不同酶强化污泥为燃料微生物燃料电池特性对比分析

采用单室无膜悬浮阴极微生物燃料电池(MFC),对比分析了蛋白酶和淀粉酶强化剩余污泥为燃料的MFC(ESMFC)产电特性、酶特性和污泥减量化效果。研究表明,投加蛋白酶的ESMFC最大功率密度比对照组增加106.2%,投加淀粉酶时ESMFC最大功率密度比对照组增加48%。蛋白酶作用主要体现在投加后的前12小时,而淀粉酶作用时间则较长,为投加后的前144小时,但在运行前期,由于高温作用,导致系统内的酶活性较强,投加的淀粉酶作用则不明显。投加蛋白酶的系统内TCOD、TSS和VSS去除率分别为82%、65%和85%,而投加淀粉酶的系统内TCOD、TSS和VSS去除率分别达到86%、67%和88%。此研究对于ESMFC中外加酶的选择具有一定意义。     

质子化改性交联壳聚糖的制备及其吸附硫酸根离子的性能

以壳聚糖为原料,甲醛为氨基保护剂,戊二醛为交联剂,采用反相悬浮交联法制备交联壳聚糖,再对其进行质子化改性得到质子化改性交联壳聚糖吸附剂。通过正交实验对该吸附剂的制备条件进行优化,并对其吸附水中硫酸根（SO₄^2-）的吸附等温特性和动力学进行研究,最后对制备和吸附过程进行能谱分析（EDS）并对吸附剂进行了再生实验。实验结果表明,交联反应的优化条件为：反应温度50℃、反应时间6 h、甲醛：戊二醛：壳聚糖为4.5：0.5：3（质量比）;该吸附过程符合Langmuir吸附等温模型,在25℃（298 K）下,吸附容量最大可达133.87 mg/g;吸附过程较好地符合拟二级动力学模型;EDS分析表明了交联反应、质子化改性和吸附反应均已发生;该吸附剂的再生性能良好,可以重复使用。     

重庆主城区秋冬季逆温对空气质量影响的观测分析

2013年9—11月利用RPG-HATPRO地基多通道微波辐射计对重庆主城区大气进行连续探测,统计了大气逆温情况,并对典型重污染天气下大气逆温与空气质量状况进行综合分析。结果表明,逆温出现的频率为63.3%,基本为接地逆温类型,逆温层厚度为953 m,逆温强度为0.3℃/hm;逆温的存在为气溶胶的积聚和凝聚创造了有利条件。     

Contamination of organochlorine pesticides in water and sediments from a waterbird-inhabited lake,East Central China

Seventeen organochlorine pesticides (OCPs) were investigated in the water and sediments from a waterbird-inhabited lake (Yangchaihu Lake) to evaluate their current pollution levels and potential risks. The concentrations of total OCPs in water and sediments were 10.12–59.75 ng/l and 4.25–27.35 ng/g dry weight, respectively. Hexachlorocyclohexanes (HCHs) and dichlorodiphenyltrichloroethanes (DDTs) were the most abundant OCPs, while HCB and cyclodiene pesticides were detected with low levels. Levels of ∑OCPs (sum of 17 OCPs) at sites highly influenced by waterbirds were significantly higher than the sites with no significant waterbird populations (one-way ANOVA, P?相似文献   

Distribution and ecological risk assessment of organochlorine pesticides in surface sediments from the East Lake,China

Organochlorine pesticides (OCPs) are ubiquitous pollutants, and their presence in urban lakes is a concern for human and ecological health. Surface sediments in the East Lake, China, were collected in winter 2012 and summer 2013 to investigate concentrations, distribution patterns, possible sources, and potential ecological risks of OCPs in this area. The total concentrations of 14 OCPs ranged from 6.3 to 400 ng g^?1 dry weight (dw) with an average concentration of 79 ng g^?1 dw. The mean values of hexachlorocyclohexanes (HCHs) (α-, β-, γ-, and δ-HCH) and dichlorodiphenyltrichloroethanes (DDTs) (p,p’-DDE, p,p’-DDD, and p,p’-DDT) were 36 and 7.6 ng g^?1 dw, accounting for 45 and 10 % of the total OCPs, respectively. The concentrations of OCPs in sediment samples collected in winter were significantly higher than those in summer, especially the HCHs, of which in winter were two times greater than summer. Composition analyses indicated that DDTs and endosulfan were mainly from historical contribution. Historical use of technical HCH and new input of lindane were probably the source of HCHs in the East Lake. Most sampling sites of HCHs and DDTs were found to have the potential ecological risk based on levels specified in the sediment quality standards.     

Measurements of the streaming potential of clay soils from tropical and subtropical regions using self-made apparatus

The streaming potential has been wildly used in charged parallel plates, capillaries, and porous media. However, there have been few studies involving the ζ potential of clay soils based on streaming potential measurements. A laboratory apparatus was developed in this study to measure the streaming potential (ΔE) of bulk clay soils’ coupling coefficient (C) and cell resistance (R) of saturated granular soil samples. Excellent linearity of ΔE versus liquid pressure (ΔP) ensured the validity of measurements. The obtained parameters of C and R can be used to calculate the ζ potential of bulk soils. The results indicated that the ζ potentials measured by streaming potential method were significantly correlated with the ζ potentials of soil colloids determined by electrophoresis (r ²?=?0.960**). Therefore, the streaming potential method can be used to study the ζ potentials of bulk clay soils. The absolute values of the ζ potentials of four soils followed the order: Ultisol from Jiangxi?>?Ultisol from Anhui?>?Oxisol from Guangdong?>?Oxisol from Hainan, and this was consistent with the cation exchange capacities of these soils. The type and concentration of electrolytes affected soil ζ potentials. The ζ potential became less negative with increased electrolyte concentration. The ζ potentials were more negative in monovalent than in divalent cationic electrolyte solutions because more divalent cations were distributed in the shear plane of the diffuse layer as counter-cations on the soil surfaces than monovalent cations at the same electrolyte concentration.     

Degradation of aqueous Rhodamine B by plasma generated along the water surface and its enhancement using nanocrystalline Fe-, Mn-, and Ce-doped TiO2 films

The degradation of aqueous Rhodamine B (RhB) was examined using a dual-channel spark switch module designed to regulate the steepness of pulsed high voltage with microsecond rise time. Depending on the energy per pulse, a spark along the water surface (SPWS) or streamer along the water surface (STWS) was formed. STWS was found to have a better degradation effect and energy efficiency toward RhB than SPWS at the same power; however, addition of H₂O₂ amounts resulted in increased degradation, the effect being more pronounced using SPWS. The initial concentration of RhB also appeared to influence the rate constant of the degradation reaction. Furthermore, TiO₂ films doped with Fe, Mn, and Ce were found to enhance the degradation performance of plasma. A possible reaction mechanism of plasma formation along the water surface was concluded by determination of the main inorganic products in the liquid and gas phases.     

发酵类抗生素废水处理工艺及运行效果

介绍了内蒙古某抗生素废水处理厂的处理工艺流程、处理单元类型及其详细设计参数,通过对该污水处理厂半年内运行效果的调研,分析评价该污水处理系统的处理效果及出水指标;该水厂工艺流程对COD、TOC、氨氮、总氮、总磷、BOD和急性毒性的平均去除率分别为96.52%、95.83%、50.24%、55.20%、62.05%、98.52%和99.14%,COD、氨氮、总氮、总磷出水水质分别为477、438、556.7和7.69 mg/L,达到排放到城区下水道要求,园区内所有废水汇集到园区污水处理厂进行集中深度处理达标后排放水体。通过对该水厂工艺的介绍和水质分析,为我国抗生素生产企业面临的废水处理工艺类型选择及工程改造升级提供一定参考。     

二氧化钛脱除高温烟气中的氯化氢

HCl是城市垃圾焚烧产生的主要气体污染物之一。将一种新型脱氯剂TiO2引入到垃圾焚烧系统中,并与其他脱氯剂的性能进行比较。研究了不同脱氯剂使用量、不同反应温度和不同HCl气体浓度对TiO2、CaO和CaTiO3脱氯效果的影响。结果显示,TiO2能在高温(800~1 000℃)、高HCl浓度(1 303.6~1 629.5 mg/m3)下获得较好的脱氯效果。与传统的脱氯剂CaO相比,TiO2更适合于高温烟气脱氯,其在1 000℃时的氯容(36.3 mg HCl/g TiO2)几乎是相同情况下的CaO氯容(9.3 mg HCl/g CaO)的4倍。而CaTiO3的脱氯效果不但受到自身分解效率的影响,还受到TiO2和CaO脱氯效果的影响,其脱氯效果较差。     

Potential toxicity of amphenicol antibiotic: binding of chloramphenicol to human serum albumin

Antibiotics are widely used in daily life but their abuse has posed a potential threat to human health. To evaluate the toxicity of chloramphenicol (CAP) at the protein level, the interaction between CAP and human serum albumin (HSA) was investigated by fluorescence, Ultraviolet–visible (UV–Vis) absorption, Fourier transform infrared (FT-IR) spectroscopy and molecular docking methods. Fluorescence data revealed that the fluorescence quenching of HSA by CAP was the result of the formation of CAP–HSA complex, and the binding constant was determined to be 3.196?×?10⁴ L mol^?1 at 310 K. The thermodynamic determination indicated that the interaction was driven by enthalpy change and entropy change together, where the multiple hydrogen bonds (CAP and the residues Arg 222 and His 242 of HSA) and van der Waals forces were the dominant binding force. The site marker competition revealed that CAP bound into sub-domain IIA of HSA. The binding of CAP induced the drastic reduction in α-helix conformation and the significant enhancement in β-sheet conformation of HSA. Molecular docking study further confirmed the binding mode obtained by experimental study. This work provides a new quantitative evaluation method for antibiotics to cause the protein damage.