絮凝#x02014;微波辐射#x02014;Fenton试剂氧化法深度处理焦化废水

用絮凝#x02014;微波辐射#x02014;Fenton试剂氧化法深度处理焦化废水,研究了微波辐射时间、微波功率、FeSO₄加入量、H₂O₂加入量和废水pH对废水处理效果的影响。实验结果表明：在聚合氯化铝加入量为350mg/L、聚丙烯酰胺加入量为12mg/L、废水pH=5、FeSO₄加入量为250mg/L、H₂O₂总加入量为1400mg/L、H₂O₂分3次投加、微波功率为400W、微波辐射时间为60min的条件下,处理后出水的浊度、色度和COD去除率分别为98.59%,97.62%,86.21%。处理后出水澄清透明,COD为50.34mg/L,满足GB50050#x02014;2007《工业循环冷却水处理设计规范》的要求。     

Structure and Properties of Cocoons and Silk Fibers Produced by Attacus atlas

Silk fibers in the three layers of Attacus atlas (A. atlas) cocoons have morphological structure and tensile properties similar to that of Bombyx mori silk. Attempts are being made to produce silk for commercial applications from cocoons of relatively unknown wild insects due to the unique properties of the fibers and as a source of income and employment. In this research, A. atlas cocoons were used to study the chemical composition, morphology, physical structure and tensile properties of the silk fibers in the cocoons and ability of the fibers to support the attachment and proliferation of mouse fibroblast cells. It was found that A. atlas cocoons consists of outer, intermediate and inner layer with average breaking tenacity of 4.1, 4.3 and 3.6 g/den, respectively similar to that of B. mori silk (4.3–5.2 g/den). The heavier cocoons, less restrictive rearing conditions and good properties of the fibers compared to B. mori silk makes A. atlas a potential alternative to common silks for commercial scale silk production. A. atlas fibers had about 80 % higher optical densities of cells and extensive growth of F-actin compared to B. mori silk fibers.     

Heavy metal pollution in vegetables grown in the vicinity of a multi-metal mining area in Gejiu,China: total concentrations,speciation analysis,and health risk

A field survey was conducted to investigate the present situation and health risk of arsenic (As), lead (Pb), cadmium (Cd), copper (Cu), and zinc (Zn) in soils and vegetables in a multi-metal mining area, Gejiu, China. Furthermore, three vegetables (water spinach, potato, and summer squash) containing high metal concentrations were selected to further analyze metal speciation. The results showed that the average concentrations of five metals in soil exceeded the limiting values, and their bioavailable concentrations were significantly positively correlated to the total ones. Heavy metals in the edible parts of vegetables also exceeded the corresponding standards. The leaves of pakchoi, peppermint, and coriander had a strong metal-accumulative ability and they were not suitable for planting. Except the residue forms, the main forms of metals in the edible parts of three selected vegetables were ethanol-, NaCl-, and HAc-extractable fractions for As, Pb, and Cd, respectively; however, Cu was mainly presented as NaCl-extractable and Zn as HAc-extractable fractions. A high proportion of ethanol-extractable As showed that As bioactivity and toxic effects were the highest. Although the total and bioavailable Cd were high in soil, its speciation in vegetables was mainly presented as HAc-extractable fraction, which has a relatively low bioactivity. Lead and arsenic were imposing a serious threat on the local residents via vegetable consumption.     

Ce-PbO_2/C电极的制备及其去除水中酸性红B

采用电沉积法制备铈修饰的PbO2/C电极,通过SEM、XRD、XPS及循环伏安对PbO2/C、Ce-PbO2/C电极进行表征,结果表明,Ce-PbO2/C电极比PbO2/C颗粒细小,表面均匀致密,电化学氧化能力较强,修饰电极中Ce以CeO2的形态存在。以Ce-PbO2/C为工作电极,电解浓度为1 000 mg/L的高盐酸性红B模拟活性染料废水,考察了电压、pH、电解质浓度、极间距对脱色率、氨氮去除率及COD去除率的影响。确定适宜工艺条件为：初始酸性红B溶液浓度为1 000 mg/L,pH值为6,电压10 V,电解时间1 h,电极间距1.5 cm,该条件下脱色率、氨氮去除率和COD去除率分别为99.98%、97.23%和90.17%。通过UV-Vis及GC-MS初步分析了降解过程可能存在的中间产物及降解途径。     

MCM-41介孔分子筛的合成及其对铜离子的吸附性能简

以微硅粉为硅源,CTAB和PEG-6000为模板剂,合成MCM-41介孔分子筛。采用XRD、N₂吸附-脱附曲线、FTIR以及TEM表征了其结构、比表面积、孔径分布及晶体形貌,并且以该样品为吸附剂,对含Cu²⁺的溶液进行了静态吸附实验。结果表明,以微硅粉为硅源成功合成了具有典型六方排列孔道结构的MCM-41,其比表面积为869.5 m²/g,孔容为0.97 cm³/g,平均孔径为3.3 nm;溶液pH为5~6时,MCM-41对Cu²⁺的去除效果最好;MCM-41对Cu²⁺的最大吸附吸附容量36.3 mg/g;MCM-41对Cu²⁺的吸附性能符合Langmuir吸附方程的特征。动力学研究表明,该过程符合准二级动力学模型。     

混凝-超滤短流程工艺处理北方水库原水简

采用混凝-超滤膜短流程工艺对大伙房水库原水进行处理,考察其除污染性能和膜污染情况,并对该短流程工艺参数进行优化。结果表明,当利用超滤膜直接过滤原水时,膜污染较重,并且对污染物质的去除率较低;而采用混凝-超滤短流程工艺时,膜污染得到一定程度上的缓解;当絮凝剂投加量为7 mg/L、膜清洗周期为30 min时,对浊度、COD_Mn和UV₂₅₄的去除率分别为95.61%、40.42%和37.12%,出水水质能够满足生活饮用水卫生标准。     

臭氧氧化法处理焦化废水生化出水的反应动力学简

对臭氧氧化去除焦化废水生化出水COD的反应动力学及其影响因素进行了实验研究,结果表明,在臭氧投加量为8.50 mg/min,反应温度为20℃和初始pH为10.61条件下,对COD的降解符合表观一级反应动力学模型,其相关系数R²=0.9991,表观反应速率常数k_Abs=1.01×10^-3 s^-1。该条件下,臭氧氧化对COD的降解主要来源于高活性羟基自由基的强氧化作用。在不同的臭氧投加量（4.25~12.75 mg/min）、不同的反应温度（10~40℃）和不同的初始pH（3.76~12.53）下,COD的降解也同样遵循一级反应动力学规律。随着臭氧投加量的增大,COD降解的表观反应速率常数从（0.554×10^-3） s^-1增加到（1.06×10^-3） s^-1;随着反应温度的升高,表观反应速率常数从（0.427×10^-3） s^-1增加到（1.40×10^-3） s^-1,温度越高反应速率提高的幅度却越小;在初始pH3.76~10.61范围内,表观反应速率常数从（0.218×10^-3） s^-1增加到（1.01×10^-3） s^-1,在初始pH为12.53时表观反应速率常数下降到（0.857×10^-3） s^-1。     

水生植物酸碱预处理对厌氧发酵联产氢气-甲烷的影响简

采用酸碱预处理乌梁素海典型沉水植物龙须眼子菜和挺水植物芦苇,通过厌氧发酵动力学分析、还原糖变化及微观结构解析,研究酸碱预处理对水生植物厌氧发酵联产氢气-甲烷的影响。实验结果表明,酸碱预处理后水生植物厌氧发酵联产氢气-甲烷两阶段累积产气量、氢气及甲烷含量均显著提高,酸处理效果优于碱处理。采用0.5 mol/L HCl预处理龙须眼子菜效果最佳,最大氢气、甲烷含量分别达42.65%和52.82%,产氢气速率为4.118 mL/h,产甲烷速率最高达14.199 mL/h。芦苇经1 mol/L HCl预处理效果最佳,最高氢气、甲烷含量分别为32.22%和65.26%。扫描电镜微观结构分析表明,酸碱预处理可显著破坏芦苇、龙须眼子菜的纤维素结构,有效增加植物与微生物接触面积,有利于厌氧发酵联产氢气-甲烷工艺的快速启动和稳定运行。     

Levels and distribution of Dechloranes in sediments of Lake Taihu,China

The occurrence and spatial distribution of dechloranes including mirex, dechlorane plus (DP), dechlorane (Dec) 602, Dec 603, and Dec 604 in surficial sediments of Lake Taihu were investigated in this study. The concentrations of mirex and DP ranged from below detection limit (BDL) to 1.29 ng g^?1 dw and 0.051 to 2.10 ng g^?1 dw, respectively. Dec 602, Dec 603, and Dec 604 on the other hand, were BDL in any of the samples. The contamination levels of DP were higher than that of Mirex at 21 of all 22 sampling sites. Levels of mirex and DP in the lake sediments were correlated when an extremely high mirex value was removed. Both mirex and DP levels were correlated with the amount of organic matters in the sediment samples. Spatial distribution of mirex and DP suggested that these two chemicals in the lake had similar input sources except for one site. Comparison to previously reported flame retardants’ levels in the sediments shows that DP levels were similar with the levels of tetrabromobisphenol A, hexabromocyclododecane but lower than PBDEs and organophosphates levels in Lake Taihu. The higher levels in the north-east part of Lake Taihu adjacent to two major cities: Wuxi and Suzhou, indicated that city effluent might be a major source for DP contamination in the lake.