溴化1-十四烷基-3-甲基咪唑对小鼠的肝脏毒性及其作用机制

研究离子液体溴化1-十四烷基-3-甲基咪唑盐([C₁₄mim]Br)对小鼠的肝脏毒性及其作用机制。实验设立3个剂量的染毒组(1/16 LD₅₀、1/8 LD₅₀、1/4 LD₅₀)和1个空白对照组,考察昆明种小鼠染毒14 d后,[C₁₄mim]Br对小鼠血清生化指标、肝脏抗氧化酶活性及脂质过氧化产物的影响,并观察肝脏组织的病理变化。与对照组相比,小鼠染毒后,血清中ALT、AST、DBIL和γ-GT明显升高;肝组织受到不同程度的损伤,HSI增大,蛋白质含量降低。当染毒剂量为1/4 LD₅₀时,肝脏中SOD活性和GSH-Px活性显著降低,MDA的含量则明显增加。实验结果表明,[C₁₄mim]Br可损伤小鼠的肝脏功能,破坏机体的抗氧化防御系统,造成氧化损伤和脂质过氧化。     

Organic Liquids Storage Tanks Volatile Organic Compounds (VOCS) Emissions Dispersion and Risk Assessment in Developing Countries: The Case of Dar-Es-Salaam City, Tanzania

The emission estimation of nine volatile organic compounds (VOCs) from eight organic liquids storage tanks companies in Dar-es-Salaam City Tanzania has been done by using US EPA standard regulatory storage tanks emission model (TANKS 4.9b). Total VOCs atmospheric emission has been established to be 853.20 metric tones/yr. It has been established further that petrol storage tanks contribute about 87% of total VOCs emitted, while tanks for other refined products and crude oil were emitting 10% and 3% of VOCs respectively. Of the eight sources (companies), the highest emission value from a single source was 233,222.94 kg/yr and the lowest single source emission value was 6881.87 kg/yr. The total VOCs emissions estimated for each of the eight sources were found to be higher than the standard level of 40,000 kg/yr per source for minor source according to US EPA except for two sources, which were emitting VOCs below the standard level. The annual emissions per single source for each of the VOCs were found to be below the US EPA emissions standard which is 2,000~kg/yr in all companies except the emission of hexane from company F1 which was slightly higher than the standard. The type of tanks used seems to significantly influence the emission rate. Vertical fixed roof tanks (VFRT) emit a lot more than externally floating roof tanks (EFRT) and internally floating roof tanks (IFRT). The use of IFRT and EFRT should be encouraged especially for storage of petrol which had highest atmospheric emission contribution. Model predicted atmospheric emissions are less than annual losses measured by companies in all the eight sources. It is possible that there are other routes for losses beside atmospheric emissions. It is therefore important that waste reduction efforts in these companies are directed not only to reducing atmospheric emissions, but also prevention of the spillage and leakage of stored liquid and curbing of the frequently reported illegal siphoning of stored products. Emission rates for benzene, toluene, and xylene were used as input to CALPUFF air dispersion model for the calculation of spatial downwind concentrations from area sources. By using global positioning system (GPS) and geographical information system (GIS) the spatial benzene concentration contributed by organic liquid storage tanks has been mapped for Dar-es-Salaam City. Highest concentrations for all the three toxic pollutants were observed at Kigamboni area, possibly because the area is located at the wind prevailing direction from the locations of the storage tanks. The model predicted concentrations downwind from the sources were below tolerable concentrations by WHO and US-OSHA. The highest 24 hrs averaging time benzene concentration was used for risk assessment in order to determine maximum carcinogenic risk amongst the population exposed at downwind. Established risk for adult and children at 2.9×10^-3 and 1.9×10^-3 respectively, are higher than the acceptable US-EPA risk of 1×10^-6. It is very likely that the actual VOCs concentrations in some urban areas in Tanzania including Dar-es-Salaam City are much higher than the levels reported in this study when other sources such as petrol stations and motor vehicles on the roads are considered. Tanzania Government therefore need to put in place: an air quality policy and legislation, establish air quality guidelines and acquire facilities which will enable the implementation of air quality monitoring and management programmes.     

两种咪唑氯盐类离子液体对水稻幼苗根部的毒性效应

按照毒性试验标准方法研究了1-癸基-3-甲基咪唑氯盐([DMIM]Cl)、1-十二烷基-3-甲基咪唑氯盐([C12MIM]Cl)对水稻幼苗生长的影响,测定了水稻根的半数抑制浓度(IC50-5d)、超氧化物歧化酶(SOD)活性、过氧化氢酶(CAT)活性、过氧化物酶(POD)活性、水稻根部丙二醛(MDA)含量及对水稻根系的生理影响.结果表明:两种离子液体(ILs)对水稻幼苗根部生长均具有抑制作用,随着浓度的增大抑制率增加,[DMIM]Cl和[C12MIM]Cl的根长IC50-5d分别为0.10 mg·L-1和0.054 mg·L-1,水稻幼苗根部对两种ILs均有氧化应激反应,在[DMIM]Cl和[C12MIM]Cl处理下,3种抗氧化酶活性均受到严重抑制,丙二醛(MDA)含量升高,加剧了水稻幼苗根部细胞膜脂质过氧化作用.[DMIM]Cl和[C12MIM]Cl处理导致根系活力降低,根系质膜透性增大.     

多元可燃混合溶液的闪点预测

为了预测多元可燃混合液的闪点,建立了一个预测模型,通过二元和三元可燃混合液闪点实测值的试验对比,证实此模型的误差在可接受的范围内。此模型可以在预知可燃混合液组分比例和单组分闪点基础上快速预测混合液的闪点。     

碳酸钙诱导结晶动力学影响因素研究

碳酸钙诱导结晶速率受到水中多种因素的影响,采用pH-stat法对pH值、过饱和度、钙和镁离子活度和金属离子（铁、锰）等因素对碳酸钙诱导结晶速率的影响进行研究.结果表明,当pH值在8.0~10.0之间,过饱和度在1.4~4.03之间时,碳酸钙诱导结晶速率随着pH值的增大或者过饱和度的增大而增大,当钙离子和镁离子活度在0~1.18之间时,碳酸钙的结晶速率随着镁离子的增多而降低.碳酸钙结晶速率介于1.0×10^-10m/s~5.0×10^-10m/s.铁离子和锰离子的存在会促进碳酸钙的诱导结晶过程,且铁离子和锰离子同时存在时碳酸钙结晶速率高于其单独存在时碳酸钙的结晶速率.通过深入研究不同因素对碳酸钙诱导结晶动力学的影响,为碳酸钙结晶造粒工艺提供数据支持.     

多孔介质中NAPLs流体毛细管指进形态及分形表征

非水相流体(non-aqueous phase liquids,NAPLs)如石油烃类和有机溶剂类污染土壤和地下水引起了广泛关注.不同粒径多孔介质中不同性质流体入渗形态的识别是确定污染范围、有效修复土壤和地下水的前提.本研究选取不同性质的4种NAPLs流体,建立可视化砂箱模型,比较4种流体在不同粒径石英砂中指流形态差异,并引入分形理论对迁移形态进行定量描述.结果表明,NAPLs流体指进过程属于毛细管指进,主要驱动力为毛细力;同种污染物或同一黏度数量级污染物之间指流宽度和渗流面积变化趋势与毛细管数和邦德数变化趋势呈负相关;指流宽度和渗流面积随着介质粒径的减小和流体黏度的增大而增加;指流宽度和渗流面积与渗流面的质量分形维数呈正相关,质量分形维数可以作为指流宽度和渗流面积的指示指标.     

二氧化碳回收技术进展

CO2的过量排放对全球的气候变暖有着不可推卸的责任,同时CO2又是一种重要的碳资源,对它的回收和利用将具有很大的经济效益和社会效益。CO2回收的方法主要是膜吸收法、变压吸附法、化学吸收法和低温分离法,特别是离子液体对CO2的吸收,为CO2的减排提供了良好的手段。     

离子类型、强度和铁氧化物影响下微塑料的迁移行为及模型计算

土壤中的微塑料（MPs）作为一种新型污染物而被广泛关注,其迁移行为受到自身理化性质、土壤溶液化学组成和土壤矿物等因素的影响.目前,铁氧化物存在时,离子类型和离子强度对MPs迁移行为的影响机制尚不明确.通过稳定性实验和迁移实验,重点考察了离子类型、离子强度和铁氧化物对带有不同官能团聚苯乙烯微塑料（PSMPs）迁移行为的影响,并用胶体迁移模型、CD-MUSIC模型及DLVO理论探讨其迁移机制.结果表明,PSMPs在NaH₂PO₄背景下的稳定性最强,标准化浓度（c/c₀）达到0.99,而在CaCl₂背景下的稳定性相对弱,c/c₀降低至0.94.不同离子种类对PSMPs的迁移行为产生不同影响,对于阳离子Na⁺和Ca²⁺,二价Ca离子有架桥作用和较强的电荷中和作用,更能阻滞PSMPs在石英砂中的迁移,出水溶液中PSMPs回收率低至（43.83±1.71）%且第二动力学位点上的一级保留系数k_2a为1.54 min^-1,铁氧化物会进一步加剧阻滞作用,回收率降低为（6.04±0.40）%且k_2a升高为5.33 min^-1;对于阴离子Cl^-和PO₄^3-,PSMPs在纯石英砂柱中的迁移主要受其自身表面电负性的控制,Cl^-离子下PSMPs电负性更低,回收率升高［（92.95±0.63）%］且k_2a降低（0.19 min^-1）,而当铁氧化物存在时,PSMPs的迁移则受控于载铁石英砂表面的Zeta电位.CD-MUSIC模型计算结果显示PO₄^3-容易吸附在铁氧化物表面形成内圈络合物,降低载铁石英砂表面的电负性,因此PSMPs在PO₄^3-背景下的回收率升高［（76.22±1.39）%］且k_2a降低（0.66 min^-1）;同时,该内圈络合物的形态受PO₄^3-浓度的控制且不同形态的内圈络合物具有不同的表面负电荷数,因此高PO₄^3-浓度下载铁石英砂表面电负性反而高,不利于PSMPs迁移.此外,PSMPs的迁移均随着离子强度的增加而降低.最后,DLVO理论计算出不同条件下PSMPs和介质间的一级势垒变化趋势与PSMPs的迁移能力一致,即较高的一级势垒表明PSMPs和介质间较大的相互斥力有利于PSMPs的迁移,可以更好地阐明PSMPs的迁移行为.     

双信号细胞电化学法检测氯酚类的毒性

以多壁碳纳米管和离子液体复合修饰电极(MWCNTs-IL/GCE)为工作电极,运用线性扫描伏安法(LSV)研究了人乳腺癌(MCF-7)细胞的电化学行为,检测到了2个明显的氧化峰,其氧化峰电位分别为0.725 V和1.038 V.结合4种嘌呤碱基与模型细胞的电化学行为比较与高效液相色谱分析,确定细胞的电化学响应来源分别为细胞质中黄嘌呤与鸟嘌呤、次黄嘌呤与腺嘌呤的电化学氧化.基于2个响应信号峰电流的变化,研究了五氯酚(PCP)、2,4,6-三氯酚(TCP)和2,4-二氯酚(DCP)对MCF-7细胞的毒性效应,根据剂量-效应关系曲线计算半数抑制效应浓度(IC50)值,并与四甲基偶氮唑盐(MTT)比色法进行比较.结果发现,氯酚类污染物对MCF-7细胞活性有明显抑制作用,细胞电化学法与MTT法测得细胞毒性顺序均为:PCPTCPDCP,表明细胞电化学法可以快速、准确地评价氯酚类污染物的细胞毒性.该研究结果可从核苷酸代谢角度为危害化学品的安全无标记、准确客观的毒性评价方法建立提供新思路.     

表面活性剂强化超声波-离子液体预处理对水葫芦酶解的影响

为探讨表面活性剂对超声波-离子液体(US-IL)预处理木质纤维素的影响,本试验采用十二烷基硫酸钠(SDS)强化US-IL对水葫芦进行预处理,通过酶解、组成成分、表面形貌、结晶度以及化学结构的变化对预处理效果进行考察.结果显示,与未添加SDS相比,超声波-离子液体-十二烷基硫酸钠(US-IL-SDS)预处理能够有效降低纤维素的结晶度并去除木质素,酶解还原糖产量、纤维转化率及其脱木率分别提高72.23%、58.74%及21.01%.并且,SEM、XRD以及FTIR结果也表明SDS能够促进US-IL对水葫芦结构的破坏.因此,将SDS运用于辅助US-IL预处理木质纤维素具有一定可行性和良好的运用前景.