Sorption of Zn(II) and Pb(II) ions in the presence of the biodegradable complexing agent of a new generation

The macroporous chelating ion exchangers containing different functional groups i.e. Purolite S-920, Purolite S-930 and Lewatit TP-208 have been used in the sorption process of Zn(II) and Pb(II) ions. The effect of the presence of biodegradable, environmentally friendly aminopolycarboxylate chelating agent, trisodium salt of methylglycinediacetic acid (MGDA) on its sorption capacity was also examined. The investigations were carried out by the static method. Besides the effect of initial concentration of Zn(II) and Pb(II) and the complexing agent the research concerns the influence of solution pH, phase contact time on effectiveness of sorption. The equilibrium and kinetics of Zn(II)–MGDA and Pb(II)–MGDA complexes sorption were obtained and fitted using the Langmuir, Freundlich, Temkin and Dubinin–Radushkevich (D–R) models as well as the pseudo first and pseudo second order kinetic models. The intraparticle diffusion model was also used. The results showed that the sorption processes of Zn(II) and Pb(II) complexes with MGDA on Purolite S-920, Purolite S-930 and Lewatit TP-208 followed well the pseudo second order kinetics.     

Removal of toxic metals using superabsorbent polyelectrolytic hydrogels

Because of the presence of carboxylic acid moieties, poly(acrylic acid) possesses a unique ability to form stable complexes with divalent metal ions. However, its practical use for the removal of heavy metals from aqueous solutions is restricted because of its inherent water solubility. To address this issue, crosslinking of this polymer has been attempted to synthesize hydrogel, which is stable in aqueous medium over a wide range of pH values. The hydrogels, prepared by redox polymerization of acrylic acid in the presence of polyethylene glycol diacrylate as the crosslinker, were characterized by Fourier transform infrared spectrometry, elemental analysis, thermal analysis, and swelling studies. This chelating hydrogel‐bearing O, O donor groups exhibited high‐metal sorption capacity of 41.1, 58.2, 43.1, and 81.2 mg/g for Cr⁶⁺, Ni²⁺, Cu²⁺, and Pb²⁺, respectively, under optimum conditions. The effect of parameters including pH, concentration, and interference of common ions on metal uptake was also investigated. Langmuir and Freundlich adsorption isotherms have been used to validate the metal uptake data. High recovery (>97%) was achievable for all metal ions with 1N HCl as eluting agent, and the regeneration tests revealed that the sorbent could be used repeatedly for at least 10 cycles without any loss in chelating efficiency. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011.     

羧乙基硫代丁二酸水介质合成及阻垢缓蚀性能研究

采用水介质由巯基丙酸与顺丁烯二酸酐反应得到羧乙基硫代丁二酸(CETSA),并采用IR、1 HNMR及13 C NMR进行了结构表征。探讨了阴离子交换树脂、阳离子交换树脂及硫酸对反应的催化作用,结果表明三种催化剂催化效果相近。测定了CETSA钙螯合值为3119mg/g,阻垢性能及缓蚀性能测试表明,当CETSA质量浓度大于1.0×10-5时,阻垢率大于99%,CETSA对金属镁、锌有明显的缓蚀作用。     

8-羟基喹哪啶螯合树脂对Cr~（6＋）的吸附性能研究

研究了8-羟基喹哪啶螯合树脂（PS-HQD）在HAc-NaAc体系中对铬离子的吸附性能。结果表明,该树脂吸附Cr6＋的最佳pH为5.0,树脂吸附的平衡时间为8 h,吸附容量9.68 mg/g。表观速率常数k298=1.87×10^-4s^-1,一次洗脱回收率达94.3%。吸附过程符合Langmuir和Freundlich模型。     

Recent Advances in Bifunctional Paramagnetic Chelates for MRI

Magnetic resonance imaging (MRI) is a non-invasive diagnostic modality routinely employed in modern clinical medicine to collect images of the internal organs of the human body. Contrast agents (CA) are usually administered to patients to improve the sensitivity of this technique and nowadays these agents are gadolinium complexes. Bifunctional chelating agents (BFCAs) are dual molecules containing a multidentate ligand, able to strongly coordinate a metal ion, and a reactive moiety for conjugation purposes. With BFCAs an easy labelling of biomolecules or vectors with paramagnetic ions is possible, allowing the in vivo MRI visualization of diseases at cellular or molecular level.     

丙烯酸—马来酸酐共聚物钠盐无磷助洗剂的合成

以丙烯酸与马来酸酐为原料,采用水溶液聚合的工艺路线,合成了丙烯酸－马来酸酐共聚物钠盐,研究了单体配比、引发剂用量、反应温度对转化率、相对分子质量及助洗性能的影响。确定了最佳工艺条件及配方。评价了其助洗性能,确定了无磷洗涤剂中其最佳用量。结果表明一种性能优良的助洗剂,各项指标均达到国外产品水平,优于国内同类产品,可以代替STPP来生产无磷粉。     

N‐arylhydroxamic acids as mineral collectors for ore‐beneficiation

Several arylhydroxamic acids were synthesized, characterized and tested as collectors in the flotation of a Cu‐Zn sulphide ore. Arylhydroxamic acids floated copper in preference to iron and zinc minerals. Substitution in the N‐phenyl ring increased the efficiency of the collector. However, increase in alkyl‐chain beyond C₆ in the acyl group decreased the flotation efficiency of the collector. N‐butanoylphenylhydroxylamine was found to give the best result and floated about 93 wt% of Cu in about 32 wt% of the feed taken and the collector usage was only about 70 g per tonne of the ore. Pyrite flotation was minimum at pH 11.     

咖啡酸体外抗氧化活性的研究

咖啡酸是一种天然的酚类化合物,属于羟基肉桂酸类,它广泛存在于水果和蔬菜中,具有良好的生物活性。本文通过多种体系对咖啡酸的抗氧化活性进行综合评价,包括总抗氧化能力、DPPH自由基清除活性、ABTS自由基清除活性、铁离子还原能力和金属离子螯合能力等。结果表明:咖啡酸具有很强的总抗氧化能力,极显著高于BHT和VC(P0.01);具有较强的DPPH自由基(IC500.023 mg/m L±0.004 mg/m L)和ABTS自由基(IC500.18 mg/m L±0.006 mg/m L)清除活性;具有较强的铁离子还原能力并极显著高于BHT(P0.01)。咖啡酸几乎不具备金属离子螯合能力。     

新型纤维素蛇笼树脂对金属离子吸附性能研究

研究了蛇笼型螯合树脂二乙烯三胺交联甘油环氧树脂／羧甲基纤维素体系对Ag^ ，Cr^3 及Hg^2 的吸附量、吸附动力学、等温吸附过程等静态吸附性能，同时研究了pH值对吸附性能的影响。实验结果表明，该树脂对Ag^ 及Cr^3 具有较强的吸附选择性能，在Ag^ ，Cr^3 及Hg^2 3种离子共存时能选择吸附Ag^ ，其选择性系数分别为KAg^ ／Hg^2 =8．16，KAg^ ／Cr^3 =1.85、KCr^3 /Hg^2 =4．40。该树脂对上述3种离子的吸附量可分别达3．02、1．63、0．37mmol／g，可用于含重金属离子污水的处理和金属离子的分离等方面。