阿特拉津对绿麦隆吸附-解吸作用的影响

采用批平衡实验,研究绿麦隆在单一及复合污染体系中的吸附-解吸行为。结果表明,无论是单一体系还是复合体系,吸附等温线均可用Freundlich模型进行良好的拟合。随着阿特拉津浓度的增加,土壤对绿麦隆的吸附作用降低,表明绿麦隆和阿特拉津之间存在竞争吸附,这可能与土壤的有机质类型和绿麦隆、阿特拉津的性质、结构有关。解吸实验表明,随着阿特拉津的浓度增加,绿麦隆的解吸作用增加。吸附过程的拟合指数n值大于解吸过程的对应值,即绿麦隆在不同体系中的解吸作用均存在一定的滞后性。应用Freundlich解吸等温线参数对吸附-解吸等温线的滞后作用进行量化,CT、（CT＋0.5AT）、（CT＋1AT）和（CT＋2AT）处理解吸等温线的滞后系数ω分别为165.200,146.132,94.534和85.945,即随阿特拉津浓度增加,绿麦隆解吸等温线的滞后性降低。     

p,p′-DDT在黄河兰州段沉积物上的吸附/解吸特性及影响因素研究

采用批量平衡实验,研究了黄河兰州段沉积物对p,p′-DDT的吸附/解吸特性,并考察了环境因素温度、pH值、沉积物粒度等对吸附的影响。结果表明,p,p′-DDT在黄河兰州段沉积物上的吸附在24h内可以充分达到平衡。吸附过程是非线性的,Freundlich模型可以较好地描述吸附行为,分配作用和表面吸附作用同时存在;解吸过程存在明显滞后性,即解吸要比吸附困难。正交结果表明吸附质浓度和吸附剂浓度对p,p′-DDT在沉积物上的吸附量有显著影响,而温度、pH值、有机质含量、沉积物粒度影响不显著。     

[A环-U-~(14)C]丙酯草醚在土壤中的吸附与解吸特性研究

丙酯草醚(ZJ0273)是我国拥有自主知识产权的新型高效油菜田除草剂。本文以[A环-U-14C]丙酯草醚为示踪剂,在实验室模拟条件下,采用液体闪烁测量技术对其在7种土壤中的吸附和解吸特性进行了研究。结果表明:(1)丙酯草醚在7种土壤中的吸附等温线均能极显著符合Freundlich、Langmuir和线性模型,相对而言,前两种模型的相关系数R2(0.9883~0.9998)明显高于线性模型(R2=0.9173~0.9593);(2)丙酯草醚在7种土壤中的解吸等温线能被Freundlich模型和线性模型很好地描述;(3)丙酯草醚极易被土壤吸附,不同类型的土壤对其吸附的差异较大,吸附常数KF与土壤有机质含量呈显著正相关,与之对应的解吸率极低。丙酯草醚吸附解吸过程存在明显的滞后现象,应科学合理地在有机质丰富的土壤中使用。     

澳洲坚果果仁粉水分解吸-吸附等温线的测定与分析

为给澳洲坚果果仁粉的干燥和贮藏条件的确定提供技术依据,试验测定了其在室温(25℃)下的水分解吸-吸附等温线。采用非线性回归的方法,应用常见的BET、GAB、Halsey、Henderson、Oswin和Smith模型对试验所得解吸-吸附等温线进行拟合分析,以确定最佳拟合模型及其参数。结果表明,其解吸等温线属于国际理论和应用化学联合会分类的第Ⅱ种类型,其吸附等温线属于第Ⅲ种类型,解吸-吸附滞后现象属于H3型;GAB模型是其最佳的解吸等温线拟合方程,Henderson模型是最佳的吸附等温线拟合方程;GAB模型拟合解吸等温线的参数A、B、C分别为8.2439、0.4815、1.3545。Henderson模型拟合吸附等温线的参数A、B分别为0.3006、0.8682。     

稻谷水分吸附与解吸等温线拟合模型的选择及其参数优化

评价5种最常用的数学模型对中国不同类型的稻谷(籼稻、粳稻、糯稻)吸附与解吸等温线数据的拟合效果，以确定最佳拟合模型及其参数。测定中国不同类型稻谷的吸附与解吸等温线数据，用非线性回归进行统计分析并评价数学模型的拟合效果。结果表明，美国农业工程学会(ASAE)推荐的修正Chung-Pfost模型及其参数并不能与中国稻谷的吸附与解吸等温线数据很好地拟合。Strohman-Yoerger模型最适于拟合籼稻、粳稻的吸附与解吸等温线及糯稻的吸附等温线。而修正Oswin模型最适合拟合糯稻的解吸等温线。Strohman-Yoerger模型拟合籼稻、粳稻吸附等温线的参数C₁、C₂、C₃、C₄分别为1.44871、0.20898、7.32345、0.18647；拟合解吸等温线的参数C₁、C₂、C₃、C₄分别为2.25071、0.24167、8.32543、0.19035；拟合珍糯吸附等温线的参数为1.55680，0.19179，6.19676，0.17155。修正Oswin模型拟合珍糯的解吸等温线的参数为13.63642，-0.05638，3.60042。本研究为中国的稻谷贮藏与加工提供了基础性数据。     

土壤/沉积物中全氟辛酸(PFOA)、全氟辛烷磺酸(PFOS)吸附–解吸行为研究进展

全氟辛酸(PFOA)和全氟辛烷磺酸(PFOS)在土壤/沉积物–水中分配、吸附–解吸作用是影响其在环境中的残留浓度、迁移、转化及生物可利用性、毒性等的重要因素之一。本文对土壤/沉积物中PFOA、PFOS吸附–解吸行为影响因素,吸附–解吸机理,常用的土壤/沉积物中PFOA、PFOS吸附/解吸等温线方程、常数及参数等的研究情况进行综述,吸附–解吸过程Freundlich方程的相关系数为0.74~0.99,线性方程的相关系数为0.91~0.99。PFOS在土壤/沉积物中吸附常数logKoc的平均值为3.0,变异系数为23.3%;解吸常数logKoc的平均值为1.8,变异系数为15.4%。PFOA在土壤/沉积物中吸附常数logKoc的平均值为2.1,变异系数为45.6%;解吸常数logKoc的平均值为5.4,变异系数为52.3%。实验室基础上计算所得吸附常数logKoc比野外条件下实测数据计算值(PFOA为3.7,PFOS为4.2)小,野外条件下土壤/沉积物中PFOA和PFOS吸附–解吸过程和土壤–植物共生系统对其污染控制效应有待于进一步研究。     

土壤/沉积物中天然有机质对疏水性有机污染物的吸附作用

通过对土壤/沉积物中天然有机质的组成分析,阐述了天然有机物在吸附疏水性有机污染物过程中所起的重要作用,其中包括可溶性有机质的增溶作用和不溶性有机质的吸附作用。本文着重探讨了天然有机质结构的异质性对吸附作用的影响,导致吸附等温线的非线性,从而从土壤/沉积物有机质的微观结构上进一步解释了非线性吸附机理。     

萘在土壤上的吸附行为及温度影响的研究

采用批量平衡法研究了多环芳烃萘在塿土耕层土、塿土粘化层土、塿土古土壤、黄壤、紫色土和石灰土上的吸附行为,比较了不同吸附模型方程对实验数据的拟合情况,并探讨了温度对萘在土壤上吸附行为的影响机理及吸附热力学特征。Henry模型、Freundlich模型和deBoer-Zwikker极化模型均能较好地拟合萘的吸附等温线;45℃下的吸附等温线明显地高于25℃的吸附等温线,表现出随温度升高吸附量增大的趋势。Freundlich模型的吸附容量参数Kf和deBoer-Zwikker模型的起始吸附势ε0在两个温度下有极显著的差异;但Freundlich模型的n参数表征了土壤颗粒表面的性质,对温度变化不敏感。在25℃条件下,萘在土壤有机碳上的分配可能是吸附的主要机制,但随着温度增加,吸附机制变得复杂。土壤对萘的吸附是一吸热反应,整个吸附体系中熵增是吸附作用进行的主要驱动力。     

土壤中黑碳对农药敌草隆的吸附-解吸迟滞行为研究

采用批处理振荡法和连续稀释法分别测定了敌草隆在人工添加黑碳土壤和自然形成的不同有机质和黑碳含量的土壤中的吸附一解吸行为。吸附结果表明，人工添加黑碳的土壤对敌草隆的吸附强度和吸附容量以及吸附等温线的非线性均随土壤黑碳添加浓度的增加而逐步增大；自然土壤的吸附容量和吸附强度随土壤总有机质含量增加而增加，但吸附等温线的非线性则与土壤中黑碳对有机质的相对含量有关，黑碳比例越高，等温线非线性越大。解吸实验结果表明，无论是人工添加黑碳的土壤还是自然土壤，对敌草隆的解吸迟滞作用均随土壤黑碳含量增高而愈明显。     

对硝基氯苯在土壤和腐殖酸上的长期吸附与多步解吸的研究

采用批量平衡实验法研究了对硝基氯苯（p-NCB）在土壤和腐殖酸上的长期吸附和多步解吸,比较了连续的多步解吸与一步解吸的差异。结果表明,随着吸附时间的增加吸附量均会有所增加,随吸附时间增加吸附等温线的非线性增强。p-NCB在液相和固相上的初始浓度对吸附速率有一定影响,低浓度比高浓度时达到平衡的速率要低。对于两种受试土壤,两次解吸得到的等温线均无法与吸附等温线重合,表现出很强的吸附不可逆性。而尽管p-NCB在腐殖酸上表现出明显的非线性吸附（n = 0.794）,但4次解吸后所得到的平衡位点与吸附所得的平衡位点基本落在同一条直线上,对数坐标下进行线性拟合的相关系数（R2）可达0.988,说明吸附过程是完全可逆的。     

The Role of Soil Properties in Pyrene Sorption and Desorption

Soil type will greatly affect the sorption and subsequent desorptionof hydrophobic contaminants. To gain a better understanding of theimpact of soil type on sorptive behavior, the sorption-desorption of pyrene (PYR) with three different soils was studied. The first soil originated from Colombia and is classified as silty sand with3.54% soil organic matter (SOM) and 18% clay materials (<2 microns). The New Mexico soil is a sandy lean clay comprisedof 8.4% SOM and 10% clay. The last soil originated fromOhio and is a silty sand with 1.84% SOM and 9.6% clay. Based on soil mineralogy and sorption-desorption isotherms,the Colombia soil had the greatest binding potential followedby the New Mexico and Ohio soils. The Freundlich model couldfit both the Colombia and New Mexico soils. For the Ohiosoil, a two-stage Freundlich model was required. For allthree soils, PYR desorption was slow and resistant, anddepicted an apparent hysteresis. The extent of sorption-desorption for each soil was attributed to its individual classification.For instance, the SOM present in the New Mexico soil (8.4%) enabled a relatively easy desorption in comparison to the other two soils. For the Ohio and Colombia soils, the interaction with the clay fractions rendered a stronger sorptive bond.     

金霉素在不同耕作土壤中的吸附－解吸行为

用批平衡吸附试验研究了金霉素在河南封丘潮土、南京黄棕壤、常熟水稻土和江西鹰潭红壤4种土壤中的吸附行为。结果表明,金霉素的土壤吸附-解吸行为均可用Freundlich模型和Langmuir模型进行良好的线性拟合。其Kf值差异较大,分别为潮土1135Lkg-1,黄棕壤1250Lkg-1,水稻土2618Lkg-1和红壤4315Lkg-1,显示金霉素在4种土壤中的吸附行为存在较大的差异。此外,金霉素在4种土壤上的解吸过程存在明显的滞后现象。研究还表明4种土壤中金霉素的吸附参数Kf值与土壤pH呈显著负相关。     

天然土壤对BDE-47的吸附特征

研究了BDE-47在3种不同有机质含量的天然土壤上的吸附行为,包括吸附过程动力学和热力学等温线。结果表明,双室一级动力学模式较单室一级动力学模式更适于描述BDE-47在天然土壤上的吸附过程动力学特征,尤其是在吸附初始阶段（0-49h）。快吸附在自吸附初始到表观吸附平衡的整体吸附过程中占据优势地位,而慢吸附的贡献率则逐渐增加并在97h后达到相对稳定。快吸附达到其吸附容量的时间远快于慢吸附。在吸附开始阶段的3~5h,BDE-47吸附总量的增加主要决定于快吸附,但在后续的吸附阶段,慢吸附的影响逐渐成为主导。因BDE-47水相溶解度很低,在较窄的平衡浓度范围内,线性分配模式和非线性Freundlich模式对BDE-47的吸附等温线都能提供很好的拟合结果。在Freundlich模型结果中,具有较低（0.72%）和较高（7.90%）TOC分数的土样的非线性指数n都明显低于1.0（分别为0.75±0.03和0.74±0.02）,表明2种土样在相应的BDE-47平衡浓度范围内表现出一定的非线性吸附特征;而另一TOC分数居中（2.86%）的土样则表现出显著的线性行为,其非线性指数n明显接近1.0（1.03±0.03）。     

Dicyandiamide sorption-desorption behavoir on soils and peat humus

The sorption-desorption behavior of dicyandiamide (DCD) is an important chemical process that affects DCD fate and mobility in soils. Therefore, this study quantified DCD sorption-desorption on a phaeozem (Mollisol), a burozem (Alfisol), a soil with organic matter-removed and peat humus using the batch-equilibration procedure, and identified soil properties that influenced DCD sorption. The sorption on peat humus was higher than that on the phaeozem and the burozem, with much lower sorption observed on the soil with organic matter-removed, indicating that soil organic matter was the main carrier of DCD sorption. Due to its amphipathic property the DCD molecule sorption on the phaeozem and the burozem decreased as pH increased from about 2 to 5, but a further increase in pH led to a rise in DCD sorption.The DCD desorption hysteretic effect for peat humus was greater than that for the phaeozem and the burozem using 0.01 mol L^-1 CaCl2 as the background electrolyte, suggesting that the hydrophobic domains of organic matter may play an important role in DCD sorption.     

Sorption and desorption behaviors of diuron in soils amended with charcoal

Charcoal derived from the partial combustion of vegetation is ubiquitous in soils and sediments and can potentially sequester organic contaminants. To examine the role of charcoal in the sorption and desorption behaviors of diuron pesticide in soil, synthetic charcoals were produced through carbonization of red gum (Eucalyptus spp.) wood chips at 450 and 850 degrees C (referred to as charcoals BC450 and BC850, respectively, in this paper). Pore size distribution analyses revealed that BC850 contained mainly micropores (pores approximately 0.49 nm mean width), whereas BC450 was essentially not a microporous material. Short-term equilibration (< 24 h) tests were conducted to measure sorption and desorption of diuron in a soil amended with various amounts of charcoals of both types. The sorption coefficients, isotherm nonlinearity, and apparent sorption-desorption hysteresis markedly increased with increasing content of charcoal in the soil, more prominently in the case of BC850, presumably due to the presence of micropores and its relatively higher specific surface area. The degree of apparent sorption-desorption hystersis (hysteresis index) showed a good correlation with the micropore volume of the charcoal-amended soils. This study indicates that the presence of small amounts of charcoal produced at high temperatures (e.g., interior of wood logs during a fire) in soil can have a marked effect on the release behavior of organic compounds. Mechanisms of this apparent hysteretic behavior need to be further investigated.     

磺胺嘧啶在黑土及其不同粒径组分中的吸附行为研究

采用批平衡吸附试验法,研究了磺胺嘧啶在黑土及其不同粒径中的吸附行为。结果表明,磺胺嘧啶的吸附不同程度地偏离线性模型,但均可用Freundlich模型和Langmuir模型进行良好地线性拟合。黑土（〈0.2mm）及其不同粒径（粘粒：〈0.002mm、粉粒：0.002~0.02mm、砂粒：0.02~0.2mm）的Freundlich容量因子Kf值分别为29.6、53.1、32.9L.kg-1和21.6L.kg-1,说明磺胺嘧啶在黑土及其不同粒径中的吸附行为存在差异。将吸附参数Kf进行碳标化处理后,Koc值除粉粒外,其他基本一致。随着溶液pH的持续增加（1.0~10.0）,黑土及其不同粒径中的磺胺嘧啶的吸附参数lgKf呈现先急剧降低然后稍微回升的趋势,由此推测,阳离子交换作用可能是磺胺嘧啶土壤吸附的重要机制。过氧化氢处理去除土壤有机质后,黑土的Kd值从1.92L.kg-1降为1.22L.kg-1,磺胺嘧啶的吸附量由16.5mg.kg-1降低到11.2mg.kg-1,说明有机质含量也是影响磺胺嘧啶吸附行为的重要因素。     

Sorption and desorption characteristics of sulfamethazine in three different soils before and after removal of organic matter

Organic matter (OM) is the most critical factor in controlling the sorption-desorption of SMZ in soil, however, few studies have explored the effects of OM removal on these important behaviors among different soils. Batch experiments were conducted to investigate the sorption and desorption characteristics of SMZ in three different soils: fluvo-aquic soil (FS), paddy soil (PS), and red soil (RS). The SMZ sorption in the evaluated soils was dominated by physisorption. The SMZ sorption capacities of FS and PS, which had a relatively higher OM content than RS, were higher than that of RS. The SMZ sorption in FS was dominated by linear partitioning. In contrast, the SMZ sorption in PS and RS was mainly nonlinear surface adsorption. After OM removal, the SMZ sorption capacity was significantly reduced in FS but increased in PS and RS. Furthermore, OM removal restrained the sorption intensity of SMZ in soils. Relatively higher OM and clay contents inhibited the SMZ desorption in FS and PS. The strong negative desorption hysteresis of SMZ in the three soils indicated that SMZ was able to move into the soil solution, thereby posing a risk to humans. Taken together, the findings of this study showed that OM indeed plays an important role during SMZ sorption-desorption in soil.     

四环素在土壤中的吸附与解吸以及镉在其中的影响

采用批平衡实验方法,研究了四环素（TC）在褐土和红壤中的吸附和解吸,以及Cd2＋对四环素在两种土壤上吸附和解吸的影响。结果表明,四环素在褐土和红壤中的吸附可以用Freundlich等温吸附方程拟合,所得lgKf分别为3.039和3.169,这表明四环素在红壤中的吸附能力较强。此外,四环素在两种土壤上的解吸过程都存在滞后现象,所得lgKf,des分别为3.292和3.877,这将可能威胁到土壤环境和人体健康。常见重金属Cd2＋的存在会促进四环素在两种土壤上的吸附,在红壤中表现显著（P〈0.05）;同时红壤中四环素的lgKf,des有所增加,而在褐土中的变化不大。     

Effect of soil properties on the degradation of isoxaflutole and the sorption-desorption of isoxaflutole and its diketonitrile degradate

The transformation of isoxaflutole (ISOX) to its herbicidally active diketonitrile degradate (DKN) was significantly enhanced in the presence of soil and occurred more rapidly in systems containing soil with a greater soil pH. Sorption-desorption of ISOX and DKN in five soils collected within a field revealed both ISOX and DKN were more readily sorbed to soils with greater organic matter, clay content, and lower soil pH. Sorption of ISOX residues occurred within 2 h, and extracts contained similar concentrations of ISOX and DKN at 24 h, suggesting the 24-h sorption coefficients for ISOX-treated systems were actually for mixed ISOX residues. Freundlich sorption coefficients were 3 and 4 times greater for ISOX than for DKN. On the basis of the Freundlich organic carbon sorption constants, ISOX and DKN can be categorized in the very high and high mobility classes, suggesting their potential to leach in the soils needs to be evaluated.