Acylation modification of konjac glucomannan and its adsorption of Fe (â ¢) ion.

A biodegradable adsorbent, modified konjac glucomannan (MKGM), was prepared by konjac glucomannan (KGM) acylated with phthalic anhydride catalyzed using concentrated sulfuric acid. The modified conditions such as reaction temperature, mass ratio of phthalic anhydride to KGM, catalyst dosage and reaction time were investigated, respectively. MKGM exhibited preferable adsorption performance for the removal of Fe (Ⅲ) ion. The adsorption behavior was discussed using the Langmuir and Freundlich isotherm models. The results showed that the Freundlich linear model was suitable for describing the adsorption process of Fe (Ⅲ). The maximum adsorption capacity of MKGM for Fe (Ⅲ) ion was 31.87 mg g-1 at 298 K. The kinetics studies suggested that adsorption process followed the pseudo-second-order model and the adsorption process was mainly controlled by both surface reactivity and intra-particle diffusion. Together with the evaluation of the thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes, the results indicated that the adsorption process of Fe (Ⅲ) was endothermic, feasible, and spontaneous in nature. Hence, as a bioadsorbent, the MKGM has a promising potential for the removal of Fe (Ⅲ) ion from aqueous solutions.

Iron-Cobalt Phosphomolybdate with High Electrocatalytic Activity for Oxygen Evolution Reaction.

Iron-cobalt phosphomolybdate (FeCoPM12 ) nanoparticles, which are highly efficient catalytic materials for the oxygen evolution reaction (OER), were fabricated through a coprecipitation route. Compared with iron-cobalt hydroxide and state-of-the-art RuO2 electrocatalysts, the as-prepared FeCoPM12 sample exhibited robust OER catalytic activity with a low overpotential of 258 mV at a current density of 10 mA cm-2 and a small Tafel slope of 33 mV dec-1 . Moreover, the as-synthesized sample presented preferable stability and after 10 h at 1.52 V the current density degraded by merely 8.3 %. This is ascribed to the high electrochemical stability and small porous structure of FeCoPM12 , which provide effective electron transmission and improve the catalytic performance for OER in alkaline media.

[The interface fluorescence and resonance scattering spectral properties of Ag2S nanoparticles in liquid phase].

S2- and Ag+ form stable Ag2S nanoparticles in the presence of sodium dodecyl sulphate (SDS). It exhibits a strong resonance scattering peak at 470 nm and a strong fluorescence peak at 470 nm when excitation wavelength is at 200 nm. The effects of TAA and Ag+ concentration on the fluorescence intensities are consistent with those on the resonance scattering signals. The resonance scattering and fluorescence intensities all increase with Ag+ concentration in the range of 0-8.0 x 10(-5) mol x L(-1). The results verified that there is a correlation between the fluorescence and resonance scattering. The fluorescence is the interface fluorescence of Ag2S nanoparticles in liquid phase.