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In this study, it was aimed to produce low-cost activated carbons from cornelian cherry stones (CCS) by ultrasound-assisted chemical activation with the use of LiOH, KOH, NaOH, and ZnCl2. In the study, adsorption capacities of the activated carbon samples for CH4 compared with that of commercially obtained activated carbon (AC), multi-walled carbon nanotubes (MWCNT), mesoporous silica (MCM-41), and various zeolites. BET and t-plot analysis have been used for the characterization of adsorbents with the use of N2 adsorption-desorption data and SEM. In the evaluation of the adsorption data, several isotherm models such as DR, Harkins-Jura, Temkin, Freundlich, and Langmuir have been used. It was observed that activated carbons showed higher CH4 adsorption capacity than commercial mesoporous adsorbents and microporous zeolites. The CH4 adsorption capacity of commercial activated carbon was measured to be 0.939 mmol/g, while the CH4 adsorption capacities of activated carbons obtained with the use of NaOH, KOH, LiOH, and ZnCl2 were found to be 2.455, 1.584, 1.477, and 1.433 mmol/g, respectively. Results showed that activated carbons obtained from CCS with the use of KOH, NaOH, LiOH, and ZnCl2 are effective low-cost adsorbents for CH4 adsorption. [ABSTRACT FROM AUTHOR]

Highly ordered TiO2nanotube arrays were fabricated by anodisation of titanium, and then anodic TiO2nanotubes were modified in calcium ion-containing solution using ultrasound-assisted impregnation. For reference, the experiments were also carried out by conventional impregnation. The ability to form apatite on specimens was examined upon exposure to modified simulated body fluids combined with FESEM, EDS, XRD, FTIR and Zeta potential investigations. The results reveal that it had a negligible effect on the morphology of nanotubes with varying calcium source and impregnation time using conventional impregnation. Nevertheless, TiO2nanotubes were modified by the method of ultrasound-assisted impregnation, the mouth of nanotubes became glossy, the diameter of nanotubes became non-uniform and the amount of adsorbate in the inner wall of nanotubes increased. The calcium ion-modified nanotubes were more efficient in promoting apatite formation than the unmodified nanotubes, which may be attributed to the release of calcium ions and the significantly high amount of Ti–OH groups on its surface. [ABSTRACT FROM PUBLISHER]

A simple and effective ultrasound-assisted wet impregnation method was developed for the preparation of magnetically separable TiO 2 /maghemite-silica photo-active nanocomposites. The resulting nanomaterials were characterized by several techniques and subsequently tested for their photocatalytic activities in the liquid phase selective oxidation of benzyl alcohol. An unprecedented selectivity in organic media (90% in acetonitrile) towards benzaldehyde was achieved at a benzyl alcohol conversion of ca. 50%, being remarkably superior in terms of activity to any other supported transition metal catalysts reported to date as well as commercial titania Evonik P-25 photocatalyst. [ABSTRACT FROM AUTHOR]

Abstract: Novel chromium doped titania zeolite or silica supported photocatalysts were prepared via ultrasonically modified wet impregnation method. In this method, rotary evaporator was coupled with ultrasonic bath. The resulting nanomaterials were characterized by several techniques such as XRD, DR UV–vis, N2 physisorption, XPS, ICP-MS, XRF, HRTEM–EDS and they were subsequently tested for their photocatalytic activities in liquid phase processes: selective oxidation of glucose and total mineralization of phenol. Two carboxylic acids (glucaric acid and gluconic acid) were detected as the liquid phase products in the glucose photo-oxidation and better selectivity was achieved for the photocatalyst supported on zeolite. In phenol photodegradation, although conversion rate was not meaningful (ca. 30% after 4h illumination time), negligible amounts of harmful phenol-derived compounds were detected in water compared with photodegradation using the commercial P-25 photocatalyst. This ultrasonically improved photocatalysts synthesis method was found to have a significant effect on textural properties, spherical shape, good dispersion and visible-light responsiveness of nanophotocatalysts. [Copyright &y& Elsevier]

Abstract: Fe incorporated TiO2 nanotube arrays (Fe–TiO2NTs) were prepared by an ultrasound-assisted impregnating-calcination method. Scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and UV–vis diffuse reflectance spectroscopy (DRS) indicated that α-Fe2O3 nanoparticles were deposited into the TiO2 nanotubes, and in the mean time, some Fe3+ ions were doped into TiO2 lattice. The absorption of Fe–TiO2NTs in the visible light region increased with the increase of Fe content. The photocatalytic activity of Fe–TiO2NTs was evaluated by the degradation of methylene blue aqueous solution under visible light irradiation. The results demonstrated that the Fe–TiO2NTs exhibited significantly enhanced photocatalytic activity compared with pure TiO2NTs. Photoluminescence (PL) and electrochemical impedance spectroscopy (EIS) analyses further confirmed that the increased photocatalytic activity of the Fe–TiO2NTs was attributed to an enhanced separation and transfer of photogenerated charge carriers. [Copyright &y& Elsevier]

• Ultrasound-assisted is proposed to modified coal-based carbon electrode material. • AC-20 show high C of 309 F g−1, brilliant rate performance and cycle stability. • AC-20//AC-20 exhibits ultra-high energy density of 9.6 Wh kg−1 at 250 W kg−1. • Carbonyl, hydroxyl, carboxyl and lactone on carbon surface promote K+ adsorption. Abundantly available low-grade coal is used to prepare activated carbon (AC) for supercapacitor (SCs) electrode materials. Aiming to transform low-grade coal into pore structure, microcrystalline, and surface chemistry multi-scale coordinated AC, a new ultrasound-assisted bimetallic activation strategy is proposed. The introduction of ultrasonic waves in the FeCl 3 /MgCl 2 co-impregnation process synergistically controls the pore and microcrystalline structure of the precursor. Meanwhile, the surface modification is performed in a CO 2 atmosphere. Comparative experiments and density functional theory (DFT) calculations show that the AC-20 possesses abundant micropores (0.92 cm3 g−1), appropriate mesopores (0.40 cm3 g−1), high specific surface area (SSA, 2329 cm2 g−1), low impurity content, and is highly O-doped (13.65 at.%), which are essential for enhancing carbon-based electrochemical processes. Meanwhile, the graphitization degree improves (I D /I G is down to 0.89), stability enhances (TGA curves shift right), and electrical resistivity decreases (R e is 0.15 Ω cm−1). Therefore, AC-20 has a specific capacitance (C) of 309 F g−1 at 0.5 A g−1. Furthermore, AC-20//AC-20 can reach an energy density (E) of 9.6 Wh kg−1 when the power density (P) is 250 W kg−1. Combined with low price, abundant reserves, a simple preparation method, and good practicability, the obtained AC-20 has great potential to expand production. [ABSTRACT FROM AUTHOR]