RESUMO
Catalytic combustion of benzene, toluene, and hexane (BTH) was carried out to investigate in this study the effect of palladium precursor on the property and performance of 1 wt.% Pd/γ-Al2O3. Properties were characterized by X-ray diffraction (XRD), Brunauer Emmett Teller (BET) surface area, temperature programmed reduction (TPR), Transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analyses. When palladium precursor was used to prepare the catalyst, it had a great effect on the property and performance of the supported palladium catalyst. Total acidity, size of palladium particle, and oxidation state of palladium were associated with catalytic activity of the catalyst. Higher total acidity of the catalyst and larger particle size of palladium favorably affected the catalytic activity. In addition, palladium species with high oxidation state might be useful to increase catalytic activity in BTH combustion.
RESUMO
The catalytic oxidation of benzene and toluene (VOCs) was carried out in order to assess the properties and catalytic activities of spent vanadium-based catalyst and that modified with copper and manganese. The properties of the prepared catalysts were characterized by the Brunauer Emmett Teller (BET) surface area method as well as X-ray diffraction (XRD), Attenuated total reflection-Fourier transform infrared (ATR-FTIR), and Scanning electron microscopy-Energy dispersive X-ray (SEM-EDX) analyses. The experimental results showed that oxalic acid treatment significantly affected the activity of the spent vanadium-based catalyst, ultimately attributing to the removal of catalyst poison such as sulfur and the even redistribution of catalyst components. Moreover, the addition of copper or manganese to the spent vanadium base catalyst treated with oxalic acid (SVO) enhanced its catalytic activity.
RESUMO
To recover the spent vanadium compound, Rhodamine-B-based Schiff's base ligand (L1) was synthesized via ultrasonication process and was evaluated with vanadyl sulfate (VOSO4), which has shown considerable selectivity towards V(IV). The change of the solution color from colorless to pink is attributed to L1 after the reaction with vanadium ion owing to the successful formation of the vanadium complex and the opening of the spirolactam ring in the L1 structure. In FT-IR spectra, the vanadyl peaks are co-existed with the L1 structure, which confirmed the complex formation of the L1 with vanadium. Similarly, the binding energy of V(IV) was identified at 516.2 eV for V2p3/2 in XPS spectra. The new strategy for VOSO4 recovery was established through solvent extraction and acid leaching. After recovery process, the absence of vanadium peak in the XPS confirmed the complete removal of V(IV) from the complex. The recovered VOSO4 solution used as an electrolyte in vanadium redox flow battery (VRFB) systems, where the unit cell performance is comparable with the conventional electrolyte solution. The advantage of study is reuse of VOSO4 as a resource for energy storage applications.
RESUMO
Sulfonated poly(phenylene) oxide (sPPO) polymer is coated in a dopamine hydrochloride solution to prepare a highly durable, low-price polymer membrane for vanadium redox flow batteries (VRFBs). The polydopamine (PDA) coating on the sPPO membrane is confirmed using SEM and EDX analysis. sPPO coated with PDA exhibits decreased proton conductivity due to high resistance. However, VO+2 reducibility tests shows that the chemical stability is improved due to the introduction of the PDA coating layer on the sPPO membrane, which has a chemical structure with poor durability in VO+2 solution under the operating conditions of a VRFB. These results show that this polymer electrolyte membrane based on PDA-coated sPPO is a candidate for application in the long-term operation of VRFBs.