超临界水氧化法处理造纸黑液

采用自制的超临界水氧化反应装置,对造纸工业排放的黑液进行处理。考察了反应温度、反应压力、反应时间、过氧量(初始反应时所加氧气的量与废水完全氧化所需氧气的理论量的比,%)等对黑液中COD去除率的影响。实验结果表明,处理黑液的最佳反应条件为:反应温度500℃,压力26M Pa,过氧量500%,反应时间120s。在此最佳条件下处理COD为85 000m g/L的造纸黑液,COD去除率可达99.9%。     

Tracking nitrogen losses in a greenhouse crop rotation experiment in North China using the EU-Rotate_N simulation model

Vegetable production in China is associated with high inputs of nitrogen, posing a risk of losses to the environment. Organic matter mineralisation is a considerable source of nitrogen (N) which is hard to quantify. In a two-year greenhouse cucumber experiment with different N treatments in North China, non-observed pathways of the N cycle were estimated using the EU-Rotate_N simulation model. EU-Rotate_N was calibrated against crop dry matter and soil moisture data to predict crop N uptake, soil mineral N contents, N mineralisation and N loss. Crop N uptake (Modelling Efficiencies (ME) between 0.80 and 0.92) and soil mineral N contents in different soil layers (ME between 0.24 and 0.74) were satisfactorily simulated by the model for all N treatments except for the traditional N management. The model predicted high N mineralisation rates and N leaching losses, suggesting that previously published estimates of N leaching for these production systems strongly underestimated the mineralisation of N from organic matter.     

Aquatic biomonitoring of Giardia cysts and Cryptosporidium oocysts in peninsular Malaysia

An aquatic biomonitoring of Giardia cysts and Cryptosporidium oocysts in river water corresponding to five villages situated in three states in peninsular Malaysia was determined. There were 51.3 % (20/39) and 23.1 % (9/39) samples positive for Giardia and Cryptosporidium (oo)cysts, respectively. Overall mean concentration between villages for Giardia cysts ranged from 0.10 to 25.80 cysts/l whilst Cryptosporidium oocysts ranged from 0.10 to 0.90 oocysts/l. Detailed results of the river samples from five villages indicated that Kuala Pangsun 100 % (9/9), Kemensah 77.8 % (7/9), Pos Piah 33.3 % (3/9) and Paya Lebar 33.3 % (1/3) were contaminated with Giardia cysts whilst Cryptosporidium (oo)cysts were only detected in Kemensah (100 %; 9/9) and Kuala Pangsun (66.6 %; 6/9). However, the water samples from Bentong were all negative for these waterborne parasites. Samples were collected from lower point, midpoint and upper point. Midpoint refers to the section of the river where the studied communities are highly populated. Meanwhile, the position of the lower point is at least 2 km southward of the midpoint and upper point is at least 2 km northward of the midpoint. The highest mean concentration for (oo)cysts was found at the lower points [3.15?±?6.09 (oo)cysts/l], followed by midpoints [0.66?±?1.10 (oo)cysts/l] and upper points [0.66?±?0.92 (oo)cysts/l]. The mean concentration of Giardia cysts was highest at Kuala Pangsun (i.e. 5.97?±?7.0 cysts/l), followed by Kemensah (0.83?±?0.81 cysts/l), Pos Piah (0.20?±?0.35 cysts/l) and Paya Lebar (0.10?±?0.19 cysts/l). On the other hand, the mean concentration of Cryptosporidium oocysts was higher at Kemensah (0.31?±?0.19 cysts/l) compared to Kuala Pangsun (0.03?±?0.03cysts/l). All the physical and chemical parameters did not show significant correlation with both protozoa. In future, viability status and molecular characterisation of Giardia and Cryptosporidium should be applied to identify species and genotypes/subgenotypes for better understanding of the epidemiology of these waterborne parasites.     

石英砂滤料表面润湿改性

采用硅烷偶联剂、钛酸酯偶联剂和铝酸酯偶联剂对石英砂进行表面改性,以制备亲油疏水性滤料。研究得出,钛酸酯偶联剂改性石英砂的最佳工艺条件为:偶联剂用量15%,反应温度90℃,搅拌时间15 min;硅烷偶联剂和铝酸酯偶联剂改性石英砂的最佳工艺条件均为:偶联剂用量15%,反应温度110℃,搅拌时间15 min。水对钛酸酯偶联剂改性石英砂滤料的润湿重量由改性前的1.5589 g降低到0.0282 g,水对硅烷偶联剂改性石英砂滤料的润湿重量降低到0.0607 g,水对铝酸酯改性石英砂滤料的润湿重量降低到0.2664 g。静态吸附实验表明,硅烷偶联剂、钛酸酯偶联剂和铝酸酯偶联剂改性石英砂滤料对油的吸附容量分别增加了33.67%、42.87%和22.30%。XPS和FT-IR分析表明,偶联剂均以化学键的方式包覆在石英砂滤料表面,结合稳定。     

Impacts of invasive plants on ecosystems in natural reserves in Jiangsu of China

To estimate the impacts of invasive plants on ecosystems, a survey has been conducted in three sites including both buffer zones and core zones. 13, 19 species are found in the Yuntai Mountain and Longchi Mountain natural reserve respectively, and 23 in the Purple Mountain Natural Park. Altogether 25 species belonging to 12 families, the majority of which are native to North America, some of them have set up stable reproducible populations. Among them, Solidago canadensis is found in Longchi Mountain and Purple Mountain. Communities of Galinsoga parviflora, Gynura crepidioides, Ageratum conyzoides, and Ambrosia artemisiifolia pose a serious threat to local biodiversity.     

北京市人口老龄化的时空变化特征

人口老龄化现已成为当今主要的人口问题之一,并引起越来越多的关注,人口老龄化进程与老年人口空间分布特征研究是未来人口问题研究的一个重要分支.本文基于ESDA全局和局部空间自相关分析,利用北京市第四次和第五次人口普查数据以及1995和2005年1％人口抽样调查数据,对北京市县域尺度老龄人口分布总体和局部空间差异的变化趋势、特征进行了初步探索.结果表明,北京市老龄人口空间分布各区县差异较大,且呈现出明显的圈层结构特征,中心四城区老龄人口比重较高,近郊区老龄人口比重较全市平均水平低,远郊区老年人口比重又有所回升;同时,北京地区老年人口各区县的空间分布差异随着时间的推移而不断扩大,中心老城区呈现不断增强的集聚趋势,而远郊区的老年人口扩散效应明显大于集聚效应.     

吉林省“十二五”环保政策措施研究

十二五期间,吉林省将处在经济高速发展时期,完善环境保护政策措施,是有效实施十二五环保规划的关键。通过全省环境保护政策措施的回顾,科学预测新时期环境保护工作形势,研究全省十二五时期环境保护法规体系、协调机制、经济政策、环保投入、科技创新等方面的对策措施。     

Bioconversion of dairy manure by black soldier fly (Diptera: Stratiomyidae) for biodiesel and sugar production

Modern dairies cause the accumulation of considerable quantity of dairy manure which is a potential hazard to the environment. Dairy manure can also act as a principal larval resource for many insects such as the black soldier fly, Hermetia illucens. The black soldier fly larvae (BSFL) are considered as a new biotechnology to convert dairy manure into biodiesel and sugar. BSFL are a common colonizer of large variety of decomposing organic material in temperate and tropical areas. Adults do not need to be fed, except to take water, and acquired enough nutrition during larval development for reproduction. Dairy manure treated by BSFL is an economical way in animal facilities. Grease could be extracted from BSFL by petroleum ether, and then be treated with a two-step method to produce biodiesel. The digested dairy manure was hydrolyzed into sugar. In this study, approximately 1248.6 g fresh dairy manure was converted into 273.4 g dry residue by 1200 BSFL in 21 days. Approximately 15.8 g of biodiesel was gained from 70.8 g dry BSFL, and 96.2 g sugar was obtained from the digested dairy manure. The residual dry BSFL after grease extraction can be used as protein feedstuff.     

Enhanced arsenate removal from aqueous solution by Mn-doped MgAl-layered double hydroxides

Environmental Science and Pollution Research - In this study, Mn-doped MgAl-layered double hydroxides (LDHs) were successfully synthesized for efficient removal arsenate from aqueous solution. The...     

Producing biodiesel from waste animal oil by modified ZnO

Biodiesel produced by transesterification of waste animal oil is a promising green fuel in the future. ZnO-Al₂O₃ and ZnO/Zn₂Al composition oxides were prepared by co-precipitation method and impregnation method, respectively. The above catalysts were characterized by X-ray diffraction (XRD), Brunauer--Emmett--Teller (BET) and CO₂ adsorption and temperature-programmed desorption (CO₂-TPD) and show that the high activity for the catalyst is attributed to its high alkalinity. The reaction parameters were optimized and the results show that the transesterification ratio of waste animal oil can reach 98.7% with 10% ZnO/Zn₂Al catalyst after 2 h. Moreover, 10%ZnO/Zn₂Al compound oxides can be active for the successive cycles. The glycerol as a predominant by-product after transesterification is of high purity with high use value.