微生物吸附处理低浓度含铀废水的效能

生物吸附是目前处理低浓度含铀废水最有前途的方法之一.本文探讨了不同种类微生物的来源及其对铀的吸附效能.分析了生物吸附过程的影响因素和吸附机理.细菌、放线菌、真菌和藻类对铀的吸附能力依次递减,pH值、菌种预处理、共存离子和金属初始浓度是生物吸附的主要影响因素;微生物的细胞结构在生物吸附过程中发挥了重要的作用,静电吸附、酶促反应、无机微沉淀和氧化还原等是生物吸附的主要机理.最后预测了生物吸附处理低浓度含铀废水的研究方向.     

三阶段温度控制堆肥接种法对有机氮变化规律的影响

利用原生生活垃圾,通过三阶段温度控制技术进行堆肥试验,探讨在堆肥过程中有机态氮组分的动态变化规律.结果表明,全氮、酸水解有机态氮、氨基酸态氮均在堆肥的前期呈明显的下降趋势,呈较好的相关性.与CK（对照组）处理相比,在堆肥的后期,三阶段温度控制堆肥酸水解有机态氮、氨基酸态氮、氨基糖态氮及酸解未知态氮含量呈不同程度的上升趋势,增加幅度依次为：10.67%、16.17%、7.17%、22.44%.表明三阶段温度控制技术能减少堆肥中氮素的损失,堆肥产品施入土壤后,可提高土壤的供氮潜力.     

Complete catalytic oxidation of o-xylene over Ce02 nanocubes

The activities of CeO2 nanocubes calcined at different temperatures were tested for catalytic oxidation of o-xylene. Using CeO2 nanocubes as catalysts, complete catalytic oxidation of o-xylene was achieved below 210℃. The CeO2 nanomaterials were characterized by means of BET, X-ray diffraction (XRD), transmission electron microscopy (TEM), and high-resolution transmission electron microscopy (HRTEM). From the TEM images, all Ce02 nanocubes displayed cubic morphology irrespective of calcination temperature. The HRTEM images revealed that these nanocubes were enclosed by reactive {001}planes, which may contribute to the intrinsically catalytic property of o-xylene oxidation. The higher activity of Ce02 nanocubes calcined at 550℃ than those calcined at above 550℃ was attributed to their smaller crystallite size and larger surface area. The influences of reaction conditions were also studied, which found that a higher reaction temperature was necessary for complete catalytic oxidation of o-xylene at higher weight hourly space velocity (WHSV) and o-xylene concentration.     

不同波长紫外光催化降解活性艳蓝KN-R动力学研究

以蒽醌类染料活性艳蓝KN-R(以下简称KN-R)为对象,以TiO2为光催化剂,实验了不同波段紫外光条件下KN-R的降解过程。结果表明:365 nm和254 nm两种波段对于KN-R的光催化降解过程均符合假一级动力学方程,但是通过对比各初始浓度下活性艳红KN-R的反应速率常数(Kapp)可以发现,在相同紫外灯功率下,短波辐射下的Kapp平均为长波辐射下Kapp的3倍,说明短波紫外更有利于活性艳蓝KN-R的降解。     

两种喹诺酮类抗生素对亚心形扁藻的毒性效应研究

研究了恩诺沙星和盐酸环丙沙星两种喹诺酮类抗生素对亚心形扁藻的毒理学效应。经多组不同浓度的两种抗生素处理后,分别对扁藻的96EC50、叶绿素和胞外聚合物（EPS）进行分析。结果表明,两种抗生素在低浓度时对扁藻生长具有促进作用,而在高浓度时体现抑制毒性作用。高浓度时,抗生素浓度越高对扁藻的生长、叶绿素和胞外聚合物抑制效果越明显,但当浓度达到一定高度后,抑制会达到其阈值。恩诺沙星和盐酸环丙沙星对扁藻的半生长抑制率分别为19.8 mg/L和28.7 mg/L。     

Flammability of heat transfer fluid aerosols produced by electrospray measured by laser diffraction analysis

Accidental release of pressurized high flash point heat transfer fluids can result in fire and explosion hazard scenarios in the process industry. An experimental investigation on ignition of aerosols of a heat transfer fluid is carried out, and characterization of aerosol and its ignition process by non-intrusive laser diffraction technique is reported. Propagation speed of the aerosol combustion flame front as analyzed from the laser diffraction measurement agrees with high-speed visual camera observation. Flammability of the aerosol, which is based on the chances of the global flame appearance in the aerosol, is mainly controlled by aerosol droplet size and the droplet volume concentration.     

壳聚糖改性粘土对高藻水中藻类的絮凝去除

对壳聚糖改性粘土用于天然高藻水中藻类的絮凝去除进行了研究。实验表明,经壳聚糖改性后的粘土对高藻水中藻细胞有较好的去除效果。粘土的种类对除藻效果有一定影响,其中以高粘凹凸棒石为最佳,其最佳投加量为66mg/L(壳聚糖6 mg/L),此时的叶绿素去除率达到95.45%。相比单独投加壳聚糖,粘土的加入增加了絮体密实度,减少了絮体体积,并使絮体分布更均匀。粘土的粒径对絮凝效果基本没有影响,粒径范围在25～74μm时,改性粘土对藻细胞的凝聚效果是一致的。经壳聚糖改性的粘土在酸性条件下絮凝效果较好,当pH值大于7时,其絮凝能力迅速下降。     

The development and prospects of the end-of-life vehicle recycling system in Taiwan

Automobiles usually contain toxic substances, such as lubricants, acid solutions and coolants. Therefore, inappropriate handling of end-of-life vehicles (ELVs) will result in environmental pollution. ELV parts, which include metallic and non-metallic substances, are increasingly gaining recycling value due to the recent global shortage of raw materials. Hence, the establishment of a proper recycling system for ELVs will not only reduce the impact on the environment during the recycling process, but it will also facilitate the effective reuse of recycled resources. Prior to 1994, the recycling of ELVs in Taiwan was performed by related operators in the industry. Since the publishing of the “End-of-life vehicle recycling guidelines” under the authority of the Waste Disposal Act by the Environmental Protection Administration (EPA) in 1994, the recycling of ELVs in Taiwan has gradually become systematic. Subsequently, the Recycling Fund Management Board (RFMB) of the EPA was established in 1998 to collect a Collection–Disposal–Treatment Fee (recycling fee) from responsible enterprises for recycling and related tasks. Since then, the recycling channels, processing equipment, and techniques for ELVs in Taiwan have gradually become established. This paper reviews the establishment of the ELV recycling system, analyzes the current system and its performance, and provides some recommendations for future development. The reduction of auto shredder residue (ASR) is a key factor in maximizing the resource recovery rate and recycling efficiency. The RFMB needs to provide strong economic incentives to further increase the recycling rate and to encourage the automobile industry to design and market greener cars.     

高铁酸盐处理有机废水的研究进展

综述了高铁酸盐去除水中藻类、细菌、烃类衍生物、药品、农药、染料等有机污染物的国内外最新研究进展,并对高铁酸盐的高效利用进行了探讨。高铁酸盐可破坏藻类和细菌细胞的完整性,将大分子芳香烃衍生物氧化为低毒的小分子中间体,将小分子链烃衍生物矿化,破坏药品、农药及染料的不饱和双键。无机矿物在溶液中负载高铁酸盐或将高分子有机物与固体高铁酸盐混合造粒,将是高铁酸盐高效利用领域的研究热点。     

Accumulation and quantitative estimates of airborne lead for a wild plant (Aster subulatus)

Foliar uptake of airborne lead is one of the pathways for Pb accumulation in plant organs. However, the approximate contributions of airborne Pb to plant organs are still unclear. In the present study, aerosols (nine-stage size-segregated aerosols and total suspended particulates), a wild plant species (Aster subulatus) and the corresponding soils were collected and Pb contents and isotopic ratios in these samples were analyzed. Average concentration of Pb was 96.5 ± 63.5 ng m⁻³ in total suspended particulates (TSP) and 20.4 ± 5.5 ng m⁻³ in the fine fractions of size-segregated aerosols (SSA) (<2.1 μm), higher than that in the coarser fractions (>2.1 μm) (6.38 ± 3.71 ng m⁻³). Enrichment factors show that aerosols and soils suffered from anthropogenic inputs and the fine fractions of the size-segregated aerosols enriched more Pb than the coarse fractions. The order of Pb contents in A. subulatus was roots > leaves > stems. The linear relationship of Pb isotope ratios (²⁰⁶Pb/²⁰⁷Pb and ²⁰⁸Pb/²⁰⁶Pb) among soil, plant and aerosol samples were found. Based on the simple binary Pb isotopic model using the mean ²⁰⁶Pb/²⁰⁷Pb ratios in TSP and in SSA, the approximate contributions of airborne Pb into plant leaves were 72.2% and 65.1%, respectively, suggesting that airborne Pb is the most important source for the Pb accumulation in leaves. So the combination of Pb isotope tracing and the simple binary Pb isotope model can assess the contribution of airborne Pb into plant leaves and may be of interest for risk assessment of the exposure to airborne Pb contamination.