Xinshan Rong

Coupling with a narrow-band-gap semiconductor for enhancement of visible-light photocatalytic activity: preparation of Bi2S3/g-C3N4 and application for degradation of RhB

A coupled system for the photodegradation of Rhodamine B dye was realized using a Bi2S3/g-C3N4 composite as a photocatalyst under visible light irradiation. The Bi2S3/g-C3N4 composite was prepared by a hydrothermal method and characterized by Fourier transform-infrared spectroscopy (FT-IR), X-ray diffraction (XRD), UV-vis diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Compared with pure g-C3N4, the Bi2S3/g-C3N4 sample exhibits an enhanced photocatalytic activity and the best photocatalytic efficiency is 3.68 times more than that of pure g-C3N4. The obtained results indicate that a coupled system of Bi2S3 and g-C3N4 could overcome the drawback of low photocatalytic efficiency brought by electron–hole recombination and a narrow photoresponse range. On the basis of the corresponding energy band positions, the mechanism of photocatalytic activity enhancement was proposed.

Preparation and Properties of Waterborne Polyurethane Containing Hyperbranched Polyester Linkages

Different generations of hydroxyl-terminated hyperbranched polyesters (HBPEs) were synthesized in sequence, all of the HBPEs based on methyl methacrylate (MMA) and diethanolamine (DEA) as AB2 monomer and trimethylolpropane (TMP) as core molecule. Then a series of hyperbranched waterborne polyurethane dispersions (HPUs) were prepared with the 3rd generation hyperbranched polyester (HBPE-3) used as an original cross-linking agent in this article. The intrinsic viscosity of each HBPE vs temperature and properties of HPUs was studied. The experimental data indicated that, compared with the linear one, the hyperbranched HPU aqueous dispersion exhibited larger particle size and higher surface tension, when the hydroxyl-ratio was 1:6, the HPU achieved maximum particle size of 78.0 nm and surface tension of 52.48 mN/m, respectively. For the hyperbranched HPU films, the thermal stability and mechanical properties increased, resulting from the effects of the cross-linking structures in the HPU system.

Silver carbonate loaded on activated carbon composite photocatalyst with enhanced photocatalytic activity under visible light irradiation

A composite photocatalyst based on silver carbonate (Ag2CO3) loaded on activated carbon (AC) was prepared by ion-exchange deposition method. The obtained photocatalyst was characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), UV/Vis diffuse reflection spectroscopy (DRS), N2 adsorption–desorption measurements and transient photocurrent measurements. The removal efficiency of Ag2CO3/AC composite including adsorption and photodegradation was studied for degrading Rhodamine B (RhB) in aqueous solution under visible light irradiation. Compared with the pure Ag2CO3, the prepared composite catalyst has larger surface area and adsorption capacity of organic pollutants. It could be summarized that synergy of photodegradation and adsorption has a great improvement for the removal of RhB under visible light irradiation compared with that of only adsorption without light. A remarkable RhB removal efficiency of 96.6% was achieved by the prepared Ag2CO3/AC (20%) composite. The possible catalytic reaction mechanism of Ag2CO3/AC was also proposed.

Scale Inhibitor Copolymer Modified with Oxidized Starch: Synthesis and Performance on Scale Inhibition

A series of scale inhibitor copolymers modified with oxidized starch have been synthesized. The effects of content of monomer and initiator, reaction time, reaction temperature to inhibit calcium carbonate scale were studied by orthogonal experiment. The structure, thermal property and morphology of the copolymer were characterized by FT-IR, TGA and SEM. Using the static experiment method, the scale inhibition efficiency for CaCO3 scale was investigated. The experimental results showed that the scale inhibitor copolymer modified with oxidized starch had an excellent efficiency of scale inhibition, good tolerance of calcium and could be used in the high hardness water.

Removal of basic fuchsin dye from aqueous solutions using graphite oxide modified aromatic polyurethane foam material

Graphite oxide modified polyurethane foam (GO/PUF) was used for adsorption of basic fuchsin from aqueous solution and adsorption conditions were optimized to attain an efficiency of 99.5%. The adsorption isotherm was in agreement with the Langmuir model. Kinetic study followed pseudo-second order. Determination of Gibbs free energy and enthalpy change of adsorption indicated spontaneous and endothermic adsorption behavior, suggesting that the adsorbent had a potential for the removal of dyes from industrial wastewater.