膜过滤-气相色谱法测定涂料中的苯系物、环己酮和甲苯二异氰酸酯

采用膜过滤-气相色谱法测定涂料中的苯系物、环己酮和甲苯二异氰酸酯（TD I）。用7种规格的石英毛细管色谱柱对混合标准溶液和涂料试样进行了分析实验,实验结果表明,不同属性的涂料试样添加固定量的正十四烷作内标物,经膜过滤净化后,苯系物、环己酮和TD I可采用DB-1-3或DB-1-2色谱柱同时分离并测定。测试数据经多级校准曲线处理后涂料试样中苯系物、环己酮和TD I的加标回收率为98.6%～101.8%,各组分分析结果的变异系数均小于2.0%,检出限均小于1.50×10^-5g。     

Leaching of styrene and other aromatic compounds in drinking water from PS bottles

Bottled water may not be safer, or healthier, than tap water. The present studies have proved that styrene and some other aromatic compounds leach continuously from polystyrene （PS） bottles used locally for packaging. Water sapmles in contact with PS were extracted by a preconcentration technique called as ＂purge and trap＂ and analysed by gas chromatograph-mass spectrometer （GC/MS）. Eleven aromatic compounds were identified in these studies. Maximum concentration of styrene in PS bottles was 29.5 μg/L. Apart from styrene, ethyl benzene, toluene and benzene were also quantified but their concentrations were much less than WHO guide line values. All other compounds were in traces. Quality of plastic and storage time were the major factor in leaching of styrene. Concentration of styrene was increased to 69.53 μg/L after one-year storage. In Styrofoam and PS cups studies, hot water was found to be contaminated with styrene and other aromatic compounds. It was observed that temperature played a major role in the leaching of styrene monomer from Styrofoam cups. Paper cups were found to be safe for hot drinks.     

PbO_2复合电极预处理甲苯二胺废水

通过涂覆—热分解法与电沉积法制备了β-PbO_2/α-PbO_2/SnO_2-Sb2O3/Ti复合电极(PbO_2复合电极),采用X射线衍射(XRD)、扫描电子显微镜(SEM)、循环伏安法(CV)、线性极化法(LSV)和加速寿命试验对电极进行表征。将PbO_2复合电极用于处理甲苯二胺(TDA)废水,考察了电解质浓度、电流密度对TDA降解效果的影响。实验结果表明:α-PbO_2呈梭状,β-PbO_2呈花菜状,多层结构的PbO_2电极利于提高电极的稳定性和活性;PbO_2复合电极的析氧电位(1.9 V)明显高于TDA的氧化电位(1.28 V),其使用寿命长达486 d;在电流密度为60 m A/cm2、Na2SO4质量浓度为10 g/L、电解时间为240 min的条件下,对COD为4 791.74 mg/L、TDA质量浓度为486.4mg/L的废水进行处理,TDA去除率高达97.3%,COD去除率可达88.1%。     

Comprehensive Environmental Investigation at Former Industrial/Petroleum Underground Storage Tank Sites in Long Beach,CA: A Forensic Perspective

Two industrial sites were investigated based on years of available hydrogeologic information and monitoring data for soil and groundwater. Collected data were forensically evaluated using age-dating and fingerprinting methods. The previous business uses of the project sites were as a gas station, laundry/dry-cleaning service, and car wash with petroleum underground storage tanks (USTs). As a result, these sites were exposed to a number of toxic contaminants at relatively high concentrations. Source control was necessary for successful remediation and the ultimate removal of the remaining compounds from these industrial sites. Although contaminated soil around the source was excavated during the remedial action and the high concentrations of contaminants were reduced, typical groundwater contaminants such as petroleum hydrocarbons as gasoline (TPH-G), benzene, toluene, ethylbenzene, xylenes (BTEX), and oxygenates including methyl tert-butyl ether (MTBE), diisopropyl ether (DIPE), ethyl tert-butyl ether (ETBE), tert-amyl methyl ether (TAME), and tert-butyl alcohol (TBA) were persistently found at the studied sites around the source points. The plume and concentration of contaminants had changed their shapes and strength for all monitoring periods. Thus, additional source control seems to be a requirement for the complete removal of source contamination, which must be ascertained with groundwater and soil monitoring on a regular time base. For the study sites, monitored natural attenuation was relatively feasible for the long-term plan; however, it did not offer a perfect remediation solution for an ultimate goal because of residual toxic compounds that might have affected the surrounding residential areas at higher concentrations than their health limits. Therefore, as a remediation strategy, the combination of clean-up technology and natural attenuation with monitoring activities are more highly recommended than either clean-up or natural attenuation used separately.     

甲苯对UASB反应器中溶解性微生物产物的影响

以乙酸钠为外加碳源,考察了UASB反应器内甲苯对可溶性微生物产物（SMP）的影响。实验结果表明：低质量浓度（20~70 mg/L）的甲苯对微生物有刺激作用,使得污泥增殖速率变小,SMP的质量浓度也逐渐减少,经过一段时间的驯化后,系统COD和TOC的去除率分别达到93%和94%以上,下降趋势较小;较高质量浓度（70~200 mg/L）的甲苯对微生物有抑制作用,污泥活性下降,反应器运行状况开始恶化,SMP的质量浓度也逐渐增大,经过一段时间的驯化后,系统COD和TOC的去除率分别维持在81%和83%以上;当甲苯质量浓度超过200 mg/L时,表现为污泥活性严重下降,对COD的去除效果极差。     

MnxCe1-xO2／γ-Al2O3催化剂的制备及其催化甲苯的燃烧性能

以γ-Al2O3为载体,以MnxCe1-xO2为催化活性组分,采用浸渍法制备了一系列负载型MnxCe1-xO2／γ-Al2O3催化剂（x=0、0．2、0．4、0．6、0．8、0．9、1）,在固定床反应器中评价了催化剂对甲苯的催化燃烧性能。结果表明,MnxCe1-xO2／γ-Al2O3催化剂的催化活性与催化剂的焙烧温度、活性组分MnxCe1-xO2的负载量以及Mn、Ce摩尔比有显著关系,其中焙烧温度550℃、负载量为20％、Mn、Ce摩尔比为4：1时,即MnxCe1-xO2／γ-Al2O3催化剂对甲苯的催化性能最佳,反应温度为180℃时,甲苯的转化率达到95％。并在连续100h的稳定性操作后,催化剂的活性基本无变化。采用XRD、BET以及SEM等分析测试手段对催化剂的结构以及表面进行了表征。     

甲苯在两相厌氧系统中降解及其抑制作用

运用两相厌氧工艺处理含甲苯废水,甲苯浓度的提升对两相厌氧系统的高效性和稳定性影响较小。在提升进水中甲苯浓度的初期,即甲苯浓度≤20 mg/L时,产酸相COD去除率及酸化度下降,驯化一段时间后可恢复正常。当浓度高于150 mg/L时,甲苯将对产甲烷相微生物产生抑制作用,系统COD去除率开始下降。但进水甲苯浓度提高至200mg/L,两相厌氧系统对甲苯的去除率仍可达99%以上。在高浓度甲苯影响下,出水中高分子量物质增多,推测高浓度甲苯刺激微生物代谢分泌大分子物质。     

介质阻挡放电联合催化臭氧化降解甲苯

采用介质阻挡放电区后结合MnOx/Al2O3/发泡镍去除甲苯,考察甲苯进气方式、臭氧产生方法及湿度对甲苯与O3同时去除的影响。结果表明,O3是等离子体区后催化降解甲苯的主要物种,介质阻挡放电联合催化臭氧化可实现甲苯及O3的同时高效去除。输入电压为9.0 kV时,甲苯的去除效率达92.8%,在80 min内O3的去除效率维持在99%以上。水蒸气对催化剂催化分解臭氧的活性没有直接的影响,O3浓度较高时湿度对甲苯降解效率的影响很小。GC-MS分析结果表明,甲苯降解的主要气相副产物有烷烃、酸、酮和含苯环有机物,提出了甲苯的降解途径。     

活性炭吸附和脱附-等离子体氧化净化有机废气的研究

根据滑动弧放电等离子体适于降解高浓度有机物废气的特性,结合活性炭吸附法,提出了吸附器的吸附浓缩和热脱附-等离子体氧化净化有机废气的方法。在活性炭吸附过程中,最初2 h内甲苯净化率达到100%,随着时间的增加净化率下降;在热脱附滑动弧放电等离子体净化过程中,甲苯降解效率最高为97.3%。将滑动弧放电等离子体反应器出口气相产物收集进行FT-IR检测,发现放电后有CO2、CO、H2O和NO2产生,并分析了甲苯的降解机理。     

一种新型活性半焦吸附剂的制备及其表面特征分析

对一种原料半焦进行粉碎、筛分,取其中10～20目的颗粒;用去离子水冲洗后高温下烘干至恒重;依次进行HNO3活化、KOH活化和加压水热化学活化,制备出活性半焦吸附剂。经实验证明,该活性半焦吸附剂对甲苯的吸附等温线符合Langmuir模型,其甲苯吸附容量可达207 mg/g,穿透时间由80 min延长至235 min。该活性半焦吸附剂的比表面积为555.56 m2/g,碘值为811.38 mg/g,表面酸碱总量为0.8649 mmol/g,并通过SEM扫描进行了表面微观形态分析。数据表明,经改性后制备出的新型活性半焦对甲苯的去除率明显增加,其表面物化性质也有明显改变,是一种优良的有机废气吸附剂。