Henan Normal University

About: Henan Normal University is a education organization based out in Xinxiang, China. It is known for research contribution in the topics: Catalysis & Ionic liquid. The organization has 10863 authors who have published 11077 publications receiving 166773 citations.

Structural Effects of Anions and Cations on the Aggregation Behavior of Ionic Liquids in Aqueous Solutions

Abstract: The formation of ionic liquids aggregates in aqueous solution is of great importance to the future applications of ionic liquids. In this work, aggregation behavior of 1-alkyl-3-methylimidazolium salts [C8mim]X (X = Cl, Br, [NO3], [CH3COO], [CF3COO], [CF3SO3], and [ClO4]), 1-octyl-4-methylpyridinium bromide (4m-[C8pyr]Br), and 1-methyl-1-octylpyrrolidinium ([C8mpyrr]Br) has been investigated in aqueous solutions by conductivity, volume, fluorescence, dynamic light scattering, and transmission electron microscopy. The critical aggregation concentration (CAC), ionization degree of the aggregates alpha, the standard Gibbs energy of aggregation deltaG(m)degrees, the average aggregation number N, the apparent molar volumes at critical aggregation concentration V(phi,CAC), the apparent molar volumes in aggregation phase V(phi)mic, and the change of the apparent molar volumes upon aggregation deltaV(phi,m), have been derived from the experimental data for these ionic liquids. It is found that both nature of the anions and ring type of the cations significantly affect the aggregation in aqueous solution. The anionic effect basically follows the Hofmeister series, and the ability of anionic hydration is predominant for the aggregation behavior of the ionic liquids. Hydrophobicity and steric hindrance of the cations as well as binding strength of the cations with the anions are suggested to play important roles in the aggregation of [C8mim]Br, 4m-[C8pyr]Br, and [C8mpyrr]Br. The investigated ILs were found to form spherical aggregates. Structures of anions and cations have very weak effects on the morphology, but they do affect the aggregate sizes.

Photocatalytic degradation and kinetics of Orange G using nano-sized Sn(IV)/TiO2/AC photocatalyst

Abstract: Sn(IV) doped and nano-sized TiO 2 immobilized on active carbon (AC) (Sn(IV)/TiO 2 /AC) were prepared by the sol–gel and dip-calcination method. An azo dye, Orange G (OG), was used as a model compound to study its photocatalytic activity in a fluidized bed photoreactor. The addition of Sn(IV) on TiO 2 could greatly improve the activity of TiO 2 , and the optimal amount of tin was 2.5 at.%. The effects of calcination temperature, pH value, the initial hydrogen peroxide concentration ([H 2 O 2 ] 0 ), the catalyst amount ([TiO 2 ]), the initial OG concentration ([dye] 0 ) and co-existing negative ions on the photocatalytic activity of Sn(IV)/TiO 2 /AC were studied. The optimal conditions were as follows: pH 2.00, [H 2 O 2 ] 0 = 1.5mL/L, [dye] 0 = 50 mg/L, [TiO 2 ] = 12.5 g/L, when the 300 W high pressure mercury light was used as the light source. Under these conditions, the degradation efficiency of OG reached 99.1% after 60 min reaction. The kinetics of the OG degradation was also analyzed. The results showed that the kinetics of this reaction fit the Langmiur–Hinshelwood kinetics model well and the absorption of OG on the Sn(IV)/TiO 2 /AC surface was the controlling step in the whole degradation process. In addition, the catalyst, liquid and gas were separated effectively, and the integrative process of reaction and separation was achieved during the experiment.