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981.
This work focused on anaerobic biodegradation of blends composed of glycerol-plasticized polyvinyl alcohol (PVA) and biopolymer (starch, gellan, xanthan) in an aqueous environment, after inoculation with digested activated sludge from a municipal wastewater treatment plant. Glycerol degradability is comparable to degradability of used modifying agents. Modifying agents added in the 20–40 wt% range proportionally increased biodegradation degree (Dt) calculated from balance of transformed carbon in the system. Biodegradation degree of polysaccharides and glycerol attained 95% and over. For PVA it was only 6.5% (in breakdown times up to 500 h). Content of polysaccharides favorably affects biodegradation degree of polyvinyl alcohol blends, but at the expense of reduced mechanical properties of resultant products.  相似文献   
982.
含汞废弃荧光灯管处理现状及分析   总被引:2,自引:0,他引:2  
废弃荧光灯管中含有金属汞,属于《国家危险废物名录》中的HW29含汞废物类,随意处置会破坏环境,危害人类健康,因此必须采取合理的方法对其进行处理。综合比较后发现资源化、无害化回收金属汞是最佳的处理方法。部分发达国家通过法律和技术手段的加强实现了对废弃荧光灯管的无害化回收处理,但我国在这方面的工作尚且不足,主要存在着灯管收集难、处理成本高等问题。因此,我国需要借鉴国外的管理经验,出台有效的法规措施,同时需要不断完善处理技术和大型工程建设。在我国节能减排和环境保护形势日益严峻的大环境下,辅之以合理的管理体制和技术手段,才能实现社会效益和经济效益双赢的局面。  相似文献   
983.
介绍了内电解技术的基本原理和特点,详细阐述了内电解技术处理印染、制药等多种有毒有害工业废水的应用进展,总结了内电解技术目前存在的主要问题和在工艺优化、新型材料和反应器形式开发三个方面的改进措施,展望了内电解技术未来的发展趋势和研究方向。  相似文献   
984.
Here we present the methodology used for terrestrial biodiversity analysis and site selection in Phase B of the UNDP/GEF COAST project. The analysis was focused on the problem of biodiversity evaluation in four Croatian counties stretching from sea level to the highest mountain in Croatia. Data on habitats, vascular flora, and fauna (mammals, birds, reptiles, amphibians, butterflies, ground beetles, and underground invertebrates) were collected and analyzed for each of the four counties. Emphasis was given to the richness of endangered species and the rarity of endemic species. Based on the spatial analyses of habitat, fauna, and flora data, four to six areas were selected from each county and ranked according to their biodiversity importance. Overlap between areas important for richness and those important for rarity was highest for data on flora (65.5%) and lowest for data on fauna (16.7%). When different data sets were compared, the lowest overlap was between flora and fauna (17.1%) and largest between fauna and habitats (23.9%). Simultaneous overlap among all three data sets was found in just 6.5% of the overall selected areas. These results suggest that less specific data, with respect to taxa threat status, could better serve as surrogate data in estimating overall biodiversity. In summary, this analysis has demonstrated that Dalmatia is a region with a high overall biodiversity that is important in a broader European context.  相似文献   
985.
Open interior sands represent a highly threatened habitat in Europe. In recent times, their associated organisms have often found secondary refuges outside their natural habitats, mainly in sand pits. We investigated the effects of different restoration approaches, i.e. spontaneous succession without additional disturbances, spontaneous succession with additional disturbances caused by recreational activities, and forestry reclamation, on the diversity and conservation values of spiders, beetles, flies, bees and wasps, orthopterans and vascular plants in a large sand pit in the Czech Republic, Central Europe. Out of 406 species recorded in total, 112 were classified as open sand specialists and 71 as threatened. The sites restored through spontaneous succession with additional disturbances hosted the largest proportion of open sand specialists and threatened species. The forestry reclamations, in contrast, hosted few such species. The sites with spontaneous succession without disturbances represent a transition between these two approaches. While restoration through spontaneous succession favours biodiversity in contrast to forestry reclamation, additional disturbances are necessary to maintain early successional habitats essential for threatened species and open sand specialists. Therefore, recreational activities seem to be an economically efficient restoration tool that will also benefit biodiversity in sand pits.  相似文献   
986.
Activity concentrations of 210Po and 210Pb in the species Mytilus galloprovincialis from Croatian Adriatic coast were determined. The samples were collected in thirteen sampling places which are also a part of Croatian Mediterranean mussel watch project. The results of 210Po and 210Pb activity concentrations were found to vary between (22.1 ± 2.5)-(207 ± 21) Bq kg−1 fresh weight and (2.8 ± 1.4)-(9.3 ± 0.7) Bq kg−1 fresh weight, respectively. 210Po/210Pb ratio ranged between 6.2 and 30.7. The highest measured activities were found in the enclosed basins of the Neretva channel, where the majority of Croatian mussel cultivation is taking place. The estimated consequent average total annual effective ingestion dose due to 210Po and 210Pb from mussel consumption in Croatian coastal region is 202 ± 99 μSv with 96% contribution of 210Po to the total effective dose.  相似文献   
987.
A simple and efficient residue analysis method for direct determination of ioxynil octanoate in maize and soil was developed and validated with High Performance Liquid Chromatography-Ultra Violet (HPLC-UV). The samples were extracted with mixtures of acetonitrile and deionized water followed by Solid Phase Extraction (SPE) to remove co-extractives prior to analysis by HPLC-UV. The recoveries of ioxynil octanoate extracted from maize and soil samples ranged from 86 %-104 % and 84 %-96 %, respectively, with relative standard deviation (RSD) less than 7.84% and sensitivity of 0.01 mg kg(-1). The method was applied to determine the residue of ioxynil octanoate in maize and soil samples from experimental field. Data had shown that the dissipation rate in soil was described as pseudo-first-order kinetics and the half-life (t(1/2)) was less than 1.78 days. No ioxynil octanoate residue (<0.01 mg kg(-1)) was detected in maize at harvest time withholding period of 60 days after treatments of the pesticide. Direct confirmation of the analytes in field trial samples was realized by Liquid Chromatography-Mass Spectrometry (LC-MS).  相似文献   
988.
采用水热法制备出LiFePO4催化剂,通过电子显微镜(SEM)、X射线衍射(XRD)和傅立叶红外光谱(FTIR)对其进行表征,并将其作为非均相Fenton催化剂处理亚甲基蓝(MB)染料溶液。实验结果表明,在催化剂用量为4 g/L,H2O2浓度为0.04 mol/L,pH值为3,温度为50℃,反应时间为60 min的条件下,浓度为500 mg/L的亚甲基蓝脱色率达99%。根据实验结果,讨论了LiFePO4作为非均相Fenton催化剂对亚甲基蓝的降解机理。  相似文献   
989.
以不同添加剂采用浸没沉淀相转换法制备基于无纺布支撑的聚偏氟乙烯(PVDF)平板疏水膜,考察了不同添加剂的加入对膜性能与结构的影响;并利用扫描电子显微镜(SEM)、原子力学显微镜(AFM)、红外光谱(FTIR)、接触角测量及膜蒸馏实验等对疏水膜的结构及性能进行表征。结果表明,引入混合型添加剂制备的膜具有较高通量和盐截留率,其疏水性最强,而添加剂对聚合物的晶型影响较小。以35 g/L的NaCl盐溶液为进料液对制备的平板膜进行直接接触式膜蒸馏实验,在热侧进水温度为50℃、冷侧温度为20℃的条件下,所制备的疏水膜通量最高可达12.45 kg/(m2.h),截留率为99.99%。  相似文献   
990.
为了预测紫外反应器的消毒效率,提高模拟的准确度,对两种紫外光强模型进行了比较分析。利用CFD技术,采用数值模拟的方法,对线源和柱源两种光强模型进行了光强分布以及消毒效率的模拟,并采用生物实验进行了验证。结果表明:与柱源模型相比,线源模型在近灯管处强度高42.3%,在1.2 cm处二者趋于一致;针对同一管式紫外反应器,透光率为95%时,线源模型的模拟结果偏大,柱源结果偏小;透光率为80%时,线源及柱源模型的模拟结果都偏大,流量及模型影响较小,透光率成为主要影响因素。综合比较,柱源模型适用于小型管式紫外灯消毒数值模型的开发。  相似文献   
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