Comparative equilibrium studies of sorption of Pb(II) ions by sodium and calcium alginate

The absorption of Pb(II) ions from aqueous solution by di erent alginate compounds was studied in a batch sorption system. Water soluble sodium alginate and insoluble calcium alginate beads were investigated. The lead-binding capacity of both alginate compounds was highest within the pH range 6–8. The binding capacities and rates of Pb(II) ions by alginate compounds were evaluated. The Langmuir, Freundlich, and Bruneaur, Emmet and Teller (BET) sorption models were applied to describe the isotherms and isotherm constants. Sorption isothermal data could be well interpreted by the Langmuir model. The results obtained through the study suggest that alginate compounds are favorable sorbents. The largest amount of Pb(II) ions were bound by sodium alginate although the di erence between two compounds was slight. Therefore, alginate substances may be considered as an alternative for sorption and removal of Pb(II) ions from wastewaters.     

Inventory routing for dynamic waste collection

We consider the problem of collecting waste from sensor equipped underground containers. These sensors enable the use of a dynamic collection policy. The problem, which is known as a reverse inventory routing problem, involves decisions regarding routing and container selection. In more dense networks, the latter becomes more important. To cope with uncertainty in deposit volumes and with fluctuations due to daily and seasonal effects, we need an anticipatory policy that balances the workload over time. We propose a relatively simple heuristic consisting of several tunable parameters depending on the day of the week. We tune the parameters of this policy using optimal learning techniques combined with simulation. We illustrate our approach using a real life problem instance of a waste collection company, located in The Netherlands, and perform experiments on several other instances. For our case study, we show that costs savings up to 40% are possible by optimizing the parameters.     

Learning from the Bhopal disaster to improve process safety management in Singapore

The Singapore process industry is mainly made up of chemical and energy companies such as Mitsui Chemicals, Clariant, Exxon Mobil, Shell, Sumitomo, Petrochemical Corporation of Singapore and Infineum. Majority of these companies are located on Jurong Island, southwest of Singapore. Jurong Island houses nearly 100 leading petroleum, petrochemicals and specialty chemicals companies and the total investment is about S$42 billion in total. With a land surface area of only 716 km² and a high concentration of process plants, the Singapore government places strong emphasis on safety and risk management. In this paper, four process industry veterans from the government, academic and private sectors were interviewed. Through the interviews, the authors sought to understand the veterans’ perspectives on lessons that the Singapore process industry should learn from the Bhopal disaster. The veterans expanded their thoughts beyond the Bhopal disaster and provided many insights and suggestions critical to process safety management in Singapore and other countries. A systemic model of process safety management was derived from the interviews and key elements of operational process safety management were identified. In addition, a research agenda was identified based on the inputs from the veterans.     

国内外污染场地环境管理比较研究

本文通过国内外污染场地环境管理比较研究,从完善法律法规角度提出相关政策建议,以期为我国进一步加强污染场地环境管理提供决策参考。具体建议：一是从立法角度看,我国对污染场地管理采取专门立法的模式;二是从框架要素看,进一步建立和完善完整有效的配套法规、标准和指南;三是从责任体系看,建议根据“污染者负担”原则,应明确定义各类责任人在何种情况下承担修复责任;四是从因地制宜的管理目标看,中央政府应制定全国统一的风险管理的政策,并制订指导性的修复筛选值,省市政府可以根据本地区的土地规划和开发需求,制定当地的法规和标准。     

钚在某处置工程屏障水环境中化学形态及影响因素

针对某放射性废物包装容器回填处置工程屏障结构特征,采用岩体裂隙水浸泡工程屏障样品的方式,在对各平衡水样化学成分分析的基础上,利用地球化学模拟软件EQ3/6对钚在回填工程屏障水环境中的存在化学形态进行了模拟计算,得出钚在回填工程屏障水环境中主要以Pu(Ⅳ)价态Pu(OH)5-形式存在,同时水环境中pH值和Eh值的变化皆会影响钚的存在化学形态和价态。     

厌氧－好氧生物工艺对制药废水处理研究

目前,大多数制药废水处理研究的方向是处理抗生素制药废水,缺乏对营养类型制药废水处理工艺方面的研究,通过对营养型制药废水处理工艺研究,可以得出废水处理相关的参数。在本文中,厌氧－好氧法废水处理工艺作为制药废水处理的最主要工艺,重点对营养型基础制药废水做出分析,对污水处理厂生产条件、运行参数进行实验研究。     

新OG系统旋流脱水器气液分离特性数值研究

根据旋流脱水器的内部流动特性,基于欧拉-拉格朗日方法,对旋流脱水器内部气液两相流动进行了数值计算和分析,研究了液滴直径、进口质量含气率和湍流扩散效应对流场分布、脱水效率、出口质量含气率和出口液滴粒度分布的影响.结果表明：当质量流量一定时,旋流脱水器进出口压降随着进口质量含气率的增加而显著提高.对于单一直径的液滴,在不考虑湍流扩散效应的情况下,脱水效率随进口质量含气率的增加而增加.当考虑湍流扩散效应时,对于直径较小的液滴（0.1~1μm）,这种规律刚好是相反的,连续相速度的增加提升了湍流扩散速度,使湍流运动更加紊乱,但脱水效率高于不考虑湍流扩散效应时的计算结果.在混合粒径条件下,随着进口质量含气率的增加,脱水效率和出口质量含气率增加,计算表明湍流扩散效应有利于混合直径液滴的分离.随着进口质量含气率的增加,液滴质量分数的峰值逐渐向小粒径方向移动,粒径分布范围逐渐减小.     

丙烯氨氧化制丙烯腈反应器开车过程尾气燃爆危险性研究

丙烯直接氨氧化制丙烯腈工艺由于反应温度高,且反应器内的气相空间存在丙烯、丙烷、丙烯腈、乙腈、氧气、氮气等可燃性气体混合物,极易发生燃爆危险。为研究和评估该工艺装置反应器尾气的燃爆特性,采用11 L爆轰管测试在400℃、40 k Pa (G)工艺条件下,装置开车进料及反应过程中不同进料配比时反应器尾气组成的爆炸极限,并以此绘制爆炸极限三元相图,最终得到爆炸极限和极限氧体积分数。结果表明:反应器内可燃尾气的爆炸上限随氧气体积分数增加而升高,爆炸下限没有明显变化;在开车进料及反应过程中,反应器可燃尾气的极限氧体积分数LOC范围在8. 0%～8. 5%。因此,为避免反应器气相空间在开车过程中发生燃爆危险,需监测反应器内氧气体积分数,并设置氧体积分数报警值小于8. 0%。     

微污染原水的生物流化床预处理技术试验研究

以二相颗粒活性炭生物流化床(FBBR)为反应器,对以有机物和NH4+N为主要污染物的某大城市内河原水进行了预处理试验研究,在HRT12～18min,气水比20～25∶1,回流比3～4∶1的条件下FBBR对CODCr、NH4+N、NO2-N、浊度、色度的去除率分别为4132%、100%、97%～100%、6880%、30%～50%,而且对NH4+N和NO2+N有较强的抗冲击负荷能力。     

铝-锂合金垂直半连铸凝固过程温度场模拟

在阐述Al-Li合金熔铸特点基础上讨论了该合金垂直半连铸凝固过程温度场模拟问题.讨论时.把问题当作非稳态,并考虑结晶潜热.用交替隐式差分法计算了不同熔铸工艺条件下的温度场.对计算结果作了分析.讨论并和实验结果作了对比,指出了熔铸工艺条件对温度场的影响.