A novel magnetic bio-material (MCIT) was synthesized via coupling reaction and functional modification after load of Fe3O4 nano-particle on the puckered surface of cyclosorus interruptus (CI). The synthesized material was characterized by fourier transform infrared (FTIR), field emission scanning electron microscope (FE-SEM), X-ray photoelectron spectroscopy (XPS) and X-ray powder diffractometer (XRD). The influence factors like pH, temperatures, contact time, initial concentration and cycle times on the adsorption of Hg (II) in aqueous solution were studied. Adsorption isotherm, kinetics, selectivity and mechanism were investigated. The results indicated that the isotherm model well agreed with monolayer adsorption model. The adsorption process could be divided into three steps, which included a fast step controlled by chemical adsorption, a slow step limited by intraparticle diffusion and an equilibrium stage. The maximum adsorption capacity of Hg (II) was 385.3 mg/g at 318 K. MCIT possessed high reusability (retained 93% after five successive cycles) and sharply magnetic nature (9.5 emu/g), which endowed it easy and efficient separation from aqueous solution.Download high-res image (116KB)Download full-size image

PS-PAMAM-IDA chelating resins were prepared by low-generations of polyamidoamine (PAMAM) and then chloroacetic acid functionalizing commercially available ammoniated polystyrene matrix, to preconcentrate Ni2+ from synthetic aqueous samples. Different generations of PAMAM were used to obtain different chelating resins, PS-IDA, PS-1.0G PAMAM-IDA and PS-2.0G PAMAM-IDA. The synthesized resins were characterized by FTIR and elemental analysis. The effect of solution pH, kinetic studies, resin loading capacity, matrix effects etc., on metal ion adsorption to adsorbent phase, were studied by batch method. The PS-1.0G PAMAM-IDA resin was the most excellent adsorbents, with a maximum adsorption capacity of (24.09±1.79) mg/g for Ni2+ ion at pH=7. The interpretation of the equilibrium data was given by Langmuir isotherms model, and the correlation coefficient values for PS-IDA, PS-1.0G PAMAM-IDA and PS-2.0G PAMAM-IDA resins were 0.992, 0.994 and 0.987, respectively.

Graft copolymers of poly(methyl methacrylate) and polyamide-6 (PMMA-g–PA6) were investigated via in situ anionic polymerization of ε-caprolactam, using PMMA precursors with N-carbamated caprolactam pendants (PMMA–CCL) as macroactivators and sodium caprolactamate as catalyst. Three grades of PMMA–CCLs obtained by free radical copolymerization were used for synthesizing the PMMA-g–PA6 copolymers with different PMMA content. The resulting graft copolymer was characterized by Fourier-transform infrared spectroscopy and selective extraction. Scanning electron microscopy is used to clarify the phase morphology of obtained polymer by fracture surface. The thermal property, crystallinity and dimensional stability of graft copolymer were studied using differential scanning calorimetry, X-ray diffraction and water absorption measurement. The results show the Tg of graft copolymer is higher than that of neat PA6, but the onset and peak points of graft copolymer melting point are shifted to lower temperature. The percentage crystallinity and water absorption of PMMA-g–PA6 copolymer decrease with increasing PMMA content, but the crystal structure of PA6 is scarcely affected by the presence of PMMA. Graft copolymers have improved dimensional stabilities relative to neat PA6. Upon the incorporation of 19.9 wt% PMMA into PA6, the water absorption of PMMA-g–PA6 copolymer has been reduced from 4.8 for neat PA6 to 2.1%.

In recent years, resins prepared via molecular imprinting technology have received considerable attention owing to their recognition and selective adsorption. This paper deals with the comparative investigation between a uranyl sulphate imprinted ion-exchange based on self-assembling molecular imprinting technology and two kinds of commercial uranium resins (the medium pore resin D263 and strong base resin 201 × 7). The studies were focused on their kinetics performance, adaptability toward pH, and performance of saturation and elution in laboratory-scale column. The results show that the imprinted ion exchange resin has the fast kinetics, high adaptability toward pH, and good adsorption and elution performance.

•Cyclosorus interruptus was used as precursor for the development of new biosorbent for lead ions removal.•Cyclosorus interruptus has an excellent selective biosorption property to Pb (II).•The maximum biosorption capacity of Pb(II) determined according to the Langmuir model was 46.25 mg g−1 at 25 °C.•The new biosorbent have a short equilibrium time (about 60 min) which is of great significance for developing a biosorbent material for water-treatment technology.Cyclosorus interruptus (abbreviated as CI thereafter) is a perennial growth and disease resistant plant abundant in China. In this study, CI was used as a biosorbent for the removal of Pb(II) from aqueous solutions. The selective adsorption experiments were conducted and found that the CI has an excellent selective property to Pb (II) adsorption. The Langmuir isotherm model yields a much better fit than that of Freundlich isotherm model in describing Pb(II) adsorption. The biosorption process fitted well to pseudo-second-order kinetics and equilibrium was attained in about 30 min. The activation energy (Ea) of Pb(II) biosorption was determined at 12.79 (kJ mol−1) which indicated that biosorption may be an activated chemical biosorption. The equilibrium data was analyzed using the Langmuir models. The maximum biosorption capacity of Pb(II) determined according to the Langmuir model was 46.25 mg g−1 at 25 °C. The FITR, XRD and SEM were also studied for CI. The results showed that CI was a excellent biosorbent for adsorption of Pb(II) from an aqueous solution.Download high-res image (152KB)Download full-size image

•CI was used as precursor for the development of new adsorbents for U(VI) removal.•CI has an excellent selective property to U(VI) adsorption by nature.•The stem of CI has a good adsorption capacity compared to the leaf and root of CI.•The unpolluted CI showed its superiority in adsorption capacity than the polluted CI.•The MgCl2/H2O2 is found to be more effective than CaCl2 and MgCl2 for CI modification.Batch experiments were conducted to investigate the biosorption of U(VI) onto Hottentot Fern (Cyclosorus interruptus). The selective adsorption, the adsorption of different sections of Cyclosorus interruptus (CI), and the adsorption of polluted CI compared with that of unpolluted one were studied in detail. The raw CI and the CI modified by CaCl2, MgCl2, MgCl2/H2O2 were investigated for adsorption of U(VI) from aqueous solution. The results indicate that raw CI showed good adsorption selectivity for U(VI), compared with the adsorption of Cu(II), Co(II) and Ni(II). The stem of CI possesses a prominent adsorption capacity compared to the leaf and root of CI, and the unpolluted CI showed its superiority in adsorption capacity than the polluted CI. Adsorption rate was very fast during the first 30 min in the whole adsorption process. The pseudo-second-order kinetics model was proposed for the adsorption of U(VI) and the equilibrium data fitted well to Langmuir adsorption isotherms. The maximum adsorption capacity of R-CI, Ca-CI, Mg-CI and Mg/H2O2-CI is 41.67, 52.63, 62.50 and 71.43 mg g−1 at 20 °C, respectively.