Mehanochemical synthesis of calcium oxalate from calcium sulfate

Kalcijevi oksalati su sastavni dio bubrežnih kamenaca i oni su kalcijeve soli oksalne kiseline. Sve više ljudi u današnje vrijeme ima problema sa bubrežnim kamencima stoga su istraživanja na tu temu sve intenzivnija, najviše se istražuju procesi taloženja kalcijevih oksalata te načini njihova mogućeg uklanjanja ili prevencije njihova nastanka. U medicinskom smislu ovaj problem se naziva urolitijaza ili nefrolitijaza. Ovisno o uvjetima, kalcijev oksalat može kristalizirati u tri hidratna oblika, kalcijev oksalat monohidrat (COM) koji je termodinamički najstabilniji, te metastabilni dihidrat (COD) i trihidrat (COT) koji se vrlo rijetko može naći u sastavu bubrežnih kamenaca. U ovom radu je cilj bio provjeriti koji hidratni oblik kalcijeva oksalata nastaje mehanokemijskom sintezom i to na dva načina, bez dodatka otapala (samo praškasti reaktanti) i s dodatkom minimalne količine otapala, u ovom slučaju vode. Dobiveni rezultati su obrađeni i interpretirani FT-IR spektroskopijom, termogravimetrijskom analizom te optičkom mikroskopijom.Calcium oxalates are components of kidney stones and they are calcium salts of oxalic acid. Nowadays more and more people have problems with kidney stones therefore research on this subject are more intensive, mainly precipitation processes of calcium oxalate and the ways of their possible removal or prevention of crystal growth. In medical way this problem is known as urolithiasis of nefrolithiasis. Depending on conditions, calcium oxalate cristallizes in three hidrate forms, calcium oxalate monohydrate (COM) which is thermodynamically most stable, and metastable dihydrate (COD) and trihydrate (COT) which is the rarest to be found in kidney stone composition. The goal of this work was to see which hydrate form of calcium oxalate will form by mechanochemical synthesis and it was done in two ways, without adding minimum quantity of solvent (only pulverised reactants) and with adding a minimum quantity of water, in this case water. Results were processed and interpreted with FT-IR spectroscopy, thermogravimetric analysis and optical microscopy

Mechanochemical synthesis of calcium oxalate

Ova studija prikazuje mehanokemijsku sintezu kalcijeva oksalata u planetarnom kugličnom mlinu, bez i uz prisutnost otapala. Dosadašnja istraživanja su uglavnom bila usmjerena na otopinsku sintezu kalcijeva oksalata. U ovom radu opisujemo drugačiji pristup, koji će donijeti nova saznanja o sintezi kristala kalcijeva oksalata, a koje su uzrokovane utjecajem mehaničke energije. Cilj istraživanja je sinteza, identifikacija i karakterizacija pojedine oksalatne hidratne faze sintetizirane iz kalcijevih soli (klorida, nitrata i sulfata). Ispitivan je utjecaj brzine mljevenja i praćena je reakcija u ovisnosti o vremenu sinteze. Strukturalna i termička svojstva uzoraka ispitana su FTIR spektroskopijom i termogravimetrijskom analizom (TGA). Morfološke karakteristike kalcijeva oksalata te raspodjela veličine čestica određene su optičkom mikroskopijom i dinamičkim raspršenjem svjetlosti (DLS)

Development of solvent-free synthesis using planetary ball mill for CaFe systems of complex metal oxides

Perovskiti su spojevi opće formule ABX3 gdje je A kation većeg ionskog promjera, B kation manjeg ionskog promjera, a X kisikov ili halogenidni anion. U ovom su radu istraživani optimalni uvjeti za sintezu trostrukog perovskita $Ca_{3}Fe_{2}WO_{9}$ sintetskom metodom bez otapala uz pomoć planetarog kugličnog mlina. Pri tomu za kation na A položaju odabran je $Ca^{2+}$, B položaj dijele $Fe^{3+}$ i $WO^{6+}$ u omjeru 2:1, a na anionskom položaju nalazi se kisik Parametri koji su mijenjani s ciljem poboljšanja sintetskih uvjeta su brzina vrtnje mlina (100, 150, 200, 250, 500 i 750 okr/min) te vrijeme sinteze u razmacima od 10 min do ukupno 120 min. Dobiveni uzorci su kalcinirani na različitim temperaturama te analizirani termogravimetrijski (TGA), infracrvenom spektroskopijom (FT-IR) i rentgenskom difrakcijom na prahu (PXRD). Produkt sintetiziran pri 250 okr/min i vremenu od 10 minuta imao je najveći udio ciljanog spoja, čak 92 wt %. Veličina kristalita izračunata preko Scherrerove jednadžbe je iznosila 24 nm. Ciljani $Ca_{3}Fe_{2}WO_{9}$ je po prvi put sintetiziran u nanokristalitnom obliku.Perovskites are compounds of general formula ABX3 where A is a cation of a larger ionic diameter, B is a cation of a smaller ionic diameter and X stands for oxygen or halide anions. In this thesis optimal conditions for a synthesis of a triple perovskite $Ca_{3}Fe_{2}WO_{9}$ using solvent-free method by means of planetary ball mill were investigated. As it can be seen, as A site cation $Ca^{2+}$ was chosen, $Fe^{3+}$ and $WO^{6+}$ share the B site in 2:1 ratio and oxygen anion was chosen for anionic site. Parameters which have been varied in the attempt to optimize synthesis conditions are rotational speed (100, 150, 200, 250, 500 and 750 rpm) and synthesis time in intervals of 10 minutes up to 120 minutes. Obtained samples were calcined at different temperatures and analyzed by thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR) and powder X-ray diffraction (PXRD). Product synthesized at 250 rpm for 10 minutes contained 92 wt% of the targeted compound. Crystallite size calculated from the Scherrer equation was 24 nm. Targeted $Ca_{3}Fe_{2}WO_{9}$ has been synthesized in nanocrystalline form for the first time

Mehanochemical synthesis of calcium oxalate from calcium sulfate

Kalcijevi oksalati su sastavni dio bubrežnih kamenaca i oni su kalcijeve soli oksalne kiseline. Sve više ljudi u današnje vrijeme ima problema sa bubrežnim kamencima stoga su istraživanja na tu temu sve intenzivnija, najviše se istražuju procesi taloženja kalcijevih oksalata te načini njihova mogućeg uklanjanja ili prevencije njihova nastanka. U medicinskom smislu ovaj problem se naziva urolitijaza ili nefrolitijaza. Ovisno o uvjetima, kalcijev oksalat može kristalizirati u tri hidratna oblika, kalcijev oksalat monohidrat (COM) koji je termodinamički najstabilniji, te metastabilni dihidrat (COD) i trihidrat (COT) koji se vrlo rijetko može naći u sastavu bubrežnih kamenaca. U ovom radu je cilj bio provjeriti koji hidratni oblik kalcijeva oksalata nastaje mehanokemijskom sintezom i to na dva načina, bez dodatka otapala (samo praškasti reaktanti) i s dodatkom minimalne količine otapala, u ovom slučaju vode. Dobiveni rezultati su obrađeni i interpretirani FT-IR spektroskopijom, termogravimetrijskom analizom te optičkom mikroskopijom.Calcium oxalates are components of kidney stones and they are calcium salts of oxalic acid. Nowadays more and more people have problems with kidney stones therefore research on this subject are more intensive, mainly precipitation processes of calcium oxalate and the ways of their possible removal or prevention of crystal growth. In medical way this problem is known as urolithiasis of nefrolithiasis. Depending on conditions, calcium oxalate cristallizes in three hidrate forms, calcium oxalate monohydrate (COM) which is thermodynamically most stable, and metastable dihydrate (COD) and trihydrate (COT) which is the rarest to be found in kidney stone composition. The goal of this work was to see which hydrate form of calcium oxalate will form by mechanochemical synthesis and it was done in two ways, without adding minimum quantity of solvent (only pulverised reactants) and with adding a minimum quantity of water, in this case water. Results were processed and interpreted with FT-IR spectroscopy, thermogravimetric analysis and optical microscopy

Development of solvent-free synthesis using planetary ball mill for CaFe systems of complex metal oxides

Perovskiti su spojevi opće formule ABX3 gdje je A kation većeg ionskog promjera, B kation manjeg ionskog promjera, a X kisikov ili halogenidni anion. U ovom su radu istraživani optimalni uvjeti za sintezu trostrukog perovskita $Ca_{3}Fe_{2}WO_{9}$ sintetskom metodom bez otapala uz pomoć planetarog kugličnog mlina. Pri tomu za kation na A položaju odabran je $Ca^{2+}$, B položaj dijele $Fe^{3+}$ i $WO^{6+}$ u omjeru 2:1, a na anionskom položaju nalazi se kisik Parametri koji su mijenjani s ciljem poboljšanja sintetskih uvjeta su brzina vrtnje mlina (100, 150, 200, 250, 500 i 750 okr/min) te vrijeme sinteze u razmacima od 10 min do ukupno 120 min. Dobiveni uzorci su kalcinirani na različitim temperaturama te analizirani termogravimetrijski (TGA), infracrvenom spektroskopijom (FT-IR) i rentgenskom difrakcijom na prahu (PXRD). Produkt sintetiziran pri 250 okr/min i vremenu od 10 minuta imao je najveći udio ciljanog spoja, čak 92 wt %. Veličina kristalita izračunata preko Scherrerove jednadžbe je iznosila 24 nm. Ciljani $Ca_{3}Fe_{2}WO_{9}$ je po prvi put sintetiziran u nanokristalitnom obliku.Perovskites are compounds of general formula ABX3 where A is a cation of a larger ionic diameter, B is a cation of a smaller ionic diameter and X stands for oxygen or halide anions. In this thesis optimal conditions for a synthesis of a triple perovskite $Ca_{3}Fe_{2}WO_{9}$ using solvent-free method by means of planetary ball mill were investigated. As it can be seen, as A site cation $Ca^{2+}$ was chosen, $Fe^{3+}$ and $WO^{6+}$ share the B site in 2:1 ratio and oxygen anion was chosen for anionic site. Parameters which have been varied in the attempt to optimize synthesis conditions are rotational speed (100, 150, 200, 250, 500 and 750 rpm) and synthesis time in intervals of 10 minutes up to 120 minutes. Obtained samples were calcined at different temperatures and analyzed by thermogravimetric analysis (TGA), infrared spectroscopy (FT-IR) and powder X-ray diffraction (PXRD). Product synthesized at 250 rpm for 10 minutes contained 92 wt% of the targeted compound. Crystallite size calculated from the Scherrer equation was 24 nm. Targeted $Ca_{3}Fe_{2}WO_{9}$ has been synthesized in nanocrystalline form for the first time