固定化SRB吸附乳酸钠的动力学及再生动力学研究

用聚乙烯醇包埋硫酸盐还原菌(SRB),探讨固定化SRB小球的动力学规律及再生动力学控制机理,同时利用膜扩散控制模型与粒内扩散控制模型,描述固定化SRB小球循环吸附乳酸钠的动力学过程,计算出不同条件下的膜扩散系数D/δ和粒内扩散系数D的值.通过对固定化SRB小球吸附乳酸钠的动力学和再生动力学研究,为固定化SRB小球的营养源吸附与再生工艺参数的确定提供理论依据.     

氧化镁湿法烟气脱硫回收工艺的技术经济可行性初步分析

介绍了回收结晶硫酸镁的氧化镁湿法烟气脱硫工艺的基本工艺流程,在抛弃法脱硫系统上所作的工业试验证明了吸收液循环提浓MgSO4的可行性.参照工业硫酸镁生产工艺对130t/h燃煤锅炉烟气脱硫作了回收工艺的投资效益分析和整体工艺的经济性评价,结果表明回收工业硫酸镁具有良好的经济效益.     

Regional distribution of organochlorinated pesticides in pine needles and its indication for socioeconomic development

The regional distribution of 10 potentially harmful organochlorinated pesticides (OCPs) was investigated in pine needles from 18 sites in six Chinese regions. The OCPs concentrations in six regions were as follows: sigmaHCH (sigmaHCH=alpha-+beta-+gamma-+delta-HCH), 4.7-51.5 ng/g; sigmaDDT (p,p'-DDT+p,p'-DDE+p,p'-DDD), 0.9-30.9 ng/g; hexachlorobenzene (HCB), 1.1-5.3 ng/g; sigmachlordane (cis-chlordane+trans-chlordane), no detected-4.3 ng/g, on dry weight basis. Samples from southeast Chinese area contained the highest concentrations of sigmaHCH, sigmaDDT and sigmachlordane, while the contamination levels of most OCPs in southwest Chinese area were the lowest. The ratios of alpha/gamma-HCH (ranged from 1.7 to 5) were observed to be noticeable increase from north to south China, and the ratio of 1.7 revealed the presence of the recent use of lindane in north Chinese area. The significant decrease of the sum concentrations of alpha-+gamma-HCH from mid-1980s to the present and the strong correlation between alpha-, beta-, gamma-, delta-HCH (r=0.87-0.98, n=18, p<0.05) indicated the main usage of the technical HCH in history in China. The p,p'-DDE/p,p'-DDT ratios of <1 revealed the new input of p,p'-DDT in south, southeast and southwest Chinese areas, which could be partly contributed to the new use of impure dicofol. Economic development will leave its mark in the environment, however, its impact on the input and distribution of OCPs on a regional scale is unknown. We attempted to use the socioeconomic index (gross domestic product (GDP) per capita) to explain the distribution and input of OCPs and found that HCB and sigmaDDT seemed to be linked to the economic development, while no relationship of HCH was observed. DDE% of sigmaDDT also showed a negative correlation with the GDP per capita.     

Multiplex approach for screening genetic markers of microbial indicators.

Genetic markers are expected to provide better specificity in epidemiological studies and potentially serve as better indicators of waterborne pathogens. Methods used to assess genetic markers of emerging microbial indicators include pulsed field gel electrophoresis, polymerase chain reaction (PCR), and microarrays. This paper outlines a high-throughput approach to screen for such genetic markers using a set of theoretical and experimental screening tools. The theoretical screening involves evaluating genes related to the ribosomal RNA and specific functions from emerging indicator groups, followed by experimental validation with appropriate sampling schemes and high-throughput and economical screening methods, such as microarrays, real time PCR, and on-chip PCR. Analysis of a wide range of samples covering temporal variability in location, host, and waterborne disease outbreaks is essential. The proposed approach is expected to shorten the time and cost associated with searching for new genetic markers of emerging indicators by at least 10-fold.     

湿法回收砷碱渣中锑的工艺研究

本研究先以水浸实现砷碱渣中的砷锑分离，再对水浸渣进行盐酸浸出，得到了可作为工业原料氯化锑溶液。研究结果表明，在液固比为6：1，温度40℃，浸出时间40min的条件下，可使水浸过程中锑的浸出率低于3％，砷的浸出率达到99％；盐酸浸出中，控制酸浓度为1：1，液固比10：1，温度60℃，授出时间30min，能使锑的浸出率达到88％以上。经过水浸和盐酸浸出，锑的直接回收率为85．36％。     

Preparing graphene from anode graphite of spent lithium-ion batteries

With extensive use of lithium ion batteries (LIBs), amounts of LIBs were discarded, giving rise to growth of resources demand and environmental risk. In view of wide usage of natural graphite and the high content (12%–21%) of anode graphite in spent LIBs, recycling anode graphite from spent LIBs cannot only alleviate the shortage of natural graphite, but also promote the sustainable development of related industries. After calcined at 600°C for 1 h to remove organic substances, anode graphite was used to prepare graphene by oxidation-reduction method. Effect of pH and N₂H₄·H₂O amount on reduction of graphite oxide were probed. Structure of graphite, graphite oxide and graphene were characterized by XRD, Raman and FTIR. Graphite oxide could be completely reduced to graphene at pH 11 and 0.25 mL N₂H₄·H₂O. Due to the presence of some oxygen-containing groups and structure defects in anode graphite, concentrated H₂SO₄ and KMnO₄ consumptions were 40% and around 28.6% less than graphene preparation from natural graphite, respectively.

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Simultaneous enhancement of sludge dewaterability and removal of sludge-borne heavy metals through a novel oxidative leaching induced by nano-CaO2

Environmental Science and Pollution Research - The production of sewage sludge with the presence of various contaminants has been a serious issue for the operation of wastewater treatment plants on...     

Characterization of humic and fulvic acids extracted from landfill by elemental composition, 13C CP/MAS NMR and TMAH-Py-GC/MS

Humic acid (HA) and fulvic acid (FA) extracted from landfills at different landfill ages were characterized by elemental composition, (13)C CP/MAS NMR, and TMAH-Py-GC/MS. The elemental composition analysis revealed high O/C and low H/C ratios in the FA, indicating a high proportion of O-alkyl and carboxylic acids in the FA. The analytical results of (13)C CP/MAS NMR suggested that there were more oxygenated aliphatic carbons and fewer aromatic carbons in FA than in HA. The Py-GC/MS products showed that the HA and FA extracted from the refuse in the landfill were mainly composed of various lignin-derived compounds. Oxidized aromatic acid derivatives originated from the oxidation of side-chains of lignin-like compounds, and this process played a significant role in the process of HA and FA formation in the landfill. All of the results demonstrated that the degree of humification increased with landfill age.     

Leucobacter spp.菌株Ch1还原高浓度Cr(Ⅵ)的研究

利用一株新分离Cr(Ⅵ)还原菌Leucobacter spp. Ch1进行高浓度Cr(Ⅵ)还原的研究.发现生长于Luria Broth培养基中的Leucobacter spp. Ch1最大能还原1800mg/LCr(Ⅵ),而休眠Leucobacter spp. Ch1细胞悬液可以完全还原2100mg/L Cr(Ⅵ).扫描电镜观察到还原cr(Ⅵ)后的细菌末端黏附大团反应产物,电子顺磁共振分析确定产物的成分为Cr(Ⅲ).在分批加Cr(Ⅵ)还原实验中,休眠Leucobacter spp. Ch1细胞悬液在1060min内还原了2368mg/L Cr(Ⅵ),重新加入的乳酸钠可以再次启动Cr(Ⅵ)的生物还原.结果表明,乳酸钠的存在是Leucobacter spp. Ch1还原Cr(Ⅵ)的必要条件,推测该物质在反应中起电子供体的作用.     

施工现场临时用电的通病及防治

建设工程施工用电最大的特点是“临时”。施工现场是临时的，竣工后就转移；施工人员是临时的，不同工种轮番作业，工人流动性大；施工机具是临时的，不同的分部工程所用的设备、机具各有不同，用完就撤；甚至施工供电设施也是临时的，随着施工的进展，供电设施需要经常拆装移位。