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SO3H-functionalised mesoporous materials with different pore structures (SBA-15 and SBA-16) were prepared by the post-synthesis surface modification. The materials were thoroughly characterized by X-ray powder diffraction, nitrogen physisorption, temperature-gravimetric analysis, elemental analysis and solid state NMR spectroscopy. The acidic properties were investigated by the temperature-programed desorption of ammonia. The catalytic performance of SO3H-functionalised mesoporous materials was studied in glycerol esterification with acetic acid.The different amount of silanol groups in the initial SBA-15 and SBA-16 silicas predetermined the different amount of propylsulfonic groups which are formed in them and therefore significantly influenced the acidity and the catalytic performance in glycerol esterification. Much higher amount of Brönsted acid sites was generated in SO3H modified SBA-15 catalyst, which exhibited higher activity to value-added triacetyl glycerol.

High-grade zeolite nanocomposites are synthesized utilizing solid by-products from combustion of coal for energy production in Thermal Power Plants applying alkaline aging, hydrothermal and fusion-hydrothermal activation procedures. The obtained coal ash zeolites were studied with respect to their chemical and phase composition, morphology, surface parameters and thermal properties. It was found that they are distinguished in nanocrystalline morphology and significant content of iron oxide nanoparticles (γ-Fe2O3, α-Fe2O3, γ-Fe3O4) and doping elements (Cu, Co, Mn, V, W, etc.) transferred from the raw coal ash, and therefore they are assumed as nanocomposites. Coal fly ash zeolite nanocomposites are characterized by a mixed micro-mesoporous texture, significant concentration of acidic Brønsted centers due to their high surface insaturation, high chemical and thermal stabilty. This unique combination of compositional and textural properties predetermines the application of these materials as catalysts for thermal oxidation processes, anticorrosion barrier coatings, carbon capture adsorbents, matrices for hosting functional groups, detergents etc. Examples for coal fly ash zeolite applications for substitution of critical raw materials in practice are provided.

SBA-15 and MCM-48 mesoporous silicas were modified with functionalized (3-aminopropyl)triethoxysilane (APTES) by using the post-synthesis method, thus introducing N- and P-containing groups to the pore surface. The structure of the newly synthesized modifiers (aldimine and aminophosphonate derivatives of (3-aminopropyl)triethoxysilane and their grafting onto the porous matrix were proved by applying multinuclear NMR and FTIR spectroscopies. The content of the grafted functional groups was determined via thermogravimetric analysis. The physicochemical properties of the adsorbent samples were studied by nitrogen physisorption and UV-Vis spectroscopy. The adsorption capacity of CO 2 was measured in a dynamic CO 2 adsorption regime. The modified silicas displayed an enhanced adsorption capacity compared to the initial material. The 13 C NMR spectra with high-power proton decoupling proved the presence of physically captured CO 2 . A value of 4.60 mmol/g was achieved for the MCM-48 material grafted with the Schiff base residues. The total CO 2 desorption was achieved at 40 °C. A slight decrease of about 5% in CO 2 adsorption capacities was registered for the modified silicas in three adsorption/desorption cycles, indicating their performance stability.

Mono-, and bimetallic Ni-, Ru-, and Pt-modified nanosized Beta zeolite catalysts were prepared by the post synthesis method and characterized by powder X-ray diffraction (XRD), nitrogen physisorption, HRTEM microscopy, temperature-programmed reduction (TPR-TGA), ATR FT-IR spectroscopy, and by solid-state MAS-NMR spectroscopy. The presence of nanosized nickel-oxide, ruthenium-oxide, and platinum species was detected on the catalysts. The presence of Brønsted and Lewis acid sites, and incorporation of nickel ions into zeolite lattice was proven by FT-IR of adsorbed pyridine. The structural changes in the catalyst matrix were investigated by solid state NMR spectroscopy. The catalysts were used in a gas-phase hydrodemethoxylation and dealkylation of 2-methoxy-4-propylphenol as a lignin derivative molecule for phenol synthesis.

The post-synthesis procedure for cyclic amine (morpholine and 1-methylpiperazine) modified mesoporous MCM-48 and SBA-15 silicas was developed. The procedure for preparation of the modified mesoporous materials does not affect the structural characteristics of the initial mesoporous silicas strongly. The initial and modified materials were characterized by XRD, N 2 physisorption, thermal analysis, and solid-state NMR. The CO 2 adsorption of the obtained materials was tested under dynamic and equilibrium conditions. The NMR data revealed the formation of different CO 2 adsorbed forms. The materials exhibited high CO 2 absorption capacity lying above the benchmark value of 2 mmol/g and stretching out to the outstanding 4.4 mmol/g in the case of 1-methylpiperazin modified MCM-48. The materials are reusable, and their CO 2 adsorption capacities are slightly lower in three adsorption/desorption cycles.

Mono- and bimetallic Ni-, Ru- and Pt-modified hierarchical ZSM-5 materials were prepared by impregnation technique and characterized by X-ray diffraction (XRD), N 2 physisorption, temperature-programmed reduction (TPR-TGA), ATR-FTIR and solid state NMR spectroscopy. Formation of finely dispersed nickel, ruthenium and platinum species was observed on the bimetallic catalysts. It was found that the peculiarity of the used zeolite structure and the modification procedure determine the type of formed metal oxides and their dispersion and reducibility. The samples' acidity was studied via FTIR spectroscopy of adsorbed pyridine. The changes in the zeolite structure were studied via solid-state NMR spectroscopy. The catalysts were investigated in a gas-phase hydrodeoxygenation, transalkylation and dealkylation reaction of model lignin derivative molecules for phenol production.

The combustion of coal in Thermal Power Plants generates fine dust particles (coal fly ash, CFA), which are collected from the flue gas streams and deposited as solid wastes. One of the technologically reliable solutions for utilization of CFA is its alkaline conversion into zeolites. The present study focuses on the influence of calcium content in CFA on the chemical and phase composition, morphology and surface properties of coal fly ash zeolites. Comparative studies of the capacity of zeolites of Na-X and Na-Ca-X types from coal fly ash to capture carbon emissions under static and dynamic conditions have been performed. The present study answers a key question from a practical point of view, how does moisture in flue gases affect the adsorption of carbon dioxide on zeolites. The development of efficient adsorbents from CFA with varying composition will contribute to a number of environmental benefits and to the development of efficient CO 2 capture technologies in the context of the circular economy., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

Magnetic iron oxide containing MCM-41 silica (MM) with ~300 nm particle size was developed. The MM material before or after template removal was modified with NH 2 - or COOH-groups and then grafted with PEG chains. The anticancer drug tamoxifen was loaded into the organic groups' modified and PEGylated nanoparticles by an incipient wetness impregnation procedure. The amount of loaded drug and the release properties depend on whether modification of the nanoparticles was performed before or after the template removal step. The parent and drug-loaded samples were characterized by XRD, N 2 physisorption, thermal gravimetric analysis, and ATR FT-IR spectroscopy. ATR FT-IR spectroscopic data and density functional theory (DFT) calculations supported the interaction between the mesoporous silica surface and tamoxifen molecules and pointed out that the drug molecule interacts more strongly with the silicate surface terminated by silanol groups than with the surface modified with carboxyl groups. A sustained tamoxifen release profile was obtained by an in vitro experiment at pH = 7.0 for the PEGylated formulation modified by COOH groups after the template removal. Free drug and formulated tamoxifen samples were further investigated for antiproliferative activity against MCF-7 cells.

Fly ash (FA) from lignite coal combusted in different Thermal Power Plants (TPPs) was used for the synthesis of zeolites (FAZs) of the Na-X type by alkaline activation via three laboratory procedures. FAZs were characterized with respect to their morphology, phase composition and surface properties, which predetermine their suitability for applications as catalysts and adsorbents. FAZs were subsequently modified with metal oxides (CuO) to improve their catalytic properties. The catalytic activity of non-modified and CuO-modified FAZs in the total oxidation of volatile organic compounds was investigated. FAZs were studied for their potential to retain CO 2 , as their favorable surface characteristics and the presence of iron oxides make them suitable for carbon capture technologies. Thin films of FAZs were deposited by in situ crystallization, and investigated for their morphology and optical sensitivity when exposed to pollutants in the gas phase, e.g., acetone. This study contributes to the development of novel technological solutions for the smart and valuable utilization of FA in the context of the circular economy and green energy production.

ZSM-5/KIT-6 and ZSM-5/SBA-15 nanoparticles were synthesized and further modified by a post-synthesis method with (CH 2 ) 3 SO 3 H and (CH 2 ) 3 NHCO(CH 2 ) 2 COOH groups to optimize their drug loading and release kinetic profiles. The verapamil cargo drug was loaded by incipient wetness impregnation both on the parent and modified nanoporous supports. Nanocarriers were then coated with a three-layer polymeric shell composed of chitosan-k-carrageenan-chitosan with grafted polysulfobetaine chains. The parent and drug loaded formulations were characterized by powder XRD, N 2 physisorption, thermal analysis, AFM, DLS, TEM, ATR-FT-IR and solid state NMR spectroscopies. Loading of verapamil on such nanoporous carriers and their subsequent polymer coating resulted in a prolonged in vitro release of the drug molecules. Quantum-chemical calculations were performed to investigate the strength of the interaction between the specific functional groups of the drug molecule and (CH 2 ) 3 SO 3 H and CH 2 ) 3 NHCO(CH 2 ) 2 COOH groups of the drug carrier. Furthermore, the ability of the developed nanocomposites to positively modulate the intracellular internalization and thereby augment the antitumor activity of the p-gp substrate drug doxorubicin was investigated in a comparative manner vs. free drug in a panel of MDR positive (HL-60/Dox, HT-29) and MDR negative (HL-60) human cancer cell lines using the Chou-Talalay method., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The present study is aimed at investigations on the catalytic activity for total oxidation of volatile organic compounds (VOCs), such as toluene, acetone, n-hexane and dichlorobenzene onto zeolite-like materials synthesized from coal fly ash (FA) directed to development of an economically efficient approach for degradation of VOCs. Fly ash zeolites (FAZ) were prepared by alkaline conversion of FA collected from Thermal Power Plants supplied with lignite coal from "Maritza-East" basin in Bulgaria. Different synthesis procedures double stage fusion-hydrothermal activation, fusion-atmospheric crystallization and atmospheric aging were applied. The synthesis products were identified by X-ray diffraction, and were assigned to zeolite Na-X. Scanning electron microscopy images reveal submicron dimensions of the composing crystallites. Nitrogen adsorption/desorption measurements reveal a mixed micro-mesoporous structure and specific surface area between 116 and 396 m 2 /g for the obtained FAZ. Relationships between surface properties, iron content and the catalytic activity of FAZ were investigated and discussed. Copper-modified fly ash zeolites (Cu-FAZ) were prepared by incipient wetness impregnation technique with copper acetylacetonate. The loading of 5 wt. % copper on the zeolite samples was achieved. The catalytic activity of FAZ and Cu-FAZ in the total oxidation of model VOCs mixture containing n-hexane, acetone, toluene, 1,2 dichlorobenzene was evaluated., (Copyright © 2018 Elsevier B.V. All rights reserved.)

The hydrogenation of levulinic acid (LA) to γ-valerolactone (GVL) in vapor-phase is economically more viable route if compared to reaction in liquid-phase. To improve the GVL yield in the vapor-phase reaction, the optimization of nickel modified zeolite as bi-functional catalyst (Ni/HZSM-5) was studied. Ni/HZSM-5 materials with fixed Al/Si molar ratio of 0.04 and different nominal Ni/Si molar ratios (from 0.01 to 0.05) were synthesized without the use of organic template and with the most affordable sources of silica and alumina. Materials were characterized by X-ray powder diffraction, SEM-EDX, TEM-EDX, pyridine TPD and DRIFTS, H 2 -TPR, N 2 physisorption and isoelectric point. In the synthesized materials, 61-83% of nickel is present as bulk NiO and increases with nickel content. Additionally, in all catalysts, a small fraction of Ni 2+ which strongly interacts with the zeolite support was detected (10-18%), as well as Ni 2+ acting as charge compensating cations for Brønsted acid sites (7-21%). Increasing the nickel content in the catalysts leads to a progressive decrease of Brønsted acid sites (BAS) and concomitant increase of Lewis acid sites (LAS). When BAS/LAS is approaching to 1 and at the same time the amount of NiO reducible active sites is around 80%, the bi-functional Ni/HZSM-5-3 catalyst (Ni/Al = 0.59) leads to 99% conversion of LA and 100% selectivity to GVL at 320°C. This catalyst also shows stable levulinic acid hydrogenation to GVL in 3 reaction cycles conducted at 320°C. The concerted action of the following active sites in the catalyst is a key element for its optimized performance: (1) Ni metallic active sites with hydrogenation effect, (2) Lewis acid sites with dehydration effect, and (3) nickel aluminate sites with synergetic and stabilizing effects of all active sites in the catalyst.