石灰湿法脱硫传质－反应过程机理

对以族流板塔作吸收器的石灰湿法烟气脱硫技术进行了试验研究,分析了石灰浆液吸收ＳＯ２的传质－反应过程,并提出了Ｃａ（ＯＨ）２浆液吸收ＳＯ２的传质－反应过程机理。本机理认为,总反应速度由气相中ＳＯ２的扩散（气相阻力）和液相中Ｃａ（ＯＨ）２固体的溶解（包括在液相阻力之内）及扩散控制;同时认为,反应过程可分为气相阻力控制、气液相阻力共同控制、液相阻力控制３个阶段。此外,本机理得到了实验的验证。以上结果将有助于改进石灰湿法烟气脱硫工业装置的设计和操作。     

内电解法白腐菌生物处理活性染料染色废水

研究采用从自然界中采集 ,经分离、纯化 ,得到的对染料废水脱色效果较为明显的菌株 ,应用内电解法对染料废水进行预处理 ,以改善其可生化性之后 ,进行活性染料染色废水的生物处理实验。确定了最佳组合工艺条件 :内电解进水pH值为 3 5 ,停留时间 15min ,白腐菌纤维球载体固定化生物处理 ,进水pH值为 4 5 ,溶解氧浓度 >8mg L ,停留时间 12h ,脱色率达到近 10 0 % ,CODCr、BOD5去除率分别达到 90 7%及 94 8%。     

千岛湖生态环境主要问题及保护对策

1998—2000年的研究结果表明,千岛湖的富营养化进程明显加速。千岛湖上游安徽境内输入的大量营养盐、周边地区的生态环境变化、农田地表径流及水土流失是引起湖水水体质量变化的主要原因。控制上游安徽境内的入湖水质、减少农业面源污染和水土流失对水体的影响、恢复与重建湖滨植被保护带、改善整个周边地区的生态环境等是保护千岛湖生态环境的主要对策。     

污泥电子传递体系(ETS)活性测定中萃取剂的选择

比较了丙酮、乙醇、正丁醇、磷酸三丁酯、乙酸乙酯、甲苯和三氯甲烷等7种萃取剂检测活性污泥电子传递体系(ETS)活性的特性.结果表明,这7种萃取剂制作标准曲线的性能相近;在实际污泥样品检测中,37℃下丙酮的萃取时间仅需10min,待测样品量相同时,其萃取速度约是其它萃取剂的4～22倍,37℃下丙酮萃取污泥样品中三苯基甲脂(TF)的能力大于其它萃取剂在37℃或90℃下的萃取能力,同时以丙酮作萃取剂测定的污泥电子传递体系活性也最大,说明丙酮是污泥电子传递体系活性测定中萃取剂的最佳选择.     

低强度紫外线催化降解活性艳红X-3B溶液研究

研究了低强度紫外线对活性艳红X 3B溶液的处理效果 ,考察了紫外线波长、溶液pH、起始浓度、催化剂用量、温度及曝气条件对染料降解的影响。结果表明 ,36 5nm紫外线 (UV3 65nm)的处理效果明显优于 2 5 4nm紫外线 (UV2 54nm) ,反应最适pH为 3 0～ 5 0 ,最佳TiO2 投加量为 2 0g/L ,最适温度为 4 0℃ ,通入空气或氧气均能加速活性艳红X 3B的降解。在上述条件下 ,起始浓度为 5 0mg/L的活性艳红X 3B在 1 5 0min内可完全分解     

环境中丙烯酰胺检测方法和健康危害的研究进展

丙烯酰胺广泛应用于工业生产,是一种潜在的环境污染物。本文从丙烯酰胺的检测方法和健康危害2个方面总结了目前的研究进展。检测方法上,以高效液相色谱-质谱串联法(HPLC-MS/MS)最为常用,一些新技术也逐渐应用到分析中。健康危害方面,丙烯酰胺可引起实验生物的神经、生殖、遗传和发育等毒性和潜在致癌性。其毒性机理为:直接损坏神经元;使活性氧(ROS)积累导致氧化损伤;诱发基因位点突变,或与DNA形成加合物而致其损伤等。鉴于目前研究存在的问题,对以后的工作进行了展望:加强监管与治理工作,保护生态环境和人类健康;深入开展丙烯酰胺对生物体的毒性效应研究;加强我国环境中丙烯酰胺的跟踪监测工作;建立一种快捷的生物测试系统来评估水体(尤其是海洋环境)中丙烯酰胺的毒性风险。     

污水生物除磷若干影响因素分析

在系统阐述污水生物除磷机理的基础上,深入分析了微生物群体平衡、城市污水水质、环境因子以及工艺运行参数和运行方式等方面对生物除磷效果的影响.分析结果表明:生物除磷系统的溶解氧浓度不宜太高,一般好氧区DO＜2 mg/L,厌氧区DO＜0.2 mg/L;厌氧段存在硝酸盐对生物释磷有负面影响,缺氧段存在一定浓度的硝酸盐有利于生物聚磷;碳源必须充分、易降解;TKN/COD＜0.1的城市污水有利于生物除磷;pH偏碱性可提高生物除磷效率;低温对生物除磷效果影响不明显.     

Differences in distributions,assembly mechanisms,and putative interactions of AOB and NOB at a large spatial scale

● Nitrifiers in WWTP were investigated at large spatial scale. ● AOB populations varied greatly but NOB populations were similar among cities. ● Drift dominated both AOB and NOB assembling processes. ● DO did not show a significant effect on NOB. ● NOB tended to cooperate with AOB and non-nitrifying microorganisms. Ammonia-oxidizing bacteria (AOB) and nitrite-oxidizing bacteria (NOB) play crucial roles in removing nitrogen from sewage in wastewater treatment plants (WWTPs) to protect water resources. However, the differences in ecological properties and putative interactions of AOB and NOB in WWTPs at a large spatial scale remain unclear. Hence, 132 activated sludge (AS) samples collected from 11 cities across China were studied by utilizing 16S rRNA gene sequencing technology. Results indicated that Nitrosomonas and Nitrosospira accounted for similar ratios of the AOB community and might play nearly equal roles in ammonia oxidation in AS. However, Nitrospira greatly outnumbered other NOB genera, with proportions varying from 94.7% to 99.9% of the NOB community in all WWTPs. Similar compositions and, hence, a low distance–decay turnover rate of NOB (0.035) across China were observed. This scenario might have partly resulted from the high proportions of homogenizing dispersal (~13%). Additionally, drift presented dominant roles in AOB and NOB assembling mechanisms (85.2% and 81.6% for AOB and NOB, respectively). The partial Mantel test illustrated that sludge retention time and temperature were the primary environmental factors affecting AOB and NOB communities. Network results showed that NOB played a leading role in maintaining module structures and node connections in AS. Moreover, most links between NOB and other microorganisms were positive, indicating that NOB were involved in complex symbioses with bacteria in AS.     

Evolution of chemical composition of fogwater in winter in Chengdu, China

Two sampling sites representing the urban and suburban area of Chengdu, China were sampled and analyzed for selected chemicals to characterize the evolution of the chemical composition of fogwater. A trend of total organic carbon (TOC) > total nitrogen (TN) > total inorganic carbon (TIC) was observed for both sites. Variation of inorganic ions indicated that inorganic pollutants were not accumulated in the fog. Concentrations of n-alkanes (C11-C37) at the urban site ranged from 7.58 to 27.75 ng/mL while at the suburban site concentrations were 2.57-21.55 ng/mL. The highest concentration of n-alkanes was observed in the mature period of fog (393.12 ng/mL) which was more than ten times that in the fog formation period (27.83 ng/mL) and the fog dissipation period (14.87 ng/mL). Concentrations of Σ15PAHs were in the range of 7.27-38.52 ng/mL at the urban site and 2.59-22.69 ng/mL at the suburban site. Contents of PAHs in the mature period of fog (27.15 ng/mL) > fog dissipation period (11.59 ng/mL) > fog formation period (6.42 ng/mL). Concentrations of dicarboxylic acids (C5-C9) ranged from 10.92 to 40.78 ng/mL, with glutaric acid (C5) as the dominant dicarboxylic acid. These data provide strong indications of the accumulation of certain organic chemicals of environmental concern in fog and fog water, and provide additional insights about processes in urban and suburban air acting on organic chemicals with similar physical chemical properties.     

Polyclonal antibody-based indirect competitive enzyme-linked immunosorbent assay for screening of paclobutrazol in fruits

Abstract

Paclobutrazol (PBZ) is a plant growth regulator (PGR) widely used in fruit and vegetable cultivation. However, due to the severe toxicity of PBZ, a sub-ppm level maximum residue limit (MRL) was established worldwide. Therefore, it is significant to propose a rapid, sensitive and high throughput screening method for monitoring the PBZ residues in foods. In this study, a simple and sensitive indirect competitive Enzyme-linked immunosorbent assay (icELISA) was established for PBZ detection in fruits basing polyclonal antibody. For both economy and pollution prevention, a microwave-solvent-free method was used to synthesize the PBZ hapten with high efficiency. The detection conditions, such as coating antigen concentration, antibody concentration, organic reagent concentration, ionic strength and pH, were optimized. Under the optimized conditions, this method showed high sensitivity and specificity. The detection range is 1.27-138.23?ng/mL, half-maximum inhibition concentration (IC₅₀) is 13.26?ng/mL, and the IC₂₀ was lower than the reported ELISAs for PBZ. Additionally, this method had high accuracy and precision. The recoveries were ranged from 88.78% to 96.80% in PBZ spiked apple samples with RSD below 4%. All the results showed that the polyclonal antibody based icELISA could be useful for PBZ screening in fruit samples.