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The position of Pd species in/on zeolites is crucial for activity of metal/metal oxide catalysts. It is still a challenge to highly disperse and stabilize the metal species on zeolites and shorten ...

The present study aims to investigate the adsorption of anionic dye, alizarin red s (ARS), on activated clay modified by iron oxide (Fe-clay) in a batch reactor. The adsorption process reached equilibrium within 90 min, and the removal efficiency increased with the enhancement of initial dye concentration, adsorbent dosage, and contact time, but decreased with the enhancement of solution pH. The adsorption kinetics was investigated according to three theoretical models, but the best fit was achieved by the pseudosecond-order kinetics model. The adsorption isotherms could be well-defined with the Langmuir isotherm model instead of the Freundlich isotherm model, and the calculated maximum adsorption capacity was found to be 32.7 mg g–1. The obtained results indicate that Fe-clay is suitable for adsorption of ARS from aqueous solutions.

A series of Aerosol-OT (AOT, sodium bis(2-ethylhexyl)sulfosuccinate) analogue fluorinated surfactants, i.e., the sodium salt of bis(2,2,3,3,3-pentafluoropropyl) 2-sulfosuccinate (di-CF2), the sodium salt of bis(2,2,3,4,4,4-hexafluorobutyl)2-sulfosuccinate (di-HCF3), the sodium salt of bis(3,3,4,4,5,5,6,6,6-nonafluorohexyl)2-sulfosuccinate (di-HCF4), and the sodium salt of bis(2,2,3,3-tetrafluoropropyl) 2-sulfosuccinate (di-HCF2), were synthesized and characterized by 1H NMR, 13C NMR, 19F NMR, melting point, and elemental analysis. The pressure−temperature (P−T) phase diagrams for water-in-CO2 (W/CO2) and water-in-1,1,1,2-tetrafluoroethane (W/HFC-134a) microemulsions stabilized by the surfactants were determined. In this work, the phase behaviors for different surfactants are obtained in supercritical CO2 (scCO2) and 1,1,1,2-tetrafluoroethane (HFC-134a) as a function of temperature, pressure, and water-to-surfactant ratio. At a fixed temperature, the cloud-point pressures increased with the increase of wat...

Dyeing of ramie fiber with C.I. disperse red 74 (DR74) at the temperatures from 343.15 to 403.15 K and under the pressures of 12−20 MPa has been thoroughly investigated using supercritical carbon dioxide (scCO2) as a solvent. Ramie fiber was first treated with alkali and then with benzoyl chloride to improve the affinity and interaction between disperse dye and ramie fiber. The morphological and structure transformations in fiber induced by pretreatment were determined by a Fourier transform infrared spectrometer (FT−IR), X-ray diffraction (XRD), scanning electro-microscopy (SEM), differential scanning calorimetry (DSC), and thermogravimetry analysis (TGA). The modification of ramie fiber with benzoyl chloride was characterized by a degree of substitution (DS). The damage to ramie fiber caused by pretreatment and scCO2 dyeing was determined by stress−strain measurements. The color strength of the fiber was evaluated by K/S measurements. The dyeing effects have been studied by means of time, pressure, temp...