Performance evaluation of reverse logistics enterprise – an agent-based simulation approach

Reverse logistics (RL) has been applied in many industries and sectors since its conception. Unlike forward logistics, retracing consumer goods from the point of consumption to the point of inception is not a well-studied process. It involves many uncertainties such as time, quality and quantity of returns. The returned products can be remanufactured, have parts harvested, or be disposed safely. It is important to implement these activities in a cost-effective manner. The aim of this research is to measure the performance of the RL enterprise with the help of an agent-based simulation model. The major entities in the RL network are considered as Agents that can act independently. There are several different agents: collector agent, sorting-cum-reuse agent, remanufacturing agent, recycler agent, supplier agent and distributor agent. The individual performances of the agents are measured and recommendations are given to improve their performance, leading to the enhancement of the total performance of the RL enterprise. The approach is applied to a case study involving cell phone remanufacturing.     

Recycling-oriented characterization of plastic frames and printed circuit boards from mobile phones by electronic and chemical imaging

This study characterizes the composition of plastic frames and printed circuit boards from end-of-life mobile phones. This knowledge may help define an optimal processing strategy for using these items as potential raw materials. Correct handling of such a waste is essential for its further “sustainable” recovery, especially to maximize the extraction of base, rare and precious metals, minimizing the environmental impact of the entire process chain. A combination of electronic and chemical imaging techniques was thus examined, applied and critically evaluated in order to optimize the processing, through the identification and the topological assessment of the materials of interest and their quantitative distribution. To reach this goal, end-of-life mobile phone derived wastes have been systematically characterized adopting both “traditional” (e.g. scanning electronic microscopy combined with microanalysis and Raman spectroscopy) and innovative (e.g. hyperspectral imaging in short wave infrared field) techniques, with reference to frames and printed circuit boards. Results showed as the combination of both the approaches (i.e. traditional and classical) could dramatically improve recycling strategies set up, as well as final products recovery.     

碱活化过一硫酸盐降解水中环丙沙星

采用碱活化过一硫酸盐(peroxymonosulfate,PMS)对环丙沙星(ciprofloxacin,CIP)的去除进行了系统地研究.结果表明,碱活化PMS体系能够高效地去除CIP.通过自由基捕获实验确定了单线态氧(~1O_2)和超氧自由基(O_2~-·)是反应体系中的主要活性物种.NaOH浓度、PMS浓度、反应温度和共存阴离子等对CIP在碱活化PMS体系中的去除均有一定影响.随着NaOH和PMS浓度的增加,CIP的降解均呈现出先增加后降低的趋势.提高反应温度能够加大CIP的反应速率,经过阿伦尼乌斯方程拟合得到的反应活化能为5.09 k J·mol~(-1).不同的阴离子对CIP的去除呈现不同的影响:Cl~-、SO_4~(2-)和NO_3~-对CIP的降解没有呈现明显的作用,H_2PO_4~(2-)能够有效地抑制环丙沙星的去除,而CO_3~(2-)极大地促进了反应进程.通过UPLC-MS/MS可检测到10种降解产物,CIP分子结构中的哌嗪环易于受到活性物种的攻击.     

Research on the degradation mechanism of pyridine in drinking water by dielectric barrier discharge

Pyridine, an important chemical raw material, is widely used in industry, for example in textiles,leather, printing, dyeing, etc. In this research, a dielectric barrier discharge(DBD) system was developed to remove pyridine, as a representative type of nitrogen heterocyclic compound in drinking water. First, the influence of the active species inhibitors tertiary butanol alcohol(TBA),HCO_3~-, and CO_3~(2-)on the degradation rate of pyridine was investigated to verify the existence of active species produced by the strong ionization discharge in the system. The intermediate and final products generated in the degradation process of pyridine were confirmed and analyzed through a series of analytical techniques, including liquid chromatography–mass spectrometry(LC–MS), high performance liquid chromatography(HPLC), ion chromatography(IC), total organic carbon(TOC) analysis, ultraviolet(UV) spectroscopy, etc. The results showed that the degradation of pyridine was mainly due to the strong oxidizing power of ozone and hydroxyl radical produced by the DBD system. Several intermediate products including 3-hydroxyl pyridine, fumaric acid, 2, 3-dihydroxypyridine, and oxalic acid were detected. Nitrogen was removed from the pyridine molecule to form nitrate. Through analysis of the degradation mechanism of pyridine, the oxidation pathway was deduced. The study provided a theoretical and experimental basis for the application of DBD strong ionization discharge in treatment of nitrogen heterocyclic compounds in drinking water.     

西安市建筑垃圾渣土资源再利用研究

建筑垃圾渣土作为"建筑副产品",已造成严重的城市环境问题。通过对西安市建筑垃圾渣土的现场调查及工程再利用,借鉴发达国家及国内省市建筑垃圾渣土的成功管理经验和资源再利用的成功范例,提出了西安建筑垃圾资源再利用的对策建议,对"十三五"期间减少已有建筑垃圾的存量并遏制增量和建设西安森林城市具有参考意义。     

构建中国快递行业包装废弃物产业链对环境影响重要性研究

互联网和电子商务的快速发展带动了快递行业的飞速发展,使社会对快递包装物的需求增加.庞大的快递废弃物给环境造成了严重的破坏.然而由于相关法律不健全、回收体系不完整、企业不积极以及回收渠道少等原因导致了中国的快递包装废弃物回收率非常低.构建快递包装废弃物回收产业链,并降低快递包装废弃物对环境造成的影响就成了社会经济发展的一个迫切需要.为此推广环保材料和环保产品以及提高消费者环保意识入手,构建快递包装废弃物回收产业链势在必行.     

再生水灌溉土壤人工合成麝香累积模型模拟

人工合成麝香(HHCB/AHTN)是近几年来受关注较多的药品与个人护理品(PPCPs)类新型污染物之一,再生水灌溉是HHCB/AHTN输入土壤的主要途径.本研究结合再生水灌溉土壤的实地检测结果,采用HYDRUS-1D模型,模拟了长期灌溉再生水条件下土壤中HHCB和AHTN的迁移转化和累积趋势.结果表明,尽管土壤中这两种麝香的含量极低,但是再生水灌溉土壤中的含量是自来水灌溉土壤的5倍;再生水灌溉下HHCB/AHTN累积趋势从lgKoc较低为3.44时的指数型增加,到lgKoc较高为4.12和4.86时的线性增加;半衰期的变化对再生水灌溉途径输入土壤的HHCB/AHTN的表层累积影响并不明显;再生水灌溉下土壤中HHCB/AHTN的垂直迁移能力较小,灌溉40 a以后最大迁移距离只有53 cm,且受Koc变化的影响较大;通过灌溉水途径进入土壤的HHCB和AHTN通过生物降解与植物吸收途径消解的比例较低,最高只占输入总量的7.69%,但是随着lgKoc的减小和灌溉时间增加,通过生物降解和根系吸收的消解率增加.本研究结果能够为准确评估再生水灌溉途径引起的土壤中人工合成麝香HHCB/AHTN的生态风险提供依据.     

城市污水处理厂及其受纳水体中5种典型PPCPs的赋存特征和生态风险

以5种药品及个人护理用品(pharmaceuticals and personal care products,PPCPs)包括氯贝酸、酮洛芬、萘普生、双氯芬酸和布洛芬为目标物,初步研究了它们在上海某生活污水处理厂不同污水处理单元中的赋存特征和去除特性,探讨了污水处理厂受纳河流中5种PPCPs的分布情况,并对其在受纳水体中的生态风险进行了初步评估.结果表明,5种PPCPs在污水处理厂进水中均被检出,表明生活污水是污水处理厂中PPCPs的来源之一.5种PPCPs在整个污水处理工艺中不能全部去除,微生物转化/降解是主要降解机制.受纳污水河流中5种PPCPs的分布特征与污水处理厂出水中的相似,且排污口下游水体中目标物浓度普遍高于上游,反映出污水处理厂排放可能是其受纳水体中PPCPs的主要来源之一.初步风险评估结果表明,受纳水体中双氯芬酸存在高生态风险,而酮洛芬、萘普生、氯贝酸和布洛芬的生态风险相对较低.     

单光子/光电子在线质谱实时分析聚氯乙烯热分解/燃烧产物

实验室研制了低能光电子磁场增强电离(MEPEI)和单光子电离(SPI)复合电离源,该电离源具有电离化合物范围宽、碎片离子少、质谱图简单等优点,结合飞行时间质谱(TOF-MS)实现了聚氯乙烯(PVC)热分解/燃烧产物的在线分析.针对不同的目标化合物,MEPEI/SPI复合电离源通过调节电离区电场强度,可以快速在SPI和SPI-MEPEI之间切换.PVC热分解/燃烧产物中电离能大于光子能量(10.60 eV)的HCl和CO2(12.74 eV、13.77 eV)利用MEPEI模式电离;而烯烃、二氯乙烯、苯系物、氯苯、苯乙烯、茚满及萘系物等可通过SPI-MEPEI复合模式电离.通过实时监测PVC主要燃烧产物的信号强度随温度的变化趋势可推断出,PVC燃烧产物主要是通过两种机制生成:①250～370℃时,PVC发生脱氯及分子内环化反应,产生大量的HCl、苯和萘;②380～510℃时,PVC发生分子间交联反应,生成烷基芳烃,如甲苯和二甲苯/乙苯等.实验结果表明,SPI/SPI-MEPEI复合离子源TOF-MS分析速度快,应用范围广,在在线分析中具有广泛的应用前景.     

日本交通部门碳排放与低碳交通相关因素研究

本文就日本向低碳社会体系转型的过程中,交通部门碳排放现状、都市交通体系构成、实施对策等方面进行了分析,探讨其交通运输领域低碳交通的相关因素及发展模式,为中国低碳交通体系的构建提供参考。