Synthesis of Polyacrylaminothiourea Chelating Fiber and Properties of Concentration and Separation of Trace Noble Metal Ions from Samples

A novel polyacrylaminothiourea chelating fiber was synthesized simply andrapidly from nitrilon (an acrylonitrile-based synthetic fiber), which was applied to preconcentrateand separate of trace amount of Au(III), Pt(IV), Pd(IV) and Ir(IV) ions from solution of samples.The analyzed ions can be quantitatively concentrated by the fiber up to a flow rate of 20.0 mL/minat pH 2, and can also be desorbed with 15 mL of 4 mol/L HCl+3% thiourea from the fiber column withrecoveries of 96.5%-100%. The chelating fiber can be reused for ten times, the recoveries of theseions are still over 92%, and hundred to thousand times of excess of Fe(III), Al(III), Ca(II),Mg(II), Ni(II), Mn(II), Cu(II), Zn(II), and Cd(II) cause no interference on the determination of theanalyzed ions by inductively-coupled plasma atomic emission spectrometry (ICP-AES). The staticsaturation adsorption capacities of the fiber for the analytes are in the range of 1.15-2.80 mmol/g.The relative standard deviations for the determination of 20.0 ng/mL each of Au(III), Pt(IV),Pd(IV) and Ir(IV) are in the range of 0.7%-3.0%. The recoveries for test from standard additions toreal solution samples are between 96% and 100%. The concentration of each ion in powder sampledetected by the method is in good agreement with the certified value.

Fast removal of Pb^(2+) from water using new chelating fiber modified with acylamino and amino groups

The graft copolymerization of acrylic acid（AA） onto polyethylene glycol terephthalate（PET） fiber initiated by benzoy peroxide （BPO） was carried out in heterogeneous media.Moreover,modification of the grafted PET fiber（PET-AA） was done by changing the carboxyl group into acylamino and amino groups through the reaction with ethylenediamine.The new modified chelating fiber （NDWJN6） was characterized using elementary analysis,SEM and FT-IR spectroscopy.Adsorption kinetic curve indicated that NDWJN6 could fastly remove Pb^（2＋） from water,and adsorption isotherm also indicated that NDWJN6 had high equilibrium adsorption capacity for Pb^（2＋）.

Preparation and characterization of polyphenylene sulfide-based chelating fibers

A series of novel chelating fibers containing sulfur, nitrogen, oxygen heteroatoms were prepared via the functionalization of chloromethylated polyphenylene sulfide （CMPPS）. The structures, micromorpholo- gy and physicochemical properties of these fibrous adsorptive materials were characterized by FT-IR, elementary analysis, TG and SEM-EDS. The results show that chelating fibers had high functional group contents （3.94 mmol/g for thiourea, 3.85 mmol/g for mercapto, 5.00 mmol/g for methylamine and 6.07 mmol/g for ethylenediamine, respectively）. Owing to the unique matrix of polyphenylene sulfide fiber, these fibrous adsorbents possess excellent thermostability. This synthetic method proved a simple and efficient way for the preparation of chelating fibers.

Fast removal of heavy metal ions and phytic acids from water using new modified chelating fiber

The graft copolymerization of acrylic acid（AA） onto polyethylene glycol terephthalate（PET） fiber initialed by benzoy peroxide （BPO） was carried out in heterogeneous media.Moreover,modification of the grafted PET fiber（PET-AA） was done by changing the carboxyl group into acylamino group through the reaction with dimethylamine.The modified chelating fiber（NDWJN1） was characterized using elementary analysis,SEM and FT-IR spectroscopy.Adsorption kinetic curves indicated that NDWJNl could fast remove heavy metal ions and phytic acids from water effectively.Furthermore,batch kinetic studies indicated that heavy metal ions adsorbed to NDWJNl could be filted well by both pseudo-first-order and pseudo-second-order adsorption equations,but the intra-particle diffusion played a dominant role in the adsorption of phytic acids.