Nitrate removal to its fate in wetland mesocosm filled with sponge iron: Impact of influent COD/N ratio

• CW-Fe allowed a high-performance of NO₃^‒-N removal at the COD/N ratio of 0. • Higher COD/N resulted in lower chem-denitrification and higher bio-denitrification. • The application of s-Fe⁰ contributed to TIN removal in wetland mesocosm. • s-Fe⁰ changed the main denitrifiers in wetland mesocosm. Sponge iron (s-Fe⁰) is a porous metal with the potential to be an electron donor for denitrification. This study aims to evaluate the feasibility of using s-Fe⁰ as the substrate of wetland mesocosms. Here, wetland mesocosms with the addition of s-Fe⁰ particles (CW-Fe) and a blank control group (CW-CK) were established. The NO₃^‒-N reduction property and water quality parameters (pH, DO, and ORP) were examined at three COD/N ratios (0, 5, and 10). Results showed that the NO₃^‒-N removal efficiencies were significantly increased by 6.6 to 58.9% in the presence of s-Fe⁰. NH₄⁺-N was mainly produced by chemical denitrification, and approximately 50% of the NO₃^‒-N was reduced to NH₄⁺-N, at the COD/ratio of 0. An increase of the influent COD/N ratio resulted in lower chemical denitrification and higher bio-denitrification. Although chemical denitrification mediated by s-Fe⁰ led to an accumulation of NH₄⁺-N at COD/N ratios of 0 and 5, the TIN removal efficiencies increased by 4.5%‒12.4%. Moreover, the effluent pH, DO, and ORP values showed a significant negative correlation with total Fe and Fe (II) (P<0.01). High-throughput sequencing analysis indicated that Trichococcus (77.2%) was the most abundant microorganism in the CW-Fe mesocosm, while Thauera, Zoogloea, and Herbaspirillum were the primary denitrifying bacteria. The denitrifiers, Simplicispira, Dechloromonas, and Denitratisoma, were the dominant bacteria for CW-CK. This study provides a valuable method and an improved understanding of NO₃^‒-N reduction characteristics of s-Fe⁰ in a wetland mesocosm.     

Cu2O-g-C3N4异质结催化剂光催化降解甲基橙

采用水热还原法和高温煅烧法将Cu₂O生长到石墨型氮化碳（g-C₃N₄）表面,制得Cu₂O-g-C₃N₄异质结复合光催化剂。通过XRD、XPS、SEM、TEM、DRS、PL、BET等技术对催化剂进行了表征,研究了Cu₂O-g-C₃N₄降解甲基橙的光催化性能及主要活性物种。实验和表征结果表明： Cu₂O与g-C₃N₄面面接触,两相间化学作用强烈;Cu₂O-g-C₃N₄催化剂能有效利用太阳光,电子-空穴得到有效分离;当n（Cu₂O）∶n（g-C₃N₄）=5∶1时,Cu₂O-g-C₃N₄催化剂的活性最佳,在可见光下反应30 min时,甲基橙降解率达84.1%;Cu₂O-g-C₃N₄具有较好的活性稳定性,重复使用6次,甲基橙降解率降至64.7%;电子-空穴是Cu₂O-g-C₃N₄光催化降解甲基橙的主要活性物种。     

Global Climate Talks from Failure to Cooperation and Hope: Swedish News Framings of COP15 and COP21

The purpose of this study is to offer an analysis of how two UN Conferences of Parties, COP15 in Copenhagen 2009 and COP21 in Paris 2015, were covered and debated in Swedish newspapers. Two national and two regional newspapers were selected for the study, and a qualitative frame analysis was conducted on 309 articles. A typology of frames applicable to science-related policy and climate change debates was used and its relevance for global climate summit context was discussed. Having territory in the Arctic region, indigenous populations affected by climate change measures, and political and public sensitivity to environmental issues, the climate debate has particular significance in the Swedish case. Findings indicate a trust in the role of national and supra-national governance to address climate change problems, but also that newspapers in Sweden maintained a focus on the global aspects of the two meetings, rather than framing them as surrogate battlefields for domestic politics.     

N,N-二膦酰基甲基牛磺酸的制备与阻垢缓蚀性能

以牛磺酸、甲醛和三氯化磷为原料制备了N,N-二膦酰基甲基牛磺酸（BPMT）。探讨了原料配比、反应温度、反应时间对BPMT质量的影响,考察了BPMT的阻垢缓蚀性能,并与N,N-二膦酰基甲基氨基磺酸、N,N-二膦酰基甲基氨基甲磺酸、丙烯酸／2-丙烯酰胺-2-甲基丙磺酸、2-膦酸基-1,2,4-三羧基丁烷等进行了比较。实验结果表明,当n（牛磺酸）：n（三氯化磷）：n（甲醛）=1：2：4、反应温度110℃、反应时间2h时,BPMT的质量较好。BPMT的阻碳酸钙垢和稳定锌的性能优于其他阻垢剂,阻磷酸钙垢和分散氧化铁的性能仅次于丙烯酸／2-丙烯酰胺-2-甲基丙磺酸。当BPMT加入量为40mg／L时,缓蚀效果最好。     

深圳市社会经济发展与近岸水体富营养化关系研究(Ⅰ)

通过对深圳市近年来近海海域水体水质数据分析,研究和评价该海域水质演变趋势,并对这种趋势进行环境经济原因分析。得出以下结论:1.西部海域水体富营养化程度比较严重;2.深圳东、西部海域近年N:P值都远远超过16,属于严重的P缺乏型海域;3.深圳海域的大部分水质指标在1998年以后都有大幅上升的趋势,反映了深圳市近年向近海水体排放污染物量有加剧趋势;4.深圳市社会经济的发展加剧了近海水体的污染;5.深圳市人民生活水平近年有较大的提高,排放的生活污染造成环境危害远远大于工业污染。     

湖南蔡家塘森林小流域氮和硫的输入输出特征

以湖南韶山蔡家塘小流域2001～2003年的监测数据为基础,对森林在酸沉降作用下无机氮(NH 4,NO-3)和硫输入、输出的月均通量进行了研究.结果表明,总氮的年输入通量为24～28 kg·hm-2·a-1,主要以NH 4形式(占总输入氮的62%～67%)输入该森林生态系统;年氮输出通量为2～3kg·hm-2·a-1,主要以NO-3形式(占总输出N的83%～98%)输出该森林生态系统.韶山森林年无机氮的滞留量达到22～26kg·hm-2·a-1,其中NH 4占到总氮净截留量的68%～72%.硫的截留量为13～21 kg·hm-2·a-1.高氮沉降导致了一部分氮的输出,但是输出氮仅占到输入氮的8%～9%.有超过90%的氮被生态系统截留.由此可以推断,韶山森林尽管有高氮输入,但是生态系统远没有达到氮饱和状态.     

垃圾渗滤液氨态氮与挥发性脂肪酸馏出规律研究

为了提高垃圾渗滤液氨态氮（NH4^＋-N）与挥发性脂肪酸（VFA）联合滴定分析结果的准确性,试验研究了NH4^＋-N与VFA的馏出规律,并在此基础上对联合滴定方法的优化进行了探讨。结果表明：测得的NH4^＋-N质量浓度（Y1）、VFA浓度（Y2）与馏出液体积（X）分别符合函数关系式;联合滴定分析过程中,渗滤液样品NH4^＋-N质量浓度应稀释至150mg／L-200mg／L,NH4^＋-N馏出液应大于蒸馏液体积的60％;VFA分析应采用“一次蒸馏80％＋二次蒸馏”的方式,且VFA二次馏出液应大于蒸馏液体积的75％（相对误差限εr〈5％）。     

毛细管柱气相色谱法同时测定水中甲醇、乙醇和N,N-二甲基甲酰胺

采用HP-PLOT Q毛细管柱,气相色谱氢火焰离子化检测器同时测定地表水和废水中甲醇,乙醇,N,N-二甲基甲酰胺,方法不受水中苯系物的干扰,在甲醇,乙醇,N,N-二甲基甲酰胺分别为7.92~792 mg/L,7.98~798 mg/L和9.45~945 mg/L范围内线性良好,相关系数均0.999,准确度高,加标回收率均94.2%,精密度好,相对标准偏差均≤5.79%,检出限分别为1.17,1.31和2.05 mg/L。     

环境预测中灰色模型的EXCEL解法

提出了利用EXCEL应用软件建立GM（1,N）预测模型的建模方法,并结合实例介绍了建立河流高锰酸盐指数GM（1,3）模型的操作过程。