Ferric carboxylmethyl konjacglucomannan gel microspheres (CMKGM-Fe) were prepared by cross-linking carboxyl methyl konjac glucomannan (CMKGM) with ferric ions (Fe3+). The complex of CMKGM-Fe/benzoic acid was characterized by IR spectroscopy. The adsorption capacity of CMKGM-Fe for benzoic acid was studied by UV–vis spectroscopy. Several parameters including the adsorption time, temperature, microsphere size, and the concentrations of CMKGM, FeCl3, and benzoic acid were investigated. The results showed that adsorption equilibrium could be established in about 11 h. When the temperature was 298 K, the CMKGM concentration was 1.5 % (w/v), the mass ratio of Fe3+ was 2.5 % (w/v), and the initial concentration of benzoic acid was 1000 mg·L–1 and the adsorption capacity attained 0.4954 mmol·g–1. According to the adsorption isotherms of benzoic acid on CMKGM-Fe, the thermodynamic parameters of adsorption process were calculated. The experimental data were fitted with the Freundlich equation, and it was found that the equation was suitable for the study of the investigated adsorption system. The entropy value of the system is negative, and cooling is beneficial for the adsorption, suggesting that the system is a spontaneous exothermic process.

Cr 2 O 3 catalysts were prepared by a precipitation method and tested for vapor phase fluorination of HCFC-1233xf (2-chloro-3,3,3-trifluoropropene) to HFC-1234yf (2,3,3,3-tetrafluoropropene) to investigate the effect of calcination temperature on the catalytic performance. The catalysts were characterized by XRD, Raman, NH 3 -TPD, and BET techniques. The results show, with increasing calcination temperature, the crystallite size of the catalyst increased while the surface acid sites decreased. It was found that the catalyst calcined at 500 °C exhibited the highest catalytic activity, with a HCFC-1233xf conversion of 63.3% and selectivies to HFC-1234yf and HFC-245eb (1,1,1,2,3-pentafluoropropane) of 59 and 38%, respectively, at a reaction temperature of 320 °C. Moreover, it was found that the carbon deposit on the surface was responsible for the deactivation of the catalyst during the reaction.

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Amorphous Cr2O3 materials with high surface areas were prepared via a precipitation process with CrCl3 · 6H2O as the raw material, (NH4)2CO3, NH3 · H2O, and KOH as precipitating agents. Calcination of Cr(OH)3 precipitation at low temperatures (300–400 °C) resulted in amorphous Cr2O3 materials with high surface areas, while high‐temperature calcination (500–600 °C) led to crystalline Cr2O3. The hydrogen‐adsorption phenomenon was clearly observed in a hydrogen atmosphere on the amorphous Cr2O3 materials with high surface area. The adsorbed hydrogen desorbed at about 550 °C due to the phase transition from amorphous to crystalline. However, this phenomenon was not observed for crystalline Cr2O3.