Microbial electrolysis cells with biocathodes and driven by microbial fuel cells for simultaneous enhanced Co(II) and Cu(II) removal

Cobalt and copper recovery from aqueous Co(II) and Cu(II) is one critical step for cobalt and copper wastewaters treatment. Previous tests have primarily examined Cu(II) and Co(II) removal in microbial electrolysis cells (MECs) with abiotic cathodes and driven by microbial fuel cell (MFCs). However, Cu(II) and Co(II) removal rates were still slow. Here we report MECs with biocathodes and driven by MFCs where enhanced removal rates of 6.0±0.2 mg?L⁻¹?h⁻¹ for Cu(II) at an initial concentration of 50 mg?L⁻¹ and 5.3±0.4 mg?L⁻¹ h⁻¹ for Co(II) at an initial 40 mg?L⁻¹ were achieved, 1.7 times and 3.3 times as high as those in MECs with abiotic cathodes and driven by MFCs. Species of Cu(II) was reduced to pure copper on the cathodes of MFCs whereas Co(II) was removed associated with microorganisms on the cathodes of the connected MECs. Higher Cu(II) concentrations and smaller working volumes in the cathode chambers of MFCs further improved removal rates of Cu(II) (115.7 mg?L⁻¹?h⁻¹) and Co(II) (6.4 mg?L⁻¹?h⁻¹) with concomitantly achieving hydrogen generation (0.05±0.00 mol?mol⁻¹ COD). Phylogenetic analysis on the biocathodes indicates Proteobacteria dominantly accounted for 67.9% of the total reads, followed by Firmicutes (14.0%), Bacteroidetes (6.1%), Tenericutes (2.5%), Lentisphaerae (1.4%), and Synergistetes (1.0%). This study provides a beneficial attempt to achieve simultaneous enhanced Cu(II) and Co(II) removal, and efficient Cu(II) and Co(II) wastewaters treatment without any external energy consumption.     

一株高效解磷细菌的紫外诱变选育及其在红壤稻田施用效果

红壤对磷有强大吸附固定力,磷肥易被土壤中活性铁、铝固定而使有效态磷转化为各种形态的非有效磷,从而大大降低磷肥的利用率。解磷菌能使土壤中难溶性或不溶性的磷转化为易于被植物吸收利用的磷。通过对江西鹰潭红壤分离筛选并经过紫外诱变获得一株性状稳定的高效解磷细菌Y8。经鉴定,菌株Y8为蜡状芽孢杆菌（Bacillus cereus）。通过与生产中应用的徐州华龙高效复合菌肥厂的解磷细菌X3相比,菌株Y8降解有机磷、溶解Ca3（PO4）2的能力均比较高,分别为155.3mg·L^-1和240.1mg·L^-1。研究各种理化因子对菌株Y8解磷能力的影响,确定了菌株Y8的最佳培养条件为葡萄糖20g·L^-1、NH4（SO4）21.5g·L^-1、pH7.0、温度为35℃,在该条件下菌株Y8溶解Ca3（PO4）2的量为295.6mg·L^-1。在江西鹰潭红壤稻田的施用试验表明,将菌株Y8制成微生物菌剂施用于水稻田可起到减施化肥的作用。     

环境污染对生态危害经济损失评估模式的研究

定量评估环境污染对生态环境危害的经济损失,是环境科学研究的课题。本文从风险评价和环境经济学角度,提出环境污染对生态环境危害经济损失的评估模式。     

环境质量评价中若干评价方法的比较

探讨了目前用于环境质量评价的若干方法－－模糊综合评判法,灰色聚类法,灰关联分析方法及改进形式,物元分析方法及改进形式的共点与异点,指出要推求一种适合环境质量评价实际的方法尚有大量工作要做。     

新疆工业固体废物状况及对策与建议

根据新疆工业固体废物的产生特点及工业固体废物处理处置现状,提出适用于本地的对策与建议。     

A novel auditory working-memory vigilance task for mental fatigue assessment

An auditory working-memory vigilance task (AWVT), which involves higher mental abilities of a person, like working-memory and decision-making, in addition to vigilance, is presented for measuring human mental fatigue in this paper. A 25-h sleep deprivation study, with hourly testing by AWVT (3 min), PalmPVT (5 min) and self-report of sleepiness, is conducted on eight healthy subjects. The trend of mental fatigue level as measured by a specially proposed score, AWVT Fatigue Index (AFI), during the 25-h study shows very similar pattern to those of PalmPVT lapses and self-report sleepiness. AFI even shows closer correspondence to self-report sleepiness than PalmPVT lapses. This suggests that AWVT is able to measure performance decrement due to sleep deprivation, and it can even provide better measurement of mental fatigue than PalmPVT. AWVT shows a learning curve of less than 3 trials indicating that no skill is required in performing AWVT. Furthermore, repeat studies are done on five of the eight subjects. Pearson’s correlation analysis and other statistical exhibits suggest that AWVT has good test–retest reliability and within subject consistency, which are even better than those of PalmPVT. These results suggest that the AWVT can be used as a reliable objective measure of mental fatigue, and it can even track mental fatigue more accurately than PalmPVT in the real world where most tasks require not just a reaction time type response, but also higher mental abilities.     

水产养殖水、沉积物中抗生素检测方法优化及残留特征研究

抗生素作为疾病预防和促进生长的药物被广泛用于水产养殖业中,不可避免地造成了周围环境抗生素的残留,从而带来各种潜在风险。为了对水产养殖水和沉积物中的抗生素残留特征进行研究,建立了环境样品中抗生素的富集方法。对沉积物中抗生素的提取溶剂、HLB小柱活化溶剂和洗脱溶剂进行了筛选,利用高效液相色谱串联质谱仪对15种抗生素进行检测分析,并检测了上海市某水产养殖区7个养殖塘2018年9、12月抗生素的残留水平。结果表明,选用乙腈/磷酸盐缓冲溶液(V∶V=1∶1)作为提取溶剂,依此用甲基叔丁基醚、甲醇和超纯水作为活化溶剂,甲醇作为洗脱溶剂时目标抗生素的回收率最高;在养殖塘水体中共检测出10种抗生素,检出浓度中间值依次为:磺胺类>甲氧苄啶>阿莫西林>氟喹诺酮类>喹乙醇>四环素类和呋喃唑酮。养殖塘沉积物中共检测出13种抗生素,检出浓度中间值依次为:氟喹诺酮类>四环素类>磺胺类>甲氧苄啶>喹乙醇>阿莫西林和呋喃唑酮;不同品种的养殖塘中抗生素的检出种类均不相同,其中青鱼塘和白水鱼塘10种、虾塘9种、扣蟹塘仅5种。对比抗生素检出浓度发现:氟喹诺酮类抗生素在鱼类养殖塘中检出浓度最高,磺胺甲恶唑仅在蟹塘检出,喹乙醇在虾塘检出浓度达3 612.85 ng·L~(-1)。9月与12月抗生素的残留水平也存在差异,抗生素在9月的平均含量比12月高。     

Characterization and sources of PAHs in an urban river system in Beijing,China

Water samples from 20 locations on rivers in the Tongzhou District of Beijing were collected four times from July 2005 to March 2006. In addition, sediment samples were collected in July 2005. All samples were analyzed for 16 US Environmental Protection Agency (EPA) priority pollutants polycyclic aromatic hydrocarbons (PAHs). The concentration, distribution, seasonal variation, and sources of the 16 PAH compounds identified in the water samples, suspended particles, and surface sediments were then evaluated. The concentrations of PAHs in the water and suspended particle and surface sediment samples ranged from 87.3 to 1,890 ng l⁻¹, 1,330 to 27,700 ng g⁻¹, and 156 to 8,650 ng g⁻¹, respectively. These results demonstrated that rivers in the Tongzhou District of Beijing had a high level of PAH pollution, especially in the suspended particles. The highest and lowest concentrations of PAHs in the water samples were observed in summer and spring. However, the seasonal variations in the concentration of PAHs in the suspended particles were more complicated. The dominant compounds in the water, suspended particle, and surface sediment samples were two-, three- and four-ring PAH compounds, respectively. Ratio analysis illustrated that fuel-burning was the primary source of PAHs in the study area. Gasoline, diesel, coal, and coke oven sources were identified and the contributions of the different fuel-burning sources were then calculated using factor analysis and multiple linear regression. These analyses revealed that coal combustion, gasoline combustion plus coke oven emission, and diesel combustion accounted for 38.8%, 38.5%, and 22.7% of the PAHs in suspended particles, respectively.     

稳定代谢葡萄糖和木糖产乙醇的重组酿酒酵母工程菌初步构建

分别克隆了休哈塔假丝酵母(Candida shehatae)的木糖还原酶基因XYL1和热带假丝酵母(Candida tropicalis)的木糖醇脱氢酶基因XYL2,构建出重组表达质粒pACT2-xy11和pDR195-xy12,并使其分别转化酿酒酵母受体细胞.酶活测定结果显示,转化子中木糖还原酶和木糖醇脱氢酶均在宿主菌中得到活性表达.并将这两个基因连同各自重组表达质粒上的表达元件进行了克隆,进而构建出重组酵母染色体整合质粒YIp5.kanR-x12,以期今后通过同源重组的原理将上述基因整合到发酵性能良好的酿酒酵母基因组中,得到稳定代谢葡萄糖和木糖产乙醇的重组酵母菌株.图3表1参15     

Factors influencing the photodegradation of N-nitrosodimethylamine in drinking water

In order to provide basic data for practical application, photodegradation experiment of N-nitrosodimethylamine (NDMA) in aqueous solution was carried out with a low-pressure Hg lamp. Effects of the initial concentration of NDMA, solution pH, dissolved oxygen, and the presence of humic acid on NDMA photodegradation were investigated. NDMA at various initial concentrations selected in this study was almost completely photodegraded by UV irradiation within 20 min, except that at 1.07 mmol/L, NDMA could be photodegraded almost completely in the acidic and neutral solutions, while the removal efficiency decreased remarkably in the alkaline solution. Dissolved oxygen enhanced the NDMA photodegradation, and the presence of humic acid inhibited the degradation of NDMA. Depending on the initial concentration of NDMA, NDMA photodegradation by UV obeyed the pseudo-first-order kinetics. Dimethylamine, nitrite, and nitrate were detected as the photodegradation products of NDMA. ¹O₂ was found to be the reactive oxygen species present in the NDMA photodegradation process by UV, based on the inhibiting experiments using tert-butanol and sodium azide.