土壤对苯系物的吸附行为研究

为保护石化工业区重要的地下水源地,选取淄博市代表性土壤,采用静态吸附平衡法,研究了苯系物在天然土壤中的吸附行为.以吸附理论为基础,考察了混合苯系物在土壤中的吸附动力学过程、吸附-解吸等温线和不同因素对吸附的影响.结果表明,Henry直线型吸附模型较好地拟合了土壤中苯系物的吸附-解吸等温线,解吸过程存在明显滞后现象,且有机质仍然是影响吸附的主要因素.由于土壤体系自身具有较强的缓冲能力,pH值和盐度对吸附过程的影响不显著.另外,温度升高,土壤对混合苯系物的吸附量增大,这可能与苯系物溶解度随温度变化的规律有关.     

溶解性有机质对黑炭吸附和解吸苯并[a]芘的影响

通过静态吸附实验,研究了3种不同类型的溶解性有机质(L-苯丙氨酸、蛋白胨和柠檬酸)对苯并[a]芘(BaP)在黑炭表面吸附解吸的影响。结果表明,3种溶解性有机质的存在均会增加BaP在黑炭表面吸附的非线性程度。L-苯丙氨酸和蛋白胨的存在均可以抑制BaP在黑炭表面的吸附,同时促进了BaP的解吸,这主要取决于L-苯丙氨酸和蛋白胨对BaP的增溶作用。但是由于BaP可以分配到黑炭表面吸附态的蛋白胨中,在相同添加浓度下,L-苯丙氨酸对BaP吸附的抑制作用更强。与L-苯丙氨酸和蛋白胨相反,柠檬酸的存在增加了BaP在黑炭表面的吸附并减小了吸附过程的可逆性,这主要是由于吸附在黑炭表面的柠檬酸对BaP的吸附作用。当柠檬酸的浓度从0mg·L-1增加到50和100mg·L-1时,BaP的吸附能力参数Kd值(在ce=100μg·L-1下)分别从119 268mL·g-1升高到134 877和180 639mL·g-1,解吸滞后指数H分别从0.44减小到0.41和0.39。本研究为预测多环芳烃在溶解性有机质污染的环境中的分布特征和最终归趋提供了理论依据。     

土壤主要组分对多氯联苯吸附及共存Cu2+的影响

采用选择性萃取分离方法对土壤中的主要化学组分锰氧化物、铁氧化物和有机质进行分离,在此基础上,采用批量平衡法研究了25℃下土壤原样、去锰氧化物样品、去铁氧化物样品和去有机质样品对多氯联苯(PCBs)的吸附热力学特征和吸附机理,以及不同含量的共存重金属Cu2+对多氯联苯吸附规律的影响.结果表明:Langmuir和Freundlich吸附模型均可较好地描述多氯联苯在土壤各级样品上的吸附热力学过程.通过比较Langmuir和Freundlich模型所获得的拟合参数可知,土壤各级样品对多氯联苯的吸附规律为:去锰氧化物样品>去铁氧化物样品>土壤原样>去有机质样品.土壤中的有机质和铁氧化物对多氯联苯吸附起主要作用,锰氧化物则抑制多氯联苯的吸附.吸附体系中的共存重金属Cu2+与多氯联苯产生了竞争吸附作用,抑制了土壤各级样品对多氯联苯的吸附,二者之间的竞争吸附作用主要可能发生在铁氧化物和有机质中.     

季铵盐在土壤中的吸附行为

通过静态吸附实验研究了土壤对季铵盐的吸附行为,进行吸附等温线的测定并考察吸附时间、吸附温度、土壤有机质含量对吸附效率的影响.结果表明,3种不同土样对季铵盐的吸附等温线均较好地符合Langmuir吸附模式,并且计算得到各方程组成的参数项数值都能较好地反映土壤的吸附特性.季铵盐在土壤中的吸附过程很快,振荡30min即已达到最大吸附率的90%,1h就达到了吸附平衡.温度的升高不利于季铵盐在土壤中的吸附,温度从25℃升高到45℃,季铵盐的饱和吸附量从32.0mg.g-1降低到29.9 mg.g-1,吸附量与土壤有机质含量具有线性关系,随着有机质含量的增大而增大.     

黄陇煤田煤层甲烷解吸滞后规律及解吸滞后定量评价

为研究黄陇煤田低阶煤甲烷解吸滞后规律并定量评价解吸滞后,采集郭家河井田3号煤层煤样(GJH3)、大佛寺井田4号煤层煤样(DFS4)与黄陵二矿井田2号煤层煤样(HL2),采用液氮吸附与等温吸附/解吸试验,分析其孔隙结构特征与吸附/解吸特征,基于Langmuir方程与热力学计算结果,定量评价解吸滞后与吸附/解吸前后吸附热差异.结果表明:(1)温度相同时,煤样吸附能力大小顺序为DFS4,HL2,GJH3,煤样残余吸附量大小顺序为HL2,GJH3,DFS4,温度对残余吸附量的影响略有区别,温度并非与残余吸附量呈线性负相关关系,因此需要综合考虑温度对解吸的影响.(2)DFS4,GJH3,HL2的解吸滞后系数为0.4～0.6,其中,20℃时HL2解吸滞后系数最大,吸附/解吸可逆性较差;GJH3解吸滞后系数最小,吸附/解吸可逆性最好;解吸滞后系数随温度升高而减小,吸附/解吸可逆性随温度升高变好.(3)解吸时的等量吸附热均大于吸附时的等量吸附热,解吸需要从体系外吸收热量,吸附和解吸过程的能量差异可能是解吸滞后的关键因素.     

原煤和型煤吸附-解吸瓦斯变形特性对比研究

基于不同瓦斯压力条件下的原煤和型煤吸附-解吸瓦斯变形全过程试验,研究了2种煤样在吸附-解吸瓦斯过程中的变形规律.结果表明:原煤在不同瓦斯压力下的吸附-解吸瓦斯全过程应变曲线可划分为6个阶段,而型煤为3个阶段;以时间为参照变量,2种煤样吸附膨胀和解吸收缩应变曲线均具有朗格缪尔方程形式;原煤吸附膨胀和解吸收缩变形均呈各向异性,而型煤均近似各向同性;2种煤样平衡吸附应变与吸附瓦斯压力关系对朗格缪尔方程均具有拟合效果,平衡解吸应变与原始瓦斯压力呈幂函数关系;2种煤样解吸瓦斯后均存在一定的残余应变;原煤吸附-解吸瓦斯全过程应变曲线的卸压膨胀变形阶段能较好的表征煤与瓦斯突出特性.     

土壤类型、温度和pH值对诺氟沙星吸附的影响

通过静态吸附实验,研究了黏土、壤土和砂土3种土壤对诺氟沙星的吸附行为,考察了温度和pH值对诺氟沙星吸附的影响.结果表明,3种土壤对诺氟沙星的吸附等温线均能较好地符合Freundlich吸附模式;303.15 K时诺氟沙星有机质吸附常数Kom平均值为14.475,吸附自由能△G为-7.549～-5.284 kJ·mol-1.     

2,4-二氯苯酚在松花江沉积物上的吸附解吸

在松花江3个典型断面(哈尔滨、达连河和佳木斯)采集了3类不同性质的沉积物,分别研究了2,4-二氯苯酚在松花江沉积物上的吸附-解吸特性.结果表明:2,4-二氯苯酚在3种沉积物上的吸附在24h内均可达到吸附平衡,其吸附-解吸过程符合Freundlich方程(R20.92).在3类沉积物样品上的吸附作用强度大小依次为佳木斯沉积物达连河沉积物哈尔滨沉积物.2,4-二氯苯酚在3种沉积物上吸附-解吸滞后系数(HI)都小于1,说明2,4-二氯苯酚的解吸行为存在较为明显的滞后现象,HI值大小依次为:哈尔滨达连河佳木斯.HI值与沉积物理化性质成正相关(R20.444).     

溶解性有机质对土壤中Cd解吸和植物富集的影响

研究鸡粪、秸秆及腐殖土等溶解性有机质(DOM)对土壤中Cd解吸的影响,结合盆栽试验,分析不同DOM对植物生长和富集Cd的影响。结果表明:DOM对土壤中Cd具有较强的解吸作用,当DOM的添加量为30mL、温度为20～25℃、提取时间为4h时解吸效果最佳;三种DOM相比,鸡粪DOM对Cd的解吸效果最优,其次是腐殖土和秸秆DOM;向土壤中添加DOM不仅可促进植物的生长,而且明显提高超富集植物红叶甜菜对Cd的富集系数;鸡粪DOM在促进植物富集Cd方面的作用最强。实验结果可为Cd污染土壤的植物修复提供理论依据。     

农药废液中氧乐果及其中间体土壤吸附系数和降解速率的测定

应用美国国家环境保局(EPA)建议试验条件和规程,测定了含铵磷农药废液中氧乐果及其合成中间体(氧硫磷酯) 在3 种供试土壤中的吸附系数和降解速率;分析了土壤有机质含量对其吸附和降解性能的影响.从而为其做为肥料资源化利用提供了重要的环境影响依据,也为它们在土壤环境中的残留预测提出了参数     

聚偏氟乙烯多孔膜对水中刚果红的吸附性能

采用相转化法制备了聚偏氟乙烯（PVDF）多孔膜,并通过扫描电子显微镜、热重⁃差热分析仪对样品的表面及断面形貌、热稳定性进行了表征。研究了PVDF膜对水中刚果红的吸附性能。结果表明,PVDF膜的最佳投加质量为30 mg;在303 K下,PVDF膜的最大吸附量为64.6 mg/g;Freundlich等温模型更适合于描述刚果红的吸附行为,吸附动力学符合准二级动力学模型;热力学参数表明PVDF膜对刚果红的吸附是自发行为且为吸热反应;乙醇对吸附过刚果红的PVDF膜具有良好的脱附效果,经过8次吸附⁃脱附,PVDF膜对刚果红仍保持较高的吸附能力。     

Influence of types and charges of exchangeable cations on ciprofloxacin sorption by montmorillonite

As one of the most important soil components, montmorillonite plays a vital role in transport and retention of organic pollutants in soils. Ciprofloxacin (CIP), an antibiotic of fluoroquiolones, has been frequently detected in water and soil environments due to its wide use in human and veterinary medicine. In this study, the adsorption of CIP onto different homoionic montmorillonite such as Na-, Ca- and Al-MMT was investigated, and the influence of types and charges of exchangeable cations in the interlayer of montmorillonite on CIP adsorption was evaluated. The results showed that different homoionic montmorillonite exhibited different sorption capacity of CIP. At pH 3, the sorption capacity of CIP decreased in the order Na-MMT > Ca-MMT > Al-MMT, following the lyotropic series. When solution pH increased to 11, the sorption capacity of CIP followed the order Ca-MMT > Al-MMT > Na-MMT. Accompanying CIP adsorption on Ca-MMT, a certain amount of Ca2+ was released into solution. Compared to pH 3, the lower Ca concentration in solution at pH 11 indicated that the adsorption of CIP on Ca-MMT at strong alkaline pH was no longer via cation exchange, and surface complexation or cation bridging might contribute to CIP adsorption. The adsorption of CIP on Na- and Ca-MMT at pH 3 and 11 resulted in the expansion of d-spacing, indicative of intercalation of CIP into the interlayer space of the montmorillonite. However, a decrease of d-spacing was observed when CIP adsorbed on Al-MMT at pH 11, which might be attributed to the dissolution of Al-CIP complex formed between CIP and Al3+ in the interlayer of montmorillonite. The results suggest that the types and charges of exchangeable cations in the interlayer of montmorillonite play an important role in CIP adsorption on montmorillonite.     

湿-载-热对粉质黏土持水性能的影响特征及预测模型

非饱和土的持水性能通常以土水特征曲线的变化规律来体现。荷载和温度等因素对土水特征曲线的重要影响已逐渐被认识,但综合考虑湿-载-热对土水特征曲线共同作用的研究鲜见报道,对其主导性影响因素的分析更为罕见。为了探究粉质黏土在湿-载-热共同作用下的持水性能,本文开展了在不同竖向应力和温度条件下粉质粘土的干湿循环实验,分析了各因素的影响机理、特征和重要性, 并建立了反映多因素共同作用的预测模型。研究结果表明：（1）随着竖向应力的增加,非饱和土的进气值增加、减湿率降低、干湿循环过程的滞回效果变强,且在各个温度下皆表现出相同的特征;（2）对比在相同的竖向应力、不同温度下的实验曲线,发现在温度较高的状态下,土体的进气值相对略低;（3）竖向应力对于土体持水性能的影响最大,但主要局限于低吸力阶段;干湿循环的作用排第二,且随着循环次数增加会快速衰减;温度的影响较小且在吸力值或密实度较高时可忽略不计;（4）基于Logistic曲线改进后的L模型比常用的V-G模型更适用于巴东粉质粘土的土水特征曲线拟合 。综合研究结果得出：竖向应力引起特征值变化的根本原因在于内部孔隙结构的改变,进而导致持水性能产生差异;温度主要影响土体处于低应力低吸力状态时的持水性能; 三种赋存条件对粉质黏土持水性能的影响程度呈竖向应力>干湿循环>温度分布;改进后的L模型可以有效反映粉质黏土在湿-载-热共同作用下的持水性能演变特征。     

Meso-macroporous Fe-doped Cu O: Synthesis,characterization, and structurally enhanced adsorption and visible-light photocatalytic activity

The meso-macroporous Fe-doped Cu O was prepared by a simple hydrothermal method combined with post-annealing. The samples were characterized by X-ray powder diffraction(XRD), scanning electron microscopy(SEM), Brunauer-Emmett-Teller N2 adsorption-desorption analyses and UV-vis diffuses reflectance spectroscopy. The Fe-doped Cu O sample shows higher adsorption capacity and photocatalytic activity for xanthate degradation than pure Cu O under visible light irradiation. In addition, the adsorption process is found to fit Langmuir isotherms and pseudo-second-order kinetics. The the first order kinetic Langmuir Hinshelwood model was used to study the reaction kinetics of photocatalytic degradation, and the apparent rate constant( k) was calculated. The value of k for Fe-doped Cu O is 1.5 times that of pure Cu O. The higher photocatalytic activity of Fe-doped Cu O is attributed to higher specific surface area together with stronger visible light absorption.     

Characterization and application of tourmaline and beryl from Brazilian pegmatite in adsorption process with divalent metals

In this study, the original tourmaline and beryl mineral samples have been collected from a Brazilian pegmatite. The objective of this study was to examine the adsorption behavior of Brazilian ciclosilicate samples, towards divalent metals (Pb²⁺, Mn²⁺, and Zn²⁺) in ethanol solution has been studies by a batch technique. The ciclosilicate samples were characterized by elemental analysis, Fourier transform infrared spectroscopy, helium picnometry, mercury porosity, and nitrogen adsorption–desorption. The Langmuir expression for adsorption isotherm was applied in order to determine the adsorption capacity to form a monolayer and the constant related to the adsorption intensity. In aqueous solution there was a significant adsorption increase with the temperature and pronounced synergistic effects were observed. The maximum number of moles adsorbed was determined to be 12.48 and 11.49 mmol/g for systems Pb²⁺/beryl and Pb²⁺/tourmaline, respectively. The energetic effects caused by metal cations adsorption were determined through calorimetric titrations. Thermodynamics indicated the existence of favorable conditions for such Pb²⁺-, Mn²⁺-, and Zn²⁺–OH interactions.     

复合吸附剂对二级出水中溶解性有机物的吸附特性研究

使用壳聚糖（CS）和粉末活性炭（PAC）复配制备了一种复合吸附剂（CS-PAC）,用于对污水厂二级出水中溶解性有机物（DOM）的吸附,以UV254作为DOM浓度的检测参数,研究复合吸附剂对DOM的吸附性能及其动力学特性。实验结果表明,DOM去除率随吸附质浓度的增加而升高,随复合吸附剂投加量的增大和接触时间的延长先增大后趋于稳定,吸附60 min基本达到平衡,DOM最高去除率达到74.17%。吸附动力学研究表明,吸附过程更加符合Freundlich模型,由多层吸附主导;复合吸附剂对DOM的吸附过程适合用二级动力学描述,主要吸附作用为化学吸附。     

Synthesis of modified D401 chelating resin and its adsorption properties for Pb^2＋

A novel chelating resin with sulfonic group was synthesized by chemical modification of D401 resin with sulphonation reaction and characterized by FT-IR spectrometry. The adsorption properties of the novel chelating resin for Pb²⁺ were studied by batch adsorption, and the adsorption process was analyzed from thermodynamics and kinetics aspects. The adsorption mechanism of Pb²⁺ on the modified D401 chelating resin was discussed by FT-IR spectrometry. Experimental results show that in the Pb²⁺ concentration range of 200–400 mg/L, the adsorption capacities of the modified D401 chelating resin for Pb²⁺ increase by 77%–129%, and Langmuir isothermal adsorption model is more suitable for the equilibrium adsorption data. Adsorption is an endothermic process that runs spontaneously. Kinetic analysis shows that the adsorption rate is mainly governed by liquid film diffusion. The best pH value under adsorption condition is 4–5. The saturated resin can be regenerated by 3 mol/L nitric acid, and the adsorption capacity remains stable after five consecutive adsorption-desorption cycles. The maximal static saturated adsorption capacity of the resin is 206 mg/g at 333 K in the Pb²⁺ concentration range of 200–400 mg/L. The modified D401 chelating resin is an efficient adsorbent for the removal of Pb²⁺ from its single-metal ion solution. Foundation item: Project(708049) supported by the Important Item Cultivation Foundation of Scientific Innovation Project of Colleges and Universities of China     

吸附汽油蒸气活性炭的制备研究

以市售活性炭和炭化料为原料,NH4NO3和K2CO3混合物为复合添加剂,水蒸汽活化法制备了汽油蒸气吸附用活性炭.通过测定活性炭的丁烷工作容量（BWC）、碘吸附值和氮吸附等温线,研究了活性炭制备条件特别是添加剂对丁烷工作容量和孔隙结构的影响.结果表明,制备条件对BWC的影响顺序依次为活化温度、添加剂用量和活化时间;较高的活化温度和较大的添加剂量均促进了活性炭中孔的发育;活性炭的BWC与中孔孔容呈明显正相关性,同时受微孔表面积和总孔容影响也较大;活性炭吸附丁烷后的首次解吸率在60%左右,循环解吸率达95%以上.     

含大尺寸块石岩土材料土水特征曲线的试验

利用压力板法对乐昌峡坝肩边坡岩土材料的土水特性进行了室内试验研究,测量并分析了含大尺寸块石的强风化岩层的土水特征曲线.首先,对于含大尺寸块石的强风化岩层,本试验依据颗粒级配配比原料,按照一定的干密度制备试样,测量了强风化重塑试样的土水特征曲线,比较了左、右岸强风化岩层的土水特性;其次,测量了全风化原状土和重塑土的土水特征曲线,对比分析了强风化岩层与全风化岩层的土水特性差异,总结了含大尺寸块石强风化材料土水特性的特点,并就试验合理性展开相关讨论;最后,拟合了各种材料的土水特征曲线,得到相关表征各材料土水特性的参数.试验研究表明:影响含大尺寸块石岩土材料土水特性的因素中,颗粒级配的影响明显强于矿物成分的影响;与全风化土质材料相比,含大尺寸块石强风化岩层试样含水量较低,残余含水率偏小,持水能力较弱,且相对于全风化岩层原状试样和重塑试样,强风化岩层重塑试样的土水特性更接近于全风化岩层重塑试样.该试验对含大尺寸块石岩土材料土水特性的试验研究进行了初步探索,试验结果对乐昌峡工程具有一定的指导意义.