电镀废水膜法回用后浓水达标处理研究

本文对电镀废水经物化预处理--反渗透回收处理后的膜浓废水作为对象,将微电解--芬顿破反应处理方法作为破络合反应,对重金属、COD的去除方法进行了研究,确定了pH4,双氧水加药量3‰,反应时间60 min,是比较好的破络合反应条件;经破络处理后的废水中,进行pH调节后,投加硫化钠浓度50 mg/L,重金属捕捉剂10 mg/L可以将反渗透膜浓水中较低浓度的重金属及COD处理至国家排放标准。     

Fenton氧化技术处理高浓度间苯三酚发酵液废水研究

Fenton试剂是一种氧化能力较强的氧化剂,广泛应用于废水处理中。生物合成技术的迅猛发展导致发酵废水量不断增大;发酵产生的水溶性中间体和产物以及后期产品分离过程中有机溶剂的使用为废水处理提出了新的挑战。本文利用Fenton试剂处理高浓度间苯三酚发酵液废水,考察了Fenton反应对COD去除率的最佳条件。通过实验得出的最佳条件为∶双氧水与COD的浓度比为1.5∶1,Fe2+与H2O2的最佳摩尔比为1∶12,最佳初始pH值为3.0,反应时间为5h。在此最佳条件下,废水COD的最大去除率为90.62%。通过多次Fenton反应得出,Fenton试剂对高浓度工业废水COD具有更好的去除率。     

Regulating non-precious transition metal nitrides bifunctional electrocatalysts through surface/interface nanoengineering for air-cathodes of Zn-air batteries

Zn-air batteries (ZABs), especially the secondary batteries, have engrossed a great interest because of its high specific energy, economical and high safety. However, due to the insufficient activity and stability of bifunctional electrocatalysts for air-cathode oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) processes, the practical application of rechargeable ZABs is seriously hindered. In the effort of developing high active, stable and cost-effective electrocatalysts, transition metal nitrides (TMNs) have been regarded as the candidates due to their high conductivity, strong corrosion-resistance, and bifunctional catalytic performance. In this paper, the research progress in TMNs-based material as ORR and OER electrocatalysts for ZABs is discussed with respect to their synthesis, chemical/physical characterization, and performance validation/optimization. The surface/interface nanoengineering strategies such as defect engineering, support binding, heteroatom introduction, crystal plane orientation, interface construction and small size effect, the physical and chemical properties of TMNs-based electrocatalysts are emphasized with respect to their structures/morphologies, composition, electrical conductivity, specific surface area, chemical stability and corrosion resistance. The challenges of TMNs-based materials as bifunctional air-cathode electrocatalysts in practical application are evaluated, and numerous research guidelines to solve these problems are put forward for facilitating further research and development.     

地下停车场VOCs污染特征与健康风险评价

机动车尾气和蒸发排放的VOCs在地下停车场的半密闭环境中不断积累,威胁居民健康.为探究停车场内挥发性有机物（VOCs）浓度水平和变化特征与车队活动水平之间的关系,阐明其对居民健康的影响,选取天津市某居民小区地下停车场,开展了为期9d的VOCs样品采集,利用臭氧生成潜势（OFPs）,·OH反应速率（L_·OH）和二次有机气溶胶生成潜势（SOAPs）综合评价停车场内VOCs大气反应活性,对人体健康风险进行评价.结果表明：①停车场内VOCs浓度和组分变化主要受车队活动影响,工作日和周末的浓度峰值均与进场和出场车流峰值同步出现,即早晚高峰时段,工作日和周末早高峰浓度分别为（463.76±148.42）μg·m^-3和（391.47±135.37）μg·m^-3,晚高峰为（334.29±176.57）μg·m^-3和（416.20±134.64）μg·m^-3.停车场夜间几乎没有车辆活动,但夜间ρ（VOCs）［工作日（320.33±115.57）μg·m^-3;周末（364.77±155.32）μg·m^-3］仍高于午间［工作日（255.76±103.65）μg·m^-3;周末（350.91±108.73）μg·m^-3］,且夜间时段烯炔烃质量分数明显高于其他时段,这是由于夜间车辆静置时发生昼间排放产生较多的烯烃.②烯炔烃和芳香烃对OFPs和L_·OH贡献率最大（84.10%~88.04%）,芳香烃对各时间段的SOAPs贡献率最大（98.03%~98.99%）,说明芳香烃和烯炔烃的大气反应活性强且广泛存在于机动车源,是提高排放标准、升级油品时需首要考虑降低的关键组分.③健康风险评价结果表明,停车场内VOCs非致癌风险危险指数（HI）：0.19~0.55,暂无健康风险.而各时间段致癌风险均超过阈值（1×10^-6）1.56~3.11倍,停车场作为居民每天必经场所,应开启机械通风措施保证其中空气流通性.     

矿用润湿型压裂液的制备与性能分析*

为有效减少煤矿开采时粉尘的生成量,降低综采区粉尘含量。基于自由基聚合和季铵化反应制备1种润湿型压裂液。通过单因素实验,确定最优配比是200 mL水,5 g油酸,0.3 g过硫酸钾,3 g N,N′-亚甲基双丙烯酰胺,2 mL环氧氯丙烷,2 g氯化钾和2 g水杨酸钠。对压裂液的反应过程、微观结构、剪切黏度、剪切稳定性、滤失性、润湿型性和清洁性进行研究。研究结果表明:该压裂液具有较高的剪切黏度和较佳的剪切稳定性,有利于注入煤层;具有较低的滤失性,便于压裂造缝;具有良好的润湿能力,能够有效地渗透到煤层中去;具有残渣含量少等特点,清洁性良好。     

Effects of copper chloride on formation of polychlorinated dibenzo-p-dioxins in model waste incineration

Combustion experiments in a laboratory-scale fluidized-bed reactor were conducted to elucidate the effects of copper chloride as a catalyst on polychlorinated dibenzo-p-dioxins (PCDDs) formation in municipal waste incineration. We used model wastes with and without copper chloride (CuCl₂ · 2H₂O), both of which contained polyvinyl chloride as a chlorine source. Combustion temperature was set to 900 °C, and the amount of air supplied was twice the stoichiometric ratio. The experimental setup was carefully planned to suppress the influences of experimental conditions except the waste composition. Results of these experiments showed that copper chloride in the waste increased the amount of PCDDs formed and made the homologue profile to shift towards the highly chlorinated species. Copper chloride contributes to the PCDDs formation by promoting chlorination, whereby the reaction is important in that organic matter is chlorinated directly by copper compounds. Copper chloride did not exert a great influence on the isomer distribution patterns of PCDDs, while there appeared a significant difference in the case of PCDFs. This points out the difference of the major formation mechanisms between PCDDs and PCDFs. PCDDs are less formed by the catalytic reactions from carbon/polycyclic aromatic hydrocarbons than PCDFs in our experimental conditions.     

Calorimetric behaviors of hydroxylamine and its salts caused by Fe(III)

The objective of this study is to obtain information on the calorimetric behaviors of aqueous solutions of hydroxylamine (HA), hydroxylamine chloride (HACl), and hydroxylamine nitrate(HAN) caused by different Fe(III) states (free Fe(III) from Fe(NH₄)(SO₄)₂, Fe(CN)₆³⁻, and Fe(EDTA)⁻). The calorimetric data were obtained with a small-scaled reaction calorimeter, Super-CRC.

In the mixing with Fe(III), HA showed the highest reactivity among three substrates. Free Fe(III) and Fe(EDTA)⁻ showed catalytic effects in the reactions. In the overall heat of reactions, Fe(EDTA)⁻ exceeded free Fe(III), which precipitated as Fe(OH)₃ and decreased the chances of interactions with HA. It was suggested that the generation of NH₃ had taken place in the process of reducing HA along with Fe(II) oxidation. Fe(CN)₆³⁻ was less reactive than free Fe(III) and Fe(EDTA)⁻.

The ability of masking Fe(III) was estimated for CyDTA. The HA including CyDTA had no exothermic peak; however, there was an endothermic peak of the heat flow at Fe(III) injection. CyDTA was found to have the ability to inhibit a violent exothermic reaction of HA.     

基于详细化学动力学的甲烷热着火影响因素分析

利用化学动力学软件CHEMKIN4.1,在不同初始温度、浓度、湿度和压强下,对甲烷热着火进行了详细化学动力学 模拟。通过对主要组分摩尔浓度分析和温度敏感性分析,得到了甲烷热着火过程的主要基元反应和引发热着火发生的主 要原因。通过对甲烷热着火的延迟时间、热着火发生后主要生成物摩尔浓度和反应后的温度的对比分析,揭示了初始浓 度、湿度和压强对甲烷热着火的影响规律。本研究可以为甲烷为主的气体如瓦斯、天然气等可燃气体的燃烧和爆炸提供 理论支撑,从而有效利用这些可燃气体,降低灾害的发生。     

劳动负荷与作业能力研究

劳动负荷的提高会导致作业疲劳,但适当的劳动负荷对作业能力的提高可能有一定促进作用。设计实验,分析了RPE值和相对心率的相关性,并以相对心率和RPE值为解释变量,分析了它们和反应时、两点阈之间的关系,发现反应时和两点阈在负荷增加过程中存在一个最小值点,而导致这个点出现的劳动负荷即为最佳负荷。以此最佳负荷量安排作业对合理利用劳动力,提高劳动效率,保护劳动者有一定的意义。     

脉冲电晕等离子体降解有毒气体

采用脉冲电晕放电等离子体对化学毒剂模拟剂氯膦酸二乙酯(DECP)进行降解,结果表明,对初始浓度为70 mg·m-3的DECP降解率为96.4%.通过GC-MS和离子色谱分析,其降解产物主要有CHCl2-CH2Cl、CHCl2-CHCl2、二氯膦酸乙酯、HCl和H3PO4,并根据降解产物探讨了等离子体对DECP的降解反应机理.DECP分子中的P—Cl和C—O键断裂促使DECP矿化为H3PO4和HCl,而C—O键断裂形成的乙基与氯自由基反应形成CHCl2-CH2Cl和CHCl2-CHCl2;同时DECP分子中的一个P—O键发生断裂后与氯自由基结合形成了二氯膦酸乙酯.对DECP的反应动力学进行了分析讨论,得到其反应速率常数为0.0516 m.3(W.h)-1.