土壤和沉积物中持久性有机污染物分析的不确定度评估

土壤和沉积物中POPs分析过程中的不确定度来源于样品制备、运输和保存、前处理和分析4个环节.土壤经四分法采样、均质化制样、快速溶剂萃取、多层符合硅胶柱净化、GC/MS分析.以p,p'-DDT为例,评定了各环节不确定度的大小,结果表明:样品前处理的不确定度分量对合成不确定度的贡献最大,约占90.6%;样品制备、保存和分析...     

多孔有机聚合物吸附分离水体系中有机污染物研究和应用进展

有机物对水体的污染严重威胁生态环境安全和人类健康。 如何有效控制和消除水体系中的有机污染物是当前全球性热点问题之一,基于多孔材料的高效吸附是处理水体有机污染的有效方法。 多孔有机聚合物(Porous Organic Polymers,POPs)具有比表面积高、物理化学稳定性好、易修饰等特点,作为新型吸附剂在处理水体系有机污染方面具有广阔的应用前景。 本文综述了近10年来新型多孔有机聚合物对水体系中有机溶剂、农药与杀虫剂、有机染料等污染物的吸附分离研究进展。     

土壤柱液相色谱多级吸附法测定污染物的土壤有机碳吸附常数

建立了利用土壤柱液相色谱多级吸附测定污染物的土壤有机碳吸附常数(KOC)的新方法。用这种方法通过一次实验就可获得多个不同浓度的样品在土壤中的吸附量,从而通过吸附等温线计算出KOC。用该法测定的戊唑醇、保棉磷、敌草隆、莠去津、扑草净、苯酚、萘在欧洲3#标准土壤中的log KOC分别为2.70,2.87,2.47,2.26,3.09,1.51和2.77,与文献值基本一致。     

金属有机框架材料MIL-101在吸附去除水中有机污染物中的应用进展

金属有机框架材料（MOFs）是一种极具前景的水中污染物吸附材料,其中,拉瓦锡研究所材料（MIL）凭借较好的稳定性和较多的可调节位点在众多MOFs中脱颖而出。与其他MILs相比,MIL-101具有比表面积较大和表面活性位点多的特点,在水中的稳定性高,已成为一种新兴的吸附材料。鉴于此,该文对近年来MIL-101在水中有机污染物去除领域的应用研究进行了综述,主要对MIL-101结构、改性修饰及其在水污染物吸附去除方面的应用及吸附机理进行了介绍。最后对MIL-101吸附材料的应用前景进行了分析和展望。     

加速溶剂提取-GC/MS分析沉积物中氯酚类有机污染物

以不同比例的甲醇水溶液作为提取溶剂 ,设定两种提取程序 ,应用加速溶剂提取技术提取沉积物中氯酚类有机污染物 ,用气相色谱 -质谱进行分析。初步探讨了溶剂极性 ,不同温度和压力程序对提取结果的影响。研究发现两种程序下氯酚分析结果相同 ;不同比例的甲醇水溶液对氯酚类有机污染物提取量相同。这表明采用加速溶剂提取技术 ,可用价格较低的甲醇取代昂贵的正己烷和丙酮。该法回收率高( >90 %) ,仪器检出限低 ( 0 .5 ng· g- 1)和测定速度快     

废水中有机污染物降解机理的研究方法

我国废水排放总量较大,且废水中含有的多种有机污染物一直是人类生命健康的潜在威胁,因此对废水处理的研究必不可少,而理解废水中有机污染物的降解机理是处理各种废水的基础.本综述概述了国内外针对各种有机污染物降解机理的研究方法,主要包括实验手段和计算模拟两大类.实验手段中主要采用光谱分析技术检测有机污染物降解过程中生成的中间产物,进而推测有机污染物的降解路径.但是由于实验条件和实验方法的不同,对于同种物质的降解机理研究,不同的实验结果存在着争议.基于量子化学计算、定量构效关系模型（QSAR）、定量结构-生物降解性能关系模型（QSBR）、统计分子碎化模型（SMF）等计算模拟方法为有机污染物降解机理的研究提供了新的方法.将实验手段和计算模拟有机结合起来,可为有机污染物的降解机理研究提供参考和指导.     

北京近郊土壤中痕量半挥发性有机污染物的分析方法研究

利用超声提取、吸附色谱分离以及气相色谱和气-质谱联用的方法对土壤中痕量半挥发性有机污染物进行了提取、分离以及定性定量分析。优化了硅胶和弗罗里土吸附净化正构烷烃和多环芳烃以及有机氯农药和酞酸酯类化合物的分离条件。正构烷烃、多环芳烃、有机氯农药和酞酸醑的平均回收率分别为82％-105％、103％～110％、94％-117％和86％-l14％；检出限分别为3—22、3—42、0．004—0．088和10—220ng/g；相对标准偏差均小于15％。本方法用于分析北京近郊土壤中的上述有机污染物，经质量控制分析，结果可靠。     

疏水多孔硅制备及其对水中有机污染物的吸附

以硅酸钠为硅源,盐酸为催化剂,三甲基氯硅烷(TMCS)为表面改性剂,经溶胶-凝胶和表面改性过程制备出一种疏水性多孔硅材料.采用傅里叶变换红外(FTIR)光谱仪、接触角分析仪、氮气物理吸附仪和扫描电子显微镜(SEM)对其结构和性质进行表征.结果表明:所制备的多孔硅具有分等级孔道结构(中孔-大孔),比表面积为566m2·g-1,孔体积高达2.28cm3·g-1,多孔硅与水的接触角为156°,显示出超疏水特征.对甲苯、汽油、柴油和润滑油的吸附量均可高达自身质量的14倍,丰富的孔道使其在几分钟内即可达到饱和吸附.这种多孔硅在汽油/水混合体系中对汽油具有较高的选择性,同时具有良好的再生能力.经正己烷萃取再生后,多孔硅仍能基本保持初始吸附容量.此方法制备的多孔硅材料在吸附分离污水中的有机物和溢油处理方面具有很好的应用前景.     

全二维气相色谱分析持久性有机污染物的应用进展

持久性有机污染物（POPs）组分复杂,在自然界中超痕量存在,其分离分析十分困难。全二维气相色谱（GC×GC）作为一种新型色谱技术,与传统的一维气相色谱相比,具有峰容量大、分辨率和灵敏度高等优势,越来越广泛地应用于环境有机污染物的分析。该文综述了近十年来全二维气相色谱在持久性有机污染物分析中的应用进展,主要包括全二维气相色谱在解决一些复杂POPs定性定量分析难题方面的应用,如二恶英、毒杀芬和短链氯化石蜡等;概述了全二维气相色谱对多种POPs同时定性定量分析的应用进展;讨论了全二维气相色谱在非目标有机污染物筛查分析中的应用,并对发展趋势及相关应用前景进行了总结展望。     

金属有机骨架材料在吸附分离大气污染物中的应用

大气污染问题是关系人民生命健康和经济社会和谐发展的重大问题.因此需要开发高效的吸附材料用于大气污染物的吸附和分离.金属有机骨架材料(MOFs)是一类新型的多孔材料,该材料具有结构多样、孔结构有序、大比表面积和高孔隙率等结构特点.MOFs通过调节有机配体的长度和官能团调节孔径和孔道尺寸,并进行功能化修饰在孔道中引入功能性...     

Recent progress on adsorption and membrane separation for organic contaminants on multi-dimensional graphene

Graphene, a two-dimensional (2D) layered nanomaterial, which has attracted great attention in the environmental field due to its excellent physical and chemical properties, including easily modified surface characteristics, tunable structure, and excellent stability. However, the inherent problems of nanomaterials, such as serious aggregation, difficulty in recycling, and potential ecological risks, have severely hindered the large-scale application of graphene. Therefore, immobilization of nanomaterials into macroscopic structures is one of the most feasible strategies to solve these problems, which is of great significance to promote the progress of nano-water treatment chemistry and technology. With the deepening of related studies, diverse dimensional graphene materials with large specific surface area, internal interconnected porous network and novel functionalities have been successively developed. Herein, we review the structural characteristics and synthesis methods of multi-dimensional graphene materials and highlight some examples with impressive and unique properties. Furthermore, we specifically emphasize their removal performance and mechanisms for organic contaminants in adsorption and membrane separation. Finally, the future outlooks, research directions and foreseeable challenges in this filed are summarized and prospected as concluding remarks based on our understanding.     

磁性Co/C纳米复合材料的合成及其对水中刚果红吸附性能研究

This comprehensive experiment has successfully introduced the frontier of scientific research into undergraduate laboratory teaching. A magnetic Co/C nanocomposite was synthesized by using ZIF-67 as the precursor. Upon calcination at high temperature in inert atmosphere, ZIF-67 was degraded and carbonized to form Co/C nanocomposite. The adsorption performance of Co/C nanocomposite for Congo Red was investigated in detail. The structure and composition of the nanocomposite were investigated by X-ray diffraction (XRD) and scanning electron microscope (SEM). The concentration of Congo Red was determined by UV-Vis spectrophotometry. The kinetics data was fitted with the pseudo-first-order and pseudo-second-order kinetic models. The adsorption isotherms were analyzed according to Langmuir and Freundlich isotherm models. This experiment covers the synthesis of inorganic-organic hybrid material, characterization of materials, concentration determination of dyes, analysis of dynamics data and adsorption isotherms. Therefore, this experiment enables students to practice their experimental skills, increase their interest in scientific research, and broaden their professional knowledge.     

Recent advances in the environmental applications of biosurfactants

Biosurfactants can be used for heavy metal or organic contaminant removal from contaminated soil or for bioremediation enhancement. Most research has been performed on the use of rhamnolipids. However, present and future studies involve new biosurfactants and new applications as sustainable, renewable additives for nanoparticle production and use.     

Engineering covalent organic frameworks in the modulation of photocatalytic degradation of pollutants under visible light conditions

Mixtures of triphenylamine (TPA) and phenyl phenothiazine (PTH) fragments have been incorporated into a series of extended polyimine structures that have been applied in the photodegradation of pollutants of different nature under visible light irradiation. Results obtained revealed that materials containing PTH as the sole photoactive unit resulted in the most active photocatalytic material in the degradation of polybrominated diphenyl ether-1 and Sudan Red III. In contrast, the covalent organic framework containing only TPA acted as the best photocatalyst for the degradation of Methylene Blue. These different trends are related to the versatility of PTH moiety to trigger both photoredox and energy transfer processes, while TPA is only an effective energy transfer catalyst.     

Enhancing the organic dye adsorption on porous xerogels

We investigate the adsorption of four different organic dyes (i.e., methyl orange, alizarin red S, brilliant blue FCF, and phenol red) on porous xerogels. To understand the factors affecting the adsorption capacity of the xerogels, we vary the hydrophobicity and the textural properties of the xerogels as well as the solution pH. We control the hydrophobicity by mixing two different precursors (i.e., vinyltriethoxysilane (VTES) and tetraethoxysilane (TEOS)) and the textural properties by using cetyltrimethylammonium bromide (CTAB) as a templating agent. We find that the adsorption capacity is enhanced as the organic/inorganic hybrid xerogel or the templated xerogel is used instead of the purely inorganic or the untemplated xerogel. In all the cases studied, adsorption decreases as the pH is increased due to the electrostatic repulsion between the dyes and the xerogel surface. We find that both the hydrophobic surface and larger pore size/volume are required to enhance the adsorption capacity significantly.     

四环素在海洋沉积物上的吸附

研究了四环素在不同pH、盐度、温度下在海洋沉积物上的吸附特征. 结果表明, 在实验浓度范围内吸附行为都可以用线性等温式进行描述. 通过一种包含四环素3种形态与沉积物界面相互作用的模型对不同pH下的吸附常数进行拟合, 发现四环素正价态的吸附常数K_d⁺远大于中性态的K_d⁰与负价态的K_d^-. 随着盐度的减小四环素在海洋沉积物上的吸附增强, 而温度的升高则不利于吸附的进行. 热力学计算结果得出, ΔG^0-=-9.746~-9.713 kJ/mol; ΔH^0-=-10.056 kJ/mol; ΔS^0-<0, 表明该吸附过程是一个自发的、放热的熵减过程.     

Computational Study on Interactions between CO2 and (TiO2)n Clusters at Specific Sites

The energetic pathways of adsorption and activation of carbon dioxide (CO₂) on low-lying compact (TiO₂)_n clusters are systematically investigated by using electronic structure calculations based on density-functional theory (DFT). Our calculated results show that CO₂ is adsorbed preferably on the bridge O atom of the clusters, forming a "chemisorption" carbonate complex, while the CO is adsorbed preferably to the Ti atom of terminal Ti-O. The computed carbonate vibrational frequency values are in good agreement with the results obtained experimentally, which suggests that CO₂ in the complex is distorted slightly from its undeviating linear configuration. In addition, the analyses of electronic parameters, electronic density, ionization potential, HOMO-LUMO gap, and density of states (DOS) confirm the charge transfer and interaction between CO₂ and the cluster. From the predicted energy profiles, CO₂ can be easily adsorbed and activated, while the activation of CO₂ on (TiO₂)_n clusters are structure-dependent and energetically more favorable than that on the bulk TiO₂. Overall, this study critically highlights how the small (TiO₂)_n clusters can influence the CO₂ adsorption and activation which are the critical steps for CO₂ reduction the surface of a catalyst and subsequent conversion into industrially relevant chemicals and fuels.     

气相色谱法研究有机物在河流沉积物上的吸附

本文提出用有机物在沉积物上的色谱比保留体积值估算沉积物有机碳吸附系数，为此，以河流沉积物作气相色谱固定相，用测定气相色谱固定液相对极性和有机物比保留体积的方法，测定了沉积物相对极性和有机物在其上比保留体积，研究了Ｖｇ与Ｋｏｃ的相关性，结果表明，萘的线性关系式为ｌｏｇＫ＝０．１８＋３．１１（ｒ＝０．９８３１，ｎ＝５）。硝基苯的关系为ｌｏｇＫ＝０．２４ｌｏｇＶｇ＋２．５９（ｒ＝０．９５４４，ｎ＝５）．     

锌-硫氰酸盐-孔雀绿体系溶剂浮选机理及影响因素的探讨

本文通过对锌(Ⅱ)—硫氰酸盐—孔雀绿体系溶剂浮选过程的考察,提出了待测Zn~(2+)离子从水相被输送到有机相,可以用吸附机理和粘附机理来解释;同时还对影响锌溶剂浮选的主要因素:溶液的pH,气泡的大小和气体流速等进行了讨论。     

土壤对外源钍的吸附行为表征

外源钍对土壤的污染风险和程度取决于钍在土壤中的吸附行为. 以包头稀土工业区土壤样品和土壤环境矿物组分为研究对象, 通过静态吸附方法研究外源钍在土壤样品和环境矿物组分(高岭土、蒙脱土、碳酸钙、水合氧化铁/锰和腐殖酸)上的吸附, 并对吸附行为进行了表征. 结果表明, 土壤样品对外源钍有很强的吸附能力, 对加入的外源钍(10^-4 mol/L)吸附率在97%以上; 土壤环境矿物组分对加入的外源钍(1 g/L)吸附率在28%～46%之间. 通过扫描电镜-能谱(SEM-EDS)分析可知, 外源钍进入土壤后与矿物组分发生相互作用, 可能形成了稳定化钙质钍碳酸盐和钍磷酸盐; 傅里叶变换红外光谱(FTIR)分析表明, 钍是与土壤环境矿物组分上的活性吸附位点发生相互作用而吸附并保持在土壤中, 是物理吸附和化学吸附共同作用的过程; X射线衍射分析(XRD)表明, 土壤在吸附钍前后, 其矿物组分基本相同, 而矿物晶体相态发生明显变化. 由于不同土壤矿物组分对钍的吸附方式不同, 导致吸附的钍以不同形态存在于土壤中.