Cloud point extraction coupled with HPLC-UV for the determination of phthalate esters in environmental water samples

A method based on cloud point extraction was developed to determine phthalate esters including di-ethyl-phthalate （DEP）, di- （2-ethylhexyl）-phthalate （DEHP） and di-cyclohexyl-phthalate （DCP） in environmental water samples using high-performance liquid chromatography separation and ultraviolet detection （HPLC-UV）. The non-ionic surfactant Triton X-114 was chosen as extraction solvent. The parameters affecting extraction efficiency, such as concentrations of Triton X-114 and Na2SO4, equilibration temperature, equilibration time and centrifugation time were evaluated and optimized. Under the optimum conditions, the method can achieve preconcentration factors of 35, 88, 111 and detection of limits of 2.0, 3.8, 1.0 ng/ml for DEP, DEHP and DCP in 10-ml water sample, respectively. The proposed method was successfully applied to the determination of trace amount of phathalate esters in effluent water of the wastewater treatment plant and the lixivium of plastic fragments.     

Comparison of properties of traditional and accelerated carbonated solidified/stabilized contaminated soils

The investigation of the long-term performance of solidified/stabilized (S/S) contaminated soils was carried out in a trial site in southeast UK. The soils were exposed to the maximum natural weathering for four years and sampled at various depths in a controlled manner. The chemical properties (e. g. , degree of carbonation (DOC), pH, electrical conductivity (EC)) and physical properties (e. g. , moisture content (MC), liquid limit (LL), plastic limit (PL), plasticity index (PI)) of the samples untreated and treated with the traditional and accelerated carbonated S/S processes were analyzed. Their variations on the depths of the soils were also studied. The result showed that the broad geotechnical properties of the soils, manifested in their PIs, were related to the concentration of the water soluble ions and in particular the free calcium ions. The samples treated with the accelerated carbonation technology (ACT), and the untreated samples contained limited number of free calcium ions in solutions and consequently interacted with waters in a similar way. Compared with the traditional cement-based S/S technology, e. g. , treatment with ordinary portland cement (OPC) or EnvirOceM, ACT caused the increase of the PI of the treated soil and made it more stable during long-term weathering. The PI values for the four soils ascended according to the order: the EnvirOceM soil, the OPC soil, the ACT soil, and the untreated soil while their pH and EC values descended according to the same order.     

新型光电催化反应器的设计及其反应动力学

研制了一种新型的光电催化反应器,并对PEG-2000模拟废水进行了降解动力学研究。结果表明,电解、光催化、光电催化去除0.5 g/L的PEG-2000模拟废水中COD为零级反应,从动力学角度来看,光电协同作用明显;在不同的外加偏压、初始pH值、曝气量和光强条件下,反应符合零级动力学规律;不同初始浓度PEG-2000模拟废水的光电催化反应具有不同的反应级数,高浓度时,此光电催化体系符合零级反应动力学规律,低浓度时,光电催化氧化符合一级反应动力学规律。     

地膜覆盖对菜地土壤剖面温室气体的影响

为了解地膜覆盖对菜地剖面温室气体的影响,本研究利用扩散箱法测定了2014-2015年西南地区辣椒-萝卜轮作菜地10、20和30 cm土壤剖面的CH4、CO2和N2O的浓度.结果表明,整个观测季覆膜(F)和不覆膜(NF)处理土壤剖面的CH4浓度均随土壤深度增加而降低.与NF相比,覆膜极显著提高了辣椒季30 cm土层的CH...     

部分国家及地区塑料袋减量化经济政策对我国的启示

对我国(不包括港澳台地区)塑料袋管理制度特点分析的基础上,总结其成效以及存在的问题。根据价格杠杆、税收杠杆对部分国家及地区的塑料袋减量化经济政策进行分类,在分析其发展历程、政策内容和管理方式等基础上,借鉴其管理经验,对完善我国塑料袋经济政策提出两方面建议:完善现行塑料袋收费制度,包括扩展管理范围,设置价格下限等;建立塑料袋税收制度,包括实施专款专用,合理化制定税率等。     

CdS/TiO2复合半导体薄膜的制备及其光催化性能

以微弧氧化法制备出锐钛矿型TiO₂,进而以化学水浴法沉积CdS,通过调控时间,制备CdS/TiO₂复合半导体薄膜. X射线检测表明,微弧氧化所制备的TiO₂为锐钛矿结构, 化学水浴法制备的CdS主要以离子离子的方式沉积在TiO₂薄膜上. SEM及可见光催化降解亚甲基蓝的试验表明,沉积时间为15 min的复合半导体薄膜上的CdS粒子呈圆球形、单层孤立、均匀地分散在TiO₂表面,绝大多数粒子的粒径在nm级别,分布比较均匀,对亚甲基蓝有着较好的光催化性能,与TiO₂薄膜相比,复合半导体薄膜的光催化性能有很大的提高. 结合光催化评价结果,对复合半导体薄膜的光催化剂机制进行了讨论.      

覆膜对土壤-青菜体系Cu和Zn迁移特性的影响

地膜覆盖(覆膜)是一种国际上广泛采用的农作物栽培方式,极大地改变了土壤的水热生态效应,从而影响土壤中重金属元素的生物有效性.通过田间对比试验,研究覆膜对土壤-青菜体系中Cu和Zn迁移及分布特征的影响.结果表明:覆膜栽培方式在促进青菜生长的同时,显著地改变了土壤的理化性质.覆膜地块中土壤pH值和SO2-4含量比不覆膜地块分别降低12.77%和33.90%,差异达到显著水平(P＜0.05).覆膜对Cu形态分布和迁移影响很小,对Zn影响则大得多.土壤中Zn的BCR(community bureau of reference)3步提取态含量分别降低25.87%、35.80%和28.17%.覆膜地块青菜根和叶中Zn含量分别较不覆膜地块增加130.9%和13.6%,但茎中减少了23.7%.覆膜栽培对土壤中Zn有一定活化作用,释放出来的Zn大部分被青菜根吸收,因此覆膜地块中青菜根对Zn的吸收量远远大于不覆膜地块.     

In situ measurements of concentrations of Cd, Co, Fe and Mn in estuarine porewater using DGT

Vertical profiles of metals were measured by the in situ application of DGT (diffusive gradients in thin films). Well-defined laboratory systems ensured the good reproducibility and precision DGT accumulated metals on a chelex resin after diffusional transport through a layer of hydrogel. Three kinds of DGT probes (with three thicknesses of diffusive gel: 0.40 mm, 0.80 mm and 1.92 mm) measured interfacial concentration and induced flux from solid to solution phase which had intricate variations with depth. The DGT induced flux and interfacial concentration of four metals belonged to “partially sustained” state, indicating a labile equilibrium of metals between solid phase and porewater. The concentration profiles showed the good correlation between Mn and Co and peak concentrations of Mn and Fe between −2.00 cm and −5.25 cm with depth.     

分离剂甲酸溶液浓度和温度对于铝塑湿法分离的影响研究

主要针对无菌复合包装废弃物中去除了纸浆后的铝塑部分的湿法分离工艺进行研究,选用甲酸作为分离溶剂,分析其反应机理。并着重对分离过程的影响控制因素进行实验研究,就不同的分离剂浓度、不同反应温度以及不同液固比条件下铝塑分离的效果及反应速率的变化分别进行分析研究,寻找铝塑片分离各影响因素之间的关系,为工业化生产应用提供参考,以提高无菌复合包装废弃物的再生利用率。     

复合内嵌筋材加固混凝土梁破坏模式分析

对螺旋肋钢筋施加预应力,将其与碳纤维筋组合后,以不同的方式嵌入到混凝土梁受拉区混凝土保护层中,对混凝土梁进行加固,能显著提高混凝土梁的承载能力。在对承载能力试验结果做简单阐述的前提下,针对加固梁中多材料、多界面存在的客观现实,全面系统地分析了加固梁可能存在的破坏模式,且与试验梁的破坏模式进行对比,对不同加固方式加固的试验梁的破坏模式及破坏机理进行了分析。分析表明,多界面的存在严重影响了加固梁的承载力;不同的破坏界面,应对加固材料断面总内力采取不同的取值,在试验中应特别注意破坏界面的判别,否则计算结果会产生很大误差。