海藻酸钠基吸附材料去除水中重金属离子的研究进展

重金属污染是当今工业发展所面临的一个重要环境问题之一,由于吸附法具有原材料来源广泛、价格低廉、可循环利用等特征,被认为是一种绿色环保的重金属离子去除方法.海藻酸钠是一种天然多糖,其表面存在大量对重金属离子吸附能力优良的羟基和羧基,目前已被广大科研人员用于实验室吸附材料的制备及研究.通过表面嫁接、交联等改性手段制备的海藻...     

表面离子印迹聚合物金属离子吸附材料研究进展

离子印迹聚合物吸附材料对模板离子具有强识别能力,对其可实现高选择吸附,因而离子印迹技术常用于制备高选择性吸附材料。但传统方法制备的离子印迹吸附材料,因识别位点容易被包埋导致其吸附容量小、吸附-脱附速率低,而表面离子印迹技术则是采用模板离子和聚合单体直接在载体表面或附近区域构筑选择性识别位点,所有活性位点均暴露,从而有效地解决了上述问题。本文从技术原理与合成原料、制备工艺方法以及载体材料类型等方面对表面印迹聚合物吸附材料近期研究进展情况进行了概述。针对相关研究现状,从载体材料、功能单体、目标离子等角度分析和讨论了表面离子印迹聚合物吸附材料当前发展中的不足及其所面临的挑战,并对表面离子印迹技术发展趋势和前景进行了展望。     

Nickel(Ⅱ) removal from water using silica-based hybrid adsorbents:Fabrication and adsorption kinetics

A series of novel silica-based hybrid adsorbents were prepared by the crosslinking reaction of N-[3-(trimethoxysilyl)propyl] ethylene diamine(TMSPEDA) with epichlorohydrin(ECH) via a sol–gel process.Fourier transform infrared(FTIR) spectra confirmed that the reaction occurred.TGA curves showed that the thermal stability of these hybrid adsorbents reached as high as 180 °C.As a typical example,the adsorption performance of nickel(II) ions onto an adsorbent(the volume ratio of TMSPEDA and ECH was 4:1) was explored.It was found that the adsorption of nickel(II) ions onto this adsorbent followed the Lagergren pseudo-second-order kinetic model.The investigation of the adsorption mechanism demonstrated that nickel(II) adsorption was chiefly controlled by diffusion–chemisorption,suggesting that more diffusion processes were involved in the adsorption of nickel(II) ions onto this type of adsorbents.Desorption experiment indicates that these hybrid adsorbents can be regenerated.These findings reveal that this type of silica-based hybrid adsorbent is promising in the separation and recovery of nickel(II) ions from Ni-containing wastewater or contaminated water.     

Chemically modified sunflower stalks as adsorbents for color removal from textile wastewater

Quaternary ammonium groups were chemically grafted onto sunflower stalks in order to improve their adsorption performance to anionic species in wastewater. The chemically modified sunflower stalks were evaluated as adsorbents for two basic dyes (Methylene Blue and Basic Red 9) and two direct dyes (Congo Red and Direct Blue 71) in aqueous solutions by using equilibrium isotherms and kinetic adsorption. Before the modification, sunflower stalks exhibited relatively low adsorption to the direct dyes but very high adsorption to the basic dyes. The modified sunflower stalks showed increased adsorption to the anionic dyes, but slightly reduced adsorption to the cationic dyes, due to the existence of quaternary ammonium ions on the surface of the residues. The maximum adsorption capacities of two direct dyes on the modified sunflower stalks are 191.0 and 216.0 mg g for Congo Red and Direct Blue 71 at 50°C, respectively, which were at least four times higher than that of the unmodified residues. The adsorption rates of two direct dyestuffs are much higher on the modified residues than on the unmodified ones. Within 30 min, about 80% of direct dyes were removed from the solutions by the residues. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 71: 1841–1850, 1999     

CrO4 2− Ions Adsorption by Fe-Modified Pozzolane

Abstract

A Fe-modified pozzolane was prepared and employed for the removal of CrO₄ ^2? ions from aqueous solution under batch type experiments as a function of contact time, initial concentration of metal ion and temperature. The adsorption isotherms are described by means of Freundlich, Langmuir, and Dubinin-Radushkevich (D-R) models. The pozzolane was characterized by XRD diffraction analysis. The results showed that the maximum adsorption capacity of Fe-modified pozzolane for CrO₄ ^2? ions was (3.23 ± 0.01)×10^?3 mmol g^?1. The adsorption was found to be initial concentration and temperature dependent. The thermodynamic parameters values such as ΔH⁰, ΔG⁰, and ΔS⁰ were obtained to predict the nature of adsorption. These values show that the adsorption reaction is endothermic and spontaneous. The results show that the Fe-modified pozzolane, that is an easily available material, can be successfully used as adsorbent of anionic species, such as CrO₄ ^2? ions in aqueous solutions, and can be an alternative for more costly adsorbents used for chromates removal in wastewater treatment processes.     

菌丝体-甲壳素水处理剂对重金属离子吸附性能的研究

The adsorption properties of chitin adsorbent from mycelium of fermentation industries for the removal of heavy metal ions were studied.The result shows that the chitin adsorbent has high adsorption capacity for many heavy metal ions and Ni^2 in citric acid.The influence of pH was significant:When pH is higher than 4.0,the high adsorption capacity is obtained.otherwise H^ ion inhibits the adsorption of heavy metal ions.The comparison of the chitin adsorbent with some other commercial adsorbents was made,in which that the adsorption behavior of chitin adsorbent is close to that of commercial cation exchange adsorbents,and its cost is much lower than those commercial adsorbents.     

介孔Cr(OH)3的制备及其对钒(Ⅴ)离子的吸附性能

以CrCl₃·6H₂O作为铬源,通过添加强碱制备出大比表面积（312.70 m²·g^-1）、高孔隙率（0.48 cm³·g^-1）的介孔Cr（OH）₃,并研究了其对溶液中钒（V）离子的吸附性能,考察了溶液pH、吸附剂用量、吸附温度、吸附时间等条件对吸附效果的影响。结果表明,当溶液pH在2.0~9.0、钒离子浓度为100~500 mg·L^-1时,采用该吸附剂均可实现溶液中钒离子的高效去除。在最优实验条件下,钒去除率接近100%,钒离子浓度可由500 mg·L^-1降至0.81 mg·L^-1。吸附热力学的研究结果表明,Cr（OH）₃对钒离子的吸附过程遵循Langmuir等温吸附;吸附过程符合拟二级反应动力学方程,反应级数为拟二级。     

Adsorption of cationic-anionic surfactant mixtures on activated carbon

This paper reported the adsorption of cationic-anionic surfactant mixtures, such as octyltriethylammonium bromide/sodium dodecylbenzenesulfonate (OTEAB/SDBS) and dodecylpyridinium chloride/sodium octanesulfonate (DPC/SOS), on activated carbon (AC) in deionized water and in mineralized water systems. The AC surface chemistry was characterized by X-ray photoelectron spectroscopy and ζ-potential determinations. It was observed that in deionized water solution, the addition of SOS obviously promoted the adsorption of DPC, while the existence of OTEAB increased the adsorption of SDBS first and then decreased that slightly with increasing SDBS concentration. In mineralized water solution, the addition of cationic (anionic) surfactants reduced the adsorption of anionic (cationic) surfactants. It was shown that the adsorption of the surfactants on the AC was predominated mainly by the hydrophobic interaction between AC surface and surfactants because of the low oxygen content and very low ζ-potential on the AC surface. There might exist synergism between cationic and anionic surfactants when adsorbing on AC in deionized water due to the electrostatic interaction between oppositely charged surface active ions. Such synergism might be greatly weakened when a large number of inorganic salts exist owing to the “screen” effect of the counter ions of the salt on the electrostatic attraction of oppositely charged surface active ions.     

离子强度对吸附有机污染物影响的研究进展

吸附由于其高效、低成本、易操作等特点,是目前国内外应用最广泛、最有效的废水处理方法之一。废水成分复杂,尤其是存在的背景离子会通过改变吸附剂和吸附质的相互作用影响有机物的吸附效果,造成主要吸附机制难以确认、吸附条件难以优化等问题。因此,研究离子强度对废水中有机物吸附性能的影响是提高吸附处理废水效果的重要途径。本文以吸附剂种类进行分类,阐述了在最常见氯化钠盐存在条件下钠离子和氯离子对于各类吸附剂吸附分离废水中有机物的影响,总结了各个研究者对此所做的研究,并以此展望了在离子存在条件下吸附剂在废水处理中的应用发展,指出开发新型、高效、经济、绿色、环保的吸附剂必将成为未来的发展趋势。     

Silica nanoparticles modified with a Schiff base ligand: An efficient adsorbent for Th(IV), U(VI) and Eu(III) ions

Modification of SiO₂ nanoparticles by salicylaldiminepropyl results in efficient adsorbents for removal of Th⁴⁺, UO ₂ ²⁺ and Eu³⁺ ions from aqueous solutions. The effect of parameters influencing the adsorption efficiency such as aqueous phase pH, contact time, initial metal ions concentration, adsorbent dosage and temperature dependency of the process was verified and discussed. Under optimal conditions (pH 5.5, adsorbent dosage 0.05 g, contact time 30 min. and 25 °C), thorium and uranyl ions (initial concentration 20 mg/l) were quantitatively removed from 20 ml of sample solution. Under such conditions 85% of europium ions was removed. Comparison of the adsorption efficiency of the studied modified nano-particles with those unmodified ones shows a shift for uptake of the metal ions vs. pH curves towards lower pH values by applying the modified adsorbents. In addition, a significant improvement of europium ions adsorption was observed by using the modified nanoparticles. Kinetics of the process was studied by considering a pseudo second-order model. This model predicts chemisorption for the adsorption mechanism. Freundlich, Langmuir and Temkin models were suitable for describing the equilibrium data of Th⁴⁺, UO₂ ²⁺ and Eu³⁺ adsorption process, respectively. Thermodynamic investigation reveals the adsorption process of the studied ions is entropy driven.     

Removal of strontium ions from aqueous solution using hybrid membranes: Kinetics and thermodynamics

The removal of radionuclide from radioactive wastewater has captured much attention. Strontium-90 is one of the major radionuclides. To develop a new type of adsorbents to remove strontium ions from the radioactive wastewater, in this study, novel hybrid membranes were prepared and characterized. The adsorption kinetics, thermodynamic parameters of ΔG, ΔH and ΔS, as well as surface SEM and EDS images were used to investigate the removal of strontium ions from stimulated radioactive wastewater using the previously prepared hybrid membranes as efficient adsorbents. The study of kinetic model confirmed that the adsorption of strontium ions on these hybrid membranes followed the Lagergren pseudo-second order model. Moreover, it was proved that the adsorption of strontium ions on these samples was solely controlled by intraparticle diffusion. The negative values of ΔG and the positive values of ΔH indicated that the adsorption of strontium ions on samples A-D is a spontaneous and endothermic process in nature. Furthermore, surface SEM and DES images give significant evidence to confirm the existence of strontiumions on the surface of the adsorbed samples. These findings demonstrate that these hybrid membranes are promising adsorbents for the removal of strontium ions from aqueous solution and can be potentially applied in the adsorptive separation of radionuclides from the radioactive wastewater.     

Adsorption of Congo Red from Aqueous Solutions Using Chitosan Hydrogel Beads Formed by Various Anionic Surfactants

The structural organization of chitosan hydrogel beads (CSBs) formed by various anionic surfactants, sodium dodecyl sulfate (SDS), sodium decyl sulfate (DS), dodecyl benzenesulfonic acid sodium salt (SDBS), and dioctyl sulfosuccinate sodium salt (DSS), and their applications as adsorbents for environmental purifications were investigated using Congo red (CR) as a model dye. The adsorption capacities of CSB as a function of surfactant concentration revealed that CSBs formed by 5 g/L anionic surfactant were the most effective for CR adsorption. The structure of CSBs and their adsorption capacities for CR depend on the nature of anionic surfactants. The maximum adsorption capacities of CSB_SDS, CSB_DS, CSB_SDBS, and CSB_DSS obtained from the Langmuir isotherm model were 186.02, 209.28, 207.25, and 113.83 mg/g, respectively, indicating that CSB_DS was the best adsorbent for CR.     

Adsorption of congo red by three Australian kaolins

This study investigated the potential use of kaolin as alternative adsorbents for removal of congo red from wastewater. The effect of adsorbent dosage, dye concentration, pH and temperature were experimentally studied to evaluate the adsorption capacity, kinetics and equilibrium. Experimental results revealed that optimal adsorption took place at acidic pH and high dye concentration. Ceram kaolin had the highest removal efficiency among studied kaolins, followed by K15GR and Q38. The dye uptake process obeyed the pseudo-second order kinetic expression and was best described by the Langmuir isotherm. Intra-particle diffusion studies showed that the adsorption mechanism was not exclusively controlled by the diffusion step and was more likely to be governed by external mass transfer. Thermodynamic studies showed congo red adsorption on all kaolins was exothermic and spontaneous in nature. Recovered Q38 and K15GR kaolin demonstrated an enhanced adsorption capability. The results indicate that these local kaolins could be employed as low-cost alternatives for removal of anionic dyes from industrial wastewater.     

Removal of uranium ions from liquid radioactive waste using modified aluminosilica

This study focused on the synthesis of mesoporous aluminosilica monoliths to be used as highly sensitive adsorbents for the removal of U(IV) ions from aqueous solutions. The adsorbents are prepared through functional immobilization of 3-glycidoxypropyltrimethoxysilane (GPS) followed by a nitrogen containing ligand. SEM, TEM, SAXS, nitrogen adsorption, TGA, TDA, and elemental analysis were used to characterize the prepared mesoporous adsorbent. The uptake behavior of the modified aluminosilica toward U(VI) under different experimental conditions of pH, time, and concentration was studied. Based on our results, these unique features of the adsorbents allow highly efficient removal of U(IV) ions from liquid nuclear waste.     

Unravel the potential of zinc oxide nanoparticle-carbonized sawdust matrix for removal of lead(Ⅱ) ions from aqueous solution

Zinc oxide nanoparticles(ZnOnp) are molecular nanoparticles synthesized by a chemical precipitation method from zinc nitrate tetrahydrate and sodium hydroxide.Carbonized sawdust(CSD) was prepared from sawdust obtained from a local wood mill.The matrix of both provides a better material as an adsorbent.The present study applied the functionality of ZnOnp,CSD,and ZnOnp-CSD matrix as adsorbent materials for the removal of Pb(Ⅱ) ions from aqueous solution.The method of batch process was employed to investigate the potential of the adsorbents.The influence of pH,contact time,initial concentration of adsorbate,the dosage of adsorbents,and the temperature of adsorbate-adsorbent mixture on the adsorption capacity were revealed.The adsorption isotherm studies indicate that both Freundlich and Langmuir isotherms were suitable to express the experimental data obtained with theoretical maximum adsorption capacities(q_m) of 70.42,87.72,and 92.59 mg·g~(-1) for the adsorption of Pb(Ⅱ) ions onto ZnOnp,CSD,and ZnOnp-CSD matrix,respectively.The separation factors(R_L) calculated showed that the use of the adsorbents for the removal of Pb(Ⅱ) ions is a feasible process with R_L 1.The thermodynamic parameters obtained revealed that the processes are endothermic,feasible,and spontaneous in nature at 25-50℃.Evaluation of the kinetic model elected that the processes agreed better with pseudo-second order where the values of rate constant(k_2) obtained for the adsorption of Pb(Ⅱ) ions onto ZnOnp,CSD,and ZnOnp-CSD matrix are 0.00149,0.00188,and 0.00315 g·mg~(-1)·min~(-1),respectively.The reusability potential examined for four cycles indicated that the adsorbents have better potential and economic value of reuse and the ZnOnp-CSD matrix indicates improved adsorbent material to remove Pb(Ⅱ) ions from aqueous solution.     

Removal of Pb(II) from Aqueous Solution by Cross-linked Starch Phosphate Carbamate

The adsorption process of Pb(II) ions from aqueous solution by water-insoluble starch phosphate carbamates was investigated. The influences of adsorption conditions, such as adsorption time, adsorbent dose, pH, content of the substituent groups, initial Pb(II) concentration, and temperature, were thoroughly studied. It was shown that an adsorption time of 20 min is sufficient to reach the adsorption equilibrium, the adsorption equilibrium data follow well the Langmuir isotherm model, and the adsorption of Pb(II) ions on cross-linked starch phosphate carbamate is endothermic in nature. For the cross-linked starch phosphate carbamate (CSPC3) with a phosphate group content of 3.10 mmol/g and a carbamate group content of 1.40 mmol/g, the maximum adsorption capacity evaluated from the Langmuir isotherm towards Pb(II) is 2.01 mmol/g. In addition, repeated adsorption/desorption cycles were performed to examine the reusability of adsorbents and the recovery efficiency of Pb(II) ions. The adsorption capacity of Pb(II) ions by CSPC3 decreased from 1.85 to 1.47 mmol/g for three cycles.     

氨基丙二醇功能化硼螯合树脂的制备及其硼酸吸附性能

分别用3-氨基-1,2-丙二醇（3-APD）和2-氨基-1,3-丙二醇（2-APD）对多孔氯甲基聚苯乙烯树脂（CMPS）进行修饰,制备得到含邻、间位二羟基官能团的硼螯合树脂：PS-3-APD和PS-2-APD。用傅里叶红外光谱仪（FTIR）、元素分析仪（EA）、压汞仪（MIP）和激光粒度仪（LPS）对材料进行表征,确认功能单体成功接枝于氯球上。对两种树脂进行了静态提硼性能研究,分别考察了原料液pH、初始硼酸浓度、外来金属离子对硼酸吸附量的影响,当溶液pH为9.15～9.20时,两种树脂对硼酸吸附量最大;溶液中Na⁺、Mg²⁺、Ca²⁺的存在会一定程度削弱树脂对硼酸吸附性能。吸附动力学表明其吸附速率较快,且均满足准二级动力学模型。与Freundlich相比,吸附等温线更符合Langmuir模型,拟合得到的理论最大吸附量分别为0.730mmol/g和0.868mmol/g。本文对未来新型硼螯合树脂的开发及工业化应用提供参考和指导。     

Synthesis and adsorption performance of fly ash/steel slag-based geopolymer for removal of Cu (II) and methylene blue

In order to realize the value-added resource utilization of solid waste, geopolymer particle adsorbents were prepared at low temperatures using silica-aluminum-rich fly ash and steel slag powders as raw materials. In order to investigate the mechanism of their adsorption of dyes and heavy metal ions from wastewater, the effects of steel slag/fly ash ratio, adsorbent dosage, initial concentration of methylene blue (MB) and Cu²⁺ solution, adsorption time and temperature on the adsorption performance of the fly ash/steel slag-based geopolymer adsorbents were investigated, systematically. Results presented that the adsorption capacities of MB and Cu²⁺ were 33.30 and 24.15 mg/g, and the removal efficiencies were 99.90% and 96.59% with the dosages of 3 and 4 g/L geopolymer adsorbents (steel slag/fly ash ratio of 20 wt.%), respectively. The adsorption processes of MB and Cu²⁺ on the adsorbents were in accordance with the proposed pseudo-second-order and Langmuir isotherm models, which mainly included physical and chemical adsorption mechanisms. The adsorption was a spontaneous endothermic process. The fly ash/steel slag-based geopolymer had good removal ability for dyes and heavy metal ions, and it could maintain good adsorption performance after three cycles of regeneration. It had potential application in wastewater treatment.     

Evaluation of sorbents for thiophene removal from liquid hydrocarbons

Thiophene is a commonly occurring sulfur compound in liquid hydrocarbon streams produced in a petroleum refinery. The concentration of thiophene often needs to be reduced to very low levels for most applications. Selective adsorption of thiophene is investigated in n-heptane, 1-octene and xylenes and their mixtures. A variety of adsorbents were tested for their selectivity and adsorption capacity. Improvements in adsorption capacity were attempted based on analysis of the adsorption mechanism. Adsorption capacity of NaX zeolite was found to be highest among tested adsorbents. However, competitive adsorption from xylenes reduced adsorption capacity for thiophene from mixtures containing large concentration of xylenes. Langmuir model is applied to describe observed competitive adsorption. Selective adsorption of organic sulfur compound could be used as a polishing step in a purification scheme which allows sulfur removal from hydrocarbons at low temperature and without the use of expensive hydrogen.     

新型除氟吸附材料的研究进展

半导体、稀土开采等行业所排放的氟废水所引发氟中毒现象备受关注。吸附法是去除废水中氟离子的有效方法之一,但传统吸附剂存在吸附容量低、选择性差等缺点,亟需研发具有高吸附容量、可再生且无二次污染的吸附材料。本文归纳了一些新型吸附材料,如高分子材料吸附剂、生物炭、层状双氢氧化物、工业废弃物、纳米材料及其改性材料在含氟废水中的研究应用;总结了这些改性材料的制备过程,介绍了这些材料吸附除氟的能力,分析了新型吸附材料吸附除氟的机理以及共存离子干扰、pH适用范围等影响因素,并指出了材料制备存在的问题,提出了制备对氟离子具有高选择性能的改性吸附材料的发展方向和材料循环利用所需解决的重要问题。