完全氧化法测定高氯废水的COD_(Cr)

从热力学的角度出发,导出了在ＣＯＤ测定过程中Ｃｌ－ 的完全氧化条件。通过不同浓度的含氯邻苯二甲酸氢钾标准溶液和含氯乙醇标准水样的测定表明, 在所提出的完全氧化条件下,由所测得的表观ＣＯＤ减去Ｃｌ－ 的理论ＣＯＤ便得到水样的真实ＣＯＤ,测定结果与实际吻合较好。最后,对测定过程中的有关问题进行了讨论。     

稻秸秆制备微生物絮凝剂及改善污泥脱水性能的研究

采用水稻秸秆制备微生物絮凝剂,研究了微生物絮凝剂对污泥脱水性能的影响,并通过响应面分析法优化了微生物絮凝剂与聚合氯化铝（Polyaluminum chloride,PAC）复配改善污泥脱水性能的过程.结果表明,制备微生物絮凝剂的最佳条件为：800mL蒸馏水、200mL水稻秸秆酸解液、4g K₂HPO₄、2g KH₂PO₄、0.2g MgSO₄、0.1g NaCl、2g尿素,在此条件下,微生物絮凝剂产量达0.96g/L.保持原污泥pH值,当微生物絮凝剂投加量为12mg/L,干污泥量（DS）较原污泥提高了59.5%,污泥比阻（SRF）降低了53.6%,表明经微生物絮凝剂絮凝处理,污泥脱水性能显著改善.保持原污泥pH值,当PAC投加量为3g/L,干污泥量（DS）为16.4%,高于原污泥的13.2%,污泥比阻为（SRF）5.4×10¹²m/kg,低于原污泥的11.3×10¹²m/kg,说明PAC对污泥脱水性能有着明显的改善作用.响应面分析结果显示,污泥脱水最佳条件为微生物絮凝剂8.1mg/L、PAC 1.9g/L、pH值8.0,相应DS和SRF分别为24.1%和3.0×10¹²m/kg.实际污泥脱水工程中,污泥pH往往不进行调节,保持原污泥pH=6.4条件下,DS和SRF分别为23.6%和3.2×10¹²m/kg,均优于单独采用微生物絮凝剂和PAC时的污泥脱水效果.     

氯盐环境下钢筋混凝土构件锈胀开裂风险概率分析

为了研究时间和空间等不确定因素下钢筋混凝土构件的锈胀开裂损伤,针对氯离子腐蚀环境,将钢筋锈蚀划分为2阶段3个特征时刻,分析了锈蚀初始时间、锈胀开裂时间以及锈胀开裂至界限宽度时间的概率特征,建立了钢筋混凝土构件生命周期内锈蚀损伤的风险概率模型,讨论了锈蚀损伤影响参数的敏感性。结果表明:钢筋锈蚀对其影响因素的敏感程度依次为混凝土保护层、临界氯离子浓度、扩散系数和混凝土表面氯离子浓度;钢筋混凝土构件从发生锈胀开裂到裂缝达到界限宽度的时间很短,界限宽度的取值对锈蚀损伤的影响并不显著。     

氨基黑10B褪色光度法测定痕量季铵盐型阳离子表面活性剂的研究

研究了在硫酸介质中,季铵盐型表面活性剂溴化十六烷基三甲基铵(CTMAB)、溴化十六烷基吡啶(CPB)对氨基黑10B的褪色作用,建立了褪色光度法测定痕量CTMAB和CPB的新方法,并探讨了褪色反应的机理和条件,测定CTMAB和CPB的线性范围皆为0～3×10-5mol L,摩尔吸光系数分别为1 77×104L mol·cm和1 17×104L mol·cm,用于水样中微量季铵盐型表面活性剂的测定,结果满意。     

Transformation of mercury speciation through the SCR system in power plants

Coal-fired utility boilers are now identified as the largest source of mercury in the United States. There is speculation that the installation of selective catalytic reduction （SCR） system for reduction of NOx can also prompt the oxidation and removal of mercury. In this paper, tests at six full-scale power plants with similar type of the SCR systems are conducted to investigate the effect of the SCR on the transformation of mercury speciation. The results show that the SCR system can achieve more than 70%-80% oxidation of elemental mercury and enhance the mercury removal ability in these units. The oxidation of elemental mercury in the SCR system strongly depends on the coal properties and the operation conditions of the SCR systems. The content of chloride in the coal is the key factor for the oxidization process and the maximum oxidation of elemental mercury is found when chloride content changes from 400 to 600 ppm. The sulfur content is no significant impact on oxidation of elemental mercury.     

改变垫水层沸点的薄层扬沸实验研究

扬沸是油池火灾的一种特殊现象,燃料和垫水层交界面的过热温度和沸腾状态是决定扬沸是否发生以及发生时间的最主要因素,过热温度由沸点决定。在垫水层中添加氯化钠能够改变垫水层的沸点,从而改变交界面的过热温度。在垫水层添加氯化钠使其成为饱和氯化钠水溶液,对此条件下的油池火燃烧进行实验探究,以验证前人关于扬沸临界条件的研究结果,并为扬沸防治提供思路。垫水层改变为饱和氯化钠溶液后,柴油实验组均没有发生扬沸,且观察到火焰温度和热辐射强度的下降。表明此方法可以有效抑制扬沸的发生。     

吹扫捕集气质联用法同时测定水中氯乙烯、乙醛、丙烯醛、丙烯腈、吡啶和松节油

建立了一种采用吹扫捕集气质联用法同时测定水中氯乙烯、乙醛、丙烯醛、丙烯腈、吡啶和松节油的分析方法,研究并优化了吹扫捕集前处理条件参数。结果表明,吹扫时间、吹扫温度和脱附时间是影响目标物的吹扫捕集效率的关键因素;优化后方法线性良好,相关系数均大于0.999,检出限范围为0.20~1.48μg/L,加标回收率范围为86.9%~105%,相对标准偏差为1.1%~9.8%。建立的吹扫捕集GC-MS联用法简便、快速、灵敏度高、定性定量准确可靠,可同时满足对自来水、地表水、地下水等水样中痕量氯乙烯、乙醛、丙烯醛、丙烯腈、吡啶和松节油监测的要求。     

Are calcareous soils in uplands less prone to damage from road salting than acidic soils?

Previous studies of upland roadside soils in Cumbria, that would normally be naturally acidic, have highlighted that (a) runoff from roads subjected to long-term road salting can dramatically raise soil pH down slope in upland areas; (b) the soil pH increase dramatically changes N cycling in soils down slope, increasing mineralisation of organic matter, ammonification, ammonium leaching down slope and nitrification and nitrate leaching; (c) the increase in nitrification substantially increases nitrate leaching to down-slope rivers, and this is readily detectable in field studies; and (d) loss of soil organic matter over decades of salting is so great that organic matter is no longer substantially solubilised by high salt concentrations found in soil solution below road drains. This paper tests and supports the hypothesis that such effects are minimal for more calcareous soil ecosystems. It examines the soil and soil solution chemistry on another Cumbrian upland highway, the A686 near Leadgate, Alston. Sodium % of soil CEC values for soil transects affected by spray containing road salt are similar at both the A6 and A686 sites. However, spatial trends in calcium, magnesium, ammonium, and nitrate concentrations as well as pH differ, as a direct result of the higher weathering rate of parent material and possibly also the presence of limestone walls above both spray-affected and control transects at the A686 site.     

K+对肝素钠废水厌氧生物处理中污泥性能的影响

以肝素钠生产废水为研究对象,研究了不同盐浓度下K+对厌氧污泥性能的影响。实验结果表明:在ρ(NaCl)小于8000mg/L的低盐浓度条件下,K+对污泥的解抑作用不明显;在ρ(NaCl)大于16000mg/L的高盐浓度条件下,K+对污泥表现出解抑作用。ρ(NaCl)为24000mg/L、K+加入量为60mg/L时,COD去除率、产气量和甲烷体积分数相比空白对照组分别提高了17.1%、43.3%和71.8%,氨化率变化不大,均在32%左右。     

光气法生产甲氨基甲酰氯的事故风险分析

对光气法生产甲氨基甲酰氯过程中的事故风险进行了分析,讨论了生产过程中存在的事故隐患,并指出了切实可行的防范对策。