Behavior and mechanism of arsenate adsorption on activated natural siderite: evidences from FTIR and XANES analysis

Activated natural siderite (ANS) was used to investigate its characteristics and mechanisms of As(V) adsorption from aqueous solution. Batch tests were carried out to determine effects of contact time, initial As(V) concentration, temperature, pH, background electrolyte, and coexisting anions on As(V) adsorption. Arsenic(V) adsorption on ANS well-fitted pseudo-second-order kinetics. ANS showed a high-adsorption capacity of 2.19 mg/g estimated from Langmuir isotherm at 25 °C. Thermodynamic studies indicated that As(V) adsorption on ANS was spontaneous, favorable, and endothermic. ANS adsorbed As(V) efficiently in a relatively wide pH range between 2.0 and 10.0, although the removal efficiency was slightly higher in acidic conditions than that in basic conditions. Effects of background electrolyte and coexisting anions were not significant within the concentration ranges observed in high As groundwater. Results of XRD and Fe K-edge XANES analysis suggested ANS acted as an Fe(II)/(III) hybrid system, which was quite effective in adsorbing As from aqueous solution. There was no As redox transformation during adsorption, although Fe(II) oxidation occurred in the system. Two infrared bands at 787 and 872 cm^?1 after As(V) adsorption suggested that As(V) should be predominantly adsorbed on ANS via inner-sphere bidendate binuclear surface complexes.     

介质阻挡放电协同Ag/Al_2O_3对NO_x脱除的影响

为有效去除发电厂烟气中产生的NOx,利用介质阻挡放电(DBD)产生低温等离子体并结合催化剂Ag/Al2O3进行烟气脱硝实验,研究了在加入乙烯的条件下,平均负载量、催化温度和装置的布置方式对NOx脱除的影响。结果表明,随着负载的增多,NO脱除率呈现先增大后减小的趋势,5种负载量中最佳为1.76%;随着催化温度的升高,NO脱除率同样呈现先增大后减小的趋势,最佳的催化温度为150℃左右;3种不同布置方式对NO和NOx脱除有明显差别,单独催化剂在NO和NOx的脱除率都比较低;单独介质阻挡放电NO脱除率很高,但是NOx很却很低;而两者结合在NO和NOx都达到了很好的效果。     

一种包埋微生物复合填料的制备及性能评价

采用包埋法制备出一种复合生物填料,测其各项理化性质,并以NO。模拟废气验证其脱硝性能。填料主要由碳酸钙、牛粪堆肥腐殖质、菌剂载体、水泥、轻质珍珠岩、立体网状纤维及脱硝功能微生物等复合而成,粒径书12mm×20mm,自然堆积密度（471±0．8）kg／m2,持水量（49±1．3）％,比表面积3．91m2／g,平均机械强度（427．3±0．2）N,pH为10．5-0．2。填料能长期在潮湿环境中保持良好的粘结强度,并具有营养缓释及pH缓冲能力。包埋脱硝功能微生物复合填料中初期微生物数量5．3×10^5 CFU／g,运行60d后微生物数量达到8．6×10 8 CFU／g,闲置停运30d微生物有所减少,但重启后净化效率基本不变。当进气负荷低于I878mg／（13m3·h）,气体停留时间为14．47s时,BF,的去除率高达93．15％。     

The fate and risk of selected pharmaceutical and personal care products in wastewater treatment plants and a pilot-scale multistage constructed wetland system

The removal of 12 pharmaceuticals and personal care products (PPCPs) in two full-scale wastewater treatment plants (WWTPs) and a tertiary treatment system was studied. The ecological risks of effluents from both secondary and tertiary treatment systems as well as excess sludge were evaluated. Primary treatment and ultraviolet light disinfection showed limited ability to remove most selected PPCPs. The combination of an anaerobic process and triple-oxidation ditches can eliminate DEET better than the anaerobic/anoxic/oxic process. Adsorption to sludge played a key role in the removal of triclocarban. Multistage constructed wetlands as a tertiary treatment efficiently removed caffeine and ibuprofen from wastewater and could decrease the risk of partial selected PPCPs. Selected PPCPs residues in excess sludge generally produced higher risks to the ecological environment than effluents from WWTPs.     

遗产旅游地生态移民影响的实证研究——以武陵源风景名胜区为例

生态移民是近年来诸多景区为保护生态环境而采取的重要举措之一。以世界遗产地武陵源风景名胜区为例,通过对安置点居民的问卷调查与实地访谈获取第一手资料,从居民感知的角度分析生态移民给安置区居民所带来的经济、社会文化、资源环境、心理及安置政策等方面的影响及其相关因素。构建生态移民影响的感知差异分析模型,探讨不同基本背景的居民对生态移民影响的感知差异性。结果表明,安置点居民对生态移民的社会文化、资源环境以及心理层面的正面影响比较认可;对于经济影响的感知分歧较大;而对于移民政策的感知十分消极;不同性别、年龄、文化程度、收入水平以及不同旅游业参与程度的居民对生态移民影响的认知态度存在显著差异。在此基础上,指出武陵源生态移民过程中所存在的主要问题及相关政策导向     

基于控制单元的水环境容量核算研究——以锦江流域为例

水环境容量核算是流域水环境容量总量分配的重要依据,关系到流域水质目标的实现。控制单元作为流域水环境管理的一个基本实施单位,以其为基础开展水环境容量核算,对于科学制定控制单元容量总量分配具有重要意义。以江西省锦江流域为例,根据水环境容量核算的基本原理,结合锦江流域的污染状况、水质现状和水环境功能区划,对流域各控制单元COD和氨氮的水环境容量进行分析,结果表明,控制单元的水环境容量与其内排污口的分布及功能区水质目标密切相关,COD的水环境容量以高安控制单元的最大,为 21 811 t/a;其次为上宜控制单元,为 21 168 t/a;再次为新丰控制单元,为 14 493 t/a;万载控制单元的最小,为 7 607 t/a。氨氮的水环境容量在各控制单元的分布特征与COD的略有不同,以上宜控制单元的最大,为790 t/a;其次为高安控制单元,为664 t/a;再次为新丰控制单元,为462 t/a;万载控制单元的最小,为303 t/a     

A survey-based evaluation of community-based co-management of forest resources: a case study of Baishuijiang National Natural Reserve in China

Community-based co-management (CBCM) mechanisms for forest management have matured through the development of new economic analysis and common property theory. However, while many local CBCM mechanisms have been initiated in Chinese Natural Reserves, there are few objective, data-based evaluations of whether these mechanisms improve forest conservation and local livelihoods. This research uses Baishuijiang National Natural Reserve (BNNR) as a study case to evaluate China’s current CBCM mechanisms. The evaluation is based mainly on three criteria: efficiency, equality and sustainability of project operation. Survey data indicate that local CBCM mechanisms provide a wide-participation platform for local villagers, associated administration managers, research institutions and NGOs to join in forest resource protection work while improving local livelihood. CBCM projects have also facilitated a reduction in forest resource dependency, the improvement of household income and encouragement of local people to participate in forest resource protection. Our analysis suggests that most CBCM organizations have made progress in efficiency, equity and sustainability. However, further study should focus on how to deal with the lingering problems of inequity in responsibility and rights among CBCM committee members, poor distribution of benefits, insufficient program-design and management expertise, faulty information dissemination, and insufficient capital investment.     

基于WebGIS三峡干流水质模拟平台研究

三峡蓄水成库后仍属于典型的河道型水库,其总体水流、水质运动特性符合一维水流水质运动规律。针对三峡库区总体水流、水质运动特性,采用一维水流水质模型对三峡库区水流和水质进行了模拟。以该模型为核心,利用Web Services技术开发并在互联网上发布了模型服务,在此基础上采用成熟的WebGIS和富客户端Flex等技术构建了适用于三峡库区的干流水质模拟平台;能够实现包括各计算断面流速、流量、水位以及污染物浓度时空过程在内的三峡库区干流流速场和浓度场的数值模拟。以库区干流清溪场至十里铺断面内的江段作为模拟实例,利用该平台模拟计算江段内水流和水质状况,并以水文水质同步观测数据对模拟结果进行验证,结果表明其具有较好的模拟效果;为三峡库区污染物总体输移扩散特性研究提供了有利工具,同时也为国家和地方政府进行库区水环境决策提供了技术支持     

低纬高原大气电场特征及其在预警中的应用

通过对2006年7月- 2007年6月云南地闪定位网探测资料和玉溪大气电场仪资料分析,研究了高原晴天大气电场和雷暴天气过程的电场演变特征.结果表明:高原晴天大气电场具有明显的日变化和月变化特征.低纬高原地区雷暴云具有偶极性和三极性两种结构,但大多数雷暴具有偶极性电荷结构,不同电荷结构的雷暴云的放电特征不同,偶极性时主要为负地闪,地闪活动较活跃;三极性时主要是正地闪,地闪活动较少.根据雷暴云近地面电场变化特征,探讨了大气电场仪预警地闪的方法,首次提出极性变化预警法,其命中率和提前预警时间都明显优于阈值预警法.