大孔吸附树脂XAD-4对聚乙二醇的吸附性能

以大孔吸附树脂XAD-4为吸附剂,采用静态平衡吸附法吸附模拟聚乙二醇(PEG)废水,考察了初始pH值、吸附时间、吸附剂投加量和温度等因素对PEG去除效果的影响. 结果表明,pH值对吸附过程的影响可忽略不计. 当XAD-4树脂投加量为0.3 g/L时,PEG去除率可达89%,平衡吸附量Qe=59.95 mg/g. PEG在XAD-4树脂表面上均一分布,Langmuir, Dubinin-Radushkevich和Sips模型可较好地模拟其等温吸附过程. 不同温度下均为自发的放热吸附过程. 动态吸附数据符合拟二级动力学方程.     

膨润土-活性炭复合吸附剂对锰离子的吸附

以膨润土和活性炭为原料制备了复合吸附剂并将之应用于含锰离子废水的吸附。考察了不同条件下该吸附剂对水体中Mn（Ⅱ）的去除效果,并研究了吸附动力学特征和等温吸附过程。结果表明膨润土和活性炭复合吸附剂对Mn（Ⅱ）具有优良的吸附能力,在25 ℃下,当投加量为4 g/L、Mn（Ⅱ）初始质量浓度为50 mg/L、溶液pH为6时,吸附180 min,吸附率为93.2%。准一级、准二级动力学和内扩散模型用来拟合吸附过程,结果表明准二级动力学符合该吸附过程,吸附速率常数为0.003 6 g/（mg·min）,内扩散过程不是吸附的限速步骤,还存在吸附机制的制约。用Langmuir和Freundlich模型描述吸附等温过程,结果得出该吸附过程服从Langmuir吸附,饱和吸附容量为27.781 mg/g。     

PBMA/GMA-SiO2吸附剂的制备及其高效去除铅离子

以甲基丙烯酸丁酯(BMA)和甲基丙烯酸缩水甘油酯(GMA)功能化的纳米SiO2为单体,通过可逆加成-断裂链转移自由基聚合(RAFT)法制备了PBMA/GMA-SiO2有机/无机复合吸附材料,并将其用于吸附含Pb2+的水溶液。考察了吸附时间、温度、pH以及Pb2+初始质量浓度对吸附效果的影响,并对其吸附动力学和热力学特性进行了探讨。结果表明,PBMA/GMA-SiO2对Pb2+具有良好的吸附性能,其对Pb2+的饱和吸附量为423.84mg/g,吸附最佳pH=5~6,平衡时间为1 h,去除率随Pb2+初始质量浓度的减小而增加。优化实验条件下,50 mg吸附剂在298 K时,对pH=6的50 mL 0.02 g/L含Pb2+溶液的去除率高达100%。热力学和动力学过程模拟结果表明,吸附的动力学过程比较符合准二级动力学速率方程,Langmuir等温方程比Freundlich等温方程更适合于描述此吸附行为。颗粒内扩散过程是吸附速率的控制步骤,但不是唯一的速率控制步骤。吸附剂经过5次脱附、吸附后,依然具有较强吸附Pb2+的能力。     

米根霉磁性生物吸附剂的制备及其对刚果红的吸附

以产富马酸米根霉菌体粉末、FeSO4和FeCl3为原料,制备了米根霉磁性生物吸附剂,考察了吸附剂投加量、pH值、刚果红浓度、吸附时间及吸附动力学等对阴离子偶氮染料刚果红的吸附影响. 结果表明,刚果红去除率随吸附剂投加量增加而提高,增大溶液初始浓度能有效提高吸附量,当吸附剂为1.0 g/L, pH=7.0时,吸附效果最佳,刚果红浓度为20 mg/L去除率达98.68%以上. 米根霉磁性吸附剂对刚果红的吸附等温线符合Langmuir模型,吸附过程符合拟二级动力学方程,内扩散为主要控速步骤. 吸附剂有较强磁性,在外加磁场下能快速实现固液分离和回收,可简化刚果红偶氮染料吸附的后续处理.     

Adsorption of endocrine disrupting ethylparaben from aqueous solution by chemically activated biochar developed from oil palm fibre

The activated biochar (ABC) was prepared, characterized and examined the feasibility of removing ethylparaben (EP) from aqueous solution. The characterization results showed that ABC possessed multi-porous structure and high surface area. The adsorption isotherm was well fitted the Langmuir isotherm and the adsorption kinetic followed the pseudo-second-order model. The maximum adsorption capacity of EP onto ABC was 349.65 mg/g at 298 K. The adsorption capacity maintained 90.82% after five successive adsorption/desorption cycles. ABC possessed high adsorption capacity, usability and stability, which indicating that ABC has great potential to be a promising adsorbent for removal of EP from aqueous solution.     

颗粒化铁-铝-铈纳米吸附剂的除氟性能

采用在流化床中喷雾包覆方法将纳米吸附剂包覆在玻璃珠表面制备颗粒化吸附剂,考察了所制颗粒化纳米铁-铝-铈复合氧化物吸附剂在含氟水中的除氟性能. 结果表明,含氟初始浓度为10 mg/L时,颗粒化吸附剂的吸附速率符合拟一级反应动力学模型,吸附等温线符合Langmuir吸附模型,饱和吸附量达5.9 mg/g. 吸附容量随含氟水初始pH值升高而降低,吸附过程中溶液pH值逐渐趋近于中性;含氟水中其他阴离子对F-的吸附存在不同程度的竞争,竞争离子的影响顺序为NO3-"Cl-相似文献   

Adsorptive removal of cationic dye from aqueous solutions by ZnO/ZnMn2O4 nanocomposite

The ZnO/ZnMn₂O₄ nanocomposite (ZnMn) was used as adsorbent for the removal of cationic dye Basic Yellow 28 (BY28) from aqueous solutions. The adsorbent was characterized by X-ray diffraction, scanning electron microscope, TEM, Fourier transform infrared ray, BET, particle size distribution and zeta potential measurements. The adsorption parameters, such as temperature, pH and initial dye concentration, were studied. Kinetic adsorption data were analyzed using the pseudo-first-order, pseudo-second-order and intraparticle diffusion kinetic models. The Langmuir and Freundlich isotherm models were applied to fit the equilibrium data. The maximum adsorption capacity of BY28 was 48.8 mg g^?1. Various thermodynamic parameters, such as ΔG°, ΔH° and ΔS°, were calculated.     

The application of a natural chitosan/bone char composite in adsorbing textile dyes from water

Colored wastewaters are one of the common waste contaminants which are derived from various industries, threatening aquatic environments. Thus, it is necessary to treat them before discharge. Among various remediation technologies, adsorption is one of the popular treatment methods because of its simplicity and cost-efficiency. So, in the present study, the adsorption potential of a natural chitosan/bone char composite was investigated in adsorbing the Direct Brown 166 dye (DB-166) from aqueous solution. To investigate the adsorption potential of the chitosan/bone char composite, the effects of influencing parameters were studied. Accordingly, the optimum removal efficiency was determined at an initial pH of 3, a contact time of 60?min, an initial dye concentration of 20?mg/L, an adsorbent dosage of threatening 4?g, a mixing speed of 150?rpm, and a temperature of 55°C. Also, the maximum adsorption efficiency and capacity were obtained to be 99.8% and 21.18?mg/g, respectively. To evaluate the equilibrium and dynamics, isotherm and kinetic models were investigated. As a result, the Langmuir isotherm (R²?=?0.996) and pseudo-second-order kinetic model (R²?=?0.999) fitted the experimental data well. These results revealed that the chitosan/bone char composite can be used as an efficient adsorbent for the decolorization of aquatic solutions.     

Application of graphene-based adsorbents in the treatment of dye-contaminated wastewater; kinetic and isotherm studies

The adsorption of methylene blue (MB) on graphene-based adsorbents was tested through the batch experimental method. Two types of graphene-based adsorbents as graphene oxide (GO) and reduced graphene oxide (RGO) were compared to investigate the best adsorbent for MB removal. So that optimizing the MB removal for the selected type of graphene-based adsorbent, the diverse experimental factors, as pH (2–10), contact time (0–1440 min), adsorbent dosage (0.5–2 g/L), and initial MB concentration (25–400 mg/L) were analyzed. The conclusions indicated that the MB removal rised with an increase in the initial concentration of the MB and so rises in the amount of adsorbent used and initial pH. Maximum dye removal was calculated as 99.11% at optimal conditions after 240 min. Adsorption data were compiled by the Langmuir isotherm (R²: 0.999) and pseudo-second-order kinetic models (R²: 0.999). The Langmuir isotherm model accepted that the homogeneous surface of the GO adsorbent covering with a single layer. And the adsorption energy was calculated as 9.38 kJ mol⁻¹ according to the D-R model indicating the chemical adsorption occurred. The results show that GO could be utilized for the treatment of dye-contaminated aqueous solutions effectively.     

农业废弃物香芋柄对含Mn2+废水的吸附

以废弃香芋柄作为新型生物吸附剂,通过静态吸附实验,研究了pH、温度、吸附时间、Mn2+初始浓度等因素对香芋柄吸附Mn2+的影响,分析了吸附过程的热力学、动力学和等温吸附规律. 结果表明,溶液初始pH=4,香芋柄用量6 g/L,30℃下吸附60 min,溶液中Mn2+吸附去除率达90.79%以上,吸附容量高达18.16 mg/g. 应用Langmuir和Freundlich模型描述香芋柄对Mn2+的吸附过程,结果显示Freundlich吸附等温线拟合效果更好. 吸附动力学实验数据符合准二级动力学模型. 计算得到热力学参数DG<0, DH>0, DS>0,表明该吸附过程是自发和吸热的过程.     

H-103树脂处理含酚废水的实验研究

研究了H-103大孔吸附树脂对600~1000 mg/L苯酚水溶液中酚的吸附,考察了初始酚浓度、溶液pH值及温度对吸附性能的影响. 结果表明,在20 min内吸附达到平衡,吸附动力学可用拟二级动力学模型描述. 苯酚在大孔树脂上的吸附等温线很好地符合Langmuir吸附等温方程,在25℃下其饱和吸附量和Langmuir常数分别为86.00 mg/g和0.2719 L/mg.     

Characterization of Ag(I), Co(II) and Cu(II) removal process from aqueous solutions using dolomite powder

Dolomite, a natural adsorbent, was used for removal of Ag(I), Cu(II) and Co(II) from aqueous solutions. Adsorption parameters including pH, temperature and contact time have been investigated to obtain adsorption mechanism. The results of experiments showed that adsorption of the metal ions increased by increasing pH values up to 5.5. The adsorption process was initially fast. Equilibrium isotherm data were analyzed using Langmuir, Freundlich and Dubinin-Radushkevich isotherm models. Maximum adsorption capacity of Ag(I), Cu(II) and Co(II) was 1.34, 1.63 and 2.84 mg/g at 20 oC, respectively. Kinetic models including Lagergren first-order and pseudo-second-order were used to test kinetic data. The results showed that pseudo-second-order has good agreement with experimental data. Thermodynamic parameters of the process were also investigated at different temperatures. The negative values of Gibbs free energy and enthalpy changes for Ag(I), Cu(II) and Co(II) indicated the spontaneous and exothermic nature of the adsorption process.     

Preparation of poly(vinyl alcohol)/tetraethyl orthosilicate hybrid membranes modified with TMPTMS by sol-gel method for removal of lead from aqueous solutions

Poly(vinyl alcohol)/tetraethyl orthosilicate (PVA/TEOS) ion exchange hybrid membranes modified with 3-mercaptopropyltrimethoxysilane (TMPTMS) were prepared by the sol-gel method, and their applications for the removal of lead ions from aqueous solutions in a batch sorption process were studied. The functional groups of the hybrid membranes were characterized by FTIR. Batch adsorption studies such as TMPTMS content, pH, adsorbent dose, contact time, initial concentration and temperature were evaluated. The maximum adsorption capacity of lead ions was found to be 61.62mg g^?1, respectively. The kinetic data were analyzed by pseudo-first-order and pseudo-second-order kinetic models. The Freundlich and Langmuir isotherm models were applied to describe the equilibrium data. Thermodynamic parameters indicated that the lead adsorption onto the membrane is an endothermic and spontaneous process. The PVA/TEOS/TMPTMS hybrid membrane is regenerated by 0.5M HNO₃/0.1 M HCl in equal ratio solution and the adsorption capacity did not change remarkably after five sorption-desorption cycles.     

EFFECT OF TEMPERATURE ON THE ADSORPTION OF METHYLENE BLUE DYE ONTO SULFURIC ACID–TREATED ORANGE PEEL

The present study explains the preparation and application of sulfuric acid–treated orange peel (STOP) as a new low-cost adsorbent in the removal of methylene blue (MB) dye from its aqueous solution. The effects of temperature on the operating parameters such as solution pH, adsorbent dose, initial MB dye concentration, and contact time were investigated for the removal of MB dye using STOP. The maximum adsorption of MB dye onto STOP took place in the following experimental conditions: pH of 8.0, adsorbent dose of 0.4 g, contact time of 45 min, and temperature of 30°C. The adsorption equilibrium data were tested by applying both the Langmuir and Freundlich isotherm models. It is observed that the Freundlich isotherm model fitted better than the Langmuir isotherm model, indicating multilayer adsorption, at all studied temperatures. The adsorption kinetic results showed that the pseudo-second-order model was more suitable to explain the adsorption of MB dye onto STOP. The adsorption mechanism results showed that the adsorption process was controlled by both the internal and external diffusion of MB dye molecules. The values of free energy change (ΔG ^o) and enthalpy change (ΔH ^o) indicated the spontaneous, feasible, and exothermic nature of the adsorption process. The maximum monolayer adsorption capacity of STOP was also compared with other low-cost adsorbents, and it was found that STOP was a better adsorbent for MB dye removal.     

Removal of Astrazone Blue from aqueous solutions onto brown peat. Equilibrium and kinetics studies

The aim of this study is to characterize and assess the sorption potential of brown peat, in relation to colored pollutants from the textile industry wastewater. The objectives of this paper were: the physicochemical, morphological, and mineralogical characterization of brown peat, testing the adsorption capacity of natural and chemically treated peat samples for Astrazone Blue, evaluation of adsorption process from equilibrium isotherm and kinetic point of view. The characteristics of the peat samples were investigated using elemental analysis, scanning electron microscopy and X-ray diffractometry. Experimental data indicated that the brown peat tested confirm a high level of adsorption (removal efficiency >93.00%, adsorption capacity reaching up to 24.27 mg/g) of Astrazone Blue from aqueous solution. The Langmuir and Freundlich adsorption isotherm models were used to find the best equation able to describe the adsorption process. Experimental adsorption data were successfully described by the Langmuir equilibrium isotherm model. This fact is supported by the agreement between the q values obtained using the Langmuir equation (26.32 mg/g), and the ones obtained experimentally (24.27 mg/g). The kinetic studies showed that the pseudo-second-order model described Astrazone Blue sorption kinetics, as confirmed by the high values of R ² , which are over 0.99 for the whole investigated concentration range (200 to 800 mg/L). The use of brown peat adsorbent is more advantageous compared with other materials since it does not require a preliminary treatment, is low-cost and is an eco-friendly adsorbent. Hence, this peat appears to be a viable material for the decontamination of effluents containing dyes.     

静电纺壳聚糖/PVA纳米纤维膜对甲基橙的吸附特性

以静电纺丝制备的壳聚糖(CS)/聚乙烯醇(PVA)纳米纤维膜为吸附剂,研究了反应时间、甲基橙初始质量浓度、膜吸附剂用量和pH值对吸附甲基橙染料的影响,并通过吸附动力学行为和吸附等温线研究了其吸附机制。结果表明:当pH值在5～9之间、甲基橙初始质量浓度为100 mg/L、吸附剂用量为30 mg、反应时间为60～120 min之间时,吸附效果最佳且吸附平衡时间为3 h;CS/PVA膜对甲基橙的吸附既有物理吸附也有化学吸附,化学吸附占主导作用,CS/PVA膜对甲基橙的吸附符合Langmuir等温线和拟二级动力学模型。     

Preparation of polyacrylamide–montmorillonite nanocomposite and its application in Cr(III) adsorption

The polyacrylamide–montmorillonite “water in water” (PAM-MMT W/W) emulsion was prepared by dispersion polymerization method in the presence of organo-montmorillonite (OMMT). Based on the analysis of the polymerization process, the structure of material was investigated using thermogravimetry, Fourier transform infrared spectroscopy, X-ray diffractometry, scanning electron microscopy, and transmission electron microscopy experiments. Here, the dispersion was determined to be a blend of PAM W/W emulsion and PAM network interspersed by MMT particles, this unique structure of the material was considered to provide better adsorption ability compared to PAM without MMT. Therefore, a PAM-MMT adsorbent was made from the PAM-MMT W/W emulsion, and its adsorption capacity toward Cr(III), one of the heavy metal pollutants from the tannery waste was investigated. The PAM-MMT nanocomposite was demonstrated to have good Cr(III) removal performance, the maximum adsorption capacity of the nanocomposite was found to be 59.74 mg/g at a pH of 5.5 and temperature of 70°C. Results show that pseudo-second-order kinetic model and Langmuir isotherm were applicable for Cr(III) adsorption.     

荔枝皮吸附水中孔雀绿的响应曲面法研究

采用Box-Behnken响应曲面优化设计对荔枝皮吸附去除水中染料孔雀绿（MG）的影响因素（如吸附时间、吸附剂用量、pH值）进行研究,建立了去除率和上述因素之间的二次多项式模型,得到荔枝皮吸附孔雀绿的最佳吸附条件为：温度25℃、吸附时间122.31min、吸附剂用量2.81g/L、pH=6.75、MG浓度为100mg/L,最优条件下荔枝皮对孔雀绿的吸附去除率可以达99.75%。用Langmuir和Freundlich方程对吸附等温线进行拟合,其中Langmuir方程拟合效果最好,其最大吸附量为142.86mg/g,且吸附过程符合假二次动力学模型。此外,热力学结果表明,荔枝皮对孔雀绿的吸附属于自发的吸热过程。结合吸附-解吸循环实验和对吸附的FT-IR表征,表明荔枝皮是一种极具潜力的高效的吸附剂,能有效去除水中的孔雀绿离子。     

铜渣铁基类沸石地质聚合物吸附Pb2+、Cu2+、Zn2+性能及机理

以铜渣为原料，在NaOH+工业水玻璃活化条件下制备出了铜渣Fe3O4@铁基类沸石地质聚合物（F3O4@GM），并将其用于三种重金属Pb2+、Cu2+、Zn2+吸附。探究了溶液pH、吸附剂投加量和初始浓度对Pb2+、Cu2+、Zn2+吸附性能的影响，并通过吸附动力学、热力学以及XRD、FTIR、SEM、BET、XPS等表征手段对其吸附机理进行探讨。结果表明，F3O4@GM对Pb2+、Cu2+、Zn2+的吸附符合Langmuir模型，吸附容量分别为555 mg/g、489 mg/g、125 mg/g；吸附过程符合拟二级动力学模型。F3O4@GM高比表面积提高了材料的吸附性能，吸附机理主要为离子交换、静电吸引、表面络合和孔隙固定作用。F3O4@GM为重金属污染处理提供了一种价格低廉、制备方便的选择，同时实现了铜渣资源化和无害化处理，具有良好的经济效益和环境效应。     

Removal of methylene blue from aqueous solutions by poly(2-acrylamido-2-methylpropane sulfonic acid-co-itaconic acid) hydrogels

In this study, removal of methylene blue (MB) from aqueous solution by poly(AMPS-co-IA) hydrogels was examined by batch equilibration technique. The effects of monomer ratio, concentration of initiator and crosslinker, pH, adsorption time, initial dye concentration and adsorption temperature on the removal of MB were studied. The results show that the removal of MB was highly effected by preparation conditions of hydrogel. The maximum removal was observed at 10/90 IA/AMPS monomer ratio, 1.0% KPS, and 10.0% MBAAm concentrations. Removal of MB was strongly affected by pH. Pseudo-first-order, pseudo-second-order and intraparticle diffusion models were applied. It was concluded that adsorption of MB on hydrogel followed pseudo-second-order kinetics. It was found that the adsorption isotherm of the MB fit Langmuir-type isotherms. From the Langmuir equation, the adsorption capacity was found as 1,000 mg/g for MB dye. Thermodynamic parameters suggest that the adsorption is a typical physical process, spontaneous, and exothermic in nature. Ten adsorption—desorption cycles demonstrated that the hydrogels were suitable for repeated use without considerable change in adsorption capacity. The results revealed that this hydrogels have potential to be used as an adsorbent for the removal of MB from aqueous solution.