Nickel based catalyst on silica support for hydrogenation of vegetable oils - synthesis, characterization and catalytic properties

Iako je Ni/SiO2 katalizator u upotrebi dugi niz godina on je i danas jedan od najispitivanijih katalizatora. Istraživanja su orjentisana uglavnom na poboljšanje svojstava postojećih katalizatora. Kako je dijatomit, dominantan postojeći nosač ovog katalizatora, prirodan materijal njegove su rezerve ograničene. Osim toga dobijanje dijatomita je povezano sa znatnim negativnim uticajem na životnu sredinu. Zamena dijatomita nekim drugim silikatnim materijalom bila bi višestruko korisna: i u odnosu na cenu katalizatora i u odnosu na smanjenje uticaja njegove eksploatacije na životnu sredinu. Kao kandidati za zamenu dijatomita pojavljuju se dva silikatna materijala, koji se proizvode industrijski u velikim količinama i za koje su izvori sirovina praktično neograničeni – vodeno staklo i silika gel. Zbog toga je i cilj ove teze bio sinteza aktivnog Ni/SiO2 katalizatora za hidrogenizaciju biljnog ulja upotrebom ovih materijala kao potencijalnih zamenskih materijala za dijatomit. U ovu svrhu taložnim postupkom, pomoću Na2CO3, najpre su sintetisani prekursori katalizatora. U svim sintezama kao promotor je korišten magnezijum uz molski odnos prema niklu 1:10. Primenjenim postupkom sinteze ispitivani su uticaji različitih molskih odnosa Ni:Si, vremena starenja, temperature sinteze i sredstva za ispiranje na fizičko-hemijske karakteristike prekursora. Za temperaturu sinteze od 90 ºC i vremena starenja od 0,5 h, inicijalni molski odnosi Ni: Si iznosili su 0,10, 0,30, 0,75, 0,87, 1,50 i 10,00. Za odabrane molske odnose ove serije (0,10 do 0,87) sintetisani su prekursori postupkom produženog vremena starenja tokom 24 i 170 h. Za molski odnos Ni:Si = 0,87, vreme starenja od 0,5 h i temperature sinteze 37, 60, 90 i 100 ºC, sintetisane su dve serije prekursora. Jedna u kojoj je kao sredstvo za ispiranje korištena voda i druga, u kojoj je u poslednjoj etapi sinteze talog ispiran metanolom...Although Ni / SiO2 catalyst is in use for many years, it is still one of the most investigated catalysts. Researches are mostly focused on the improvement of the properties of existing catalysts. Reserves diatomits, which is used as the existing support, are limited because it is a natural material. Besides that, diatomite production is associated with a significant negative impact on the environment. Replacement of the diatomite with other silicate material could be highly beneficial, taking into account the cost of the catalyst and the reduction of the negative environmental impact. Two silicate materials could be promissing candidates for the replacement of diatomite. Those are water glass and silica gel, materials that are produced industrially in large quantities and for which there is practicaly unlimited sources of raw materials. Therefore, the aim of this thesis was the synthesis of the active Ni / SiO2 catalyst for the hydrogenation of vegetable oils, using these materials as potential replacement material for diatomite. For this purpose, catalyst precursors were synthesized, using precipitation procedure with Na2CO3. In all synthesized samples, magnesium was used as premotor, in molar ratio towards nickel 1:10, respectively..

Na spor. nasl. str.:Nickel based catalyst on silica support forhydrogenation of vegetable oils - synthesis,characterization and catalytic properties

Iako je Ni/SiO2 katalizator u upotrebi dugi niz godina on je i danas jedan odnajispitivanijih katalizatora. Istraživanja su orjentisana uglavnom na poboljšanje svojstavapostojećih katalizatora. Kako je dijatomit, dominantan postojeći nosač ovog katalizatora,prirodan materijal njegove su rezerve ograničene. Osim toga dobijanje dijatomita je povezanosa znatnim negativnim uticajem na životnu sredinu. Zamena dijatomita nekim drugimsilikatnim materijalom bila bi višestruko korisna: i u odnosu na cenu katalizatora i u odnosuna smanjenje uticaja njegove eksploatacije na životnu sredinu. Kao kandidati za zamenudijatomita pojavljuju se dva silikatna materijala, koji se proizvode industrijski u velikimkoličinama i za koje su izvori sirovina praktično neograničeni – vodeno staklo i silika gel.Zbog toga je i cilj ove teze bio sinteza aktivnog Ni/SiO2 katalizatora za hidrogenizacijubiljnog ulja upotrebom ovih materijala kao potencijalnih zamenskih materijala za dijatomit.U ovu svrhu taložnim postupkom, pomoću Na2CO3, najpre su sintetisani prekursorikatalizatora. U svim sintezama kao promotor je korišten magnezijum uz molski odnos premaniklu 1:10.Primenjenim postupkom sinteze ispitivani su uticaji različitih molskih odnosa Ni:Si,vremena starenja, temperature sinteze i sredstva za ispiranje na fizičko-hemijskekarakteristike prekursora.Za temperaturu sinteze od 90 ºC i vremena starenja od 0,5 h, inicijalni molski odnosi Ni: Siiznosili su 0,10, 0,30, 0,75, 0,87, 1,50 i 10,00. Za odabrane molske odnose ove serije (0,10 do0,87) sintetisani su prekursori postupkom produženog vremena starenja tokom 24 i 170 h.Za molski odnos Ni:Si = 0,87, vreme starenja od 0,5 h i temperature sinteze 37, 60, 90 i100 ºC, sintetisane su dve serije prekursora. Jedna u kojoj je kao sredstvo za ispiranjekorištena voda i druga, u kojoj je u poslednjoj etapi sinteze talog ispiran metanolom...Although Ni / SiO2 catalyst is in use for many years, it is still one of the most investigatedcatalysts. Researches are mostly focused on the improvement of the properties of existingcatalysts. Reserves diatomits, which is used as the existing support, are limited because it is anatural material. Besides that, diatomite production is associated with a significant negativeimpact on the environment. Replacement of the diatomite with other silicate material could behighly beneficial, taking into account the cost of the catalyst and the reduction of the negativeenvironmental impact. Two silicate materials could be promissing candidates for thereplacement of diatomite. Those are water glass and silica gel, materials that are producedindustrially in large quantities and for which there is practicaly unlimited sources of rawmaterials. Therefore, the aim of this thesis was the synthesis of the active Ni / SiO2 catalyst forthe hydrogenation of vegetable oils, using these materials as potential replacement materialfor diatomite.For this purpose, catalyst precursors were synthesized, using precipitation procedure withNa2CO3. In all synthesized samples, magnesium was used as premotor, in molar ratio towardsnickel 1:10, respectively..

Високо селективни водокомпатибилни молекулски обележени полимери за бензофенон-4

Molecularly imprinting technology was applied for preparing selective sorbents for benzophenone-4 (BP4), an organic UV filter used in sun-screens and cosmetics. Several imprinted polymers were prepared by bulk polymerization, using BP4 as template. Combination of stability (mechanical and chemical), selectivity and robustness of the imprinted polymers with BP4 properties resulted in a successful imprinting process (imprinting factors in range 1.05–2.60). The prepared polymers were characterised by infrared spectroscopy, elemental analysis, conductometric titrations and nitrogen physisorption at 77 K. Adsorption capacities and selectivity towards 7 other organic UV filters (benzophenone-3, benzophenone-8, homosalate, butyl methoxydibenzo-ylmethane, ethyl hexyl salicylate, ethyl hexyl p-dimethylamino benzoate and ethyl hexyl p-methoxycinnamate) were determined, proving high adsorption capacity and high selectivity for BP4 binding. The highest adsorption capacity was observed for 4-vinylpyridine/ethylene glycol dimethacrylate co-polymer prepared in dimethyl sulfoxide (1.108 mmol g-1). The imprinted polymer with the highest binding capacity was applied to solid phase extraction of BP4 from aqueous solutions with 98.5 % efficiency.Технологија молекулског обележавања примењена је у синтези селективних сорбената за бензофенон-4 (BP4), органски UV филтер који се користи у кремама за сунчање и другим козметичким производима. Полимери су добијени полимеризацијом у маси, користећи (BP4) као матрицу. Комбинацијом стабилности (механичке и хемијске), селективности и робусности молекулски обележених полимера са својствима BP4 извршено је успешно обележавање (фактор обележавања 1,05–2,60). Карактеризација добијених полимера је извршена применом инфрацрвене спектроскопије, елементалне анализе, кондуктометријских титрација и физисорпције азота на 77 К. Адсорпциони капацицети и селективност испитани су за 7 других органских UV филтера (бензофенон-3, бензофенон-8, хомосалат, бутилметоксидибензоилметан, етилхексил-салицилат, етилхексил-р-диметиламинобензоат и етилхексил-р-метоксицинамат), потврђујући велики адсорпциони капацитет и високу селективност за везивање BP4. Највећи адсорпциони капацитет показао је ко-полимер 4-винилпиридина и дивинилбензена добијен коришћењем диметил-сулфоксида као порогена (1,108 mmol/g). Полимер са највећим капацицетом за везивање BP4 примењен је као сорбент за екстракцију чврстом фазом BP4 из водених раствора са ефикасношћу од 98,5 %

Preparation of Ni/diatomite hydrogenation catalyst precursors: Effect of counter ions on textural characteristics

Diatomite supported nickel catalyst precursors (Ni/D) were prepared by the precipitation-deposition (PD) method using different nickel salts such as nitrate, chloride, acetate and formate. The effect of counter ions (NO3-, Cl-, CH3COO-, and HCOO-) on the texture of prepared samples was studied. For determination of the textural characteristics mercury intrusion porosimetry (MIP) and N2 physisorption techniques were used. MIP and physisorption data (pore volume, pore size distribution, porosity as well as N2 adsorptiondesorption isotherms and BET surface area) showed that counter ions were found to have a profound effect on the microstructure and porosity characteristics of Ni/D precursors. An order of the counter ions effect on the textural characteristics of prepared precursors was determined

Biodiesel synthesis using K2CO3/Al–O–Si aerogel catalysts

In this study, catalysts for fatty acid methyl esters (FAME or bio-diesel) synthesis with K2CO3 as the active component on an alumina/silica support were synthesized using the sol–gel method, which was followed by drying the “dense” wet gels with supercritical carbon dioxide to obtain the aerogels. The prepared catalysts were characterized by XRD analysis, FTIR spectroscopy and N2 physisorption at 77 K, and tested in the methanolysis of sunflower oil. The effects of reaction variables, such as reaction time, temperature and methanol to oil molar ratio, on the yield of FAME were investigated. The aerogel catalysts with K2CO3 as the active component on an alumina/silica support exhibited good activity in the methanolysis of sunflower oil. The leaching of potassium when the catalyst was in contact with pure methanol under the working conditions of methanolysis was also tested in this study, indicating that it occurred only at higher temperatures, while at lower ones, it was negligible

Influence of silver addition on textural properties of new synthetic activated carbon

Starting from macroreticular styrene/divinylbenzene sulfonic acid ion exchange resin the two samples of synthetic activated carbons (SAC), with and without silver, were obtained through carbonization in controlled regime. Detailed sample preparation procedure is described. Characterizations of synthesized samples were conducted using XRD, SEM and N2 physisorption at –196 °C measurements. The influence of applied silver on textural properties of CAS was discussed.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Removal of methyl orange using combined ZnO/Fe2O3/ZnO Zn composite coated to the aluminium foil in the presence of simulated solar radiation

Four immobilized ZnO/Fe2O3 photocatalysts with different mоlar ratiоs оf Zn to Fe (0.42, 0.84, 1.68, and 3.36) were synthesized viа the chemicаl precipitatiоn methоd on optimized electrochemically synthesized ZnO-Zn coating on aluminium foil support (ZnAF). The efficiency оf these catalysts for methyl orange removal in the presence оf simulated solar radiation (SSR) was investigated. The оptimal mоlar ratiо of Zn towards Fe, in the presence оf the SSR, was 1.68. The pоssibility оf potential reusing the catalyst was examined six times in a row. It was determined thаt the application of the 1.68Zn/Fe/ZnAF/H2O2/SSR system after the dye removal generates hydrogen at a rate of 186.5 μmol g-1 after 6 h. Using the HPLC method for 1.68Zn/Fe/ZnAF/SSR system, five primary intermediates were found to be formed.XII YuCorr International Conference, September 13-16, 2021, Tara Mountain, Serbia, [http://sitzam.org.rs/YUCORR/

Highly selective water-compatible molecularly imprinted polymers for benzophenone-4: Scientific paper

Molecularly imprinting technology was applied for preparing selec­tive sorbents for benzophenone-4 (BP4), an organic UV filter used in sun­screens and cosmetics. Several imprinted polymers were prepared by bulk polymerization, using BP4 as template. Combination of stability (mechanical and chemical), selectivity and robustness of the imprinted polymers with BP4 properties resulted in a successful imprinting process (imprinting factors in range 1.05–2.60). The prepared polymers were characterised by infrared spec­tro­scopy, elemental analysis, conductometric titrations and nitrogen physi­sorp­tion at 77 K. Adsorption capacities and selectivity towards 7 other organic UV filters (benzophenone-3, benzophenone-8, homosalate, butyl methoxydi­ben­zo­ylmethane, ethyl hexyl salicylate, ethyl hexyl p-dimethylamino benzoate and ethyl hexyl p-methoxycinnamate) were determined, proving high adsorption capacity and high selectivity for BP4 binding. The highest adsorption capacity was observed for 4-vinylpyridine/ethylene glycol dimethacrylate co-polymer prepared in dimethyl sulfoxide (1.108 mmol g-1). The imprinted polymer with the highest binding capacity was applied to solid phase extraction of BP4 from aqueous solutions with 98.5 % efficiency

Poly vinyl alcohol PVA with poly ethylene glycol PEG added as a binder for the powder compaction

Poster presented at the Advanced Ceramics and Applications VII Conference, Belgrade, 17-19 September 2018.Conference abstract: [https://hdl.handle.net/21.15107/rcub_dais_4099

Polyvinyl alcohol PVA with poly ethylene Glycol PEG added as a binder for the powder compaction

During the compaction of the powder mixture of ZnO and Mn2O3 (MnCO3) and Fe2O3 compacts were find fragile for further handling. Poly vinyl alcohol PVA was used as a binder in an unusual 20% PVA content. We made as well 2% PVA with 0.6% Poly ethylene glycol PEG and 20% PVA with 6 % PEG. Binder was wrapped over the powder by suspension forming in the polymer water solution and drying afterwards until all water content evaporates. On the these obtained powders employed characterization techniques were: Fourier transformed Infra red FTIR spectra with ATR attenuated total reflection technique as well as differential thermal analysis DTA on the device with low temperature sensitivity and TEM transmition electron microscopy. All binder concentrations gave compacts with good mechanical properties, that can be handled with ease but with adding, a PEG as plasticizer the operating of the anvil and piston were extremely difficult due to friction.Poster: [https://hdl.handle.net/21.15107/rcub_dais_4065