The Kinetics of Interesterfication on Waste Cooking Oil (Sunflower Oil) for the Production of Fatty Acid Alkyl Esters using a Whole Cell Biocatalyst (Rhizopus oryzae) and Pure Lipase Enzyme

Recent research and technology have provided promising outcomes to rely on biodiesel as the alternative and conventional source of fuel. The use of renewable sources constitutes the main stream of research. Waste Cooking Oil (WCO) was used for biodiesel production in this study. Lipase enzyme producing fungi Rhizopus oryzae 262 and commercially available pure lipase enzyme were used for comparative study in the production of FAAE. The whole cell biocatalyst and pure enzyme were immobilized using calcium alginate beads. It was prepared by optimizing with different molar ratios of calcium chloride and different percent sodium alginate. Entrapment immobilization was done for whole cell biocatalyst. PE was also immobilized by entrapment for the transesterification reaction. Four different solvents methanol, ethanol, n-propanol, n-butanol were used as the acyl acceptors. The reaction parameters like temperature, molar ratio, reaction time, and amount of enzyme to be used were also optimized for methanol alone. The same parameters were adopted for the other acyl acceptors too. Among the different acyl acceptors, methanol whose reaction parameters were optimized showed maximum conversion of triglycerides to FAAE - 94% with PE and 84% with WCB. On the whole, PE showed better catalytic converting ability with all the acyl acceptor compared to WCB, further study, it was observed that three consecutive and reversible reactions occurred in the interesterification of triglycerides. So, a kinetic model based on Michaelis-Menten equation with competitive substrate inhibition was used to find the maximum reaction rate V_i for the four solvents using pure enzyme and WCB.     

连续流动法测定沉积物中的酸挥发性硫化物

优化沉积物中酸挥发性硫化物(Acid Volatile Sulfide,AVS)的提取方法并采用连续流动分析法检测提取液中的硫化物.研究了吸收液的种类、氮气流量与吹气的时间和反应温度对AVS提取效果的影响以优化提取方法.结果表明,与传统的氢氧化钠或硫酸镉-氢氧化钠吸收液相比,以氯化锌-羧甲基纤维素钠溶液为吸收液吸附效率好,稳定性高且无毒.用连续流动分析法检测提取液中的AVS快速、准确、稳定性好.     

Response of Fish and Macroinvertebrate Bioassessment Indices to Water Chemistry in a Mined Appalachian Watershed

Multimetric indices based on fish and benthic macroinvertebrate assemblages are commonly used to assess the biological integrity of aquatic ecosystems. However, their response to specific stressors is rarely known. We quantified the response of a fish-based index (Mid-Atlantic Highlands Index of Biotic Integrity, MAH-IBI) and a benthic invertebrate-based index (West Virginia Stream Condition Index, WV-SCI) to acid mine drainage (AMD)-related stressors in 46 stream sites within the Cheat River watershed, West Virginia. We also identified specific stressor concentrations at which biological impairment was always or never observed. Water chemistry was extremely variable among tributaries of the Cheat River, and the WV-SCI was highly responsive across a range of AMD stressor levels. Furthermore, impairment to macroinvertebrate communities was observed at relatively low stressor concentrations, especially when compared to state water quality standards. In contrast to the WV-SCI, we found that the MAH-IBI was significantly less responsive to local water quality conditions. Low fish diversity was observed in several streams that possessed relatively good water quality. This pattern was especially pronounced in highly degraded subwatersheds, suggesting that regional conditions may have a strong influence on fish assemblages in this system. Our results indicate that biomonitoring programs in mined watersheds should include both benthic invertebrates, which are consistent indicators of local conditions, and fishes, which may be indicators of regional conditions. In addition, remediation programs must address the full suite of chemical constituents in AMD and focus on improving linkages among streams within drainage networks to ensure recovery of invertebrate and fish assemblages. Future research should identify the precise chemical conditions necessary to maintain biological integrity in mined Appalachian watersheds.     

Life cycle assessment analysis of active and passive acid mine drainage treatment technologies

Acid mine drainage (AMD), resulting from open-cast coal mining, is currently one of the largest environmental challenges facing the mining industry. In this study, a life cycle assessment (LCA) was conducted to evaluate the environmental impacts associated with the construction, operation and maintenance of different AMD treatment options typically employed. LCA is a well-reported tool but is not documented for AMD treatment systems despite their ubiquitous implementation worldwide. This study conducted detailed LCA analysis for various passive and active AMD treatment approaches implemented or considered at a major coal mine in New Zealand using a comparative functional unit of kg acidity removed per day for each treatment option. Eight treatment scenarios were assessed including active limestone and hydrated lime treatments, and compared to passive treatments using limestone and waste materials such as mussel shells. Both midpoint and endpoint LCA impact categories were assessed. Generally, the active treatment scenarios demonstrated greater LCA impacts compared to an equivalent level of treatment for the passive treatment approaches. Lime slaking had the greatest LCA impacts, while passive treatment approaches incurred consistently less impacts except for one passive treatment with a purchased energy scenario. A 50% reduction in transportation distances resulted in the lowest LCA impacts for all scenarios. This study highlights the importance of evaluating the environmental and social impacts of AMD treatment for the mining industry.     

Rapid decolorization of Acid Orange II aqueous solution by amorphous zero-valent iron

Some problems including low treatment capacity, agglomeration and clogging phenomena, and short working life, limit the application of pre-treatment methods involving zero-valent iron (ZVI). In this article, ZVI was frozen in an amorphous state through a melt-spinning technique, and the decolorization effect of amorphous ZVI on Acid Orange II solution was investigated under varied conditions of experimental variables such as reaction temperature, ribbon dosage, and initial pH. Batch experiments suggested that the decolorization rate was enhanced with the increase of reaction temperature and ribbon dosage, but decreased with increasing initial solution pH. Kinetic analyses indicated that the decolorization process followed a first order exponential kinetic model, and the surface-normalized decolorization rate could reach 2.09 L/(m². min) at room temperature, which was about ten times larger than any previously reported under similar conditions. Recycling experiments also proved that the ribbons could be reused at least four times without obvious decay of decolorization rate and efficiency. This study suggests a tremendous application potential for amorphous ZVI in remediation of groundwater or wastewater contaminated with azo dyes.     

不同氮肥与磷肥的互作效应

利用盆栽试验研究了潮土中不同氮肥与磷肥的互作效应，结果表明：不同氮肥与磷肥的配合施用对潮土中油菜的生长和养分吸收有显著的交互作用。生长初期，施氮并不能促进、甚至会抑制油菜的生长，氯化铵较其它氮肥作用突出。随着生长期的延长，氮肥对油荣生长的促进作用逐渐显现，但氯化铵的促进作刚仍低于其它氮肥。植株养分累积受不同氮肥影响的规律与植株干物质累积表现的规律基本一致。土壤有效磷含最受不同氮肥影响较小，而水溶性磷含量因施用不同氮肥表现出显著的差异，特别是在生长初期的土壤中。相关分析结果表明，油菜生长初期的干物质质量与土壤水溶性磷含量达到极显著相关（r=0．727^＊＊）。因此推测，不同氮肥对油菜生长的影响可能因氮肥降低土壤中磷的有效性所致，这些结果对今后的合理施肥提供了重要的参考依据。     

Application of a coupled ecosystem-chemical equilibrium model, DayCent-Chem, to stream and soil chemistry in a Rocky Mountain watershed

Atmospheric deposition of sulfur and nitrogen species have the potential to acidify terrestrial and aquatic ecosystems, but nitrate and ammonium are also critical nutrients for plant and microbial productivity. Both the ecological response and the hydrochemical response to atmospheric deposition are of interest to regulatory and land management agencies. We developed a non-spatial biogeochemical model to simulate soil and surface water chemistry by linking the daily version of the CENTURY ecosystem model (DayCent) with a low temperature aqueous geochemical model, PHREEQC. The coupled model, DayCent-Chem, simulates the daily dynamics of plant production, soil organic matter, cation exchange, mineral weathering, elution, stream discharge, and solute concentrations in soil water and stream flow. By aerially weighting the contributions of separate bedrock/talus and tundra simulations, the model was able to replicate the measured seasonal and annual stream chemistry for most solutes for Andrews Creek in Loch Vale watershed, Rocky Mountain National Park. Simulated soil chemistry, net primary production, live biomass, and soil organic matter for forest and tundra matched well with measurements. This model is appropriate for accurately describing ecosystem and surface water chemical response to atmospheric deposition and climate change.     

植物SOD活性变化与其抗污能力的关系

研究了模拟酸雨、ＳＯ２单独与复合污染对水杉、杉木、龙柏３种抗污能力不同的植物ＳＯＤ活性、细胞汁酸度、细胞膜透性的影响。结果表明，ＳＯＤ的活性经污染后变化规律在不同植物有所不同，而这种变化与其抗污能力有关。ＳＯＤ活性升高者，其抗污能力强，反之则弱，与本底值大小无关。     

酸性媒介黄GG生物降解性能的试验研究

通过试验研究酸性媒介黄GG染料在厌氧、好氧条件下的生物降解机理、降解能力及共代谢降解效果.试验结果表明,厌氧菌能够通过葡萄糖共代谢作用很快降解酸性媒介黄GG;而好氧条件下经驯化活性污泥不能降解酸性媒介黄GG,经过较长时间驯化活性污泥能降解酸性媒介黄GG,但降解效果很差.葡萄糖浓度的升高对提高酸性媒介黄GG厌氧生物降解率有利,当葡萄糖浓度为2000 mg/L时,40mg/L酸性媒介黄GG的12和60 h厌氧生物降解率分别达到81.5%和93.5%.酸性媒介黄GG浓度对厌氧菌的生物降解能力也有影响.当葡萄糖浓度为2000 mg/L,酸性媒介黄GG(浓度为20～100 mg/L)的厌氧降解率最好,降解效率达到了94%,说明厌氧菌对酸性媒介黄GG的降解能力较好.     

钛酸铋光催化降解水中酸性大红的研究

采用异丙醇助水热法制备了钛酸铋光催化剂,UV-vis漫反射测试表明其光吸收带较TiO2发生了红移,通过多点BET法计算出其比表面积为14.16m2/g,平均孔径为21.05nm。以酸性大红为模拟污染物,在三相内循环流化床光催化反应器中进行光催化反应,研究了废水的pH值以及钛酸铋投加量对酸性大红脱色率的影响。结果表明:废水的pH=3.0,催化剂投加量为0.1g/L是最佳反应条件;当流量为10L/h时,连续运行3h后,酸性大红染料的去除率可达92.0%;当处理水量增大时,经过两级处理,酸性大红染料的总去除率仍可达到94.4%。