Comparative Study of the Adsorption Thermodynamic Parameters Estimated through Different Approaches

The equilibrium constant （K0）, change in free energy （△G）, enthalpy （△H） and entropy （△S） of ammonium adsorption by a Cuban natural zeolite were estimated at the temperatures of 25, 35, 45 and 55℃ using extensively used approaches. Equilibrium data were obtained in the concentration range 50-1,200 mg·L-1 of ammonium and used in the estimation of thermodynamic parameters. Freundlich＇s isotherm model was found as with the best adjustment to equilibrium data at 25, 45 and 55℃, whereas, Redlich-Peterson＇s model had a better performance at 35 ℃. A discontinuous and unusual behavior was observed on adsorption capacity of the zeolite, with an increase from 25 ℃ to 35 ℃ followed by a decrease from 35℃ to 55 ℃. K0 values presented differences that reached up to 105 from one methodology to other. Depending on the method considered, AS results indicated both increase or decrease in system degree of disorder and △G indicated both physisorption or chemisorption process, proving the poor correlation between the estimation proceedings of such important data. The results from Gaines and Thomas method were recognized as the most correlated to calorimetric studies, as well as to equilibrium data and observations related to system entropy.     

Process design for gas condensate desulfurization and synthesis of nano-13X zeolite adsorbent: equilibrium and dynamic studies

This paper summarizes the results of a study of adsorption of sulfur compounds from a high-sulfur feed on improved spherical-shaped nano-AgX zeolite. For this purpose, the nano-AgX zeolite was initially synthesized and improved with silver compounds such as silver nitrate, and then it was utilized in the adsorption process. In order to investigate the equilibrium and dynamics of the adsorption process, adsorptive desulfurization of real feed(i.e., sour gas condensate from the South Pars gas field) was carried out in batch and continuous processes under several operating conditions; a temperature-dependent Langmuir isotherm model was used to fit the equilibrium data. The value of monolayer adsorption capacity(q_m) and adsorption enthalpy(ΔH) were calculated to be 1.044 mmol/g and 16.8 kJ/mol, respectively. Furthermore, a detailed theoretical model was employed in order to model the breakthrough experiments. The results revealed that an increase in the feed flow rate and 1/T values will cause linear and exponential increase in the total mass transfer coefficient(ks). Isotherm and dynamic breakthrough models were found to be in agreement with the experimental data.     

Performance improvement of ionic surfactant flooding in carbonate rock samples by use of nanoparticles

Various surfactants have been used in upstream petroleum processes like chemical flooding. Ultimately, the performance of these surfactants depends on their ability to reduce the interfacial tension between oil and water. The surfactant concentration in the aqueous solution decreases owing to the loss of the surfactant on the rock surface in the injection process. The main objective of this paper is to inhibit the surfactant loss by means of adding nanoparticles. Sodium dodecyl sulfate and silica nanoparticles were used as ionic surfactant and nanoparticles in our experiments, respectively. AEROSIL~? 816 and AEROSIL~?200 are hydrophobic and hydrophilic nanoparticles. To determine the adsorption loss of the surfactant onto rock samples, a conductivity approach was used. Real carbonate rock samples were used as the solid phase in adsorption experiments. It should be noted that the rock samples were water wet. This paper describes how equilibrium adsorption was investigated by examining adsorption behavior in a system of carbonate sample(solid phase) and surfactant solution(aqueous phase). The initial surfactant and nanoparticle concentrations were 500–5000 and 500–2000 ppm, respectively. The rate of surfactant losses was extremely dependent on the concentration of the surfactant in the system, and the adsorption of the surfactant decreased with an increase in the nanoparticle concentration. Also, the hydrophilic nanoparticles are more effective than the hydrophobic nanoparticles.     

Defluorination of Wet-Phosphoric Acid： Equilibrium and Kinetic Studies

This study describes the advantages of using iron-oxide-pillared MF （montmorillonite） and EDTA （ethylenediaminetetraacetic acid）-pillared MD （montmorillonite） for the removal of fluoride in the phosphoric acid. The MF and MD were characterized by using BET （Brunauer-Emmett-Teller） and SEM （scanning electron microscope） for there to appreciate their textural and structural properties and in order to appraise their capacity in the fixation of the fluorine experimental results of fluorine adsorption show a defluoration of the phosphoric acid passing beyond 90% with both clays with a light performance for the MD. The kinetics of fluorine adsorption on MF and on MD has been measured at different temperatures. Indeed, the adsorbed quantity increases more favorably to temperatures more high. This kinetics could be described by two models： pseudo-first-order or pseudo-second-order, which depends on temperature and the nature of adsorbent. At different temperatures used and with various adsorbents （MD and MF, the pseudo second order model was the most reliable to determine the order of kinetics of adsorption of fluorine, which is also reflected a good correlation coefficient （above 0.99）. The fluoride sorption was reasonably explained with Langmuir or Freundlich isotherms. Thermodynamic parameters such as AG~, AH~, AS~ and kinetic one E,, （apparent activation energy） were calculated in order to understand the nature of sorption process. Results indicate that the mechanism of adsorption of the ion of fluoride on the pillared montmorillonite is an exothermic reaction. During equilibrium conditions, both the systems showed negative Gibbs energy, which indicates stability of system. The values of apparent activation energy for the both clays show that the adsorption of F ions is easier on the MF.     

Effects of U-ore on the chemical and isotopic composition of products of hydrous pyrolysis of organic matter

In order to investigate the impact of U-ore on organic matter maturation and isotopic fractionation,we designed hydrous pyrolysis experiments on Type-II kerogen samples,supposing that the water and water–mineral interaction play a role.U-ore was set as the variable for comparison.Meanwhile,anhydrous pyrolysis under the same conditions was carried out as the control experiments.The determination of liquid products indicates that the presence of water and minerals obviously enhanced the yields of C_(15+) and the amounts of hydrocarbon and nonhydrocarbon gases.Such results may be attributed to waterorganic matter reaction in the high-temperature system,which can provide additional hydrogen and oxygen for the generation of gas and liquid products from organic matter.It is found that δD values of hydrocarbon gases generated in both hydrous pyrolysis experiments are much lower than those in anhydrous pyrolysis.What is more,δD values are lower in the hydrous pyrolysis with uranium ore.Therefore,we can infer that water-derived hydrogen played a significant role during the kerogen thermal evolution and the hydrocarbon generation in our experiments.Isotopic exchange was facilitated by the reversible equilibration between reaction intermediaries with hydrogen under hydrothermal conditions with uranium ore.Carbon isotopic fractionations of hydrocarbon gases were somehow affected by the presence of water and the uranium ore.The increased level of i-C_4/n-C_4ratios for gas products in hydrous pyrolysis implied the carbocation mechanism for water-kerogen reactions.     

Biodegradation of Petroleum Hydrocarbon by Pseudomonas Aeruginosa

A bacterial strain of the genus Pseudomonas aeruginosa was inoculated into a hydrocarbon culture medium and incubated for a definite period of time. The ability of the bacterial strain to biodegrade a hydrocarbon, viz. n-hexadecane, was evaluated through determining the hexadecane concentration in the inoculated culture medium on a gas chromatograph (GC). The effect of pH value on the degrading ability of the bacterial isolate and the impact of temperature on microbial growth were also explored. Test results showed that Pseudomonas aeruginosa was markedly effective in biodegrading n-hexadecane. Furthermore, the ability of Pseudomonas aeruginosa to biodegrade n-hexadecane was different at various pH values. Pseudomonas aeruginosa provided excellent degrading ability at a pH value of 7.0. The microbial cells of Pseudomonas aeruginosa increased with an increasing incubation duration at temperatures ranging from 28 ℃ to 35 ℃, and an exponential phase of microbial growth was observed.     

Study of asphaltene dispersion and removal for high-asphaltene oil wells

Many wellbores are blocked by asphaltene deposits,which lead to production problems in the oilfield development process.In this paper,methods such as elemental analysis,and solvent extraction are adopted for the study of wellbore blockages.The content of organic matter in blockages is higher than 96% and asphaltene is the main component of the organic matter with n-heptane asphaltene content of 38%.Based on the above analyses,an agent for asphaltene dispersion and removal(named as SDJ) was developed.The performance of the SDJ agent was evaluated,and it was found that the dissolution rate of asphaltene can reach 2.9 mg.mL-1.min-1 at 60 oC.SDJ agent(1wt%) was added to crude oil with a colloid instability index greater than 0.9 can effectively inhibit asphaltene deposition in the wellbore.By the viscosity method,the dissolution amount of SDJ agent was calculated,and it was found that when the viscosity of the system is around 2,000 mPa.s(the common viscosity of crude oil),the amount of SDJ agent added to the blockage was at least 96 g per 100 g blockages.Therefore,SDJ agent has promising application for dispersion and removal of asphaltene deposition in high-asphaltene wells.     

Adsorption of Aqueous Solution of O-Xylene on Modified Halloysite Adsorbents

In this study, the adsorption of o-xylene was investigated using modified halloysite adsorbents. The modification of the halloysite adsorbents depended on thermal processing, treated sulphuric acid（Vl） and sodium hydroxide, water solution of ammonium chloride as well as hexadecylotrimethyloammonium bromide. Adsorption rate constants of the pseudo-second order models were compared for experiment carried in the batch system. Langmuir and Freundlich to fit the adsorption equilibrium experimental data. pseudo-first and models were able     

Adsorption Studies of Chlorpropham and 3-Chloroaniline on Chemically Activated Halloysite

Chemically modified halloysite proved to be an effective adsorbent for the pesticide chlorpropham and 3-chloroaniline from an aqueous solution. Adsorption experiments were conducted using such procedures as the time-dependent （kinetic） procedure and the concentration dependent （isotherm） procedure. Results indicate that the adsorption process is related to the kind of the studied compound. The equilibrium data are well suited to a Freundlich isotherm in the case of both investigated compounds. Adsorption kinetics of chlorpropham and 3-chloroaniline on acid-treated halloysite was successfully described by pseudo-second order kinetic model and the model of Weber and Morris. From the present study, we suggest that the adsorption of chlorpropham and 3-chloroaniline on the modified halloysite is a rather complex process involving two steps： external mass transfer and intra-particle diffusion.     

Effects of Nitrogen-Containing Biodegradation Enhancers on Sorption of n-Hexadecane in Soil-Water System

Effects of nitrogen-containing biodegradation enhancers(methyl diethanolamine oleate(MDEAO) and oleic diethanolamide(ODEA)) on the adsorption of n-hexadecane in soil were studied by laboratory batch experiments. The partition coefficients(K_d values) of n-hexadecane sorption in soil-water system and those partition coefficients normalized to organic matter(K_(oc) values) were both determined. The adsorption isotherm curve of n-hexadecane in soil-water system was plotted. The measured results demonstrated that K_(oc) values changed in the soil-water system with different enhancers but are relatively invariant for the soil at the same site. The K_d values rose with the increase of the organic matter content in different soil. The average values of K_(oc) in the soil-water system with MDEAO, ODEA,and blank soil were 0.412, 0.252,and 0.309, respectively. The critical micelle concentration of ODEA and MDEAO was 0.7 mg/L and 1.9 mg/L, respectively,denoting that the solubilization capacity of ODEA was much stronger than MDEAO in the soil-water system. Consequently,the adsorption of MDEAO onto the solid surface increased the organic matter content in soil,which could make it more effective in enhancing the n-hexadecane adsorption. On the contrary, ODEA could inhibit the adsorption of n-hexadecane because of its less adsorption rate onto the soil particle surface and higher concentration in the soil-water system. According to the correlation coefficients, it was found that both the Henry linear and the Freundlich nonlinear isotherm sorption models were fitted to the data very well, however the Freundlich model was better than the Henry model.     

油酸二乙醇酰胺对润滑油在水-土体系中吸附行为的影响研究

采用振荡平衡法对含油酸二乙醇酰胺（简称ODEA）润滑油在水-土体系中的吸附行为进行研究,考察在水-土体系中含ODEA润滑油的吸附动力学特征及其吸附等温曲线。结果表明：润滑油及含ODEA润滑油均能较快地被土壤吸附,吸附动力学曲线符合Lagergren伪二级动力学方程,吸附等温曲线符合Freundlich和Henry吸附等温模型;ODEA可以抑制润滑油在土壤中的吸附量和吸附速率,ODEA质量浓度为4 mg/L时,抑制吸附效果最为显著。     

Reduction of organic matter from municipal wastewater at low cost using green synthesis nano iron extracted from black tea: Artificial intelligence with regression analysis

Nanotechnology especially green synthesis nanoparticles is the modern technology for the adsorption and degradation a wide range of wastewater contaminants. The prepared Green Synthesis nano Zero Valent Iron (GT-nZVI) extracted from soft black tea was characterized using XRD, SEM, and EDAX analysis. This study explores different nonlinear adsorption and kinetic models that can describe the adsorption mechanism of organic matter represented in COD and BOD onto GT-nZVI. The effect of GT-nZVI on COD and BOD removal were studied at different pH, adsorbent dose, contact time, stirring rate, and concentrations. The results indicated that GT-nZVI is effective in the removal of COD and BOD from wastewater, where the removal efficiencies of 87.9 and 100% were achieved for 600 ± 15.0 and 100 ± 11.8 mg/L COD, respectively, and 91.3 and 100% for 365 and 60 mg/L BOD, respectively. Also, GT-nZVI is a highly effective material for wastewater contaminants removal and pass the Egyptian Ministerial Resolution No. 92 of 2013 limits with Operating and Maintenance Cost 0.440 $ USD. The adsorption isotherm data of COD and BOD fitted well to Freundlich and khan, respectively, and Pseudo Second Order kinetic model. Artificial neural network importance data agree with the result of response surface methodology in simulating the adsorption of organic matter onto GT-nZVI indicating the most significant coverable is adsorbent dose. Finally, this study appropriates using GT-nZVI in highly salted municipal wastewater rather than traditionally activated sludge treatment techniques.     

吸附树脂对山竹黄酮化合物吸附特性的研究

研究了S-8、LSA-5B、X-53种吸附树脂分离纯化山竹夹层中黄酮类化合物的静态吸附过程。吸附动力学实验表明树脂吸附速率较快,1.5h基本达到吸附平衡,符合拟二级动力学吸附方程,吸附速率常数:k_(X-5树脂)>k_(LSA-5B树脂)>k_(S-8树脂)。在等温条件下,LSA-5B树脂、S-8树脂对黄酮类化合物的吸附量随初始吸附浓度的变化遵循Langmuir和Freundich吸附等温方程,X-5树脂仅遵循Freundich吸附等温方程。3种树脂的吸附自由能ΔG<0,是自发吸附。     

Experimental and modeling study of asphaltene adsorption onto the reservoir rocks

Abstract

In this work, amount of asphaltene adsorption onto the carbonate and sandstone rock samples was investigated at various initial concentrations of asphaltene in oil. Asphaltene adsorption onto both types of the reservoir rocks was increased by increasing the initial concentration of asphaltene. The amount of asphaltene adsorption onto the rock samples was predicted using Langmuir and Freundlich isotherm models. The results showed that Langmuir model had a better accuracy for prediction of asphaltene adsorption onto the rock samples than Freundlich model. Furthermore, asphaltene adsorption onto the reservoir rocks was studied in the presence of a recently developed asphaltene inhibitor. The inhibitor significantly reduced asphaltene adsorption at any initial concatenation of asphaltene. Moreover, changes in the rock permeability due to asphaltene precipitation were determined in the presence and absence of the asphaltene inhibitor.     

Adsorption and Desorption Kinetics of Naphthalene,Anthracene, and Pyrene in Soil Matrix

Abstract

The adsorption and desorption kinetics of naphthalene, anthracene, and pyrene in a soil slurry reactor at ambient conditions have been investigated to ascertain the mechanisms controlling the retention and release rates of these compounds in the soil matrix. A stirred-flow method was employed to perform the experiments. The extent of partitioning for the polycyclic aromatic hydrocarbons (PAHs) tested was found to be dependent on their solubility and diffusivity in the aqueous phase. Apparent adsorption and desorption rate coefficients were determined using the Langmuir and Freundlich isotherm models. Equilibrium adsorption and desorption at the external surface and in the internal pore of the soil particle obeyed the Freundlich isotherm equation. The pseudo-equilibrium condition established at the minimum contact time suggests that equilibrium adsorption attained for the contaminant PAHs was not instantaneous but rather time dependent.     

颗粒活性炭对地下水中溶解油的吸附特性

研究不同材质和粒径的颗粒活性炭对地下水中溶解油的吸附性能及影响因素,以确定最佳吸附条件。结果表明,颗粒活性炭对地下水中溶解油的吸附过程较好地符合Lagergren拟二级动力学方程,吸附平衡时间为300 min,椰壳制颗粒活性炭对溶解柴油和委内瑞拉原油的平衡吸附量分别为123.4 mg/g和26.81 mg/g,明显高于果壳和煤质制颗粒活性炭的平衡吸附量,且吸附量随颗粒活性炭粒径的减小而增大。吸附地下水中溶解柴油和原油的40～60目椰壳活性炭投加质量分别为0.1 g和0.06 g,吸附最佳温度是25 ℃,吸附柴油和原油的最佳pH值分别是7和8。盐度对于颗粒活性炭吸附溶解油的影响不大,碱性环境对于活性炭吸附柴油有明显的抑制作用,而酸性条件对于活性炭吸附原油有明显的抑制作用;颗粒活性炭对溶解柴油和原油的吸附分别适合Langmuir和Freundlich等温吸附模型,即颗粒活性炭表面对溶解柴油的吸附主要是单层吸附,而对溶解原油的吸附是非均匀异质的。     

活性炭臭氧化改性及其对噻吩的吸附热力学和动力学研究

 采用臭氧对椰壳活性炭、煤基活性炭进行氧化改性，研究了改性活性炭对噻吩的静态吸附热力学和动力学特征。结果表明，臭氧化改性提高了活性炭对噻吩的吸附容量和Langmuir、Freundlich 2种吸附等温线方程的相关性。根据热力学函数关系计算了等量吸附焓、吉布斯吸附自由能和吸附熵。吸附热小于0，活性炭对噻吩吸附是放热反应。采用拟一级、拟二级速率方程来考察吸附动力学，并计算了这些动力学模型的速率常数，拟二级模型和实验数据之间有较好的相关性。同时对吸附机理进行了分析。     

白土补充精制过程中环烷酸的吸附动力学、吸附平衡及热力学研究

研究了白土补充精制过程中,酮苯脱蜡油中的环烷酸在白土上的吸附问题。首先,借助电喷雾傅立叶变换-离子回旋共振质谱(ESI FT-ICR MS)对采自炼厂的酮苯脱蜡油中的环烷酸进行了分析鉴定,并对白土样品进行了XRD, BET, TG/DTA及SEM表征。其次,采用间歇操作的方式开展了一系列吸附实验,考察了温度、时间、初始酸浓度及剂油比对吸附过程的影响。Langmuir, Freundlich, Tempkin及 Dubinin-Radushkevich (D-R) 吸附模型被用于研究环烷酸在白土上的吸附平衡。同时,拟一级动力学模型、拟二级动力学模型及内扩散模型被用于研究环烷酸在白土上的吸附动力学。结果表明,D-R模型、拟一级动力学模型可分别较好地描述该过程的吸附平衡、吸附动力学行为。热力学计算数据表明该吸附过程可自发进行,且为吸热过程。本研究可为环烷酸在白土上的吸附脱除过程提供一个较为清晰的认识与理解。     

西加拿大沉积盆地二白斑页岩孔隙空间对微生物活动的制约

运用激光粒度仪、氮气吸附实验和色谱—质谱联用方法,对西加拿大沉积盆地（西加盆地）阿尔伯塔东南气田（Southeast Alberta Gas Field,SAGF）A井二白斑（Second White Specks）页岩13个生物气源岩样品进行粒度、比表面、孔径分布测试和烃类分子组成分析,探究浅层烃源岩孔隙空间与页岩中烃类生物降解之间的关系。研究样品有机质含量丰富,埋深浅,处于适合微生物活动的未成熟阶段,孔径分布显示样品的孔隙主要集中在中孔（2~50 nm）范围。分子地球化学参数分析表明,页岩中有机质组成主要受有机质输入和沉积环境的影响,烃类生物降解作用不明显。结合页岩孔径分析认为,目前页岩绝大部分孔隙空间都无法为微生物提供可生存环境,仅少量大孔（>200 nm）可能为页岩中的微生物活动提供有限空间。能大规模产生物气的气源岩应具有较大比例的孔径大于200 nm的孔隙。传统的生物气源岩评价标准可能对页岩孔隙空间这一限制微生物活跃性的因素有所忽视。