施加生物炭对河流沿岸土吸附铜的影响机制

为探究生物炭施加对河流沿岸土吸附铜的影响机制,采集嘉陵江流域(川渝段)内苍溪(CX)、南部(NB)、嘉陵(JL)和合川(HC)沿岸土表层(S,0～20 cm)、亚表层(D,20～40 cm)共8种土样,分别将1%(质量比)生物炭(B)加入到8种土样中形成混合土样(CX_(SB)、NB_(SB)、JL_(SB)和HC_(SB); CX_(DB)、NB_(DB)、JL_(DB)和HC_(DB))。以原始土样作为对照,批处理法研究各供试土样在不同温度、pH和离子强度下的Cu~(2+)吸附和热力学特征,并分析Cu的吸附形态。结果显示:(1)各供试土样对Cu~(2+)的等温吸附都适用Langmuir模型描述,Cu~(2+)的最大吸附量q_m在62. 20～363. 64 mmol/kg之间,S层土样对Cu~(2+)的吸附量均呈现JL NB CXHC的趋势,而D层土样呈现JL CX NB HC的趋势。施加生物炭有助于增强D层土壤对Cu~(2+)的吸附。(2) 20～40℃范围内,各供试土样对Cu~(2+)的吸附量均随温度的升高而升高,表现为增温正效应。热力学参数结果表明各混合土样对Cu~(2+)的吸附是一个自发、吸热和熵增的过程。(3) pH的升高有利于各供试土样对Cu~(2+)的吸附。随着离子强度的增加,各混合土样(HC_S和HC_D除外)对Cu~(2+)的吸附量均呈现先增后降的趋势,0. 1 mol/L时最大。(4)土样中吸附的铜主要以碳酸盐结合态和铁锰氧化物结合态铜存在,生物炭的施加增加了土样中可交换态(HC除外)和有机结合态铜含量,而对碳酸盐结合态和铁锰氧化物结合态铜影响较小。供试土样对Cu~(2+)的q_m主要是由CEC和比表面积决定的。     

两种悬浮填料在ASBBR厌氧氨氧化系统中的性能比较与微生物解析

选取聚乙烯（T1）和聚氨酯（T2）两种悬浮填料投入到两套相同厌氧序批式生物膜反应器（ASBBR）R1和R2中,以城市生活污水为配水基质,考察了两种填料在ASBBR中的性能及菌群结构特征,选出更适宜厌氧氨氧化（ANAMMOX）菌生长的填料.结果表明：R1和R2反应器分别在第93 d和73 d成功启动厌氧氨氧化,并实现稳定运行.稳定运行阶段,R1、R2系统总无机氮（TIN）平均去除率分别达88.34%、87.97%.此外,运行第150 d时,测得单个T1、T2填料的ANAMMOX菌活性分别为5.70和3.70 mg·g^-1·h^-1.同时,扫描电子显微镜（SEM）表征结果证明,球状菌在T1填料上的数量比同倍数下T2填料上多,且杂菌较少.高通量测序结果显示,T1、T2填料上Candidatus anammoxoglobus菌属相对丰度分别为75.29%和38.23%.本研究表明,相比于聚氨酯（T2）填料,聚乙烯（T1）填料更适宜ANAMMOX菌的富集.     

生物膜法光发酵制氢的研究现状与展望

21世纪被誉为氢能世纪.光发酵制氢作为绿色可持续生物制氢方式的一种,可以利用独特的光合系统固定太阳能,并利用有机物产生清洁能源氢气,因而受到广泛关注.但光发酵细菌凝集力差、底物转化效率和光能利用率低导致产氢效能下降,从而阻碍了光发酵制氢的发展.光发酵细菌可以通过形成生物膜而被有效固定,进而增加反应器内光发酵细菌的生物持有量,提高光发酵细菌对不利环境的抵抗力;同时,光发酵细菌形成生物膜后可以调控产氢细菌新陈代谢和生理活性使其更利于产氢.其中,光发酵生物膜反应器的设计尤为重要,尤其是反应器内光源的均匀分配对于光发酵制氢是一项关键因素,需要对光源设计、空间摆放和遮光性进行综合分析和设计;其次,需要考虑载体性质和载体安装以充分吸附光发酵细菌并形成生物膜;同时,结合未来可持续绿色发展的需求,光发酵生物膜反应器设计需要逐步过渡到以室外环境作为常规环境和太阳作为光源.尽管光发酵生物膜制氢前景良好,但目前对于光发酵生物膜反应器和制氢机制的研究仍然不够充分,需要更加深入地探索和优化以突破光发酵制氢的瓶颈,推动氢能行业的发展.     

透水/不透水格局特征对汇水单元径流污染的影响

深入揭示透水/不透水下垫面格局特征(组成、位置和比例等)对城市地块汇水单元地表径流及污染产生能力的影响,对减轻城市内涝及控制面源污染具有重要意义.利用景观格局指数分析透水/不透水下垫面格局特征与地表径流总量(Q)、溶解态污染物累积负荷(L_d)和颗粒态污染物累积负荷(L_p)之间的关系.结果表明:(1)表征破碎度的斑块密度(PD)与最大斑块指数(LPI)分别与Q和L_d呈正、负相关,PD与L_d呈显著正相关(r=0.59,P<0.05,以COD计),LPI与L_d呈显著负相关(r=-0.60,P<0.05,以COD计);(2)表征复杂度的景观形状指数(LSI)和平均斑块形状(MSI)分别与Q和L_p呈正、负相关性,LSI与L_p呈显著正相关(r=0.61,P<0.05,以TP计),MSI与L_p呈极显著负相关(r=-0.62,P<0.01,以TP计);(3)表征聚散度的内聚力指数(COHESION)和分散...     

Sources and distribution of sedimentary organic matter along the northern Bering and Chukchi Seas

In this study, lignin-derived phenols were used to determine the sources and distribution of sedimentary organic matter along the northern Bering Sea and Chukchi Sea of the Arctic Ocean. The lignin parameter syringyl/vanillyl (S/V) and cinnamyl/vanillyl (C/V) ratios are used to indicate vegetation sources; and the ratios of vanillic acid/vanillin, (Ad/Al)v and syringic acid/syringaldehyde, (Ad/Al)s are used as indicators of lignin diagenesis. Results showed the predominance of woody gymnosperm signal at the easternmost location in the northern Bering Sea, a mixture of refractory non-woody angiosperm and fresher gymnosperm tissues in the Chukchi Sea, and signal of fresher woody gymnosperm tissues in the northernmost locations in the Chukchi Sea. The lignin materials showed gradual increase in decomposition stage during transport along the northern Bering Sea. Hydrodynamic sorting process, which is the retention of coarser materials nearshore and transportation of finer particles farther offshore, most probably occurred along the east coast of the northern Bering Sea. In Chukchi Sea, the non-woody angiosperm tissues could have originated from the Canadian Arctic and gymnosperm tissues could be from the Russian Arctic side. The fresher materials in the northernmost Chukchi Sea could have been transported here via the ice-rafting process. Detection of fresh lignin materials and the occurrence of lignin decomposition mean that this region could be sensitive to the impact of climate change.     

Simultaneous elimination of cyanotoxins and PCBs via mechanical collection of cyanobacterial blooms: An application of “green-bioadsorption concept”

In this study, the distribution, transfer and fate of both polychlorinated biphenyls (PCBs) and cyanotoxins via phytoplankton routes were systematically investigated in two Chinese lakes. Results indicated that PCB adsorption/bioaccumulation dynamics has significantly positive correlations with the biomass of green alga and diatoms. Total lipid content of phytoplankton is the major factor that influences PCB adsorption/bioaccumulation. Cyanobacterial blooms with relatively lower lipid content could also absorb high amount of PCBs due to their high cell density in the water columns, and this process was proposed as major route for the transfer of PCBs in Chinese eutrophic freshwater. According to these findings, a novel route on fates of PCBs via phytoplankton and a green bioadsorption concept were proposed and confirmed. In the practice of mechanical collections of bloom biomass from Lake Taihu, cyanotoxin/cyanobacteria and PCBs were found to be removed simultaneously very efficiently followed this theory.     

Release characteristics of mercury in chemical looping combustion of bituminous coal

This study evaluated the release characteristics of mercury from bituminous coal in chemical looping combustion (CLC) using Australian iron ore as the oxygen carrier in a fixed bed reactor. The effects of several parameters, such as temperature in the fuel reactor (FR) and air reactor (AR), gasification medium in the FR, and reaction atmosphere in the AR, on mercury release characteristics, were investigated. The mercury speciation and release amount in the FR and AR under different conditions were further explored. The results indicate that most of the mercury in coal was released in the FR, while the rest of it was released in the AR. Hg⁰ was found to be the major species in the released mercury. The results also indicate that a higher temperature in the FR led to an increase in the total mercury release amount and a decrease in Hg⁰ proportion. However, a higher temperature in the AR resulted in a decrease in the total mercury release amount and Hg⁰ proportion. The increase in the H₂O/CO₂ ratio of gasification mediums in the FR was beneficial for the increase in the total mercury release amount and Hg⁰ proportion. A higher O₂ concentration in reaction atmosphere in AR had a negligible effect on the total mercury release amount, but a positive effect on Hg⁰ oxidization.     

氯、氯胺消毒下钱江源水源水消毒副产物形成特征研究

以钱江源水源水为研究对象,以氯、氯胺为消毒方式,研究了不同消毒条件下,三卤甲烷(THMs)、卤乙腈(HANs)、氯代酮(CKs)、二卤乙酸(DHAAs)、三卤乙酸(THAAs)等消毒副产物(DBPs)的形成情况,以便为水务工作者监测钱江源建库前后水质、DBPs形成的变化提供基础数据.结果显示,氯消毒下DBPs的产量比氯胺消毒高出3~7倍甚至1个数量级,但不管是氯消毒还是氯胺消毒,THMs、HAAs形成量均在我国饮用水标准范围内.氯消毒下,大部分DBPs产量为中、碱性条件酸性条件(除了CKs),氯胺消毒则呈现不同的情况(所有DBPs的产量均为p H=6、p H=7p H=8).消毒剂量对所有DBPs形成具有明显的促进作用;溴离子对THMs、DHANs、DHAAs的形成有明显的促进作用.进一步研究表明,钱江源水源水的水质比钱塘江下游九溪水源水好,DBPs形成也较低,某些指标(如有机碳、有机氮、HANs形成量等)甚至比同省水质较好的金兰水库还要好;而且由于其较高的比紫外吸收值(SUVA),DBPs的溴嵌入能力均比九溪水源水、金兰水库低.此外,就目前的钱江源水源水来说,控制消毒剂量(氯、或氯胺)是控制DBPs形成的有效策略.     

完全混合式曝气系统运行特性及微生物群落结构解析

利用某污水处理厂完全混合式曝气系统处理生活污水,探讨了系统同步硝化反硝化脱氮过程,解析了系统中污泥微生物群落结构.中试试验结果表明,系统运行稳定,且在无外加碳源的条件下,COD、氨氮和总氮平均去除率分别为93.2%、96.9%和75.2%,出水COD、氨氮和总氮均优于一级A排放标准.系统污泥具有较强的反硝化能力,其脱氮速率是污水处理厂污泥的2.86倍以上.通过对系统污泥周质硝酸盐还原酶聚合酶链式反应(polymerase chain reaction,PCR)扩增和高通量测序结果,发现系统中存在好氧反硝化菌,污泥中优势菌为动胶菌属(Zoogloea)、陶厄氏菌属(Thauera)和Dechloromonas菌属.     

我国主要河流中3种氯酚混合物的生态风险评价

氯酚类化合物是我国河流中广泛存在的一类优先控制污染物. 利用基于相似作用模式的混合物风险商（RQ_m）的方法,对我国主要河流中五氯酚、2,4-二氯酚和2,4,6-三氯酚组成的混合物进行了生态风险评价. 结果表明:我国河流中3种氯酚化合物的RQ_m均小于1. 黄河中3种氯酚化合物的RQ_m最高为0.377,长江、珠江、淮河和松花江中3种氯酚化合物的RQ_m分别为0.055、0.039、0.035和0.010,其他河流的RQ_m均小于0010. 整体上看,我国北部河流3种氯酚化合物的RQ_m比南部河流高.