (DEA) was used as ring opener. A series of polyurethane rigid foam were prepared by mixing polyol with TDI using an isocyanate index of 1.1. The polyol used in this paper were a mixture of soypolyol and a commercial PL-5601 polyester polyol and the mass fraction of PL-5601 was in the range of 0–60%. The thermal properties of the resins were characterized by DSC and TG. The results showed that these rigid foams possess high thermal stability. There were two glass transition temperature of each foam and Tg₁ was increasing with the increasing of OH value. The compression strength of the foam was also recorded, and the effect of mass ratio of soypolyol and PL-5601 polyester polyol on the compression strength was discussed.     

Effects of sepiolite and biochar on microbial diversity in acid red soil from southern China

Sepiolite and biochar can immobilize heavy metals and organic pollutants in soil effectively, but their impact on the soil microbial community and diversity is still unclear. High-throughput Illumina MiSeq method was used to study the effects of sepiolite and biochar on the diversity of microbial communities in acid red soil amended with cadmium and atrazine. A total of 47,472 microbiological Operational Taxonomic Units (OTUs) were found in all the treated soil samples. Sepiolite and biochar enriched the diversity of soil microbes at different classification levels and OTUs, but the effect of biochar was stronger than that of sepiolite. A Venn diagram showed that compared with other treatments, adding 2% biochar could promote the growth of specific microbes, which is better than the case for 5% biochar. The heat map of species abundance cluster showed that the dominant microbes in soil were different for different treatment doses of sepiolite and biochar. Among all the soil treatments, the top ten dominant bacterial phyla (from high to low dominance) were: Actinobacteria, Proteobacteria, Firmicutes, Bacteroidetes, Acidobacteria, Gemmatimonadetes, Chloroflexi, Planctomycetes, Cyanobacteria­, and Verrucomicrobia. The addition of sepiolite and biochar promoted the restoration of the microbial community diversity in contaminated soil.     

洞庭湖湿地Cd富集植物蒌蒿(Artemisia selengensis)的耐性生理机制研究

采用盆栽植株和外源Cd胁迫的方法,分别对不同生长期蒌蒿植株根、叶组织中的抗氧化酶活性、可溶性蛋白及MDA含量进行测定,以揭示蒌蒿在Cd胁迫下的抗氧化机理和耐受机制。研究结果表明,Cd胁迫对上述生理指标均有显著影响:≤20mg·kg-1的Cd处理可使幼苗期植株器官中的可溶性蛋白含量增加16.5%～19.1%,100mg·kg-1的Cd含量水平则导致其含量减少近30%,可溶性蛋白含量的变化与植株的生物量积累关系密切;3种酶活性在0～10mg·kg-1的Cd处理下未显示出明显变化,幼苗期植株CAT、POD活性在10～80mg·kg-1的Cd胁迫下增加明显,高于此浓度范围则使酶蛋白受到破坏而失活,中等含量水平(≤40mg·kg-1)的Cd处理经过长时间作用可使植株逐渐适应胁迫环境,胁迫强度较大的Cd处理可显著提高SOD酶的活性;Cd胁迫过程中植株MDA积累量不断增加。3种抗氧化酶活性的增强在蒌蒿植株耐受Cd胁迫方面能起到较好的防御作用。