水热溶剂对Cu/CeO2-TiO2催化CO2加氢制甲醇反应性能的影响

以高暴露（001）面锐钛矿TiO₂为载体,使用3种不同溶剂（甲醇、乙二醇和丙三醇）水热负载CeO₂,进而以CeO₂-TiO₂为载体采用硼氢化钠还原法负载Cu,合成Cu/CeO₂-TiO₂催化剂用于催化CO₂加氢制甲醇.XRD、SEM、BET、ICP-OES、XPS、H₂-TPR、EPR和CO₂-TPD等表征表明,以 甲醇/水为混合溶剂合成的CeO₂-TiO₂（CT-M）载体中CeO₂粒径较小、Ce³⁺浓度较高,更有利于Cu的负载与分散,形成紧密接触的三相界面;其负载Cu的催化剂CCT-M经焙烧、还原后形成的CuCeTi三相界面相互作用更强,可产生更多的表面Ce³⁺、氧空位和体相Ti³⁺,表面Ce³⁺、氧空位和体相Ti³⁺等缺陷有利于CO₂的吸附活化,较小粒径的Cu则可加速氢解离,因此,CCT-M具有更多的CO₂加氢反应活性位点,表现出最优的CO₂加氢产甲醇活性.     

亚热带典型小流域磷收支及流失特征对比研究

磷素（P）在环境中的过量累积是导致农业面源污染的主要因素。论文以湖南省长沙县脱甲河农区小流域（52 km²）和涧山河森林-农区小流域（50 km²）为研究单元,基于入户调查资料和连续4 a的流域把口站水文水质定位观测数据,采用物质流分析法,对比研究了亚热带丘陵区典型小流域P的收支平衡及流失特征。结果表明,农区小流域出口地表水总磷（TP）含量变化为0.03~0.68 mg·L^-1,平均含量为0.21 mg·L^-1,整体达到Ⅲ类水质标准;森林-农区小流域TP含量变化范围为0.01~0.35 mg·L^-1,平均为0.08 mg·L^-1,整体为Ⅱ类水质,表明森林-农区小流域地表水水质明显优于农区小流域。农区小流域P的环境滞留强度（32.0 kg·hm^-2·a^-1）显著高于森林-农区小流域（20.6 kg·hm^-2·a^-1）,对环境影响更大。以2013年为例,农区小流域P的主要输入项为饲料,占53.1%,森林-农区小流域则以肥料为主,占53.0%;两个流域的P输出项都以植物和畜禽产品输出为主,均占总输出量的94.0%左右。控制小流域肥料和饲料投入、增加循环利用途径以及提高P利用率是当前减轻水体富营养化的有效途径。     

溶解有机质对生物富集因子计算的影响:以东江鱼体中多溴联苯醚的生物富集为例

准确获取化合物的生物富集因子(BAF)对于判定化合物是否属于潜在毒害性污染物、评价其生态环境风险都具有重要的意义。为探究水体中溶解有机质(DOM)对BAF值的影响,以东江三角洲流域为研究区域,以多溴联苯醚(PBDEs)为目标化合物,研究了PBDEs各单体在3种鱼体中的富集特征。结果表明,PBDEs在3种鱼体中的浓度范围为42~825 ng·g-1脂肪,log BAF值位于5.0~7.4之间。由于脱溴代谢的种间差异,3种鱼类表现出2种PBDE的组成模式。在缺乏脱溴代谢途径的鱼体内,log BAF与化合物辛醇/水分配系数(log KOW)之间存在统计意义上的抛物线关系。但当BAF进行DOM的校正之后,二者之间抛物线形式的相关性消失,而呈现出显著的正线性相关性。以往研究对BAF值在化合物的log KOW达到一定程度后(7~8附近)出现下降的解释是高KOW化合物较大的分子体积降低了其穿过生物膜的可能性,但我们的研究结果表明,这种下降很可能是由于忽视了水体中DOM影响的结果。     

太湖西部入湖口沉积物中有机物分布及其潜在指示意义

太湖作为重要的工农业用水水源以及周边居民饮用水源,其水质安全受到高度关注。在太湖西部入湖口采集7个沉积物样品,研究了合成麝香、多环芳烃(PAHs)、有机磷酸酯阻燃剂/增塑剂(OPs)和有机氯农药(OCPs)含量水平和分布规律。研究结果表明,沉积物中多种污染物分布广泛,含量水平差异较大。其中,Σ15PAHs含量371 ng·g~(-1)~2.53$103ng·g~(-1),主要来源于生物质燃烧和化石燃料高温裂解;沉积物中检出4种多环麝香,主要组分为佳乐麝香(HHCB)(0.0792 ng·g~(-1)~1.17 ng·g~(-1))和吐纳麝香(AHTN)(0.123 ng·g~(-1)~1.29 ng·g~(-1)),它们指示了太湖水体已遭受一定程度生活污水输入影响;沉积物中Σ6OPs含量范围为1.63 ng·g~(-1)~21.9 ng·g~(-1),主要污染组分为磷酸三(2-氯丙基)酯(TCPP)和磷酸三(2-氯乙基)酯(TCEP),并呈现明显的点源排放特征;沉积物中六六六系列(HCHs)(0.310 ng·g~(-1)~1.11 ng·g~(-1))和滴滴涕系列(DDTs)(0.551 ng·g~(-1)~6.40 ng·g~(-1))主要来源于历史残留。位于太滆流域的几个入湖口沉积物中多种污染物含量多高于浙江省辖区3个入湖口沉积物。     

Microbial community structure and dynamics of starch-fed and glucose-fed chemostats during two years of continuous operation

The microbial community structures of two mesophilic anaerobic chemostats, one fed with glucose, the other with starch as sole carbon sources, were studied at various dilution rates (0.05–0.25 d^–1 for glucose and 0.025–0.1 d^–1 for starch) during two years continuous operation. In the glucose-fed chemostat, the aceticlastic methanogen Methanosaeta spp. and hydrogenotrophic methanogen Methanoculleus spp. predominated at low dilution rates, whereas Methanosaeta spp. and the hydrogenotrophic Methanobacterium spp. predominated together when dilution rates were greater than 0.1 d^–1. Bacteria affiliated with the phyla Bacteroidetes, Spirochaetes, and Actinobacteria predominated at dilution rates of 0.05, 0.1, and 0.15 d^–1, respectively, while Firmicutes predominated at higher dilution rates (0.2 and 0.25 d^–1). In the starch-fed chemostat, the aceticlastic and hydrogenotrophic methanogens coexisted at all dilution rates. Although bacteria belonging to only two phyla were mainly responsible for starch degradation (Spirochaetes at the dilution rate of 0.08 d^–1 and Firmicutes at other dilution rates), different bacterial genera were identified at different dilution rates. With the exception of Archaea in the glucose-fed chemostat, the band patterns revealed by denaturing gradient gel electrophoresis (DGGE) of the microbial communities in the two chemostats displayed marked changes during long-term operation at a constant dilution rate. The bacterial community changed with changes in the dilution rate, and was erratic during longterm operation in both glucose-fed and starch-fed chemostats.     

Dynamic simulation of urban water metabolism under water environmental carrying capacity restrictions

A revised concept for urban water metabolism (UWM) is presented in this study to address the inadequacies in current research on UWM and the problems associated with the traditional urban water metabolic process. Feedback loops can be analyzed to increase the water environmental carrying capacity (WECC) of the new urban water metabolism system (UWMS) over that of a traditional UWMS. An analysis of the feedback loops of an UWMS was used to construct a system dynamics (SD) model for the system under a WECC restriction. Water metabolic processes were simulated for different scenarios using the Tongzhou District in Beijing as an example. The results for the newly developed UWM case showed that a water environment of Tongzhou District could support a population of 1.1926 × 10⁶, an irrigation area of 375.521 km², a livestock of 0.7732 × 10⁶, and an industrial value added of ¥193.14 × 10⁹ (i.e. about US$28.285× 10⁹) in 2020. A sensitivity analysis showed that the WECC could be improved to some extent by constructing new sewage treatment facilities or by expanding the current sewage treatment facilities, using reclaimed water and improving the water circulation system.     

铜和镉对珠江天然仔鱼和幼鱼的毒性效应及其潜在生态风险

以静水实验法探讨珠江流域主要金属污染物铜和镉对当地天然仔鱼和幼鱼的急性毒性效应。结果显示,铜对西江赤眼鳟和鲴仔鱼(48 h)和广东鲂幼鱼(96 h)的LC50分别为0.066、0.055和0.10 mg·L-1,对应的安全浓度分别为0.006、0.010和0.010 mg·L-1;镉对赤眼鳟和鲴仔鱼(48 h)以及广东鲂幼鱼(96 h)的LC50分别为1.29、0.83和3.20 mg·L-1,对应的安全浓度分别为0.163、0.077和0.320 mg·L-1。其中,铜对上述受试鱼的安全浓度低于或接近我国《渔业水质标准》及《地表水环境质量标准》Ⅱ类水对铜的规定,而镉对这些受试鱼的安全浓度则高于相关标准对镉的规定。研究结果表明,珠江流域铜污染可能会对当地天然仔鱼、幼鱼群体的补充构成一定程度的威胁,但镉污染暂不会对该区域主要鱼类早期群体补充带来严重的生态风险。     

硝酸铊对浮萍(Lemna gibba L.)的生长抑制及其氧自由基损伤作用

为了探讨硝酸铊(Tl(I)-nitrate)对浮萍(Lemna gibba L.)的生长抑制作用及其可能的氧化损伤机制,设置了Tl(I)-nitrate的8个处理组(0.005、0.01、0.02、0.04、0.08、0.1、0.5和1.0 mg·L-1)和对照组(0.0 mg·L-1),进行96 h急性毒性实验,测定96 h内超氧化物歧化酶(SOD)、过氧化物酶(POD)和过氧化氢酶(CAT)活性及丙二醛含量。结果表明:96 h暴露时间下,浮萍生长受抑制程度与Tl(I)浓度之间呈正相关,Tl(I)-nitrate对浮萍的96 h EC50为0.076 mg·L-1,NOEC为0.01 mg·L-1。CAT活性随着Tl(I)-nitrate浓度升高逐渐降低,在0.5和1 mg·L-1时,有极显著差异(p0.01)产生,SOD活性在0.1 mg·L-1时显著升高(46%),POD活性和MDA含量在Tl(I)浓度0.5 mg·L-1时明显上升。当Tl(I)-nitrate胁迫超出浮萍抗氧化酶系统清除活性氧的能力时,活性氧积累导致浮萍受到不可逆转的氧化损伤。Tl(I)-nitrate对浮萍生长产生明显的抑制作用     

Spent rechargeable lithium batteries in e-waste: composition and its implications

The amount of spent rechargeable lithium batteries （RLBs） is growing rapidly owing to wide application of these batteries in portable electronic devices and electric vehicles, which obliges that spent RLBs should be handled properly. Identification of spent RLBs can supply fundamental information for spent RLBs recycling. This study aimed to determine the differences of physical components and chemical compositions among various spent RLBs. All the samplings of RLBs were rigorously dismantled and measured by an inductive coupled plasma atomic emission spectrometer. The results indicate that the average of total weight of the separator, the anode and the cathode accounted for over 60% of all the RLBs. The weight ratio of valuable metals ranged from 26% to 76%, and approximately 20% of total weight was Cu and Al. Moreover, no significant differences were found among different manufacturers, applications, and electrolyte types. And regarding portable electronic devices, there is also no significant difference in the Co-Li concentration ratios in the leaching liquid of RLBs.