磷钼钨杂多酸修饰金属有机骨架MOF-5复合材料吸附亚甲基蓝

采用水热合成法,在合成金属有机骨架MOF-5的过程中引入活性组分磷钼钨杂多酸(H₆P₂Mo₁₅W₃O₆₂),制备出一种新型吸附剂H₆P₂Mo₁₅W₃O₆₂/MOF-5。 利用H₆P₂Mo₁₅W₃O₆₂/MOF-5材料对亚甲基蓝溶液进行了材料的吸附性能研究,探讨了亚甲基蓝溶液的初始pH值和初始浓度以及不同吸附温度对吸附量的影响。 结果表明,在较低的温度和亚甲基蓝溶液较低的初始pH值的条件下,有利于H₆P₂Mo₁₅W₃O₆₂/MOF-5对亚甲基蓝的吸附。 实验结果能够较好地符合Langmuir吸附等温式以及二级动力学模型,对亚甲基蓝的最大吸附量可达401.6 mg/g。 热力学参数ΔG<0、ΔH<0和ΔS>0,表明H₆P₂Mo₁₅W₃O₆₂/MOF-5对亚甲基蓝的吸附过程是自发、放热的。 此外,还探讨了H₆P₂Mo₁₅W₃O₆₂/MOF-5对甲基紫、孔雀石绿、罗丹明B和甲基橙等其它染料的吸附性能,结果表明,H₆P₂Mo₁₅W₃O₆₂/MOF-5对阳离子染料有较好的吸附效果。     

球状纳米介孔碳和HZSM-5分子筛在二苯并噻吩吸附脱硫中的应用

采用软模板法制备了粒径范围为50 nm～100 nm的球状纳米介孔碳(MCN),与HZSM-5分子筛机械混合获得介/微孔混合吸附剂,用于二苯并噻吩的吸附脱硫研究。XRD、BET、SEM和TEM等分析结果表明,MCN比表面积为214 m²/g,孔径为5.1 nm,混合吸附剂的比表面积、孔容、孔径均处于MCN和HZSM-5分子筛两者之间,且两者混合均匀。吸附脱硫实验表明,HZSM-5分子筛对二苯并噻吩的吸附脱硫率最差(脱硫率4.8%),而MCN的脱硫性能最优(脱硫率70%),混合吸附剂中随MCN含量增加二苯并噻吩的吸附脱硫性能逐渐提高,且MCN表现出了较好的可重复性能,经过4次循环后吸附容量保留率为79%。Freundlich等温模型比Langmuir等温模型更适合描述二苯并噻吩在上述吸附剂表面的吸附过程,吸附动力学实验数据说明二苯并噻吩在该系列吸附剂上的吸附更符合二级动力学模型。     

新型螯合树脂聚苯乙烯负载葡糖胺对Pt(Ⅳ)吸附性能

合成了新型螯合树脂聚苯乙烯负载葡糖胺(PS-GA)。研究了树脂对Pt(Ⅳ)的吸附容量、吸附动力学、等温吸附等静态吸附性能及影响吸附的因素。结果表明,该树脂对Pt(Ⅳ)的吸附量较高;吸附动力学研究证明树脂对Pt(Ⅳ)的吸附为液膜扩散控制,吸附的活化能通过计算得10.31kJ/mol;树脂对Pt(Ⅳ)的等温吸附,与Freundlich方程相比,更加符合Langmuir方程;计算了等温吸附过程的热力学参数ΔG,ΔH,ΔS值;升高温度有利于吸附;树脂可用2%硫脲～0.1mol/LHCl溶液清洗再生,5次再生后仍保持良好的吸附能力,适合重复使用。     

H3PMo12O40/MOF-808复合材料制备及其吸附性能研究

以Keggin型磷钼酸、1,3,5-均苯三甲酸和八水氯氧化锆为原料，通过一步原位溶剂热制备了复合型吸附剂，通过XRD、SEM、FT-IR和TGA等表征手段说明，将亲水性杂多酸固定在MOF-808金属有机骨架基体上，对水溶液中亚甲基蓝溶液的吸附能力得以提升。动力学实验表明，H₃PMo₁₂O₄₀/MOF-808对亚甲基蓝的吸附符合准二级动力学模型，吸附等温线遵循Langmuir等温线模型，表明MB均匀吸附在H₃PMo₁₂O₄₀/MOF-808表面。根据Langmuir模型，在pH值为8,T=303K,吸附剂吸附性能最好。热力学研究表明，吸附过程是一个自发的放热反应。此外，H₃PMo₁₂O₄₀/MOF-808在五个连续循环实验中从其水溶液中吸附MB分子，表现出较好地可重复使用性。     

气体在固体表面吸附的热力学模型及吸附等温式

描述气体在固体表面吸附的两个著名吸附等温式Langmuir公式和Bronauer—Emmett—Teller(B·E·T)公式可以由动力学方法和统计热力学方法导出。但在导出过程中,都要引进一些基本假定之外的附加限制和近似. 根据经典热力学的唯象特点,能建立气体在固体表面吸附的吸附表面相热力学模型.从吸附平衡是一种热力学相平衡这一观点出发,可以由相平衡原理十分简洁地导出Langmuir吸附等温式和多层吸附的B·E·T吸附等温式.     

氨基功能化离子印迹硅胶对Cd2 的吸附行为及机理

研究了氨基功能化离子印迹硅胶对Cd2+的吸附行为及机理,进行了等温吸附模型和吸附动力学的测定和吸附热力学计算。结果表明,饱和吸附量的实验值为30.7mg/g;20min即可达到吸附平衡;等温吸附曲线符合Langmuir等温吸附模型,吸附过程以单层吸附为主;Cd2+的吸附动力学数据均符合准二级反应动力学模型;反应的吉布斯自由能为负值,焓变为23.01k J/mol,熵变为104.1J/mol·K,说明吸附是一个吸热的自发进行的过程。     

胸腺五肽在NH-1树脂上的离子交换过程研究

研究了胸腺五肽(TP5)在NH-1树脂上的离子交换过程.结果表明,在pH 2.O的条件下,其等温吸附过程符合Langmuir等温吸附方程,最大吸附量为221.07mg/g wet resin;静态吸附动力学的研究结果显示,NH-1树脂对TP5的吸附过程主要受颗粒扩散控制影响,TP5的颗粒内扩散系数为4.50×10-9cm2/s;对比Nernst-Planck与Fick动力学模型,可用Fick动力学模型来描述TP5在NH-1树脂内的颗粒扩散行为,其有效扩散系数为5.58×10-9cm2/s;采用固定床吸附数学模型,对TP5离子交换柱行为进行模拟,该数学模型考虑了颗粒扩散、轴向返混、非线性平衡以及液膜扩散.结果显示,模拟数据与实验结果具有较好的符合.     

As(Ⅴ)离子印迹有机-无机杂化材料的制备及其对As(Ⅴ)的选择性吸附

采用水热辅助表面印迹技术,制备了氨基功能化As(V)离子印迹有机-无机杂化材料,利用红外光谱和扫描电镜表征了其形貌和表面官能团,采用平衡吸附法研究了印迹杂化材料对As(V)的吸附行为及机理,计算了等温吸附模型和吸附动力学的参数。结果表明,水热辅助表面印迹法可以显著提高印迹杂化材料的吸附容量,在20℃时,吸附量达到47. 5mg/g,吸附平衡时间为30min;在pH 4～9范围内,pH对吸附容量没有显著性影响;离子印迹杂化材料显示出优异的选择性,其再生5次后,As(V)的吸附容量没有大幅降低;As(V)离子在离子印迹杂化材料的吸附过程符合Langmuir和准二级动力学模型。     

硅胶负载硫脲型吸附材料对Zn(Ⅱ)的吸附性能研究

研究了通过均相法和异相法合成的硅胶负载硫脲型吸附材料(HO-SG-GPTS-TS和HE-SG-GPTS-TS)对Zn(II)的吸附性能,考察了溶液p H值、温度、时间及金属离子初始浓度等因素对吸附性能的影响。结果表明,均相法合成产物HO-SG-GPTS-TS对Zn(II)的吸附量较异相法合成产物HE-SG-GPTS-TS高。对Zn(II)的最佳吸附p H值均为6。等温吸附结果表明,随温度及浓度的升高,对Zn(II)的吸附量增大,吸附过程符合Langmuir模型,为单分子层吸附;D-R模型拟合结果表明,对Zn(II)平均吸附自由能均大于8k J/mol,为化学吸附过程。动力学研究表明,吸附材料对Zn(II)的吸附符合拟二级动力学模型,为液膜扩散控制过程。     

纳米氢氧化铝-聚丙烯酰胺复合絮凝剂对镉离子的吸附研究

采用响应面法对纳米氢氧化铝-聚丙烯酰胺复合絮凝剂吸附Cd(II)过程进行了拟合和优化,分别以pH值、温度和Cd(II)浓度为自变量,研究了其对响应值镉离子最大吸附量的影响,并通过吸附动力学方程和吸附等温线数据对吸附机理进行了探讨。结果表明,采用响应面法对pH值、温度和Cd(II)浓度3个自变量进行优化后得出最大吸附量为79.07mg/g,其最优条件为:pH 6.35,镉离子浓度91.36mg/L,温度50℃;氢氧化铝-聚丙烯酰胺对Cd(II)的吸附在120min内达到平衡,且吸附动力学数据符合准二级动力学模型,表明吸附过程包含化学吸附;吸附速率的控制步骤是吸附脱附平衡步骤;吸附等温线数据与Langmuir吸附等温模型相一致,表明镉离子在氢氧化铝-聚丙烯酰胺表面形成的是单层吸附层。     

Uranium removal from nitric acid raffinate solution by solvent immobilized PVC cement

The present work deals with uranium removal from a nitric acid raffinate (waste) solution using prepared solvent (tri-butyl phosphate, TBP) immobilizing PVC cement (SIC) as a suitable adsorbent. The studied relevant factors affecting uranium adsorption onto SIC adsorbent involved; contact time, solution molarity, initial uranium concentration and temperature. The obtained adsorption isotherm of uranium onto the SIC adsorbent was fitted to Langmuir, Freundlich and Dubinin–Radushkviech (D–R) adsorption models. The results showed that the obtained equilibrium data fitted well the Langmuir isotherm. Additionally, it was found that the adsorption process obeys the pseudo second-order kinetic model. On the other hand, the calculated theoretical capacity of our prepared SIC adsorbent reached about 17 g U/kg SIC. Uranium adsorption from the studied raffinate solution was carried out applying the attained optimum conditions. The obtained data showed that 58.4 mg U/5 g SIC were adsorbed. However, using of 2 M HNO₃ solution as an eluent, 93 (54.3 mg U) from the adsorbed amount were eluted.     

Adsorption of cationic copolymer nanoparticles onto bamboo fiber surfaces measured by conductometric titration

Monosized nanoparticles of 57.3 nm were prepared by cationic emulsion polymerization using a polymerizable emulsifier DMHB. The adsorption of nanoparticles onto bamboo fibers was measured by conductometric titration. The results indicated that the adsorption capacity increased with increasing contact time until 120 min. The equilibrium data for nanoparticles adsorption onto bamboo fibers were well fitted to the Langmuir equation. Moreover, the monolayer adsorption capacity of nanoparticles in the concentration range (from 0.03 g/L to 0.6 g/L) studied, as calculated from Langmuir isotherm model at 25℃, was found to be 38.61 mg/g of fibers. The SEM images showed that the nanoparticles form a uniform monolayer on bamboo fiber surfaces.     

Adsorption of acridine yellow G from aqueous solutions using functionalized graphene nanoplatelets/modified polybutadiene hybrid composite

This paper presents an analysis of adsorption of acridine yellow G (AYG) from aqueous solutions through the use of functionalized grapheme nanoplatelets/modified polybutadiene hybrid composite (FGNPs/MPB). The adsorption of AYG onto FGNPs/MPB was investigated based on the AYG concentration, pH, contact time, temperature, and adsorbent dose. A maximum adsorption capacity was obtained at a pH of 7 (23.7 mg/g), an adsorbent dose of 1.0 g/L (20.8 mg/g), and an initial AYG concentration of 28.5 mg/L (16.9 mg/g). The value of q_e of FGNPs/MPB increases with an increase in temperature from 293 to 323 K. Equilibrium isotherm data were analyzed using the Langmuir and Freundlich isotherm models. The Langmuir model best describes the adsorption processes of AYG, which showed that the monolayer adsorption capacity of FGNPs/MBP is 22.9 mg/g. The pseudofirst-order, pseudosecond-order, and intraparticle diffusion models were used to study the kinetics of the AYG adsorption onto FGNPs/MPB. The pseudosecond-order model better described kinetic data for the adsorption of AYG onto FGNPs/MPB. Thermodynamic parameters, such as the Gibbs free energy, enthalpy, and entropy, indicated that the AYG adsorption onto FGNPs/MPB was spontaneous feasible, and endothermic.     

The Influence of Temperature on the Adsorption of Cadmium(II) and Cobalt(II) on Goethite

The adsorption of Cd(II) and Co(II) onto goethite was measured at five temperatures between 10 and 70 degrees C. For both cations the amount adsorbed at any given pH increased as the temperature was increased. Cd(II) adsorbed at a slightly lower pH at each temperature than Co(II). Adsorption isotherms at pH 7.00 for Cd(II) could be fitted closely by a simple Langmuir model, but a two-site Langmuir model was needed for Co(II). Potentiometric titrations of goethite suspensions in the presence and absence of added cation could be modeled closely by a constant-capacitance surface complexation model that assumed the adsorption reactions M2+ + SOH ⇋ SOM+ + H+ and M2+ + SOH + H2O ⇋ SOMOH + 2H+, where M represents Cd or Co. This model also fitted the experimental data from the adsorption edge and adsorption isotherm experiments. Thermodynamic parameters estimated from both Langmuir and surface complexation models showed that the adsorption of both metals was endothermic. Values obtained for the adsorption enthalpies from both modeling schemes were similar for both cations. Estimates of the adsorption entropies were model-dependent: Langmuir parameters yielded positive entropies, while some of the surface complexation parameters generated negative adsorption entropies. Copyright 1999 Academic Press.     

LIQUID-PHASE ADSORPTION KINETICS OF ISOMALTOTRIOSE ON Ca~(2+) EXCHANGE RESIN

1. INTRODUCTION Oligosaccharide is a carbohydrate comprising 2~9 monosaccharide units linked together by glucoside bond. In the digestive system of humankind, there exits no enzyme for the hydrolysis of oligosaccharides. So it can be used by bifidobacteria in large intestine, and lead to some special physiological function [1]. Oligosaccharide exits in many plants, for example, Morinda officinalis, a precious herb growing in south China. In this herb, four oligosaccharides with the funct…     

Utilization of Waste Biomass (Kitchen Waste) Hydrolysis Residue as Adsorbent for Dye Removal: Kinetic,Equilibrium, and Thermodynamic Studies

Kitchen waste hydrolysis residue (KWHR), which is produced in the bioproduction process from kitchen waste (KW), is usually wasted with potential threats to the environment. Herein, experiments were carried out to evaluate the potential of KWHR as adsorbent for dye (methylene blue, MB) removal from aqueous solution. The adsorbent was characterized using FT-IR and SEM. Adsorption results showed that the operating variables had great effects on the removal efficiency of MB. Kinetic study indicated pseudo-second-order model was suitable to describe the adsorption process. Afterwards, the equilibrium data were well fitted by using Langmuir isotherm model, suggesting a monolayer adsorption. The Langmuir monolayer adsorption capacity was calculated to be 110.13 mg/g, a level comparable to some other low-cost adsorbents. It was found that the adsorption process of MB onto KWHR was spontaneous and exothermic through the estimation of thermodynamic parameters. Thus, KWHR was of great potential to be an alternative adsorbent material to improve the utilization efficiency of bioresource (KW) and lower the cost of adsorbent for color treatment.     

LIQUID-PHASE ADSORPTION KINETICS OF ISOMALTOTRIOSE ON Ca^2＋ EXCHANGE RESIN

The adsorption of isomaltotriose from aqueous solution on Ca2+ resin was investigated.The adsorption isotherm and the rate curve were determined. The pseudo-first-order model,pseudo-second-order model and the intraparticle diffusion model were used to predict the rate constants of adsorption. The activation energy of adsorption has been also evaluated using the pseudo-second-order rate constants. The results showed that the adsorption of isomaltotriose onto Ca2+ resin is an exothermically activated process. The adsorption isotherm can be described by Langmuir equation. The pseudo-second-order model can fit well to the adsorption rate curve of isomaltotriose onto Ca2+ resin. It suggests that the adsorption of isomoltotriose onto Ca2+ resin involve chemical adsorption.     

还原态氧化石墨烯对Zn(Ⅱ)的吸附动力学与热力学

以乙二胺(EDA)还原氧化石墨烯(GO)制得一种吸附材料,即还原态氧化石墨烯(RGO)。 采用批量平衡法研究了RGO对Zn(Ⅱ)的吸附动力学与热力学,利用Lagergren准一级及准二级动力学方程、Langmuir和Freundlich等温方程对实验数据进行了拟合分析。 研究结果表明,Lagergren准二级吸附动力学模型能够较好地描述实验结果,表明该吸附过程以化学吸附为主。 RGO的吸附在所研究的Zn(Ⅱ)浓度范围内更符合Langmuir等温吸附经验式,ΔH0=-21.60 kJ/mol,吸附焓变小于零,表明该吸附为放热过程;吸附吉布斯自由能变化ΔG0为正值,表明该吸附是一个非自发的过程。     

Adsorption of fluoride from aqueous solution by graphene

A batch adsorption system was applied to investigate the adsorption of fluoride from aqueous solution by graphene. The adsorption capacities and rates of fluoride onto graphene at different initial pH, contact time, and temperature were evaluated. The experimental results showed that graphene is an excellent fluoride adsorbent with an adsorption capacity of up to 17.65 mg/g at initial fluoride concentration of 25 mg/L and temperature of 298 K. The isotherm analysis indicated that the adsorption data can be well described by Langmuir isotherm model. Thermodynamic studies revealed that the adsorption reaction was a spontaneous and endothermic process.