聚乙烯亚胺改性蔗渣纤维素/蒙脱土复合球的制备及对Cd(Ⅱ)的吸附

以甘蔗渣纤维素（SBC）和蒙脱土（Mt）为原料，碳酸钙为致孔剂，通过简单凝固浴法制备PEI-SBC/Mt复合小球。采用FTIR、SEM、XRD等对所制备的球形吸附剂结构进行了表征，并系统研究了该吸附剂对模拟废水中的镉离子Cd(Ⅱ)的吸附行为。结果表明，拟二级动力学模型和Langmuir模型能够准确描述吸附过程，在温度为25 ℃、pH=6、Cd(Ⅱ)初始质量浓度为600 mg/L时PEI-SBC/Mt对Cd(Ⅱ)的最大吸附量为234.3mg/L ，表明吸附过程是单分子化学吸附，PEI的加入为吸附剂吸附Cd(Ⅱ)提供了更多的活性位点。此外，吸附剂具有可重复使用性，经过5次循环吸脱附后，其吸附量只由原有的94%降至79.8%。     

磁性水滑石对Cd(Ⅱ)的吸附性能

文章利用四氧化三铁对水滑石进行磁化改性,通过SEM、FTIR对其形貌进行表征,探究该材料去除水中Cd(Ⅱ)的热力学模型和动力学模型。SEM、FTIR表征结果证明:磁化后表面形态有较大的改善、结构官能团变化不大。实验表明:磁性水滑石对Cd(Ⅱ)的吸附在90 min基本完成,最大吸附量为34.722 mg·g~(-1),吸附模型符合Langmuir吸附等温模型和Lagergren准二级动力学模型。     

竹炭对水溶液中Cu(Ⅱ)、Cd(Ⅱ)的吸附性能研究

研究了竹炭对溶液中Cu2+、Cd2+的吸附性能,考察了吸附时间、溶液pH值、吸附温度和溶液初始浓度对吸附效果的影响,同时研究了活性炭对Cu2+、Cd2+的吸附性能。结果表明,竹炭能有效吸附水溶液中的Cu2+、Cd2+,且单位吸附量均随时间的延长而增加,均在14 h左右达到平衡,吸附速度快于活性炭;相同pH值条件下,竹炭的单位吸附量明显高于活性炭,吸附效果最佳的pH值分别为3.8左右和7.5左右;当吸附温度为15,25,45℃时,竹炭对Cu2+的最大吸附量分别为4.13,4.45,4.23 mg/g,而竹炭对Cd2+的最大吸附量分别为0.81,1.05,2.01 mg/g。竹炭对Cu2+、Cd2+的吸附均符合Freundlich方程和Langmuir方程。     

改性膨润土对废水中Cd(II)的吸附特征及吸附动力学研究

为探讨改性膨润土对Cd(II)的吸附特征及吸附动力学机制,通过吸附实验探讨了pH值、初始浓度和吸附时间对改性膨润土吸附Cd(II)的影响。结果表明,盐酸改性膨润土对Cd(II)的去除率表现为随溶液pH值升高而升高,而氢氧化钠改性膨润土、膨润土与十二烷基磺酸钠改性膨润土的去除率分别在pH=6和7时达到最大值。膨润土及改性膨润土对Cd(II)的去除率随初始浓度的增加而降低,吸附量随平衡浓度增加而增大,并趋向平稳,吸附符合Langmuir方程,吸附为单分子层吸附。膨润土及改性膨润土的吸附反应在240 min内基本达到平衡,吸附动力学分析表明吸附过程更符合准二级动力学模型,吸附过程以化学吸附为主,膨润土及改性膨润土的吸附速率大小依次为K2HCl-B＞K2NaOH-B＞K2B＞K2SDS-B,液膜扩散与颗粒内扩散过程均为控速步骤。该研究可为改性膨润土处理含镉废水和修复镉污染土壤提供参考。     

改性泥炭对Pb(Ⅱ)和Cd(Ⅱ)的单一及竞争吸附研究

以强碱改性泥炭,研究改性泥炭对Pb⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾的吸附效果及竞争吸附机制。结果表明,改性泥炭对Pb(2+)的吸附效果及竞争吸附机制。结果表明,改性泥炭对Pb⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾具有显著的吸附效果,吸附容量分别由118,64 mg/g提高到225,95 mg/g;FTIR分析表明,吸附过程为Pb(2+)具有显著的吸附效果,吸附容量分别由118,64 mg/g提高到225,95 mg/g;FTIR分析表明,吸附过程为Pb⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾与—OH、—COO-、C—H等官能团的络合作用或者离子交换作用。当吸附时间为70 min,pH在4～8,改性泥炭添加量分别为0.8,1.6 g/L时,可达到高效与经济双层效益。竞争吸附中,Pb(2+)与—OH、—COO-、C—H等官能团的络合作用或者离子交换作用。当吸附时间为70 min,pH在4～8,改性泥炭添加量分别为0.8,1.6 g/L时,可达到高效与经济双层效益。竞争吸附中,Pb⁽²⁺⁾、Cd(2+)、Cd⁽²⁺⁾的吸附容量均低于单一离子时的吸附容量,且竞争吸附能力Pb(2+)的吸附容量均低于单一离子时的吸附容量,且竞争吸附能力Pb⁽²⁺⁾>Cd(2+)>Cd⁽²⁺⁾。     

改性泥炭对Pb(Ⅱ)和Cd(Ⅱ)的单一及竞争吸附研究

以强碱改性泥炭,研究改性泥炭对Pb~(2+)、Cd~(2+)的吸附效果及竞争吸附机制。结果表明,改性泥炭对Pb~(2+)、Cd~(2+)具有显著的吸附效果,吸附容量分别由118,64 mg/g提高到225,95 mg/g;FTIR分析表明,吸附过程为Pb~(2+)、Cd~(2+)与—OH、—COO-、C—H等官能团的络合作用或者离子交换作用。当吸附时间为70 min,pH在4～8,改性泥炭添加量分别为0.8,1.6 g/L时,可达到高效与经济双层效益。竞争吸附中,Pb~(2+)、Cd~(2+)的吸附容量均低于单一离子时的吸附容量,且竞争吸附能力Pb~(2+)Cd~(2+)。     

壳聚糖-DMC-GA共聚物对Cr(Ⅵ)和Cd(Ⅱ)的吸附性能

以壳聚糖为原料、甲基丙烯酰氧乙基三甲基氯化铵（DMC）为接枝单体、硝酸铈铵为引发剂、Span-80为乳化剂、戊二醛（GA）为交联剂,通过反相乳液聚合技术制备了壳聚糖-DMC-GA共聚物,对其进行表征并将其用于吸附水溶液中单一金属离子Cr（Ⅵ）、Cd（Ⅱ）和双元体系Cr（Ⅵ）-Cd（Ⅱ）,考察了吸附动力学和吸附平衡规律。共聚物的红外光谱和X射线光电子能谱分析表明：壳聚糖与DMC发生了接枝反应,与戊二醛发生了交联反应。吸附实验结果表明：在单一金属离子溶液中,共聚物对1 mmol/L的Cr（Ⅵ）和Cd（Ⅱ）的平衡吸附量分别为1.974和1.396 mmol/g;在双元体系中,共聚物对1 mmol/L的Cr（Ⅵ）和Cd（Ⅱ）的平衡吸附量分别为1.906和1.204 mmol/g;吸附过程均符合拟二级动力学方程,吸附等温线均与Langmuir模型更为一致,说明共聚物对2种金属离子的吸附是单分子层吸附。     

Mg-土吸附剂的吸附性能

Mg-土吸附剂是由含镁黏土经物理方法提纯,再于250℃热活化处理20min后,制得一种新的吸附材料。重点考察了Mg-土吸附剂对铜离子的吸附性能,正交实验结果表明,Mg-土吸附剂在吸附温度60℃,吸附时间30min条件下,达到吸附平衡时对Cu2+离子的吸附量为50.816mg/g,吸附率为99.99。证明了Mg-土吸附剂对Cu2+离子具有较强的吸附能力,是一种处理含铜废水的理想吸附材料。     

羊骨炭对Pb(Ⅱ)、Cr(Ⅵ)、Cd(Ⅱ)吸附性能研究

以CO2为活化剂制备羊骨炭,在不同溶液pH、初始浓度、活性炭投加量等条件下,通过动态吸附试验考察羊骨炭对Pb(Ⅱ)、Cr(Ⅵ)和Cd(Ⅱ)的吸附规律,并用Langmuir和Freundlich吸附等温模型对其吸附性能进行了分析。结果表明,当羊骨炭对Pb(Ⅱ)、Cr(Ⅵ)和Cd(Ⅱ)的最佳吸附量分别为:4.2 mg/g、0.07 mg/g和2.7 mg/g时,吸附液的pH值Pb(Ⅱ)、Cd(Ⅱ)为7～8、Cr(Ⅵ)为酸性pH<6;羊骨炭的投加量分别为:0.2、0.7、0.03 g;最佳初始浓度分别为:60 mg/L、15 mg/L、30 mg/L。羊骨炭对3种离子的吸附行为基本符合Langmuir吸附等温模型和Freundlich吸附等温模型,计算得四种离子的最大吸附量分别为:4.854、1.247、0.402 mg/g。     

Cu(Ⅱ)印迹交联壳聚糖吸附剂的制备与选择性吸附的研究

采用Cu(Ⅱ)离子为印迹离子,以壳聚糖为原料,甲醛为预交联剂,环氧氯丙烷为交联剂,通过微波法制备出改性壳聚糖吸附剂。考察了合成过程中操作条件对吸附剂吸附性能的影响。结果表明,当壳聚糖质量分数为6%、17.4 m L甲醛、8.76 m L环氧氯丙烷、酸化t为10 h、θ为70℃时,所得Cu(Ⅱ)印迹交联壳聚糖吸附剂对Cu(Ⅱ)的吸附容量高达3.466 mmol/g;在混合金属离子溶液中,该吸附剂对Cu(Ⅱ)表现出较强的吸附选择性。     

Removal of Cd（II） by Nanometer AIO（OH） Loaded on Fiberglass with Activated Carbon Fiber Felt as Carrier

A new nanometer material, nanometer AlO（OH） loaded on the fiberglass with activated carbon fibers felt（ACF） as the carrier, was prepared by hydrolytic reaction for the removal of Cd（II） from aqueous solution using column adsorption experiment. As was confirmed by XRD determination, the hydrolysis production loaded on fiberglass was similar to the orthorhombic phase AlO（OH）. SEM images showed that AlO（OH） particles were in the form of small aggregated clusters. The Thomas model was applied for estimating the kinetic parameters and the saturated adsorption ability of Cd（II） adsorption on the new adsorbent. The results showed that the maximum adsorption capacity of Cd（II） was 128.50 mg·g^-1 and 117.86 mg·g^-1 for the adsorbent mass of 0.3289 g and the adsorbent mass of 0.2867 g, respectively. The elution experiment result indicated that the adsorbed Cd ions was easily desorbed from the material with 0.1 mol·L^-1 HCl solution. Adsorption-desorption cycles showed the feasibility of repealed uses of the composited material. The adsorption capacities were influenced by pH and the initial Cd（II） concentration. The amount adsorbed was greatest at pH 6.5 and the initial Cd（II） concentration of 0.07 mg·L^-1, respectively. Nanometer AlO（OH） played a major role in the adsorption process, whereas the fiberglass and ACF were assistants in the process of removing Cd（II）. In addition, the adsorption capacities for Cd（II） were obviously reduced from 128.50 mg·L^-1 to 64.28 mg·L^-1 when Pb ions were present because Pb ions took up more adsorption sites.     

球形零价铁生物炭吸附Cd(II)的性能和机制

本研究提供了一种一步热解法制备纳米零价铁生物炭的方法。将海藻酸铁在高温缺氧条件下热解制备了球形零价铁生物炭复合材料（ZVIBC），考察了Cd(II)溶液pH、初始浓度、吸附时间、背景离子、空气中老化时间对ZVIBC吸附Cd(II)性能的影响，通过FTIR、XRD、XPS、EDS等方法对ZVIBC以及ZVIBC-Cd(II)进行了表征，研究了ZVIBC对Cd(II)的吸附机理。结果显示：pH对ZVIBC吸附Cd(II)有显著的影响，4为最佳吸附pH条件。ZVIBC吸附Cd(II)的过程符合Langmuir模型，拟合的饱和吸附量为240 mg/g。主要吸附机理为：活性官能团（O—H、C—O、C=C、C=O、COO）与Cd(II)形成配合物，以及Cd(II)与Fe2+生成Cd(OH)2沉淀。     

海藻酸镧颗粒除氟研究：吸附剂物性和吸附机理

Lanthanum alginate bead is a new, highly active adsorbent. In the present study, we investigated its ad- sorption performance and its adsorption mechanism. The adsorption isotherm for fluoride onto lanthanum alginate b ead fits the Langmuir model well, and the maximum adsorption capacity is 197.2 mg·g-1. X-ray diffraction shows the amorphous nature of lanthanum alginate bead, which allows for better accessibility to fluoride and thus better activity. Infrared spectra of lanthanum alginate bead before and after adsorption confirm its stable skeletal structure. Scanning electron microscopy shows that the dense surface structure of the adsorbent appear cracks after adsorption. T he adsorption mechanism of lanthanum alginate bead is considered as an ion exchange between F- and Cl- or OH-, as verified from the adsorbent and the solution by pH effect, energy dispersive X-ray, and ion chromatography.     

Adsorption and desorption of copper(II) from solutions on new spherical cellulose adsorbent

An investigation was conducted on the adsorption and desorption of copper(II) from aqueous solutions with a new spherical cellulose adsorbent containing the carboxyl anionic group. Various factors affecting the adsorption were optimized. The adsorption of Cu²⁺ ions on the adsorbent was found to be dependent on the initial time and pH, the concentration, and the temperature. The adsorption process follows both Freundlich and Langmuir adsorption isotherms and was found to be endothermic (ΔH = 23.99 kJ/mol). The Cu²⁺ ions adsorbed on the adsorbent can be recovered with a NaOH or HCl aqueous solution. The maximum percentage of recovery is about 100% when 2.4 mol/L HCl solution is used. In addition, only 7.2% of the adsorption capacity is lost after 30 replications of the adsorption and desorption. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 84: 478–485, 2002; DOI 10.1002/app.10114     

Preparation and adsorption performance of a cellulosic‐adsorbent resin for copper(II)

The adsorbent resin was prepared by grafting copolymerization of acrylic acid and acrylamide onto cellulose under microwave irradiation, and was applied to adsorb copper ions from wastewater. The influences of adsorption time, resin particle size, pH values, and temperature of solution on its adsorption performance were investigated. At the optimal adsorption conditions, adsorption ratio could get to 99.2% and the adsorption capability reached 49.6 mg/g. Furthermore, adsorption theory model was based and study showed that the physical adsorption was dominating and it accorded to Freundlich isotherm model. XPS of adsorbent resin complex was tested, which ensured the chelating groups onto adsorbent surface. Adsorbent resin could be regenerated using 8% NH₃·H₂O, which had good regeneration effect, and experiment showed that adsorption ratio could still keep over 90% when resin was regenerated seven times. So, heavy metal‐ions could be reclaimed from gel resin and the circulation of resources could be realized. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci, 2006     

Highly efficient and fast adsorption of Au(III) and Pd(II) by crosslinked polyethyleneimine-glutaraldehyde

An adsorbent (PEI-GA) is prepared by crosslinking polyethyleneimine with glutaraldehyde. PEI-GA shows outstanding adsorption performance towards Au(III) and Pd(II). PEI-GA presents large adsorption capacity towards Au(III) in a wide application pH range from 1 to 9. The adsorption capacities of PEI-GA for Au(III) and Pd(II) at 25°C reach 2575 and 497 mg/g, respectively. Au(III) and Pd(II) can be adsorbed completely within 10 min for 8.3 mg/L Au(III) and 20 min for 9.7 mg/L Pd(II). The adsorption equilibrium time required for 523.9 mg/L Au(III) and for 565.6 mg/L Pd(II) is 2 and 9 h, respectively. The Sips model is the most suitable to describe the adsorption isotherms which leads to more realistic adsorption capacities for both metals. PEI-GA also exhibits high selectivity and repeatability towards Au(III) and Pd(II). The adsorption mechanism involves redox, chelation coordination, and electrostatic interactions for Au(III), and coordination and electrostatic interactions for Pd(II).     

Sorption of Pb(II), Cd(II) and Zn(II) by iminodiacetate chelating resins in non-competitive and competitive conditions

Two chelating resins (CRs) bearing iminodiacetate (IDA) groups derived from acrylonitrile - divinylbenzene (AN-DVB) copolymers having 10 and 15 wt.% nominal cross-linking degrees and a high mobility of the functional groups caused by the presence of a longer spacer between the matrix and the IDA groups were synthesized and tested as sorbents for heavy metal ions like: Pb(II), Cd(II) and Zn(II) from aqueous solutions by batch and column techniques. Experimental data obtained from batch equilibrium tests have been analyzed by two isotherm models: Freundlich and Langmuir. The overall adsorption tendency of CRs toward Pb(II), Cd(II) and Zn(II), under non-competitive conditions, followed the order: Cd(II) > Pb(II) > Zn(II). Selectivity studies were performed in ternary mixture of Pb(II), Cd(II) and Zn(II) to check if the synthesized CRs can be useful for selective separation of heavy metal cations. The results revealed that the CRs with IDA groups exhibited high selectivity toward Pb(II), both in batch and column techniques. Regeneration of the resins was achieved using 0.1 M HCl solution.     

High adsorption of Cd (II) by modification of synthetic zeolites Y,A and mordenite with thiourea

Zeolites Y, A and mordenite (ZY, ZA and ZM) were obtained from diatomite in a template-free system, and the products were modified by thiourea (TU). Characterization studies results indicated that the TU molecules were loaded onto the exterior surfaces of the synthetic zeolites as well as the channels. Elemental analysis and energy-dispersive X-ray spectrometer proved that the TU molecules loaded on to ZA were more than ZY and ZM. Removal of Cd(II) was investigated, and it was found that the modified zeolites have higher removal capacity, modified ZA is especially noticeable. In the adsorption experiments, the effects of various parameters such as sorbent content, contact time, concentration of cadmium solution, pH, selectivity and regeneration were discussed. At the best removal efficiency by modified zeolites, the maximum adsorption capacity is 94.3 mg·g⁻¹, 103.2 mg·g⁻¹ and 89.7 mg·g⁻¹ at 25 °C, respectively. The sorbents show good efficiency for the removal of Cd(II) in the presence of different multivalent cations and have good regeneration effect. For the modified samples, removal experiments take place via ion exchange and complexation processes.     

Preparation and characterization of magnetic polymethylmethacrylate microbeads carrying ethylene diamine for removal of Cu(II), Cd(II), Pb(II), and Hg(II) from aqueous solutions

Magnetic polymethylmethacrylate (mPMMA) microbeads carrying ethylene diamine (EDA) were prepared for the removal of heavy metal ions (i.e., copper, lead, cadmium, and mercury) from aqueous solutions containing different amount of these ions (5–700 mg/L) and at different pH values (2.0–8.0). Adsorption of heavy metal ions on the unmodified mPMMA microbeads was very low (3.6 μmol/g for Cu(II), 4.2 μmol/g for Pb(II), 4.6 μmol/g for Cd(II), and 2.9 μmol/g for Hg(II)). EDA‐incorporation significantly increased the heavy metal adsorption (201 μmol/g for Cu(II), 186 μmol/g for Pb(II), 162 μmol/g for Cd(II), and 150 μmol/g for Hg(II)). Competitive adsorption capacities (in the case of adsorption from mixture) were determined to be 79.8 μmol/g for Cu(II), 58.7 μmol/g for Pb(II), 52.4 μmol/g for Cd(II), and 45.3 μmol/g for Hg(II). The observed affinity order in adsorption was found to be Cu(II) > Pb(II) > Cd(II) > Hg(II) for both under noncompetitive and competitive conditions. The adsorption of heavy metal ions increased with increasing pH and reached a plateau value at around pH 5.0. The optimal pH range for heavy‐metal removal was shown to be from 5.0 to 8.0. Desorption of heavy‐metal ions was achieved using 0.1 M HNO₃. The maximum elution value was as high as 98%. These microbeads are suitable for repeated use for more than five adsorption‐desorption cycles without considerable loss of adsorption capacity. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 78: 81–89, 2000