微弧氧化处理对6061铝合金电偶腐蚀防护

目的 提高船舶上铝合金的耐蚀性能。方法 使用双极性脉冲电源对6061铝合金进行微弧氧化处理,并使用环氧树脂进行封孔,通过电化学测试、扫描电子显微镜(SEM)、能谱仪(EDS)、浸泡腐蚀试验和电偶腐蚀试验等方法,对膜层的表面形貌、截面形貌、物相组成和耐蚀性能进行测试。结果 制备的6061铝合金微弧氧化膜层厚度约为40 μm,致密均匀。在240 h浸泡试验后,仍具有较强的耐蚀性,与316L不锈钢耦合的电流密度从约47 μA/cm²下降到20 μA/cm²左右,对6061铝合金的耐蚀性有显著提升。封孔处理后,浸泡腐蚀240 h,未发现明显腐蚀,电偶电流进一步下降到11 μA/cm²。结论 对6061铝合金进行微弧氧化处理,可以有效提高其耐蚀性能,对电偶腐蚀有较好的抑制作用,封孔处理则可以进一步提高铝合金的耐蚀性能。     

铁铝盐基离子对土壤中水溶性氟环境效应的影响

氧化物或粘土矿物可吸附氟离子,但磷酸根离子与氟离子存在竞争吸附效应,造成氟的环境存在量、存在形态及生物效应更加复杂,影响了环境中氟污染的治理.试验选用典型贵州黄壤和石灰土,通过向模拟高氟污染土壤中添加铁铝盐基离子和磷酸盐,采用两因素最优设计,研究外源物质对土壤中水溶性氟的影响.结果表明,FeCl3·6H2O或AlCl3·6H2O都能降低土壤中水溶性氟,而KH2PO4使土壤中水溶性氟增加,对黄壤和石灰土中水溶性氟影响效果大小依次为FeCl3·6H2O(AlCl3·6H2O)、KH2PO4.同时表明,采用铁铝盐基离子改变黄壤性质,达到降氟效果仍有很大潜力,而石灰土环境在高添加铁铝盐基离子水平下继续添加FeCl3·6H2O或AlCl3·6H2O降低土壤中水溶性氟的作用较弱.从土壤pH看,黄壤水溶性氟受试验因子影响复杂,土壤pH低水溶性氟不一定低,pH在4～6时,氟元素的形态及有效性尤其复杂,而石灰土中水溶性氟基本随pH降低而降低.     

电絮凝法去除水中微量叔丁醇的研究

采用电絮凝法对水中微量的叔丁醇(TBA)进行去除,分别考察了电极材料、极板间距、电流密度、溶液初始pH值对叔丁醇去除效果的影响.结果表明,以铝为阳极、不锈钢为阴极,极板间距为1.4cm,电流密度为20mA/cm2,溶液初始pH值为8时,电解120min后叔丁醇的去除率为80.4％,此时铝阳极实际损耗量(1.93kg/m...     

聚硅硫酸铝的制备及其絮凝性能

以Na2SiO3·9H2O,Al2（SO4）3·18H2O为原料,加入一定量稳定剂,采用复合法制备出高铝含量且稳定的聚硅硫酸铝（PASS）。研究结果表明：采用磷酸氢二钠与烷基糖苷（质量比为1：1）作为复合稳定剂,在碱化度为1．5～1．8、Ⅳ（A1）：Ⅳ（Si）=1．0～3．0的条件下,合成的PASS絮凝效果最佳;复合稳定剂对废水的COD去除率及浊度去除率影响不大,但能显著改善絮凝产品的稳定性;PASS可用于处理pH范围较宽（pH为6．0—11．0）的工业废水,且处理前后废水pH变化不大;PASS对低温低浊度废水有较好的絮凝效果;在加入量相同的情况下,PASS的絮凝性能明显优于聚合硫酸铝、硫酸铝、聚合硫酸铁,当PASS加入量为40～100恤L／L时,废水浊度去除率达98％以上。     

絮凝沉淀-Fenton试剂氧化法处理含高浓度硫酸盐的洗涤剂生产废水

采用絮凝沉淀-Fenton试剂氧化法处理含高浓度硫酸盐的洗涤剂生产废水（简称废水）,考察了各种因素对COD去除率的影响。实验结果表明：根据实际废水的水质情况,选用聚合氯化铝（PAC）为絮凝剂,PAC最佳加入量为0．3g／L,经絮凝处理后COD去除率为42．3％;Fenton试剂氧化的最佳操作条件为：n（H2O2）：n（Fe^2＋）=0．5、H2O2加入量为7mmol／L、反应时间为2h,不调节废水初始pH,经Fenton试剂氧化处理后COD去除率为70％以上。经絮凝沉淀-Fenton试剂氧化法处理后,废水COD由1950mg／L降至240mg／L,总的COD去除率为87．7％,废水处理效果良好。     

含铝离子的聚硅酸絮凝剂研究

以硅酸钠、硫骏、硫酸铝为原料制备含右铝离子的聚硅酸絮凝剂(简称PSAA),试验它的絮凝特性及影响因素,并与聚合氯化铝(简称PAC)的絮凝效果进行比较。实验结果表明,铝离子的含量对PSAA的絮凝特性影响很大,当Al~(3+)/siO_2的摩尔比为1时絮凝效果最好,在pH=5—10的范围内,PSAA具有良好的絮凝效果。与PAC相比,PSAA具有絮凝效果好、价格低廉、适用的pH范围较宽等特点。     

废铝易拉罐粉末对U(Ⅵ)的去除效果与机理

以废铝易拉罐为原料,通过除漆、研磨等制得废铝易拉罐粉末(SAlCP)。利用SAlCP处理含U(VI)废水,优化处理工艺条件,采用SEM和XPS技术对SAlCP进行表征,并探讨了SAlCP去除U(Ⅵ)的机理。实验结果表明:在反应温度为30℃、溶液初始pH为5.0、U(Ⅵ)初始质量浓度为10 mg/L、SAlCP投加量为4 g/L、反应时间为120 min的优选条件下,U(Ⅵ)的去除率达98.2%。SAlCP去除U(Ⅵ)的反应过程可用拟一级动力学模型和Langmuir-Hinshelwood模型能较好地拟合。SAlCP的作用机理是还原沉淀-吸附共沉,且还原作用是SAlCP去除U(Ⅵ)的主要途径。     

聚合氯化铁铝应用于城市污水一级处理试验研究

以济南市水质净化一厂初沉池进水为试验水样,在设定的反应条件下,以浊度、COD、TP、TN、NH3-N等为测定指标,做了大量的烧杯搅拌试验,综合分析了聚合氯化铁铝(PFAC)的处理效果。试验结果显示其最佳投药量为25mg/L左右,去除率浊度在90%以上、COD70%～90%、TP70%～95%左右、TN、NH3-N分别在30%和15%左右。     

环境对阿尔茨海默病病因影响

阿尔茨海默病是一种发生于老年人群的原发生退行性脑病。目前，关于ＡＤ病研究中的中心问题是弄清楚其发病的病理，如果可以抑制的一步和几步，将减缓或防止其发病，因此搞清ＡＤ病的发病机理对预防和治疗ＡＤ病相当重要。     

Analytical Investigations on a Releasing Agent Application in Aluminium Diecasting (6 pp)

Background, Aims and Scope Releasing agents, applied in the aluminium diecasting process, usually consist of water, oils, waxes, polysiloxanes, as well as of a set of additives like emulsifiers, corrosion inhibitors, and biocides. During spray application and part release, gases and aerosols are emitted into workplace air. The chemical compositions of these emissions are determined by the components of the releasing agents and their reaction products formed during thermal stress of more than 700 °C. In the frame of the joint project, the analytical tasks were to develop an appropriate sampling strategy for this production environment, to draw conclusions about the occurrence of hazardous chemicals from production plant studies and from laboratory-scale thermolysis experiments, and to determine the biodegradability of customary releasing agents. Methods During realistic test production, active air sampling was performed in a production hall using different adsorption materials. Cotton fabric sheets were positioned in the production area as passive samplers. Thermolysis experiments were performed at 600 °C with sealed quartz ampoules. The biodegradability of different releasing agents was determined according to German industry standard DIN 51828 (2000). For analyses, GC/MS (headspace), FTIR, HPLC, IC, and ICP-OES techniques were applied. Results and Discussion The substance spectrum, which was found in workplace air, was dominated by saturated and non-saturated aliphatic hydrocarbons. Besides these, alcohols, alkyl phenols, xylenes and other benzene derivatives, aldehydes, glycols, carboxylic acid esters, and amides were present. The German limiting value of 40 mg/m3 of complex hydrocarbon mixtures in a diecasting workplace atmosphere was clearly under-run. Total hydrocarbon contents ranged between 2.7 and 6.3 mg/m3. Five different PAH were found in the air close to the diecasting machine, with maximum concentrations between 0.05 and 3.06 μg/m3. Concentrations of nonylphenols ranged from 10 to 200 μg/m3, and those of triethanolamine from 20 to 30 μg/m3. From 17 elements analyzed, only B, Fe, P, S, Si, and Ti were emitted in small amounts. It was striking that the PAH patterns resulting from thermolysis experiments were quite the same compared to those determined during the diecasting process. An influence of water and of Fe/Al on the composition of the thermolysis products could mostly be shown. The degrees of biodegradation of three releasing agent extracts after 21 days were 21%, 29%, and 55%, respectively. Conclusion A sampling strategy was developed, which allows an emission assessment for the industrial process of aluminium diecasting. It enabled one to control limiting values, to characterise a wide variety of compounds emitted, and to identify and quantify relevant pollutants. Only a few hazardous substances could be detected during the exemplary use of one releasing agent within the compounds emitted into workplace air. Indications were found, that the prediction of the formation of harmful substances from releasing agent components should be possible via thermolysis experiments. The biodegradability test can serve to assess the expenditure of disposal of the usual leakage run-off of excess agent during production. Recommendation and Outlook Investigations on further differently composed releasing agents, e.g. powders, would be desirable. A substitution of nonylphenol ethoxylates by less harmful components would surely be an improvement of a releasing agent with regard to work safety and health care, because of avoiding the emission of toxic and endocrine active nonylphenols. The surprisingly wide range of biodegradability of the investigated releasing agents points to an optimization potential, that has obviously not yet been considered.