凹凸棒土应用于重金属离子吸附剂的研究

以新型无机矿物材料凹凸棒土作为吸附剂处理废水中的重金属离子。通过扫描电镜、红外光谱及等温吸附-脱附曲线对凹凸棒土进行了表征,并阐述了凹凸棒土对重金属离子的可能吸附机理。在室温下,分别将0.05 g凹凸棒土投入初始质量浓度为500 mg.L-1的Cu(Ⅱ)、Cd(Ⅱ)、Ni(Ⅱ)和Cr(Ⅵ)的溶液中,凹凸棒土对上述离子的平衡吸附量分别高达99、56、117、198 mg.g-1。结果表明,用凹凸棒土吸附废水中的重金属离子切实可行、经济有效。     

A pH-Sensitive Biopolymer-Based Superabsorbent Nanocomposite from Sodium Alginate and Attapulgite: Synthesis,Characterization, and Swelling Behaviors

Graft copolymerization reaction among sodium alginate (NaAlg), sodium acrylate (NaA), and nanoscale attapulgite (APT) was performed to fabricate a novel pH-sensitive NaAlg-g-PNaA/APT superabsorbent nanocomposite. FTIR spectra proved NaA monomers were grafted onto NaAlg backbone and APT participated in polymerization. FESEM, TEM, and TGA analyses revealed the better dispersion of APT fibrils in the matrix and the improved thermal stability. The swelling capacity and rate of the superabsorbent was clearly enhanced after introducing APT. The external salts and surfactants showed greater influence on the swelling behaviors. The nanocomposite exhibited reversible On-Off pH-sensitivity between pHs 2.0 and 7.4, and the intriguing pH-triggered deswelling behavior in various polyvinylperrodone (PVP) solutions was observed.     

Electrochemiluminescence of Carbon-based Quantum Dots: Synthesis,Mechanism and Application in Heavy Metal Ions Detection

In recent years, carbon-based quantum dots as luminophores and co-reactants have aroused broad interest for their ability to function in electrochemiluminescence (ECL) sensors due to their unique features, including excellent biocompatibility, low toxicity, and water solubility. In this mini review, the synthesis methods of carbon-based quantum dots are firstly introduced. Then, the mechanism of carbon-based quantum dots as luminophores and co-reactants and their latest progress application in the detection of heavy metal ions are explored. Finally, the current challenges and potential future development directions of carbon-based quantum dots in ECL sensing filed for heavy metal ions analysis are summarized.     

对二甲氨基苯甲酰腙衍生物与金属离子间的相互作用

合成了对二甲氨基苯甲酰缩噻吩(1)、呋喃(2)、苯(3)等腙类衍生物,并通过氢谱、碳谱和质谱进行表征,采用吸收光谱法研究了其与金属离子间的相互作用。结果表明,含噻吩基团的腙衍生物1与Hg2+结合,形成1∶1稳定的配合物,结合常数为9.7×104L·mol-1,噻吩衍生物1对Hg2+响应的线性范围为1.0~18μmol/L,检出限为0.28μmol/L,且Cu2+,Fe3+和Ni2+等共存金属离子不干扰测定。对照化合物中的呋喃衍生物2可1∶1结合Hg2+,Zn2+和Cd2+,其与Hg2+和Zn2+的结合常数分别为6.5×104L·mol-1和5.0×105L·mol-1;而苯衍生物3对测试的金属离子均未显示光谱变化。由此可见,化合物1对Hg2+的高选择性结合作用源于结合基团中不同配位原子的组合,其所含的S和O均参与了与Hg2+的配位作用。     

Sulfur-Doped Binary Layered Metal Oxides Incorporated on Pomegranate Peel-Derived Activated Carbon for Removal of Heavy Metal Ions

In this study, a novel biomass adsorbent based on activated carbon incorporated with sulfur-based binary metal oxides layered nanoparticles (SML-AC), including sulfur (S₂), manganese (Mn), and tin (Sn) oxide synthesized via the solvothermal method. The newly synthesized SML-AC was studied using FTIR, FESEM, EDX, and BET to determine its functional groups, surface morphology, and elemental composition. Hence, the BET was performed with an appropriate specific surface area for raw AC (356 m²·g⁻¹) and modified AC-SML (195 m²·g⁻¹). To prepare water samples for ICP-OES analysis, the suggested nanocomposite was used as an efficient adsorbent to remove lead (Pb²⁺), cadmium (Cd²⁺), chromium (Cr³⁺), and vanadium (V⁵⁺) from oil-rich regions. As the chemical structure of metal ions is influenced by solution pH, this parameter was considered experimentally, and pH 4, dosage 50 mg, and time 120 min were found to be the best with high capacity for all adsorbates. At different experimental conditions, the AC-SML provided a satisfactory adsorption capacity of 37.03–90.09 mg·g⁻¹ for Cd²⁺, Pb²⁺, Cr^3+, and V⁵⁺ ions. The adsorption experiment was explored, and the method was fitted with the Langmuir model (R² = 0.99) as compared to the Freundlich model (R² = 0.91). The kinetic models and free energy (<0.45 KJ·mol⁻¹) parameters demonstrated that the adsorption rate is limited with pseudo-second order (R² = 0.99) under the physical adsorption mechanism, respectively. Finally, the study demonstrated that the AC-SML nanocomposite is recyclable at least five times in the continuous adsorption–desorption of metal ions.     

纳米零价铁去除水中重金属离子的研究进展

重金属离子危害严重.本文综述了近几年纳米零价铁去除水中重金属离子的研究,总结了纳米零价铁去除水中重金属离子的机理,主要包括:纳米零价铁的表面吸附-配合、还原、吸附-还原,并对纳米零价铁在这一领域的应用进行了展望.     

磁性功能化酚醛树脂的合成及对金属离子的吸附性能

磁性功能化酚醛树脂的合成及对金属离子的吸附性能;环氧酚醛树脂;螯合;金属离子;溶胀;吸附容量;吸附动力学     

巯基硅球石墨烯复合材料的合成与重金属离子吸附

采用一锅法和水热法分别合成了单分散巯基修饰氧化硅球(MFS)及其石墨烯超轻复合材料(MFSGA)。利用X射线衍射、扫描电镜、红外光谱等方法对MFS和MFSGA的材料结构和形貌进行表征。MFSGA表现出良好的结构强度,MFS在复合材料中均匀分散。考察了材料粒径、修饰剂种类等因素对MFS形貌和表面结构的影响。采用X射线荧光法测试了MFS和MFSGA对Hg²⁺等重金属离子的吸附特性,二者对Hg²⁺的饱和吸附量分别为260.19和158.06 mg/g。MFS易于合成且应用经济性良好,MFSGA的结构稳定性好,易于回收与重复利用,具有较大的应用潜力。     

聚萘二胺的合成及其对重金属离子的高效反应吸附

聚萘二胺是继聚苯胺和聚吡咯之后的又一类新型导电高分子,因聚合物中含有活性 的自由胺基和亚胺基而具有新的多功能性.作者根据近期研究工作和国外最新文献,系统论述了聚1,8-、1,5-、2,3-萘二胺的化学氧化合成和电化学氧化合成及其对重金属离子的络合和还原吸附功能,详细比较了两种聚合方法的特点. 指出通过萘二胺的电化学氧化聚合可以方便地获得对重金属离子如Ag⁺、Pb²⁺、Hg²⁺、Cu²⁺、VO²⁺敏感的修饰电极,而通过化学 氧化聚合可以高产率地获得对Ag+具有极大的还原吸附容量的聚合物颗粒.聚萘二胺在痕量 金属离子的分析与探测、工业废水中贵金属离子的回收和重金属离子的清除等领域展现了广阔的应用前景.     

聚苯胺及其复合物对重金属离子的高效吸附性能

基于国外最新文献,系统总结了近年来聚苯胺及其复合物的制备方法及其重金属离子吸附性能,重点分析了吸附性能特征,指出聚苯胺及其复合物具有吸附下限浓度低、达到吸附平衡快以及解吸附性能优异等特点.填充有聚苯胺颗粒的吸附柱在动态处理初始浓度为83 ng/L的汞离子溶液时,经一次吸附与解吸循环操作后,汞离子的富集倍数可达120倍.应用于冷原子吸收光谱的待测样品的浓缩与富集,可以将汞的测试下限拓展到0.05 ng/L.聚苯胺及其复合物在痕量重金属离子的高效富集与灵敏探测等方面展示了广阔的应用前景.     

Polyaniline Modified CNTs and Graphene Nanocomposite for Removal of Lead and Zinc Metal Ions: Kinetics,Thermodynamics and Desorption Studies

A novel polyaniline-modified CNT and graphene-based nanocomposite (2.32–7.34 nm) was prepared and characterized by spectroscopic methods. The specific surface area was 176 m²/g with 0.232 cm³/g as the specific pore volume. The nanocomposite was used to remove zinc and lead metal ions from water; showing a high removal capacity of 346 and 581 mg/g at pH 6.5. The data followed pseudo-second-order, intraparticle diffusion and Elovich models. Besides this, the experimental values obeyed Langmuir and Temkin isotherms. The results confirmed that the removal of lead and zinc ions occurred in a mixed mode, that is, diffusion absorption and ion exchange between the heterogeneous surface of the sorbent containing active adsorption centers and the solution containing metal ions. The enthalpy values were 149.9 and 158.6 J.mol⁻¹K⁻¹ for zinc and lead metal ions. The negative values of free energies were in the range of −4.97 to −26.3 kJ/mol. These values indicated an endothermic spontaneous removal of metal ions from water. The reported method is useful to remove the zinc and lead metal ions in any water body due to the high removal capacity of nanocomposite at natural pH of 6.5. Moreover, a low dose of 0.005 g per 30 mL made this method economical. Furthermore, a low contact time of 15 min made this method applicable to the removal of the reported metal ions from water in a short time. Briefly, the reported method is highly economical, nature-friendly and fast and can be used to remove the reported metal ions from any water resource.     

负载型纳米二氧化钛对重金属离子吸附性能的研究

采用溶胶-凝胶法制备二氧化钛溶胶, 将其浸渍在硅胶上, 合成了负载型纳米二氧化钛材料, 以X射线衍射(XRD)、扫描电镜(SEM)等手段对其进行了表征. 以ICP-AES为检测手段, 系统地研究了负载型纳米TiO₂材料对重金属离子Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的吸附性能. 结果表明, 在pH 8～9范围内, 所研究的重金属离子均可被定量富集, 吸附的金属离子可用0.5 mol/L的HNO₃完全解脱. 负载型纳米二氧化钛对Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的静态吸附容量分别为8.3, 13.1, 12.6和5.1 mg/g, 与未负载的纳米二氧化钛相近. 将其应用于环境标准样品中Cd^2＋, Cr^3＋, Cu^2＋和Mn^2＋的分离富集与测定, 结果满意.     

蒙脱土表面键合配位体固相萃取填料的制备及其对重金属离子的吸附性能

通过酸洗、硅烷偶联剂表面活化、键合苯甲酰异硫氰酸酯对蒙脱土进行改性,制得新型固相萃取(SPE)材料。 采用红外光谱、扫描电子显微镜、X射线光电子能谱表征了改性蒙脱土的结构和形貌。 考察了制备的SPE填料对水中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺的吸附性能,确定了最佳固相萃取条件,对6种金属离子吸附容量分别为10.83、11.92、12.67、10.43、10.01及10.54 mg/g。 通过SPE与电感耦合等离子体质谱联用测定了样品中As³⁺、Bi³⁺、Cu²⁺、Sb³⁺、Sn²⁺和Pb²⁺ 6种重金属离子的含量,检出限分别为0.024、0.013、0.075、0.037、0.011和0.064 μg/L。     

辐射诱导合成水凝胶及其处理重金属废水的研究进展*

水凝胶是一种经适度交联而具有三维网络结构的新型功能高分子材料。制备水凝胶因操作简单、无须添加交联剂和引发剂等优点而受到关注。传统的处理重金属废水的方法或成本较高,或效率低,利用水凝胶处理重金属废水成为一种新的颇具潜力的方法。本文综述了辐射法制备水凝胶及其在重金属吸附去除方面的研究进展包括材料的制备、改性、去除重金属性能等方面的研究进展,并指出了水凝胶去除重金属的发展前景和今后的研究方向。     

Preparation of Iminoacetic Acid-type Composite Chelating Material IAA-PEI/SiO2 and Preliminary Studies on Chelating Adsorption Property towards Heavy Metal Ions

Polyamine polyethyleneimine (PEI) was first grafted on the surfaces of micro-sized silica gel particles in the manner of the coupling graft (the manner of “grafting to”), forming the grafting particles PEI/SiO₂. Subsequently, via a polymer reaction, the nucleophilic substitution reaction between the primary and secondary amino groups of the grafted PEI macromolecule and chloroactic acid (CAA), iminoacetic acid groups were bonded onto the grafted PEI chains, and an iminoacetic acid (IAA)-type composite chelating material, IAA-PEI/SiO₂, was formed. In this work, the preparation process of IAA-PEI/SiO₂ particles was mainly researched, and the effects of the main factors on the polymer reaction, i.e., the nucleophilic substitution reaction, were examined emphatically. The adsorption behavior of IAA-PEI/SiO₂ particles towards several kinds of heavy metal ions was preliminarily evaluated. The experiments results show that it is feasible to introduce IAA groups onto PEI/SiO₂ particles via the substitution reaction between CAA and the amino groups of the grafted PEI. The reaction rate is affected greatly by the feed ratio of the amino group of PEI to CAA, so the substitution reaction between CAA and the amino groups of the grafted PEI is a bimolecular nucleophilic substitution reaction (S_N2). The reaction temperature and the used amount of acid-acceptor NaHCO₃ affect the bonding rate of IAA groups greatly. The fitting temperature was 60°C, and 1:1 of the molar ratio of NaHCO₃ to CAA was an appropriate amount of acid-acceptor NaHCO₃. Under the above optimal reaction conditions and with 3:1 molar ratio of amino group of PEI to CAA, 72% of the IAA group bonding rate (it is based on the hydrogen atoms in the primary and secondary amino groups of the grafted PEI) in 8 h can be reached. The composite chelating material IAA-PEI/SiO₂ possesses a strong chelating adsorption ability for heavy metal ions because of the increase of the ligands and formation of stable five-membered chelate rings.     

钛酸盐纳米管与二硫化碳修饰钛酸盐纳米管的合成、表征及其去除重金属离子性能

在水热法制备钛酸盐纳米管的基础上, 通过形成黄原酸基反应合成了CS2修饰的钛氧纳米管. 采用粉末X射线衍射(XRD)、透射电镜(TEM)、红外光谱(FTIR)和拉曼光谱(Raman)等技术对产物进行了表征. 以水溶液中铅离子、铜离子和银离子作为目标重金属离子, 分别用纯钛酸盐纳米管和CS2修饰后的钛氧纳米管对其进行反应和吸附, 通过一系列对比性实验, 评价了不同形式纳米管去除重金属的能力. 实验结果表明, 与文献报道的吸附剂对重金属离子的吸附量相比, 纯钛酸盐纳米管和CS2修饰的钛氧纳米管吸附重金属离子的容量非常大, 尤其是经CS2修饰后的钛氧纳米管去除铅离子的能力明显增强, 它们去除重金属离子的能力还与重金属盐的阴离子、溶液的pH值相关. 在相同的pH条件下, 钛酸盐纳米管去除铅离子、铜离子和银离子的能力分别为599.37, 163.22和474.73 mg/g; CS2修饰的钛氧纳米管去除铅离子、铜离子和银离子的能力分别为663.37, 160.21和423.05 mg/g.     

Studies on Synthesis of a Cycloheptapeptide and Effects of Different Metal Ions on the Cyclization

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In situ One‐pot Electrochemical Synthesis of Aluminum Oxide/polyaniline Nanocomposite; Characterization and Its Adsorption Properties towards Some Heavy Metal Ions

Aluminum oxide/polyaniline nanocomposite is prepared by a new and one‐pot method including in situ electrooxidation of aluminum and electropolymerization of aniline. The product has been characterized by elemental analysis, FT‐IR spectroscopy, X‐ray diffraction (XRD), Field Emission Scanning Electron Micrographs (FESEM), and Transmission Electron Micrographs (TEM) techniques. ICP‐OES was used for determination of aluminum in the prepared nanocomposite. A porous structure of the prepared composite has been shown by FESEM images. TEM of the product confirms the presence of exfoliated aluminum oxide nanofibers. The adsorption potentials of the prepared nanocomposite towards Cu²⁺, Pb²⁺, Zn²⁺, Cd²⁺, Ni²⁺ and Co²⁺ ions were evaluated in batch adsorption experiments. The results show that the adsorption efficiency is controlled by aqueous phase pH. The experimental data was well interpreted by considering the Langmuir model. The kinetics of the adsorption processes can be well interpreted by pseudo‐second‐order equation.     

Assessment of Heavy Metal Pollution and Ecological Risk of Roadside Soils in Tlemcen (Algeria) Using Flame-Atomic Absorption Spectrometry

In Algeria, few studies have been conducted on the evaluation of roadside soil pollution. A total of 34 soil samples (28 roadside and 6 off-road) was obtained at 0–20?cm depth along the RN 35 national road. Heavy metal (Cd, Cr, Cu, Fe, Ni, Pb, and Zn) contents were extracted using aqua regia digestion and determined using atomic absorption spectrometry. Background values of heavy metal contents were determined using the robust statistical method of median plus two times the median absolute deviation. Single- and multi-element pollution and ecological risk indices were calculated. The results showed that background values were 2.5?±?0.3, 64.9?±?8.1, 28.0?±?4.1, 29371.5?±?4403.0, 32.9?±?4.4, 72.2?±?12.8, and 445.1?±?62.9?mg/kg for Cd, Cr, Cu, Fe, Ni, Pb, and Zn, respectively. The results were all higher than their corresponding median values. Single-element pollution indices (enrichment factor and geoaccumulation index) showed that the pollution is primarily due to Pb and Zn. Multi-element pollution index (Nemerow index) indicated that only 3% of the soil samples are strongly contaminated, whereas 23% are seriously contaminated. The potential ecological risk index showed that Cd is the most harmful element, followed by Pb and Zn. 65% of the soil samples had moderate potential ecological risk, while only 3% had considerable potential ecological risk. This study may be used as a baseline for future monitoring and as a tool for decision-making regarding environmental protection policies and sustainability of this semiarid agroecosystem.