某极低放废物处理场地下水中Sr迁移形式热力学分析

将化学热力学平衡分析模式与地球化学条件相结合,形成Sr元素水文地球化学迁移形式热力学分析方法体系.计算出某特定场址地下水中Sr的化学形态和迁移形式.结果表明,Sr2 迁移形式占总量的99.38%,SrHCO3 形式占0.55%,SrCO03占0.019%.     

针铁矿吸附诺氟沙星特征的研究

根据OECD Guideline 106批平衡实验.分别研究了pH值对针铁矿吸附诺氟沙星的动力学特征和吸附量的影响以及诺氟沙星的吸附热力学特征,并探讨了其可能吸附机理.结果表明,不同pH值(3.5,5.0,5.6和6.2)时,诺氟沙星在经历了约6h的快速吸附阶段后,均进入缓慢吸附阶段,吸附平衡时间为48h.伪二级动力学方程能够较好地描述不同pH值条件下诺氟沙星针铁矿上的吸附动力学特征. 影响吸附量大小的pH值依次为5.6>5.0>6.2>3.5,主要决定于诺氟沙星和针铁矿的不同形态间的乘积之和,针铁矿表面的吸附作用主要以诺氟沙星的兼性离子为主.吸附等温线较好地符合Freundlich方程,温度从15℃升高到35℃时,拟合系数1/n从0.43升至0.61,表明温度升高减弱了针铁矿对诺氟沙星的非线性吸附.ΔH0=-39.45kJ/mol和ΔG0<0表明吸附是自发进行的放热过程,且以离子交换为主,同时可能存在着偶极间作用力和氢键力等作用.ΔS0<0表明吸附过程中熵在减小.     

膨润土负载纳米铁用于降解水体中阿莫西林

采用液相还原法合成膨润土负载纳米铁(B-nZVI)和纳米铁(nZVI)并用于降解水中的阿莫西林.实验结果表明,无论是单独nZVI还是B-nZVI都能有效降解阿莫西林.在25 mL浓度为20 mg.L-1的阿莫西林溶液中加入0.1 g的B-nZVI(其中nZVI的含量为0.05 g),溶液的初始pH值为6.65,摇床的振荡速率为250 r.min-1,反应温度为25℃,反应时间为120 min的条件下,B-nZVI对阿莫西林的降解效率高达93.1%,在此实验条件下,单独nZVI(0.05 g)对阿莫西林的降解效率只有82.3%,这是由于膨润土对nZVI起到分散作用,从而使B-nZVI的反应活性得到提高.降解动力学研究表明,B-nZVI对阿莫西林的降解过程符合表观一级反应动力学规律,相关系数R2均大于0.945.B-nZVI可多次重复用于降解阿莫西林.     

MCM - 41中孔分子筛对铜离子吸附性能的研究

以MCM-41中孔分子筛（简称MCM-41）为吸附剂,对含Cu^2＋的溶液进行了静态吸附实验。结果表明：MCM-41对Cu^2＋的吸附量较大,约为283．0mg／g;Cu^2＋的去除率随吸附液pH的增大和吸附温度的升高而增加;MCM-41对Cu^2＋的吸附性能符合Langmuir吸附方程的特征;Cu^2＋的吸附过程为自发的吸热吸附过程。     

Adsorption of catechol from aqueous solution by aminated hypercrosslinked polymers

Adsorption of catechol from aqueous solution with the hypercrosslinked polymeric adsorbent NDA-100 and its derivatives AH-1,AH-2 and AH-3 aminated by dimethylamine, the commercial resin Amberlite XAD-4 and weakly basic anion exchanger resin D301 was compared. It was found that the aminated hypercrosslinked resins had the highest adsorption capacities among the tested polymers. The empirical Freundlich equation was successfully employed to describe the adsorption process. Specific surface area and micropore structure of the adsorbent, in company with tertiary amino groups on matrix affected the adsorption performance towards catechol. In addition, thermodynamic study was carried out to interpret the adsorption mechanism. Kinetic study testified that the tertiary amino groups on the polymer matrix could decrease the adsorption rate and increase the adsorption apparent activation energy.     

Thermodynamics of phenanthrene partition into solid organic matter from water

IntroductionSorptionofanorganicpollutanttosoilhasamajorinfluenceonitstransport,bioavailabilityandfateinnaturalenvironmentsanddevelopingsoilpollutionremediationtechnologies .Extensiveresearch(Chiou ,1979;1983;1985 ;1998a ;Karickhoff,1979;Kile ,1995 ;Rutherford ,1992 )suggestedthatsorptionofnonionicorganiccompounds(NOCs)fromwatertosoilisdueprimarilytothepartitioningintosoilorganicmatter(SOM ) .AdsorptionofNOCsfromwaterbyrelativelypolarsoilmineralsissuppressedbythestrongcompetitiveadsorption…     

两种盐复合改性活性氧化铝对水中氟的吸附特性

采用Fe2(SO4)3和Al2(SO4)3两种盐对活性氧化铝进行改性,通过静态吸附实验,研究了改性活性氧化铝对水中氟离子的吸附特性及影响因素.改性后的活性氧化铝吸附容量显著提高,25℃下吸附容量达到6.25 mg·g-1.改性活性氧化铝对氟的吸附动力学符合拟二级动力学模型,吸附等温线更符合Langmuir等温吸附规律.吸附过程ΔG0<0、ΔH0>0、ΔS0>0,表明改性吸附剂对氟的吸附是自发的,是吸热、熵增加的反应.吸附最佳p H值为6,吸附过程中,共存PO3-4对吸附效果影响最大.     

掺硅碳羟基磷灰石的制备及其对Pb2+的吸附性能

以废弃蛋壳、硅酸钠为原料,采用水热法制备掺硅碳羟基磷灰石(Ca10(PO4)6-x-y(SiO4)x(CO3)y(OH)2-x-y,Si-CHAP),研究其对溶液中Pb2+子的吸附性能.采用BET比表面积、红外光谱、X光衍射、扫描电镜等分析手段对样品进行表征,实验考察了pH值、反应时间以及温度等对Si-CHAP吸附Pb2+的影响.结果表明,Si-CHAP是一种具有较大比表面积的介孔材料,其比表面积为323.25m2/g.Pb2+初始浓度为300mg/L并加入2g/L的吸附剂,室温下反应时间90min后,Si-CHAP对溶液中铅离子去除率和吸附容量分别为99.39%和149.09mg/g. Langmuir等温吸附方程能较好描述铅离子在Si-CHAP上的吸附平衡,准二级动力学方程式描述铅离子在Si-CHAP上吸附的最佳吸附动力学模型,热力学参数表明Si-CHAP吸附铅离子是自发、吸热和熵值增加过程.     

Non-equilibrium phenomena in carbon dioxide expansion

Release of liquid and supercritical carbon dioxide is a fundamental research topic in CCS. Traditional approach is largely based on HEM and, in general, assumes equilibrium from the outlet to the Mach disc. Experimental results have shown that this approach is not always effective in describing the expansion phenomenon; therefore a significant lack of knowledge exists about CO₂ properties at the under-expanded jet zone boundary, which is a main focus in process safety. Here, solid formation, vapour quality, sonic velocity and final temperature are generally calculated according to equilibrium saturation condition, and this is generally incorrect. This article deals with non-equilibrium thermodynamics of liquid and supercritical CO₂ expansion, illustrating relaxation dynamics through the HRM models, and discussing the very specific singularities of CO₂ phase transitions, vapour to liquid and liquid to solid, that result away from the equilibrium condition, due to the rapid phase changes and to the specific properties of CO₂ multi phase thermodynamics, including nucleation and particle growth. Statistical rate theory has been applied with the aim at identifying the phase transition energy barrier, resulting in a significant entropy increase. A case study based on HEM conservation equations integrated with the statistical rate approach has been presented, which covers the gap of the equilibrium hypothesis. The objective of the article is to provide a more accurate method to predict the properties of carbon dioxide following an expansion.     

山茶籽粉吸附亚甲基蓝的性能研究

为研究山茶籽粉对亚甲基蓝的吸附行为,对不同温度下(298、303、308、313、318K)的吸附数据分别用Langmuir、Freundlich和Dubinin-Radushkevish模式进行拟合,用伪一级动力学方程和伪二级动力学方程描述山茶籽粉对亚甲基蓝的吸附动力学过程,并计算了Gibbs自由能变(ΔGθ)、焓变(ΔHθ)和熵变(ΔSθ)等热力学函数.结果表明,山茶籽粉对亚甲基蓝的吸附能力随着温度的升高而降低;Langmuir方程更适合描述其吸附行为.Gibbs自由能变(ΔGθ)、焓变("Hθ)和熵变(ΔSθ)均小于零,说明此吸附过程是自发进行的、放热的、趋于有序的吸附过程.伪二级动力学方程更适用于描述山茶籽粉对亚甲基蓝的吸附动力学过程.