Lijuan Pang

Preparation and characterization of superhydrophobic organic-inorganic hybrid cotton fabrics via γ-radiation-induced graft polymerization

A new kind of non-fluorine-based organic-inorganic hybrid superhydrophobic cotton fabric was successfully prepared by simultaneous radiation-induced graft polymerization of γ-methacryloxypropyl trimethoxy silane (MAPS) and subsequent end-capping modification with hexamethyldisilazane (HMDS). The chemical structure and surface topography of the pristine and modified cotton fabrics were investigated in detail by ATR-FTIR, XPS, (29)Si NMR, SEM and TGA to confirm that the graft reaction and end-capping modification had taken place. The above results demonstrated that the grafting polymerization and following end-capping reaction were completed, and a grafting layer was immobilized onto the surface of the cotton fabric. Surface wettability measurement and oil-water separation showed that the modified cotton surface not only exhibited the superhydrophobicity with a water contact angle of 165°, but also afforded a high efficiency of oil-water separation (96%). In particular, this modified cotton fabric retains superhydrophobicity even after 30 laundering cycles or 400 cycles of abrasion.

Functionalized and reusable polyethylene fibres for Au(III) extraction from aqueous solution with high adsorption capacity and selectivity

A new chelating polyethylene fibre was synthesised by the radiation-induced graft copolymerisation of glycidyl methacrylate (GMA) onto ultrahigh-molecular-weight polyethylene (UHMWPE) fibres and subsequent ring-opening reaction with 4-amino-1,2,4-triazole. The chemical structure and surface morphology of the modified fibres were characterised by Fourier transform infrared spectroscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The adsorption behaviour of the fibrous sorbent for Au(III) was investigated in terms of aqueous-solution pH, contact time, initial metal concentration and competition of coexisting metal ions. Resultant fibres exhibited much higher affinity and selectivity for Au3+ ions than all other metal ions (Mg2+, Fe3+, Cu2+, Ca2+, Ni2+ and Cr6+). The affinity coefficient obtained was as high as 97.5–99.9%. The maximum adsorption amount for Au3+ was 429.4 mg g−1. The adsorption of Au(III) followed the pseudo-second-order kinetics model controlled by chemical adsorption. The equilibrium data fitted the Langmuir isotherm model well. In particular, this fibrous adsorbent can be regenerated by treatment in 0.5 M thiourea and 0.5 M H2SO4 solution. The high adsorption capacity can be maintained after at least five adsorption–desorption cycles.