Solar energy for electricity and fuels

Solar energy conversion into electricity by photovoltaic modules is now a mature technology. We discuss the need for materials and device developments using conventional silicon and other materials, pointing to the need to use scalable materials and to reduce the energy payback time. Storage of solar energy can be achieved using the energy of light to produce a fuel. We discuss how this can be achieved in a direct process mimicking the photosynthetic processes, using synthetic organic, inorganic, or hybrid materials for light collection and catalysis. We also briefly discuss challenges and needs for large-scale implementation of direct solar fuel technologies.     

Efficacy of created and restored nesting sites for the conservation of colonial Laridae in the South of France

By rapidly modifying key habitat components, habitat restoration is at risk of producing attractive cues for animals without providing habitats of sufficient quality. As such, individual fitness components, such as reproduction, could be reduced and restored habitats could become ecological traps. This risk notably appears by using artificial constructions in restoration projects, yet few studies have evaluated their efficacy in a robust way. We investigated this by analyzing 154 islets that were created or restored to improve the conservation status of 7 colonial Laridae species in the South of France. From 2007 to 2016, we compared occupancy dynamics and breeding parameters of these species between the restored sites and 846 unmanaged nesting sites. We also explored species’ preference for different nesting site characteristics and their respective effect on breeding parameters. Restored nesting sites were 2–9 times as attractive as unmanaged sites for all species except the Black-headed Gull (Chroicocephalus ridibundus). Colonization probability was up to 100 times higher in sites already used by other species the previous year and increased with distance to the shore until >0.2 when distance was over 250 m. Abandonment probability was 29–70% lower when breeding was successful the previous year in all species except the Sandwich Tern (Thalasseus sandvicensis). Productivity and breeding success probability were 2 times higher on managed sites. Distance from the shore was an important attractive characteristic of artificial nesting sites in all species. Other nesting site characteristics had species-specific effects on colonization, abandonment, and breeding success. Our results indicate that managed nesting sites are successful conservation tools for colonial Laridae in the Mediterranean and do not act as ecological traps. Our study showed that testing the ecological trap hypothesis is a robust way to evaluate the success of restoration projects of breeding habitats.     

蠡河底泥中反硝化复合菌群富集及菌群结构研究

从无锡市滨湖区蠡河底泥中富集培养反硝化复合菌群,研究其在不同富集培养阶段TN、NO-3-N、NO-2-N、NH+4-N和COD动态变化,分析反硝化过程中气体释放总量、释放速率和成分,通过构建全长16S r DNA克隆文库研究其菌落结构.结果表明,反硝化复合菌群富集在阶段4时脱氮效果最佳,仅在9 h内,330 mg·L-1的TN负荷下,TN去除率达90.9%,NO-3-N去除率达100%,中间产物NO-2-N和NH+4-N积累量最少,分别为3.39 mg·L-1和16.64 mg·L-1,COD去除率达85%;释放气体260m L,气体主要成分为N2,同时还有少量的CH4和CO2等.富集培养反硝化复合菌群细菌属于Pseudomonadaceae科和Rhodocyclaceae科,为Proteobacteria门,OUT丰度分别为57.8%和31.6%,Pseudomonadaceae科是优势类群.     

改良剂对广西环江强酸铅锌污染土壤的修复作用

广西环江沿岸农田土壤具有强酸、多重金属污染等特点,失去了农业生产能力,为此,本研究试用了土壤淋溶实验探究不同类型改良剂(生石灰、钙镁磷肥、有机肥、聚丙烯酰胺)组合对广西环江沿岸污染土壤的修复效果,土壤重金属迁移规律及对农田适耕性的影响.结果表明,对照组T1土壤酸化严重,降低清洁接触土壤层p H值,而处理方式T2、T3、T4、T5均能显著提高污染土壤p H值(P0.05),对供试土壤p H变化大小分别为2.7~3.2、1.6~2.7,均能达到南方农业生产土壤p H值范围.较对照组T1,在污染土壤0~20 cm处,处理方式T2、T3、T4、T5能有效地活化Pb,钝化Zn的作用;在清洁土壤20~60cm处,各个处理方式对DTPA-Pb、DTPA-Zn的作用不存在显著差异(P0.05).较对照组T1,处理方式T4、T5能为植物提供良好的种植营养物质,以期能为今后结合生物修复等措施提供技术支撑.     

溴酸盐对水生生物的急性毒性效应

采用标准毒性测试方法,分析了溴酸钾、溴酸钠、溴化钾对水生生态系统中不同营养级生物包括发光菌、绿藻、水蚤、斑马鱼的急性毒性效应.结果表明,3种污染物对发光菌发光强度几乎没有影响,溴酸钾对斜生栅藻的96 h EC50为738.18mg·L-1;对大型蚤和裸腹蚤的48 h EC50分别为154.01 mg·L-1和161.80 mg·L-1,48 h LC50分别为198.52 mg·L-1和175.68mg·L-1;对斑马鱼的96 h LC50为931.4 mg·L-1.溴酸钠对斜生栅藻的96 h EC50为540.26 mg·L-1;对大型蚤和裸腹蚤的48 h EC50分别为127.90 mg·L-1和111.07 mg·L-1,48 h LC50分别为161.80 mg·L-1和123.47 mg·L-1;对斑马鱼的96 h LC50为1 065.6 mg·L-1.而溴化钾对以上几种受试生物的影响远小于溴酸钾和溴酸钠的影响,对比可知引起受试生物产生毒性效应的原因是由溴酸盐引起的.毒性作用规律显示,随着暴露时间的增加,溴酸盐的毒性效应越明显,受试生物对溴酸盐的毒性效应的敏感顺序为:大型蚤、裸腹蚤斜生栅藻斑马鱼普通小球藻、发光菌.     

宁波三江口水域原核生物群落结构分析

首次应用16S rRNA基因-Illumina Miseq高通量测序技术对甬江流域宁波三江口区域的表层水体原核生物群落进行了分析,共获得215 504条高质量序列.多样性指数分析表明,该流域的水体原核生物群落具有较高的遗传多样性和丰富度.菌群分类分析发现,β-变形菌纲(β-Proteobacterium)、放线菌门(Actinobacteria)和拟杆菌门(Bacteroidetes)是主要的优势菌群,其相对丰度占总群落的78.88%.对比不同站位的原核生物群落,发现水文环境可能是影响三江口水域原核生物群落组成和结构的重要因素之一.与以往报道对比分析表明,甬江流域分布有多种污水和粪便污染指示菌,其中余姚江污染指示菌的丰度最高,说明其受污染的风险可能较高.病原菌BLASTN分析表明,在种和亚种水平上,分别检出76和18种潜在病原菌,占序列总量的2.19%和0.40%.本研究为系统认识甬江流域原核生物群落结构及生态功能提供了重要基础数据.     

微生物对汞矿区农田土壤汞甲基化的影响

为研究典型汞矿区农田土壤中汞的甲基化作用,实验以受汞污染的旱田土壤和稻田土壤为对象,分别进行灭菌,促进硫酸盐还原菌(SRB)活性处理,抑制SRB活性处理以及促进铁还原菌(FeRB)活性处理,分析非微生物作用和微生物作用对土壤甲基汞(MeHg)生成的影响.结果表明,促进SRB活性处理的土壤MeHg生成量最高,其中旱田土MeHg增量为0.15~0.38μg·kg~(-1),稻田土壤MeHg增量为1~2μg·kg~(-1);抑制SRB活性处理和促进FeRB活性处理的MeHg增量较小,最高值仅为0.025μg·kg~(-1).相比于旱田土壤,稻田土壤具有更高的汞甲基化能力,其MeHg生成量是旱田土壤的4~9倍.土壤SRB数量与MeHg生成量具有相同的变化趋势,二者具有显著的正相关性(R~2=0.57,P0.01).因此,该研究区土壤汞甲基化作用主要是微生物汞甲基化作用,且主要的汞甲基化细菌是SRB.此外,稻田是农田中MeHg生成的活跃地区,在评估和控制MeHg对人体健康危害时需要重点关注.     

Performance of low temperature Microbial Fuel Cells (MFCs) catalyzed by mixed bacterial consortia

Microbial Fuel Cells(MFCs) are a promising technology for treating wastewater in a sustainable manner. In potential applications, low temperatures substantially reduce MFC performance. To better understand the effect of temperature and particularly how bioanodes respond to changes in temperature, we investigated the current generation of mixed-culture and pure-culture MFCs at two low temperatures, 10°C and 5°C. The results implied that the mixed-culture MFC sustainably performed better than the pure-culture(Shewanella) MFC at 10°C, but the electrogenic activity of anodic bacteria was substantially reduced at the lower temperature of 5°C. At 10°C, the maximum output voltage generated with the mixed-culture was 540–560 m V, which was 10%–15% higher than that of Shewanella MFCs. The maximum power density reached 465.3 ± 5.8 m W/m~2 for the mixed-culture at10°C, while only 68.7 ± 3.7 m W/m~2 was achieved with the pure-culture. It was shown that the anodic biofilm of the mixed-culture MFC had a lower overpotential and resistance than the pure-culture MFC. Phylogenetic analysis disclosed the prevalence of Geobacter and Pseudomonas rather than Shewanella in the mixed-culture anodic biofilm, which mitigated the increase of resistance or overpotential at low temperatures.     

Nano-sized Fe2O3/Fe3O4 facilitate anaerobic transformation of hexavalent chromium in soil–water systems

The purpose of this study is to investigate the effects of nano-sized or submicro Fe_2O_3/Fe_3O_4 on the bioreduction of hexavalent chromium(Cr(VI)) and to evaluate the effects of nano-sized Fe_2O_3/Fe_3O_4 on the microbial communities from the anaerobic flooding soil.The results indicated that the net decreases upon Cr(VI) concentration from biotic soil samples amended with nano-sized Fe_2O_3(317.1 ± 2.1 mg/L) and Fe_3O_4(324.0 ± 22.2 mg/L) within21 days,which were approximately 2-fold of Cr(VI) concentration released from blank control assays(117.1 ± 5.6 mg/L).Furthermore,the results of denaturing gradient gel electrophoresis(DGGE) and high-throughput sequencing indicated a greater variety of microbes within the microbial community in amendments with nano-sized Fe_2O_3/Fe_3O_4 than the control assays.Especially,Proteobacteria occupied a predominant status on the phylum level within the indigenous microbial communities from chromium-contaminated soils.Besides,some partial decrease of soluble Cr(VI) in abiotic nano-sized Fe_2O_3/Fe_3O_4 amendments was responsible for the adsorption of nano-sized Fe_2O_3/Fe_3O_4 to soluble Cr(VI).Hence,the presence of nano-sized Fe_2O_3/Fe_3O_4 could largely facilitate the mobilization and biotransformation of Cr(VI) from flooding soils by adsorption and bio-mediated processes.     

苯酚的褐煤吸附过程及影响因素分析

以污染物苯酚为研究对象,褐煤作为吸附剂,通过批量实验研究了褐煤对废水中苯酚的吸附特性,考察了褐煤粒径、褐煤投加量、反应温度、反应p H、反应时间对吸附作用的影响,并对吸附过程进行了分析。采用Lagergren动力学方程和拟二级吸附动力学方程分析苯酚吸附过程,结果表明,褐煤对苯酚的吸附动力学曲线更符合拟二级吸附动力学方程,反应初始速率随着苯酚初始浓度的升高而增大,但随着煤粉粒径的增大而减小。颗粒内扩散模型对苯酚的吸附动力学曲线分析结果表明:苯酚在褐煤上的吸附首先经历了速率较快的膜扩散控制阶段,进而经历了吸附较缓慢的颗粒内扩散控制阶段,最后到达吸附平衡,褐煤对苯酚的吸附过程主要受到颗粒内扩散控制。