固相萃取-气质联用法测定固体废物浸出液中的二硝基苯

建立了一种利用固相萃取法对固体废物浸出液(TCLP)中二硝基苯进行萃取,DB-5石英毛细管柱(30 m×0.25 mm×0.25μm)进行分离,质谱检测器检测二硝基苯的方法。方法在0.002 0~0.020 0 mg/L之间线性关系良好,二硝基苯三种同分异构体的检出限均为0.5μg/L,模拟样品加标回收率为93%~96%,RSD≤2%;实际固体废物样品测定的加标回收率为95%~98%。     

气相色谱-串联质谱法测定沉积物中多环芳烃

采用ASE法提取沉积物中16种多环芳烃,以固相萃取法净化提取液,用气相色谱-串联质谱法测定。通过优化测定条件,使方法在5.00μg/L~1 600μg/L范围内线性良好,方法检出限为0.15μg/kg~0.66μg/kg。空白石英砂的加标回收率为61.9%~121%,7次测定结果的RSD为2.6%~11.1%。     

连续流双室微生物燃料电池处理工业废水

以实际中药废水作为阳极基质、实际含镉废水作为阴极电解液,构建了连续流双室微生物燃料电池(MFC),考察了其产电性能及对两种废水的处理效果。78 d的运行数据表明:系统可实现最大输出电压417mV、最大体积功率密度11.8 W/m3,最大体积功率密度运行条件下的库伦效率为18.5%;在阳极进水有机物浓度变化较大的情况下,实现了阳极对中药废水中有机物的有效去除,平均COD去除率为81.5%;阴极对含镉废水中Cd2+的去除率为79.4%～84.8%。这表明MFC同步处理中药废水及重金属废水具有一定的可行性。     

Feasibility of honeycomb monolith supported sugar catalyst to produce biodiesel from palm fatty acid distillate (PFAD)

Carbon coated monolith was prepared by sucrose solution 65 wt.% via dip-coating method. Sulfonation of incomplete carbonized carbon coated monolith was carried out in order to synthesize solid acid catalyst. The textural structure characteristics of the solid acid catalyst demonstrated a low surface area and pore volume. Palm fatty acid distillate (PFAD), a by-product of palm oil refineries, was utilized as oil source in biodiesel production. The esterification reaction subjected to different reaction conditions was performed by using the sulfonated carbon coated monolith as heterogeneous catalyst. The sulfonation process had been performed by using vapour of concentrated H₂SO₄ that was much easier and efficient than liquid phase sulfonation. Total acidity value of carbon coated monolith was measured for unsulfonated sample (0.5 mmol/g) and sulfonated sample (4.2 mmol/g). The effect of methanol/oil ratio, catalyst amount and reaction time were examined. The maximum methyl ester content was 89% at the optimum condition, i.e. methanol/oil molar ratio (15:1), catalyst amount (2.5 wt.% with respect to PFAD), reaction time (240 min) and temperature 80 °C. The sugar catalyst supported on the honeycomb monolith showed comparable reactivity compared with the sugar catalyst powder. However, the catalyst reusability studies showed decrease in FFA% conversion from 95.3% to 68.8% after four cycles as well as the total acidity of catalyst dropped from the value 4.2 to 3.1 mmol/g during these cycles. This might be likely due to the leaching out of SO₃H group from the sulfonated carbon coated monolith surface. The leaching of active species reached a plateau state after fourth cycle.     

水环境中26种类固醇激素的分析方法研究

建立了固相萃取-超高效液相-串联质谱法同时测定水环境中26种类固醇激素的分析方法。明确了取样体积为500 m L,Cleanert PEP为富集柱,乙酸乙酯为洗脱剂,甲醇为溶剂进行提取操作。选择了正离子模式,以0. 1%甲酸/甲醇-水为流动相,负离子模式以0. 1%氨水/乙腈-水为流动相,试样经AcquityTMUPLC BEH C18色谱柱分离后,选用质谱检测模式进行定性、定量分析。通过方法验证,26种类固醇激素的方法检出限为0. 3～1. 5 ng/L,测定下限为1. 2～6. 0 ng/L,代表性样品测定结果的相对标准偏差为2. 6%～13. 7%(n=6),加标回收率为71. 2%～121%。该方法操作便捷,灵敏度高,精密度和准确度良好,可适用于水环境中多种痕量、超痕量类固醇激素的定性定量分析。     

Effect of admixture of solid inertant on fire hazard of dust layers oriented at varying degrees of inclination

Unlike metallic dust layers, the layer flammability levels (LFL) of non-metallic dust layers exhibit a wide range from Class 1 (No self-sustained combustion) to Class 6 (explosive combustion). However, determinations of layer flammability have not considered the effect of inclination angle, thereby potentially underestimating fire hazard of combustible dust layers in many industrial situations. In this research, inclined dust layers showed greater fire hazard than did horizontally oriented dust layers. For example, LFL of wood dust jumped from class 3 to class 5 when layers were positioned with an incline. Flame spread rate of PMMA dust layers increased from 1.8 to 3.6 mm/s when the angle of inclination increased from 0 to 40°. Even small amounts of solid inertant significantly decreased surface layer fires. The required amount of inertant to completely inert layer fires was far less than that for smoldering layer fires or dust explosions.     

Characteristics of stable biodiesel emulsion fuel with the aid of lipophilic surfactant,polyglycerol polyricinoleate (PGPR)

ABSTRACT

Biodiesel emulsion fuel is reported as one of the most feasible options capable of generating lower NOx emission than that from fossil fuels. However, oil and water in the emulsion fuel are easily separated and unstable. The aim of the present study is to consider the production and stability of biodiesel emulsion fuel by using tetraglycerin ester (CR-310), i.e., one of lipophilic surfactant, polyglycerol polyricinoleate (PGPR) and biodiesel, i.e., Waste cooking Oil Methyl Ester (WOME) produced based on waste cooking oil. The corresponding heat rate, water content, and viscosity are measured. Emphasis is placed on the effects of water content and surfactant on biodiesel emulsions. It is found that: (i) stable emulsion fuel is obtained by adding at least 2.0% of CR-310 and is maintained over 1 month, (ii) there is no effect of water content on stable emulsion fuel if CR-310 is used over 2.0%, and (iii) the viscosity of emulsion fuels is higher than that of the biodiesel fuel and is gradually increased with an increase in the water content.     

某基岩区工业固体废物填埋场地递进式场地环境调查实例

针对某基岩区简易封场后的固体废物填埋场,采用多层次、递进式调查策略,配合使用地球物理探测、直压式土壤快速取样、现场快速检测等技术,分3个阶段开展填埋场及其周边环境调查。第1阶段,调查地质环境特征,开展地球物理探测;第2阶段,调查填埋物、渗滤液主要组分及对周边积水、农田土壤、民用井水的污染情况;第3阶段,划定重点污染区域,开展土壤和地下水污染调查。调查结果显示,填埋区已发生明显渗漏,对邻近区域土壤、地下水及地表积水造成了一定污染,但未对周边农用地土壤、民用井水质等产生不利影响,总体处于可控范围。提出,通过削减污染源,切断污染物迁移、暴露途径,消除已有污染影响,长期跟踪监测等多项管控治理措施进行综合整治。     

A bayesian network-based safety assessment method for solid propellant granule-casting molding process

The safety of the solid propellant molding process is vital for the stable production of high-quality propellants. Failure events caused by abnormal parameters in the molding process may have catastrophic consequences. In this paper, a Bayesian network (BN) model is proposed to assess the safety of the solid propellant granule-casting molding process. Fault tree analysis (FTA) is developed to construct a causal link between process variables and process failures. Subsequently, expert experience and fuzzy set theory (FST) are used to obtain failure probabilities of the basic events (BEs). Based on the mapping rules, FTA provides BN with reliable prior knowledge and a network structure with interpretability. Finally, when new evidence is obtained, the probability is updated with the diagnostic reasoning capability of BN. The results of the sensitivity analysis and diagnostic inference were combined to identify key parameters in the granule-casting molding process, including curing temperature, vacuum degree, extrusion, calendering roll distance, length setting value, holding time, and polish time. The results of this paper can provide effective supporting information for managers to conduct process safety analysis.     

大气14CO2的时空分异特征及其在化石源CO2示踪中的应用

大气CO₂中放射性碳同位素(¹⁴C)的水平可以反映化石源CO₂的影响程度,这对于评估我国目前化石源CO₂的排放状况和制定节能减排政策具有重要的指导意义。本文在概述大气¹⁴CO₂采样和分析方法的基础上,简要介绍了大气¹⁴CO₂观测的起源和主要的源汇过程,重点论述了大气¹⁴CO₂的时空分异特征及其驱动因素;阐述了化石源CO₂浓度的估算方法及¹⁴CO₂在国内外化石源CO₂示踪中的应用现状,并对大气¹⁴CO₂观测在我国化石源CO₂示踪中的应用前景进行了展望;旨在为我国正确地开展大气¹⁴CO₂的观测研究,深刻地理解特定区域大气¹⁴CO₂的时空分异特征和化石源CO₂的分布状况提供参考。