Photocatalytic activity of TiO2 films grown on different substrates

Titanium dioxide films were prepared on glass, indium-tin oxide (ITO) glass and p-type monocrystalline silicon and studied for the photocatalytic degradation of rhodamine B in an aqueous medium. Raman, AFM, and XPS spectroscopic investigations of these films indicated that microstructure of titanium oxide films were greatly affected by the substrate materials. Rutile was confirmed to be easily formed on the surface of ITO glass, and TiO2 tended to grow as closely packed particles that were elongated strips with an average size of 20 nm, and had lovely contrast with the perfectly round particles grown on p-type monocrystalline silicon. Charge transfer between the film and silicon substrate was verified by surface photovoltage spectra. This may be the real reason why the films grown on ITO glass and silicon substrates exhibit higher photocatalytic reactivity than the film on glass substrate. Moreover, the different surface properties also seem to be responsible for the different activity.     

Attempt to adsorb N-nitrosamines in solution by use of zeolites

The strong adsorption of zeolite for N-nitrosamines in solution was first revealed by use of adsorption, and temperature programmed surface reaction (TPSR) techniques. N-nitrosodimethylamine (NDMA) and N-nitrosopyrrolidine (NPYR) as well as N-nitrosohexamethyleneimine (NHMI) can be adsorbed on zeolite Y, ZSM-5 and A in the solution of methylene chloride or water, which will be helpful for removal of the N-nitrosamines pollution in environmental protection. The equilibrium data were fitted to Freundlich-type isotherms, but the adsorption capacity of zeolites mainly depended on their pore size, surface area and acid-basic properties. Molecular size of adsorbate and solute-solvent interaction also strongly affected the adsorption of N-nitrosamines on zeolite in solution. The extraordinary adsorption properties of NaA zeolite for N-nitrosamines in aqueous solution is first reported and discussed.     

玻纤布上胶车间有机溶剂废气净化处理

介绍了工厂有机溶剂废气处理方案和设计及实际运行效果,具有简单经济、净化彻底的特点.     

Investigation on the influence of methanol on adsorption and leaching of pesticides with soil column liquid chromatography

The effect of methanol of low concentration on adsorption and leaching of atrazine and tebuconazole was studied in this paper. The adsorption coefficients and the retardation factors (R^m) of pesticides on EUROSOIL 3# log-linearly decreased as volumetric fraction of methanol (f^c) was increased in the binary solvent mixtures of methanol and water. These data are consistent with solvophobic theory formerly outlined for describing the adsorption and transport of hydrophobic organic chemicals from mixed solvents. Nevertheless, the adsorption of these pesticides in soil–water system slightly increased when the soil was pre-washed with methanol in comparison with that pre-washed with water (pure water system). Furthermore, their adsorption coefficients were still higher in binary solvent systems with methanol of very low concentrations, i.e. f^c<0.03 for atrazine and f^c<0.01 for tebuconazole, than those in pure water system. The adsorption coefficients (logK^w) of atrazine and tebuconazole predicted by solvophobic theory were 0.5792 and 1.6525, respectively, and their experimental logK^w were 0.3701 and 1.6275 in pure water system. Obviously, the predicted logK^w of the two pesticides was higher than the experimental log K^w in pure water system. The predicted K^w and the retardation factor (R^w) in pure water system by solvophobic theory are thus possibly inaccurate.     

污染土壤的微波辐照技术研究进展

简要介绍了土壤污染的状况,总结了国外学者对重金属和有机物两大类污染土壤所进行的微波修复工作,探讨了修复机理及影响因素,最后展望了微波修复污染土壤的研究重点.     

生物质型煤成型技术开发实验研究

通过原有成型方式的工业成型观察和模压成型实验，提出并验证了完全利用生物质纤维的交联作用实现成型的新机制。其于中高压下物料的不可再压缩性和单向挤压也会导致更高的成型压力的新认识，设计和研制成按新机制成型的型轮。经此改进的工业成型试验达到了比模压成型更好的效果：不用预实送料，且成型性能；成型压力降至120MPa以下，成型许可水分成倍提高，适合的生物质配比范围15％－60％；仅利用送料螺旋的预实功能，即可实现纯生物质型块的成型。     

Effects of heavy metals on growth and arsenic accumulation in the arsenic hyperaccumulator Pteris vittata L

The effects of Cd, Ni, Pb, and Zn on arsenic accumulation by the arsenic hyperaccumulator Pteris vittata were investigated in a greenhouse study. P. vittata was grown for 8 weeks in an arsenic-contaminated soil (131 mg As kg(-1)), which was spiked with 50 or 200 mg kg(-1) Cd, Ni, Pb, or Zn (as nitrates). P. vittata was effective in taking up arsenic (up to 4100 mg kg(-1)) and transporting it to the fronds, but little of the metals. Arsenic bioconcentration factors ranged from 14 to 36 and transfer factors ranged from 16 to 56 in the presence of the metals, both of which were reduced with increasing metal concentration. Fern biomass increased as much as 12 times compared to the original dry weight after 8 weeks of growth (up to 19 g per plant). Greater concentrations of Cd, Ni, and Pb resulted in greater catalase activity in the plant. Most of the arsenic in the plant was present as arsenite, the reduced form, indicating little impact of the metals on plant arsenic reduction. This research demonstrates the capability of P. vittata in hyperaccumulating arsenic from soils in the presence of heavy metals.     

Comparison of the effects of aluminum and iron(Ⅲ) salts on ultrafiltration membrane biofouling in drinking water treatment

Coagulation plays an important role in alleviating membrane fouling, and a noticeable problem is the development of microorganisms after long-time operation, which gradually secrete extracellular polymeric substances(EPS). To date, few studies have paid attention to the behavior of microorganisms in drinking water treatment with ultrafiltration(UF)membranes. Herein, the membrane biofouling was investigated with different aluminum and iron salts. We found that Al_2(SO_4)_3·18 H_2O performed better in reducing membrane fouling due to the slower growth rate of microorganisms. In comparison to Al_2(SO_4)_3·18H_2O,more EPS were induced with Fe_2(SO_4)_3·x18H_2O, both in the membrane tank and the sludge on the cake layer. We also found that bacteria were the major microorganisms, of which the concentration was much higher than those of fungi and archaea. Further analyses showed that Proteobacteria was dominant in bacterial communities, which caused severe membrane fouling by forming a biofilm, especially for Fe_2(SO_4)_3·x18H_2O. Additionally, the abundances of Bacteroidetes and Verrucomicrobia were relatively higher in the presence of Al_2(SO_4)_3·18 H_2O,resulting in less severe biofouling by effectively degrading the protein and polysaccharide in EPS. As a result, in terms of microorganism behaviors, Al-based salts should be given preference as coagulants during actual operations.     

电子垃圾中铅污染及对策研究

伴随着电子信息等高科技产业的快速发展,电子垃圾已成为增长速度最快的固体废弃物。电子垃圾成分复杂且其污染物众多,尤其是其中的铅污染对环境与健康的影响越来越受到人们的关注,对电子垃圾的不恰当处理势必造成了严重的环境污染。本文调研分析了中国电子垃圾中铅元素污染的现状,探讨了铅污染的原因及其防治对策,并对各种对策的可操作性进行了评价。另一方面,借鉴国外先进经验,对中国电子垃圾中铅元素的污染防治提出了建议。     

唐山市区大气环境中氮氧化物的监测与分析

通过使用分光光度法测定大气中氮氧化物浓度,采集样品分析得出唐山市西道大气中氮氧化物污染现状,了解大气中氮氧化物污染水平。由实验数据分析可知,路段中间的监测点的氮氧化物日小时均值浓度大约为0．037mg／m^3,氮氧化物浓度值受风力影响大于车流量的影响,路口监测点由于车流量大,其氮氧化物浓度值也对应升高,大约为0.046mg/m^3,其受车流量的影响大于风力影响,说明当车流量超过一定值时,风力的影响就会战弱。结果表明,唐山市新华西道氮氧化物日均值浓度大于0.05mg／m^3,氮氧化物污染指标的平均值均超过国家环境空气质量二级标准。因此,此道路属于污染区。还提出了减轻氮氧化物污染状况的几点建议。