等温吸附量方程常数的物理含义及无因次吸附量方程

LANGMUIR(兰格苗尔)于1918年发表的等温累积吸附量方程,描述了在等温条件下累积吸附量与吸附压力之间的关系。然而,应当指出,兰氏方程是利用甲烷气、氮气、一氧化碳气、二氧化碳气、氧气和氩气等气体,在由云母片制成的吸附仪上进行了大量等温吸附实验,在实验取得数据的基础上,提出的一个等温累积吸附量经验方程。该方程具有a和b两个常数。陈元千等于2018年发表了等温累积吸附量方程的推导结果。该方程也存在A和B两个常数。研究结果表明,陈氏和兰氏的等温累积吸附量方程的两个常数都具有重要的物理含义。陈氏方程的常数A和兰氏方程的常数a都表示样品的极限累积吸附量;陈氏方程的常数B和兰氏方程的常数b都表示等温瞬压吸附量递减率;陈氏方程的AB和兰氏方程的ab都表示样品的最大初始理论吸附量。同时,建立了陈氏和兰氏的等温无因次累积吸附量方程和等温无因次瞬压吸附量方程,并提出了确定等温饱和吸附压力和等温饱和累积吸附量的方法。通过16个实例应用,发现陈氏方程和兰氏方程评价样品的极限累积吸附量基本一致;对于等温瞬压吸附量递减率和最大初始理论吸附量的评价,兰氏与陈氏的结果相差明显。但应当注意到,兰氏方程是一个经验方程,其可靠程度要比陈氏方程低。     

四氯乙烷的吸附热力学和动力学研究

通过静态吸附实验,研究了四氯乙烷在吸附剂M上的吸附热力学和动力学特性。研究结果表明：四氯乙烷在吸附剂M上的吸附等温线属于典型的L型吸附曲线,吸附剂M对四氯乙烷的吸附符合Langmuir吸附等温方程,吸附可以自发进行,吸附过程为放热过程,属于物理吸附;吸附剂M对四氯乙烷的吸附动力学可用拟二级动力学方程描述,随温度升高,初始吸附速率以及吸附速率常数均呈现增大趋势。     

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。     

碳分子筛对氧、氮、氩气体的吸附速率

在等温等压下测定碳分子筛对氧、氮、氩气体吸附动力学曲线,提出并建立了以时间为变量的吸附量方程 Ｖ（ｔ） ＝ Ｖｍ Ｚｔ／（１ ＋ Ｚｔ） ,应用该方程得到碳分子筛对上述气体的微分吸附速率,并且对国内外的４ 种碳分子筛的微孔以及它们分别对氧、氮、氩气体的分离性能进行了初步对比。     

交联壳聚糖对酸性红B的吸附研究

实验以壳聚糖为原料,在碱性条件下以环氧氯丙烷对壳聚糖进行了化学改性,制得不溶于水的交联壳聚糖。研究了交联壳聚糖对偶氮染料酸性红B的吸附平衡规律,探讨了交联壳聚糖对酸性红B的吸附动力学规律以及初始浓度、pH值对吸附的影响,并且与壳聚糖在相同条件下做了对比实验。结果表明:交联壳聚糖对酸性红B的吸附性能优于壳聚糖。其吸附规律符合Langmuir吸附等温式,最大吸附容量为227.27 mg/g;其吸附动力学模型可以用准二级速率方程来描述,准二级动力学常数为4.06×10~(-4)g/(mg·min)。     

X-5大孔树脂对银杏叶总黄酮吸附性能研究

用微波辅助法得到黄酮粗提液,利用分光光度法测定样品中黄酮含量,考察了吸附剂用量、粗提液浓度、pH值、吸附时间等对吸附结果的影响。静态吸附的最佳条件：树脂质量与提取液体积比1：30、pH2．5—4．0、提取液中黄酮含量为0．22—0．32mg／mL、恒温振荡70min,X-5树脂对银杏黄酮静态吸附率达70．54％。动态吸附的最佳条件为：提取液上样浓度为0．30—0．43mg／mL、pH2．8～3．5、以0．8mL／min的流速通过径高比为1：9．5的层析柱,X-5树脂对银杏黄酮动态吸附率达45．32％。结果表明,X-5树脂可较好吸附银杏叶总黄酮。     

H-103大孔树脂对对硝基苯酚吸附行为的研究

研究了H-103大孔树脂对水溶液中对硝基苯酚的吸附动力学及热力学特性,通过静态吸附实验,探讨了温度、初始浓度、振荡速度对吸附动力学的影响。该吸附符合一级动力学吸附方程,颗粒内扩散过程是影响吸附速率的主要控制步骤。吸附符合Freundlich等温吸附方程,吸附为放热的物理吸附过程,适当降低温度有利于吸附,     

木质素磺酸钙改性树脂对亚甲基蓝的吸附

以木质素磺酸钙和丙烯酸为原料,乙二醇二甲基丙烯酸酯为交联剂,采用溶液聚合法制备了木质素磺酸钙改性丙烯酸树脂(LSAE)。考察了溶液p H、初始浓度、吸附时间和吸附温度对LSAE吸附亚甲基蓝(MB)的影响。采用SEM、N2吸附-脱附、FTIR等技术对吸附剂进行表征。实验结果表明,在初始MB质量浓度为200 mg/L、吸附温度为298 K、溶液p H=8、吸附时间为480 min时,吸附量为178.96 mg/g。表征结果显示,改性后LSAE试样的表面粗糙,具有介孔结构,比表面积和总孔体积均有所增加,平均孔径减小;LSAE对MB的吸附等温线符合Langmuir等温方程,吸附动力学过程符合准二级动力学方程。     

载铜活性炭吸附二甲基硫醚的热力学和动力学

以铜质量分数为11%的载铜活性炭（J-AC）为吸附剂,对石油醚溶液中的二甲基硫醚进行吸附,通过比表面积分析仪对吸附剂的比表面积和孔结构进行表征,利用热力学与动力学模型对试验数据进行拟合,计算热力学及动力学参数,探讨J-AC对二甲基硫醚的吸附机理。结果表明：J-AC对二甲基硫醚的吸附符合Freundlich吸附等温方程,拟合相关系数大于0.996,且不同温度下的吸附自由能（△G ）、吸附热（△H ）和吸附熵（△S ）均小于0,表明该吸附过程是一个放热的混乱度降低的自发过程;吸附过程的动力学符合拟二阶动力学模型,拟合相关系数大于0.99,随着二甲基硫醚初始浓度的增加,拟二阶速率常数逐渐减小。     

龙山矿无烟煤超临界状态下吸附甲烷动力学特征

为研究超临界状态下吸附甲烷动力学特征,以河南安阳龙山矿无烟煤为研究对象,利用磁悬浮天平进行了从亚临界到超临界状态煤吸附甲烷的等温吸附实验和吸附动力学实验,基于吸附动力学方程和单孔扩散模型,探讨了无烟煤中甲烷分子扩散、吸附至平衡整个过程中动力学特征.结果表明:实验室测得"峰值"型等温吸附线为过剩吸附曲线,使用截距法校正得...     

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。     

Influence of the properties of resins on the interactions between asphaltenes and resins

The properties of two resins (Tahe resin and Liaohe resin) and their influences on the dispersion of two asphaltenes (Tahe asphaltene and Liaohe asphaltene) are investigated by laboratory experiments. The results indicate that the adsorption isotherms of two resins are accorded with the Freundlich absorption model. The shape of the curves obtained could be attributed to both multilayer adsorption of resins on asphaltenes surfaces and the penetration of resins into the microporous structure of the asphaltenes. Based on the combined results from the shape of the curves and chemical properties of resins, the relative adsorption quantity of Tahe resin is higher than that of Liaohe resin due to the stronger polarity of Tahe resin, and the effect of Tahe resin on the dispersion of asphaltene is stronger than that of Liaohe rein. The different properties of resin can directly lead to the difference of dispersion performance on asphaltene in crude oil, which is closely related to the chemical structure of resin. The more the number of aromatic structure of the resin, the stronger the effect of resin on the dispersion of asphaltene there is.     

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。     

Kinetics and thermodynamics of Mn(II) removal from aqueous solutions onto Mg-Zn-Al LDH/montmorillonite nanocomposite

This study deals with the removal of Mn(II) from aqueous solutions by Mg-Zn-Al LDH/montmorillonite nanocomposite. LDH adsorbent was prepared by co-precipitation method and the composite was prepared by physical mixing of LDH and MMT using high-shear action. The data revealed that the maximum adsorption efficiency were 24.5, 26.4 and 28.9?mg/g at adsorbent mass of 0.25?g/L, pH of 6.0, initial Mn(II) concentration of 80?mg/L, stirring rate of 160?rpm, contact time of 75?min and different temperatures of 298, 308 and 318?K, respectively. Langmuir and Freundlich models were used to optimize the adsorption process and pseudo-first order and pseudo-second order models were used to evaluate the adsorption kinetics of Mn(II) ions onto Mg-Zn-Al (LDH)/MMT nanocomposite. The data indicated that Langmuir model fits the experimental data better than Freundlich model and pseudo-second order model is sufficient to depict the kinetics of Mn(II) onto Mg-Zn-Al (LDH)/MMT composite. Also, the data obtained from thermodynamics study; Gibbs free energy (ΔG°), Enthalpy change (ΔH°), and Entropy change (ΔS°) revealed that the adsorption process is spontaneous, endothermic and randomness at the solid-solution interface during the process of adsorption.     

S-8树脂对地榆皂苷溶液脱色的研究

考察了S-8吸附树脂吸附脱色处理地榆皂苷有色溶液的影响因素,适宜的脱色条件为:30%乙醇(质量分数)的地榆皂苷有色溶液适于脱色,吸附脱色时间为2 h,脱色树脂用量为色素含量的15～20倍;树脂再生剂为pH=1的95%乙醇溶液。实验结果表明,S-8吸附树脂对地榆皂苷有色溶液的脱色率比活性炭高,可达到93.89%,而活性炭对该溶液的脱色率是75.48%。     

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.     

Effects of the processing steps on parathion levels during honey production and parathion removal by macroporous adsorption resins

The effects of different steps in honey production on parathion levels and parathion removal from honey using macroporous adsorption resins (MARs) were investigated in this study. Parathion residues were quantified by gas chromatography with flame photometric detection (GC-FPD) after each processing step including preheating, filtration, vacuum concentration and pasteurization. The four processing steps could reduce the initial parathion level of 2.77 to 2.73, 2.53, 2.30 and 2.23 mg/kg, respectively, and the total loss of parathion was only 19%. Meanwhile, different types of MARs were used in parathion adsorption, and the results from removal experiments showed that LS-803 resin was more efficient in removing parathion from honey than other resins LS-903, LSA-21 and LSA-900B, with the adsorption rate of above 90%.     

Synthesis of silica nanoparticles from blast furnace slag as cost-effective adsorbent for efficient azo-dye removal

Synthesis of silica nanoparticles (NSBFS) from commercial blast furnace slag (BFS) and its efficiency to remove methylene blue (MB) from water as well as the desilicated blast furnace slag (DBFS) were investigated in this study. The sorbent materials were characterized by X-ray diffraction (XRD), X-ray fluorescence (XRF), N₂ adsorption-desorption isotherms, dynamic light scattering (DLS), scanning electron microscopy (SEM), and Energy Dispersive X-ray Analysis (EDAX). Different physiochemical parameters such as initial pH of the dye, sorbent dosage, contact time, and initial dye concentration were studied. The pseudo-first-order and pseudo-second-order models were applied to evaluate the kinetic mechanism of the adsorption process. The results show that the process follows the pseudo-second-order kinetics using NSBFS or DBFS. The adsorption equilibrium values were obtained using Langmuir and Freundlich equations, Langmuir model showed the best correlation indicate that NSBFS and DBFS are homogeneous surface. The batch adsorption experiments showed that the maximum sorption was observed at pH?=?10 and 8 and the maximum uptake capacities (qm) for MB were 80.8 and 109.8?mg/g using DBFS and NSBFS, respectively.     

变色硅胶对模拟柴油中喹啉或吡啶的吸附行为研究

采用XRD、FT-IR、低温N2吸附-脱附和NH3-TPD等方法对硅胶和变色硅胶进行了较详细的表征。XRD和FT-IR表征结果表明硅胶和变色硅胶都具有非晶态结构。硅胶和变色硅胶的平均孔径分别为18.46 nm和1.80 nm,BET比表面积分别为437.86 m2/g和623.39 m2/g,孔体积分别为0.972 4 cm3/g和0.344 2 cm3/g。NH3-TPD的表征结果表明变色硅胶的酸性远大于硅胶的酸性。研究了氧化铝、硅藻土、硅胶及变色硅胶对模拟柴油中的喹啉的吸附脱除效果,结果表明,变色硅胶吸附脱除喹啉的效果远远好于其它吸附剂,较强的酸性大大增强了变色硅胶吸附脱除碱性氮化物喹啉的能力。进一步研究了变色硅胶吸附脱除模拟柴油中的喹啉或吡啶的动力学,结果表明：喹啉和吡啶在变色硅胶上的吸附等温线均属于S型;采用Freundlich（F型）和Langmuir（L型）方程对喹啉吸附数据拟合所得到的R值几乎相同,说明变色硅胶吸附喹啉的动力学符合L型和F型混合模型;对吡啶数据拟合所得Freundlich方程的R值远大于Langmuir 方程的R值,说明变色硅胶吸附吡啶更接近于F型模型。