微电解-催化氧化法处理高浓度甲醇废水

采用微电解一催化氧化法处理某化工厂的高浓度甲醇生产废水。实验结果表明：在进水pH为2．0、铁炭质量比为2、微电解时间为14h、空气流量为500mL／min的条件下,废水经微电解处理后,出水COD由原来的约7000mg/L降至约1000mg／L,COD去除率达85％以上;在过滤后微电解出水COD约为950mg／L、微电解出水pH为6．5、空气流量为300mL／min、催化氧化时间为3h时的条件下,经催化氧化处理后,出水COD降至100mg/L以下,出水水质达到GB8978--1996《污水综合排放标准》的二级标准。     

四氯化钛精制除钒废弃物的综合利用

对四氯化钛铜丝除钒精制过程中产生的废弃物,采用酸碱联合法回收其中的铜和钒。考察了关键的碱处理及盐酸沉钒过程的影响因素。实验结果为：在碱处理溶液pH12．0—13．0,碱处理温度60℃,碱处理时间1h,沉钒溶液pH1．0～1．5,沉钒温度60℃,沉钒时间1h的条件下,铜和钒的回收率分别达到90％和75％以匕,获得的阴极铜和五氧化二钒的产品质量均达到国家标准。     

Fe-厌氧微生物体系降解2,4,6-三氯酚

采用Fe-厌氧微生物体系降解2,4,6-三氯酚(2,4,6-TCP).在初始pH 7.0、Fe加入量10.0 g/L、以甲酸钠为碳源的条件下,2,4,6-TCP降解效果最好.采用Fe-厌氧微生物体系降解2,4,6-TCP,比单独采用Fe或厌氧微生物体系具有明显的效果,运行60h后2,4,6-TCP开始降解,108h后2,4,6-TCP降解完全.添加2-溴乙烷磺酸盐可抑制产甲烷菌的活性,能有效促进2,4,6-TCP的降解.     

Ru/γ-Al_2O_3和Ru/AC催化剂的制备及其对氨氧化反应的催化性能

分别以γ-Al_2O_3和活性炭(AC)为载体,采用浸渍法制备了Ru质量分数均为2.0%的Ru/γ-Al_2O_3和Ru/AC催化剂,并用X射线衍射仪和透射电子显微镜等方法对催化剂结构进行了表征.实验结果表明:Ru/AC中Ru沉积在AC表面,分散度较低;而Ru/γ-Al_2O_3中Ru进入到γ-Al_2O_3内部,形成了一种高度分散体系.Ru/γ-Al_2O_3对氨的催化活性高于Ru/AC,氨在Ru/γ-Al_2O_3和Ru/AC上的起活温度分别为200 ℃和266 ℃,T_(90)(氨去除率达90%时的反应温度)分别为267℃和320 ℃.随混合气体空速增大,Ru/γ-Al_2O_3催化剂的T_(90)逐渐升高,气体空速分别为3 600,4 800,5 400 h~(-1)时,T_(90)分别为235,266,303 ℃.随反应前混合气体中氨质量分数增加,氨的去除率降低.     

pH敏感性β-环糊精微球的制备及其吸附性能

采用反相微悬浮乳液聚合技术制备了β-环糊精(β-CD)微球,用丁二酸酐对β-CD微球进行化学改性,制备了pH敏感性β-CD(pH-β-CD)微球.通过傅里叶红外光谱仪和扫描电子显微镜对微球的结构、粒径和形貌进行了表征.探讨了亚甲基蓝模拟染料废水pH、吸附时间和微球加入量对亚甲基蓝吸附性能的影响.实验结果表明,在亚甲基蓝模拟染料废水pH为10.0、吸附时间为90 min的条件下,当pH-β-CD微球加入量为50 mg时,pH-β-CD微球吸附量为16.1 mg/g;当pH-β-CD微球加入量为250 mg时,pH-β-CD微球对亚甲基蓝的脱色率达96.2%.     

Study on Biodegradable Starch/OMMT Nanocomposites for Packaging Applications

The thermoplastic starch (TPS) and nanocomposite(TPS/OMMT) was prepared with 15% carbamide, 15% ethanolamine and different contents of organic activated montmorillonite (OMMT) by twin-screw extruder with a 130 °C barrel temperature. Fourier transforms infrared spectroscopy and wide angle X-ray diffraction shown that the alkylamine in dodecyl benzyl dimethyl ammonium bromide could react with MMT via cation exchange reaction. After treated, the d(001)space distance of MMT increased from 1.5 to 1.7 nm. Scanning electron microscope revealed that the lower contents of OMMT could disperse well in the matrixes of TPS. The carbamide, ethanolamine and the OMMT could destroy the crystallization behavior of starch, but only the OMMT restrained this behavior for long-term storing. Mechanical properties investigation indicated that the tensile strength and modulus of TPS/OMMT nanocomposites were better than those of TPS, while the elongation at break was descended with the increasing of OMMT contents. When the content of OMMT was 4%, the tensile strength and modulus of TPS was improved from 4.2 and 42 MPa to 6.0 and 76 MPa, respectively.     

Concentration Effects on Competitive Sorption of Trichloroethylene and Tetrachloroethylene to the Roots of Typha latifolia: Implications for Phytomonitoring

Uptake of organic contaminants by plant roots consists of two consecutive steps: sorption to plant roots and entrance into root xylem tissues through epidermal and endodermic membranes. Most research pertaining to phytoremediation assumed that sorption to plant roots is linear and non-competitive. A growing body of evidence, however, is suggesting that sorption to plant roots is nonlinear and competitive. The objective of this study was to examine the concentration effects of chemical constituents on the competitive sorption of trichloroethylene (TCE) and tetrachloroethylene (PCE) to the roots of Typha latifolia. Competitive sorption was clearly demonstrated by the reduced sorption of TCE and PCE in bi-solute systems than in single-solute systems. Concentration is an important factor affecting the extent of competition. In bi-solute systems, the PCE/TCE ratio on root surface approximately reflected the contaminant footprints in solution. The result was attributed to limited high energetically favorable sorption sites on the root surface and similar sorption mechanisms of TCE and PCE. The results hold significant importance for the application of phytomonitoring of organic contaminant mixtures.     

Cascade-based attack vulnerability on the US power grid

The vulnerability of real-life networks subject to intentional attacks has been one of the outstanding challenges in the study of the network safety. Applying the real data of the US power grid, we compare the effects of two different attacks for the network robustness against cascading failures, i.e., removal by either the descending or ascending orders of the loads. Adopting the initial load of a node j to be L_j=[k_j(Σ_mΓjk_m)]^α with k_j and Γ_j being the degree of the node j and the set of its neighboring nodes, respectively, where α is a tunable parameter and governs the strength of the initial load of a node, we investigate the response of the US power grid under two attacks during the cascading propagation. In the case of α<0.7, our investigation by the numerical simulations leads to a counterintuitive finding on the US power grid that the attack on the nodes with the lowest loads is more harmful than the attack on the ones with the highest loads. In addition, the almost same effect of two attacks in the case of α=0.7 may be useful in furthering studies on the control and defense of cascading failures in the US power grid.     

Modification of Fe–Mn mixed oxide COS removal sorbent by rare-earth oxides addition

In order to develop highly active sorbent for COS removal, Fe–Mn mixed oxides doped with CeO₂, La₂O₃ or Sm₂O₃ were studied. The effects of these promoters on the structural properties of Fe–Mn oxides were investigated by XRD, BET, TPR and TEM techniques. XRD results revealed that the degree of crystallinity of Fe–Mn oxide phase decreased due to the addition of rare-earth oxides. Doping with CeO₂, La₂O₃ or Sm₂O₃ led to an increase in BET surface area of the sample. TPR studies showed that the reactivity of the reduction of doped samples increased in the temperature range of 300–450 °C. In addition, the desulfurization test was performed at 325 °C with a gas hourly space velocity of 1000 h⁻¹. It was found that the addition of 3% La₂O₃ greatly improved the absorption sulfur capacity of the sorbent, while the sorbent doped 3% CeO₂ achieved a sufficiently high purifying degree before breakthrough.     

企业员工不安全行为的产生原因

1企业员工不安全行为的产生原因 企业员工不安全行为的产生原因较为复杂,是多方面因素综合作用的结果。其中有个体内在因素：如生理因素、心理因素、知识和技能因素等;有外在客观因素：如环境因素、管理因素等。