Characterization of polycyclic aromatic hydrocarbon emissions from diesel engine retrofitted with selective catalytic reduction and continuously regenerating trap

Two after treatment units, selective catalytic reduction (SCR) and continuously regenerating trap (CRT), were independently retrofitted to a diesel engine, with the objective to investigate their impact on the conversion/reduction (CR) of polycyclic aromatic hydrocarbons (PAHs). The experiments were conducted under the European steady state cycle (ESC) first without any retrofits to get baseline emissions, and then with SCR and CRT respectively, on the same engine. The particulate matter (PM)-phase PAHs were trapped in fiberglass filters, whereas gas-phase PAHs were collected in cartridges, and then analyzed using a gas chromatograph-mass spectrometer (GC-MS). Both PM-phase and gas-phase PAHs were greatly reduced with CRT showing respective CR of 90.7% and above 80%, whereas only gas-phase PAHs were abated in the case of SCR, with CR of above 75%. Lower molecular weight (LMW) PAHs were in abundance, while naphthalene exhibited a maximum relative contribution (RC) to LMW-PAHs for all three cases. Further, the CR of naphthalene and anthracene were increased with increasing catalyst temperature of SCR, most likely due to their conversion to solid particles. Moreover, the Benzo[a]Pyrene equivalent (BaP_eq) of PAHs was greatly reduced with CRT, owing to substantial reduction of total PAHs.     

浅谈如何另辟蹊径解决再生金属企业“融资难”问题

介绍了我国再生金属企业融资难的现状,提出融资成本过高、融资手续复杂、融资条件不足是再生金属企业贷款难的主要原因,重点分析了企业融资风险产生的原因,同时,强调建立产业间的互助基金,既可以满足产业资金需求,有效解决产业发展中"融资难"的问题,还可以拓宽投资渠道,从资本方面推动再生金属产业健康发展。     

Preparation, characterization and performance of an electrospun carbon nanofiber mat applied in hexavalent chromium removal from aqueous solution

Hexavalent chromium, Cr(VI), a highly toxic oxyanion known as a carcinogen and mutagen,is an issue of concern due to its adverse impact on human health. Therefore, development of effective technologies and/or materials for Cr(VI) removal from water has been of great interest for researchers. In this study, an electrospun carbon nanofiber(CNF) mat was prepared via electrospinning polyacrylonitrile(PAN), followed by thermal pre-oxidation and carbonization. Scanning electron microscopy(SEM) observation showed that the fiber diameter of the CNF with carbonization temperature of 950°C(CNF_(950)) was about 266 nm.Potentiometric titration analysis demonstrated that the point of zero charge p H(pHpzc) of CNF_(950) was around 7.93. CNF_(950) demonstrated high adsorption capacity and fast adsorption kinetics for Cr(VI) at pH 3. Langmuir isotherm calculations showed that the maximum adsorption capacity of Cr(VI) on CNF_(950) was 118.8 mg/g at pH 2. The adsorption isotherm of Cr(VI) on CNF_(950) was well described by the Redlich–Peterson model, revealing that Cr(VI)adsorption was the result of a combination of monolayer and multilayer adsorption,depending on the initial Cr(VI) concentration. Solution pH greatly affected Cr(VI) adsorption onto CNF_(950) due to the electrostatic interaction, and the adsorption capacity was relatively high when pH was below 3. X-ray photoelectron spectroscopy(XPS) analysis revealed that the removal of Cr(VI) might be the result of a combination of redox reaction and electrostatic adsorption. The adsorption-saturated CNF_(950) could be regenerated by NaOH solution. This study extends the potential applicability of electrospun CNF mats for Cr(VI)-contaminated water purification.     

垃圾焚烧过程中水分促燃脱氯效果的研究

分别在转式垃圾焚烧炉和固定床加热炉中,研究了水分对垃圾焚烧及钙基脱氯效果的影响.研究结果表明,垃圾焚烧过程中一定量水分的存在能促进垃圾焚烧效率,提高钙基氯剂的脱氯效率.同时,分析水分促进垃圾焚烧率和脱氯效果提高的原因,这是由于水分能强化焚烧过程的传质传热,能活化脱氯剂,改善脱氯剂的物理和化学性质,这些研究结果将为垃圾焚烧技术在我国的进一步推广提供科学依据.     

Does the environmental inequality matter? A literature review

Environmental Geochemistry and Health - The environmental inequality theory reveals that the risk of environmental pollution exposure varies among regions and groups and that particular groups face...     

变频水处理器在锅炉除防垢上的应用试验

从变频水处理器的工作原理、使用、安装以及除防垢效果等方面介绍了变频水处理器在锅炉除防垢方面的应用试验情况.结果表明变频式水处理器技术在节能、提高整个系统的自动化水平、提高安全可靠性等方面具有明显的效果.     

江西赣南数字地震台网JOPENS系统常用地震定位方法比较

利用JOPENS系统提供单纯型法、Hypo2000、HypoSAT等地震定位方法,对赣南台网记录的赣南境内、赣粤闽交界区、中国台湾地震分别进行定位、比较,并分别提出适合赣南台网的地震定位方法.     

区域水环境承载力现状评价及对策研究——以台州市为例

以浙江省台州市为例,根据该市自然环境和社会经济现状,采用层次分析法和向量模法评价近年来台州市水环境承载力,确定水环境承载力等级和水环境状态。结果表明,近年来台州市水环境承载力等级在“差”和“一般”之间浮动,对应的水环境状态为“脆弱”到“一般”,水环境承载力总体上偏低。其主要影响指标有人均水资源量、工业用水重复利用率以及工业废水达标率和城镇生活污水处理率。本文同时根据台州市水环境承载力现状,提出相应的改善对策措施,提高水环境承载力,以促进台州市社会、经济和环境的协调发展。     

海洋油气田弃置环境影响评估方法及实践

根据相关法规和技术标准的要求,提出海洋油气田弃置环境影评估的标准工作程序为:阐述任务、评估可利用资源和限制、制定工作方案、研究弃置方案、优化弃置方案、形成报批文件,并逐一分析各步骤的主要工作内容。采用该标准工作程序对某弃置海上油田进行评估,通过分析技术和安全上可行、处置费用较低、环境影响最小、环境风险低、废弃物再利用最大化的要求,优选出最优弃置方案。弃置后连续两年的跟踪监测结果表明,尚未出现对油田海域环境和海洋使用功能的不良影响,获得了较好的经济效益和环境效益。