浒苔提取物对4种赤潮微藻生长的抑制作用

通过测定藻细胞密度和细胞体积,观察藻细胞形态,分析藻细胞内叶绿素、蛋白质和多糖含量等生理指标的变化,研究了浒苔5种溶剂(甲醇、丙酮、乙酸乙酯、氯仿和石油醚)提取物对前沟藻(Amphidinium hoefleri)、米氏凯伦藻(Karenia mikimitoi)、塔玛亚历山大藻(Alexandrium tamarense)和中肋骨条藻(Skeletonema costatum)生长的抑制作用.结果表明,5种溶剂提取物中,甲醇提取物的抑藻作用最为显著.第10 d,其对前沟藻、米氏凯伦藻、塔玛亚历山大藻和中肋骨条藻的生长抑制率依次为54.0%、 48.1%、 44.0%和37.5%.同时发现,各溶剂提取物均能降低藻细胞运动能力.其中,甲醇、丙酮和乙酸乙酯提取物致使大部分藻细胞出现空洞、破碎和细胞色素明显减褪现象;而添加丙酮和乙酸乙酯提取物的部分藻细胞出现抱团现象.此外,乙酸乙酯、氯仿和石油醚提取物明显降低了藻细胞的体积.进一步研究发现,甲醇提取物明显降低了4种微藻细胞内叶绿素、蛋白质和多糖的含量,致使添加甲醇提取物的前沟藻、米氏凯伦藻、塔玛亚历山大藻和中肋骨条藻的叶绿素、蛋白质和多糖含量比对照组的相应含量低约51%.其余溶剂提取物同样改变了4种微藻细胞内此3种生理指标的含量,但影响并不显著.在此基础上,采用石油醚、乙酸乙酯和正丁醇对甲醇提取物进一步分离,获得4种提取物(石油醚相、乙酸乙酯相、正丁醇相和水相).其中,石油醚相和乙酸乙酯相的抑制作用较强,对4种微藻的生长抑制率超过25%.结果表明,利用甲醇浸泡浒苔可以获得具有明显抑藻活性的粗提物;此粗提物通过进一步的液液分离萃取后,获得2个能抑制4种测试微藻生长的组分.     

氧芴在超临界乙醇中溶解度的实验研究

以乙醇为超临界溶剂,采用恒容加温法研究煤焦油洗油馏分中的氧芴在超临界乙醇中的溶解度。通过GC检测分析萃取余液的,结果表明在萃取温度为255℃、压力为7．0MPa时．氧芴在超临界乙醇中的溶解度达到0．01652g／mL,萃取效率达到106．5％,实验效果明显。研究得出,温度与压j々对于固体物质的超临界溶解度的具有明显的选择调节性．其中温度对于溶解度的影响较大。     

Greenhouse gas balances of molasses based ethanol in Nepal

This paper evaluates life cycle greenhouse gas (GHG) balances in production and use of molasses-based ethanol (EtOH) in Nepal. The total life cycle emissions of EtOH is estimated at 432.5 kgCO_2eq m⁻³ ethanol (i.e. 20.4 gCO_2eq MJ⁻¹). Avoided emissions are 76.6% when conventional gasoline is replaced by molasses derived ethanol. A sensitivity analysis was performed to verify the impact of variations in material and energy flows, and allocation ratios in the GHG balances. Market prices of sugar and molasses, amount of nitrogen-fertilizers used in sugarcane production, and sugarcane yield per hectare turn out to be important parameters for the GHG balances estimation. Sales of the surplus electricity derived from bagasse could reduce emissions by replacing electricity produced in diesel power plants. Scenario analysis on two wastewater processes for treatment of effluents obtained from ethanol conversion has also been carried out. If wastewater generated from ethanol conversion unit is treated in pond stabilization (PS) treatment process, GHG emissions alarmingly increase to a level of 4032 kgCO_2eq m⁻³ ethanol. Results also show that the anaerobic digestion process (ADP) and biogas recovery without leakages can significantly avoid GHG emissions, and improve the overall emissions balance of EtOH in Nepal. At a 10% biogas leakage, life cycle emissions is 1038 kgCO_2eq m⁻³ ethanol which corresponds to 44% avoided emissions compared to gasoline. On the other hand, total emissions surpass the level of its counterpart (i.e. gasoline) when the leakage of biogas exceeds 23.4%.     

微生物燃料电池利用甘薯燃料乙醇废水产电的研究

利用空气阴极微生物燃料电池(MFC)处理甘薯燃料乙醇废水,以COD为5000mg/L的废水做底物,获得的最大电功率密度为334.1mW/m2,库仑效率(CE)为10.1%,COD去除率为92.2%.实验进一步考察了磷酸缓冲液(PBS)浓度和废水浓度对MFC产电性能的影响.PBS含量从50mmol/L增加到200mmol/L,MFC输出的最大电功率密度提高了33.4%,CE增加26.0%,但PBS对废水的COD去除率影响不大.含50mmol/LPBS的废水COD从625mg/L增加到10000mg/L,COD去除率和MFC输出的最大电功率密度在废水浓度为5000mg/L处均获得最大值,但CE值有降低的趋势,从28.9%变化至10.3%.这些结果表明,MFC可以在处理甘薯燃料乙醇废水的同时获得电能;增大PBS浓度能提高MFC的产电性能;MFC输出的最大电功率密度随废水COD增加而增大,但废水浓度过高会引起酸化使MFC产电性能下降.     

IC反应器处理酒精废水的生产性启动研究

对生产性IC反应器处理酒精废水的启动过程及其处理效率进行研究。当进水COD浓度为15 000 mg/L条件下,出水COD仅有500 mg/L左右,COD去除率在95%以上。在反应器启动初期曾因操作失误出现酸化现象,后来经过投加NH4HCO3和厌氧出水中和调节pH,反应器内部环境得到一定的改善,到启动结束时,两个反应器内pH均稳定在6.8左右,VFA也下降到400 mg/L左右。     

难降解有机废水的萃取置换法预处理

针对生物法处理难降解有机废水时去除率不高,停留时间长,难地达到排放等缺点,提出一种新的预自理方法－萃取置换法,并以乙草胺废水的处理为例,从萃取剂的筛选,工艺的优化,技术经济评价等方面进行了分析研究,结果表明,二甲苯作用为萃取剂能将废水的ＢＯＤ５／ＣＯＤ从０提高到０．４７６,且不需反萃操作;当乙草胺浓度 为１００ｍｇ／Ｌ时,萃取置换法投资较小;当浓度增大到５００ｍｇ／Ｌ是,萃取置换法在投资及净现值方     

铬渣的长期稳定性试验研究

采用硫酸亚铁为还原剂，粉煤灰为添加剂对铬渣进行固化／稳定化处理，并通过冻融、碳化、模拟酸雨淋溶以及表面浸出实验研究了固化体的长期稳定性。冻融后固化体的质量损失小于1％，强度损失小于10％；碳化后其碳化深度在8mm～15mm之间；抗压强度均大于30Mpa，可用于建筑用途；六价铬的浸出毒性均低于国家标准的1．5mg／L：表明固化体长期稳定性良好，用于填埋，安全、可靠。     

化成箔工业废水综合利用的研究

化成箔生产过程中产生大量的强酸性废水,废水中含铝高达13g/L,三价铬1.8mg/L,直接排放或简单中和后排放均污染生态环境,浪费了可利用资源。文章研究综合利用化成箔废水的方法,用分步沉淀法从化成箔废水中回收钙和铝,萃取及反萃取法从废水中回收铬。处理后的排放水符合国家允许排放标准。     

大麦秆提取液对铜绿微囊藻生长的影响研究

大麦秆提取液是无害、高效的抑藻剂.未过滤大麦秆提取液对铜绿微囊藻的生长有显著的抑制效果,投加比例在10mL·L-1以上时,抑制效果与大麦秆提取液投加浓度之间无明显相关关系,6d后的抑制率均在95%以上,且培养液澄清透明;而通过0.22μm滤膜过滤后的大麦秆提取液对铜绿微囊藻的抑制效果不显著.在投加未过滤大麦秆提取液的培养液中发现大量原生动物,推测原生动物的吞食作用是大麦秆提取液抑制铜绿微囊藻生长的主要原因之一.     

Fluorescence excitation-emission spectroscopy with regional integration analysis for assessment of compost maturity

Composting of animal manures is believed as an alternative way for directly recycling them in farms, and therefore assessment of compost maturity is crucial for achieving high quality compost. Fluorescence excitation-emission matrices (EEMs) combined with regional integration analysis is presented to assess compost maturity. The results showed that the EEM contours of water-extract organic matter (WEOM) from immature composts exhibited four peaks at excitation/emission (Ex/Em) of 220/340 nm, 280/340 nm, 220/410 nm, and 330/410 nm, whereas EEM contour of WEOM from mature composts had only two peaks at Ex/Em of 230/420 nm and 330/420 nm. Pearson correlation demonstrated that peaks intensity rather than their ratios had a significantly correlation with the common indices assessing compost maturity, whereas the normalized excitation-emission area volumes (Φ_i,ns) from regional integration analysis had a stronger correlation with the common indices assessing compost maturity than peaks intensity. It is concluded that the Φ_i,ns from regional integration analysis are more suitable to assess the maturity of compost than the intensities of peaks. Therefore, the fluorescence spectroscopy combined with regional integration analysis can be used as a valuable industrial and research tool for assessing compost maturity, given its high sensitivity and selectivity.