Adsorption behavior of water and xylene isomers on AlPO-5 zeolite modified by different transition metals

Dehydration of Organic Solvents from Ternary Mixtures Containing Toluene/Methanol/Water by Pervaporation

The separation of a toluene/methanol/water ternary mixture is a difficult task due to the toluene/water and toluene/methanol azeotropes. In this article, low-energy pervaporation is proposed for the separation of the ternary azeotrope toluene-methanol-water. This work investigates the effects of feed temperature, feed flow rate, and vacuum on pervaporation and compares the energy consumption of pervaporation with that of distillation. The results showed that at the optimized flow rate of 50 L/h and a permeate side vacuum of 60 kPa at 50 °C, the water and methanol content in the permeate was about 63.2 wt.% and 36.8 wt.%, respectively, the water/ methanol separation factor was 24.04, the permeate flux was 510.7 g/m2·h, the water content in the feed out was reduced from 2.5 wt.% to less than 0.66 wt.%, and the dehydration of toluene methanol could be realized. Without taking into account the energy consumption of pumps and other power equipment, pervaporation requires an energy consumption of 43.53 kW·h to treat 1 ton of raw material, while the energy consumption of distillation to treat 1 ton of raw material is about 261.5 kW·h. Compared to the existing distillation process, the pervaporation process consumes much less energy (about one-sixth of the energy consumption of distillation). There is almost no effect on the surface morphology and chemical composition of the membrane before and after use. The method provides an effective reference for the dehydration of organic solvents from ternary mixtures containing toluene/methanol/water.

Facile synthesis of ZnMoO4/AlPO4-5 nanorod composites as visible-light-driven photocatalysts and high-performance energy storage materials

The present article describes the facile one-step hydrothermal synthesis of single-crystalline ZnMoO4/AlPO4-5 nanorod composites. The physicochemical properties of the synthesized materials, such as structure, morphology, and bandgap, were determined using techniques such as X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), N2 adsorption-desorption isotherms, X-ray photoelectron (XPS), ultraviolet-visible (UV-vis), and photoluminescence (PL). The XRD pattern of synthesized ZnMoO4/AlPO4-5 verifies the synthesis of nanocomposites. Diffuse UV-vis spectra reveal that ZnMoO4/AlPO4-5 nanorod composites exhibit an indirect semiconductor with an optical bandgap between 3.15 and 3.7 eV depending on Mo : Zn ratio. In comparison to pure AlPO4-5, ZnMoO4/AlPO4-5 nanocrystal composites showed significantly higher photocatalytic activity for the degradation of para-nitrophenol (PNP, 0.04 g l-1), with 14, 99, 70, and 54% for AlPO4-5, Mo : Zn (2)/AlPO4-5, Mo : Zn (4)/AlPO4-5, and Mo : Zn (6)/AlPO4-5, respectively. This result might be attributed to the composite's efficient charge transfer and optimized electron-hole pair recombination. The supercapacitive ability of ZnMoO4/AlPO4-5 nanorod composites was also investigated in this work. For the prepared electrodes using AlPO4-5, Mo : Zn (2)/AlPO4-5, Mo : Zn (4)/AlPO4-5, and Mo : Zn (6)/AlPO4-5, the capacitance values were 400, 725, 450, and 481.25 F g-1, respectively, at a current density of 0.5 A g-1. This study shows that ZnMoO4/AlPO4-5 nanorod composites are a potential visible-light-responsive photocatalyst. The electrochemical results further demonstrate the high capacitance of ZnMoO4/AlPO4-5 nanorod composites toward energy-storage applications.

Synthesis of self-assembled hierarchical AlPO-34 microspheres by using an ionic liquid and its application in heavy metal removal

Hierarchical AlPO-34 molecular sieves microspheres were synthesized in a [BMIm]Br ionic liquid without template or complex post-treatment process. The formation mechanism of such framework structures and their morphology were investigated. [BMIm]Br was proven to serve as both solvent and sole provider of the structure directing agent. The organic amine in the compound affects the framework density of the crystals and promotes the formation of a chabazite (CHA) type framework. After ageing for 1 h the AlPO-34 microspheres are formed due to the aggregation properties of the ionic liquid. The hierarchical mirosphere has a relatively high Brunauer-Emmett-Teller surface area and a considerably uniform mesoporous channel network. The hierarchical AlPO-34 microspheres were used as absorbers of heavy metal cations and showed a higher loading capacity and distribution coefficient compared with the AlPO-34-NH.