Optimization of esterification of fatty acid rubber seed oil for methyl ester synthesis in a plug flow reactor

To date, non-food vegetable oil has been considered as the primary source for biodiesel production. Rubber seed oil has high acid value (34 mgKOH/g) and can be used for biodiesel synthesis. The purpose of this study was to investigate esterification of fatty acid, which derived from rubber seed oil, in a plug flow reactor system at high temperature and low methanol consumption. Response surface methodology was applied for design experiment and optimization of esterification reaction. Temperature, methanol consumption, and sulfuric acid were chosen as variables to examine their influence in a conversion to methyl ester. At 140°C, at 5:1 methanol to fatty acid ratio (by mole), H₂SO₄ 1.5 (%v/w), and space time 20 min, the conversion to methyl ester attained 98.2%. Fourier transform infrared spectroscopy (FTIR) and gas chromatography-Mass spectrometry (GC-MS) were used for analysis and to confirm the formation of methyl ester. Methyl ester was characterized for biodiesel fuel properties in accordance to ASTM standard.     

Charcoal burning as a source of polyaromatic hydrocarbons in waterpipe smoking

Polyaromatic hydrocarbons (PAH) content from seven commercial waterpipe charcoals were determined during the smoking process to estimate how much PAHs would not be trapped by the water trap and could reach the lungs of the smokers. Naphthalene, 2-methylnaphthalene, acenaphthylene, acenaphthene, phenanthrene and fluoranthene were the most abundant PAH compounds produced during smoking. Naphthalene was the highest in all of the smoke contents and levels of 5 to 405 μg/15 minutes could be inhaled by the smoker. The amounts of PAHs produced during the smoking events in absence of tobacco varied greatly among different brands of charcoal. The amount and composition of the emitted PAH were not related to the amount and composition of the original chemicals in the charcoal prior to burning. Our findings suggest that public health agencies should regulate smoked charcoal products alongside tobacco.     

微污染矿井水中微絮体的形成及分形特征

利用分形理论阐述了微污染矿井水中微絮体形成的分形生长特征,考察了微絮体形成过程中的影响因素,探讨了微絮凝机理,利用絮体的分形维数表征各影响因素对微絮体形态的作用结果,结果表明,微絮体形态与其分形维数之间具有良好的相关性,且分形维数越大,微絮体更加紧实,越易于沉降,滤后水的浊度越小;同时考察了微量铁锰离子对微絮体形态的影响,为微絮凝深床过滤工艺参数的改进提出了建议.     

铁碳微电解-Fenton法预处理苯胺基乙腈生产废水

采用铁碳微电解-Fenton法对苯胺基乙腈生产废水进行预处理实验。通过静态实验确定铁碳微电解最佳条件为铁屑投加量300 g/L,Fe/C质量比为2∶3,反应75 min,不需要调节进水pH;Fenton反应最佳条件为铁碳微电解出水pH=4,30%H2O2投加量15 mL/L,在搅拌条件下反应60 min;然后沉淀反应时调节pH为9,混凝沉淀75 min。在上述条件下通过动态实验得到系统连续反应在48 h内废水的COD和苯胺去除率在50%和70%以上,可生化性BOD5/COD也保持在0.3以上,为后续生物处理创造了良好条件。     

Dioxin contamination in soils of Southern Vietnam

Dioxin is the common name for polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs), and is abbreviated as PCDD/Fs. In the case of Southern Vietnam, is of high concern dioxin contamination in the areas affected by past-use chemical defoliants. Our study related to the zone considered as a "hot spot"--Bien Hoa Airbase and surrounding areas (Bien Hung Lake). Although the war ended over 30 years ago, the adverse effects on this territory still continue. Soil and sediment were selected for our research as they act as a sink for PCDD/Fs. The samples were taken and analyzed in CECOTOX laboratory following certified procedures. The total amounts of PCDD/Fs (2,3,7,8 related congeners) in the samples were converted into WHO-TEQ and compared with standard values proposed by Canadian environmental quality guidelines. The obtained data shows a relatively high risk (up to 20.4 times higher than (probable effect level) PEL value for sediment and 46 times higher than standard value for soil). The research is continuing on the assessment of dioxin transport in food chain. Moreover, considering the obtained data a complete solution should be found urgently to solve the problem of dioxin contamination in the studied areas.     

宁镇扬地区优良级旅游资源空间结构对比研究

利用Stephen Smith总结和提出的旅游区域研究方法,以2007年江苏省旅游资源普查的数据资料为基础,运用AreGIS空间分析的相关工具,对宁镇扬地区的优良级旅游资源的空间结构作了对比研究。结果显示,扬州、镇江具有较典型的金字塔形旅游资源等级结构;宁镇扬3个城市的优良级旅游资源分布都属于集聚型分布,尤以南京的集聚程度最高。在阐述传统通达度计算方法缺陷的基础上,通过权距离修正和扩大网络范围修正之后的通达度分析结果显示,宁镇扬地区是江苏省旅游交通最为发达的区域,尤以南京的通达程度最高。     

Arsenic in groundwater and sediment in the Mekong River delta, Vietnam

A study of groundwater and sediment during 2007-2008 in the Mekong River delta in Vietnam (MDVN) revealed that 26%, 74%, and 50% of groundwater samples were above the US EPA drinking water guidelines for As (10 μg/L), Mn (0.05 mg/L), and Fe (0.3 mg/L). The range of As, Fe, and Mn concentrations in the MDVN were <0.1-1351 μg/L, <0.01-38 mg/L, and <0.01−14 mg/L, respectively. Elevated levels of As were found in groundwater at sampling sites close to the Mekong River and in wells less than 60−70 m deep. An inverse relationship was found between As and Mn concentrations in groundwater. Sediment samples from An Giang and Dong Thap had the highest As concentrations (18 mg/kg and 38 mg/kg, respectively). Arsenic sediment occurred mainly in the poorly crystalline Fe oxide phases. Reductive dissolution of the Fe oxide phase is not necessarily the dominant mechanism of As release to groundwater.     

Amine volatility in CO2 capture

Amine volatility is a key screening criterion for amines to be used in CO₂ capture. Excessive volatility may result in significant economic losses and environmental impact. It also dictates the capital cost of the water wash. This paper reports measured amine volatility in 7 m MEA (monoethanolamine), 8 m PZ (piperazine), 7 m MDEA (n-methyldiethanolamine)/2 m PZ (piperazine), 12 m EDA (ethylenediamine), and 5 m AMP (2-amino-2-methyl-1-propanol) at 40–60 °C with lean and rich loadings giving CO₂ partial pressures of 0.5 and 5 kPa at 40 °C. The amine concentrations were chosen to maximize CO₂ capture capacity at acceptable viscosity. At the lean loading condition (where volatility is of greatest interest), the amines are ranked in order of increasing volatility: 7 m MDEA/2 m PZ (6/2 ppm), 8 m PZ (8 ppm), 12 m EDA (9 ppm), 7 m MEA (31 ppm), and 5 m AMP (112 ppm). The apparent amine partial molar excess enthalpies in these systems were estimated to range from ～10 to 87 kJ/mol of amine.     

沸腾炉大气污染物初始排放因子的研究

以20台沸腾炉(≤60MW)的燃料特性分析数据和大气污染物的排放实测数据为基础,研究了颗粒物(PM)、SO2和NOX初始排放因子EFP0M、EF0SO2、EF0NOX的变化规律,并利用SPSS13.0统计分析软件,分析了EFP0M、EFS0O2、EF0NOX与影响因子间的相关性。结果表明,在沸腾炉运行负荷≥80%的条件下,EF0PM基本不受锅炉出力(W)、燃煤灰分质量分数(Aar)及过量空气系数(α)的影响,EFP0M与W、Aar、α不具有相关性;EF0SO2主要受燃煤硫质量分数(Sar)的影响,两者具有显著正相关关系;W、α、燃煤干燥基挥发分质量分数(Vdaf)对EF0NOX具有显著影响,EF0NOX与α具有显著正相关关系,而EF0NOX与W、Vdaf具有显著负相关关系;EFS0O2和EF0NOX影响因子由强到弱的顺序为:①EFS0O2:SarαW;②EF0NOX:VdafαW燃煤氮质量分数(Nar)。     

Estimation of Nitrogen and Phosphorus in Effluent from the Striped Catfish Farming Sector in the Mekong Delta,Vietnam

In this study an attempt is made to estimate nitrogen and phosphorus discharged to the environment from the striped catfish (Pangasianodon hypophthalmus) farming sector in the Mekong Delta (8°33′–10°55′N, 104°30′–106°50′E), South Vietnam. The sector accounted for 687,000 t production in 2007 and 1,094,879 t in 2008, with over 95% of the produce destined for export to over 100 countries. Commercial and farm-made feeds are used in catfish farming, currently the former being more predominant. Nitrogen discharge levels were similar for commercial feeds (median 46.0 kg/t fish) and farm-made feeds (median 46.8 kg/t fish); whilst, phosphorus discharge levels for commercial feeds (median 14.4 kg/t fish) were considerably lower than for farm-made feeds (median 18.4 kg/t fish). Based on the median nutrient discharge levels for commercial feeds, striped catfish production in the Mekong Delta discharged 31,602 t N and 9,893 t P, and 50,364 t N and 15,766 t P in 2007 and 2008, respectively. However, the amount of nutrients returned directly to the Mekong River may be substantially less than this as a significant proportion of the water used for catfish farming as well as the sludge is diverted to other agricultural farming systems. Striped catfish farming in the Mekong Delta compared favourably with other cultured species, irrespective of the type of feed used, when the total amounts of N and P discharged in the production of a tonne of production was estimated.