饮用水水质安全性的探讨

阐明了目前我国城镇供水水质安全所存在的问题：主要从藻毒素、消毒副产物、内分泌干扰物、铝浓度超标、出厂水的二次污染等五个方面加以讨论,且分析了它们的危害及产生原因。     

Surface applied water treatment residuals affect bioavailable phosphorus losses in Florida sands

Water treatment residuals (WTR) can reduce runoff P loss and surface co-application of P-sources and WTR is a practical way of land applying the residuals. In a rainfall simulation study, we evaluated the effects of surface co-applied P-sources and an Al-WTR on runoff and leacheate bioavailable P (BAP) losses from a Florida sand. Four P-sources, namely poultry manure, Boca Raton biosolids (high water-soluble P), Pompano biosolids (moderate water-soluble P), and triple super phosphate (TSP) were surface applied at 56 and 224kgPha(-1) (by weight) to represent low and high soil P loads typical of P- and N-based amendments rates. The treatments further received surface applied WTR at 0 or 10gWTRkg(-1) soil. BAP loss masses were greater in leachate (16.4-536mg) than in runoff (0.91-46mg), but were reduced in runoff and leachate by surface applied WTR. Masses of total BAP lost in the presence of surface applied WTR were less than approximately 75% of BAP losses in the absence of WTR. Total BAP losses from each of the organic sources applied at N-based rates were not greater than P loss from TSP applied at a P-based rate. The BAP loss at the N-based rate of moderate water-soluble P-source (Pompano biosolids) was not greater than BAP losses at the P-based rates of other organic sources tested. The hazards of excess P from applying organic P-sources at N-based rates are not greater than observed at P-based rates of mineral fertilizer. Results suggest that management of the environmental P hazards associated with N-based rates of organic materials in Florida sands is possible by either applying P-sources with WTR or using a moderate water-soluble P-source.     

Comparative corrosion characteristics of automotive materials in Jatropha biodiesel

This study investigated the corrosion characteristics of widely used automotive materials: copper (Cu), aluminum (Al) and stainless steel (SS) in Jatropha biodiesel. The corrosion rate of the materials was measured by the weight loss and changes in the surface morphology using immersion test in biodiesel. Before and after the immersion test, fuel samples were characterized by the change in chemical composition, viscosity, density, and water content. Experimental results revealed that Cu had the highest corrosion rate, while SS had the lowest. The main fatty acids observed in the tested biodiesel were oleic (44.6 wt %), linoelic (31.9 wt %), Palmitic (14.6 wt %), and Stearic (7.6 wt %). Apart from linoelic acid, the compositions of all other acids were increased after the immersion test of 1600 h. Also, the viscosity, density, and water content of the fuel samples were increased after the immersion test. However, these properties were within the maximum standard limit except water content.     

Fluoride removal by Al, Ti, and Fe hydroxides and coexisting ion effect

Batch experiments were conducted to evaluate fluoride removal by Al,Fe,and Ti-based coagulants and adsorbents,as well as the effects of coexisting ions and formation of aluminum–fluoride complexes on fluoride removal by co-precipitation with alum(Al_2(SO_4)_3·18H_2O).Aluminum sulfate was more efficient than the other coagulants for fluoride removal in the pH range between 6 and 8.Nano-crystalline TiO_2 was more effective for fluoride removal than Al and Fe hydroxides in a pH range of 3–5.Coexisting anions in water decreased the removal of fluoride in the order:phosphate(2.5 mg/L) arsenate(0.1 mg/L) bicarbonate(200 mg/L) sulfate(100 mg/L) = nitrate(100 mg/L) silicate(10 mg/L) at a pH of 6.0.The effect of silicate became more significant at pH 7.0.Calcium and magnesium improved the removal of fluoride.Zeta-potential measurements determined that the adsorption of fluoride shifted the PZC of Al(OH)_3 precipitates from 8.9 to 8.4,indicating the chemical adsorption of fluoride at the surface.The presence of fluoride in solution significantly increased the soluble aluminum concentration at pH 6.5.A Visual MINTEQ modeling study indicated that the increased aluminum solubility was caused by the formation of AlF~(2+),AlF~(+2),and AlF_3complexes.The AlF_x complexes decreased the removal of fluoride during co-precipitation with aluminum sulfate.     

Electrical performance of laser braze-welded aluminum–copper interconnects

The reported investigation is related to laser beam braze-welding technology for dissimilar aluminum–copper interconnects for Li-ion battery assembly. The correlation between the brittle and high-resistivity intermetallic compounds and the electrical contact resistance showed that a thin intermetallic layer is highly desirable. It was proved that highest shear strength and lowest contact resistance can be achieved within the same parameter set which is of particular interest to battery electrical vehicle applications requiring both high mechanical reliability and electrical performance.A study on the weld seam layout further showed that two parallel weld seams with optimized spacing and overlap design provide lowest contact resistance.     

Composition of Aqueous Extracts of Broiler Litter Treated with Aluminum Sulfate,Ferrous Sulfate,Ferric Chloride and Gypsum

More knowledge on the composition of aqueous extracts of broiler litter amended for Water Soluble P (WSP) reduction would help to understand how amendments work. We measured pH, concentrations of Ca, Mg, Fe, Al, Cu, Mn, Zn, Molybdate Reactive P (MRP), and Dissolved Unreactive P (DUP) in water extracts of broiler litter treated with aluminum sulfate (ALS), ferrous sulfate (FES), ferric chloride (FEC), and gypsum (GYP) at 0, 5, 15, and 25% w/w. In order to study the effects of acidification, the same properties were measured in aqueous extracts of broiler litter suspensions that were titrated to end-points 3, 4, or 6 with 0.5N HCl. Concentrations of MRP, DUP, Ca and Mg, were 61%, 53%, 3.8 times, and 2.6 times greater in extracts from suspensions acidified to pH 6 than at the original pH of 8.9. ALS, FES, and FEC reduced pH, and showed similar effects on WSP concentrations, which were greater than with GYP. The magnitude of the reductions in WSP by ALS, FES, and FEC is uncertain because the actual amount of WSP immobilized cannot be determined. This is because of two opposite effects: 1) Through adsorption, soluble aluminum and iron remove phosphates from solution, and 2) Through acidification, iron and aluminum compounds release phosphates to solution.     

Binding of aluminum to human serum transferrin,human serum albumin and rat serum proteins

Abstract

Human serum transferrin (HSTF), human serum albumin (HSA) and rat serum were compared for their interaction with AlCl₃ , in a Tris‐HCl buffer solutions (pH 7.4). The AlCl₃ was tested in series of concentrations in the range of 50 μM up to 500 μM . HSTF, HSA and their 1:1 mixture and rat serum were incubated at 37°C with series of AlCl₃ concentrations. The protein profile of the incubated solutions were compared to control using SDS‐PAGE and FPLC tests. The results indicated that HSTF was more specifically responsive to AlCl₃showing a characteristic increase in its UV absorption, peak and area dimensions. Simultaneously, HSA was less affected, but it showed a significant shift with an increase in molecular weight accompanied with a change in its profile. The respective bands of transferrin and albumin in rat serum behaved similarly. The SDS‐PAGE and FPLC data coincided and confirmed the preferential affinity of HSTF to bind with Al³⁺ . These results support the suggestion of using HSTF for monitoring levels of Al³⁺ in human blood samples of exposed population. The importance of further developing such a biomarker is the increased demand for early detection of the hazardous levels of Al³⁺ in relation to its long term neurotoxic adverse effects.     

In-depth analysis of aluminum flows in Austria as a basis to increase resource efficiency

Based on the method of material flow analysis (MFA), a static model of Austrian aluminum (Al) flows in 2010 was developed. Extensive data research on Al production, consumption, trade and waste management was conducted and resulted in a detailed model of national Al resources. Data uncertainty was considered in the model based on the application of a rigorous concept for data quality assessment. The model results indicated that the growth of the Austrian “in-use” Al stock amounts to 11 ± 3.1 kg yr⁻¹ cap⁻¹. The total “in-use” Al stock was determined using a bottom-up approach, which produced an estimate of 260 kg Al cap⁻¹. Approximately 7 ± 1 kg of Al yr⁻¹ cap⁻¹ of old scrap was generated in 2010, of which 20% was not recovered because of losses in waste management processes. Quantitatively, approximately 40% of the total scrap input to secondary Al production originated from net imports, highlighting the import dependency of Austrian Al refiners and remelters. Uncertainties in the calculation of recycling indicators for the Austrian Al system with high shares of foreign scrap trade were exemplarily illustrated for the old scrap ratio (OSR) in secondary Al production, resulting in a possible range of OSRs between 0 and 66%. Overall, the detailed MFA in this study provides a basis to identify resource potentials as well as resource losses in the national Al system, and it will serve as a starting point for a dynamic Al model to be developed in the future.     

Radiation heat transfer in transient dust cloud flame propagation

This study investigates the impact of radiation heat transfer and heat conduction on dust cloud combustion. Radiation plays a very important role in the stability of dust cloud flame, and increasing the amount of radiation drastically raises the possibility of instability and explosion in a dust cloud mixture. Flame speed, which is a function of mixture characteristics, can exhibit a fluctuating behavior. By using the discrete heat source method, it would be possible to study the transient propagation of dust flames. Thus, the propagation speed of flame can be obtained, and as time goes by, the transient speed of dust flame will reach its steady state value. By considering the radiation effect, better agreement is observed between the obtained results and experimental data.     

氧化铝表面处理对吸附腐殖酸的影响

采用酸、碱和金属盐表面修饰处理,影响氧化铝表面结构和成份分布,以达到提高吸附性能的目的。研究表明,经酸处理和酸性条件下的钙镁修饰处理的氧化铝,其对腐殖酸的吸附能力比Al-500分别提高32.3％和23.8％。同时,就改性氧化铝去除腐殖酸的影响条件、动力学、热力学性能进行了讨论。