Kinetics of heavy metal sorption on macroporous vinylpyridine based copolymer

Sorption of copper, nickel and cobalt on macroporous crosslinked copolymer of 4- vinylpyridine and ethylene glycol dimethacrylate, PVPE, was studied. The kinetics models (pseudo-first and pseudo-second order equations) were applied to the data obtained from batch sorption experiments at room temperature. The sorption of heavy metals was found to proceed according to pseudo-second order kinetics.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Characterization of glycidyl methacrylate based magnetic nanocomposites

Magnetic and non-magnetic macroporous crosslinked copolymers of glycidyl methacrylate and trimethylolpropane trimethacrylate were prepared by suspension copolymerization and functionalized with diethylenetriamine. The samples were characterized by mercury porosimetry, scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDS), Fourier transform infrared spectroscopy analysis (FTIR-ATR), thermogravimetric analysis (TGA), X-ray diffractometry (XRD), atomic force microscopy (AFM), transmission electron microscopy (TEM) and SQUID magnetometry. The FTIR-ATR analysis of synthesized magnetic nanocomposites confirmed the presence of magnetite and successful aminofunctionalization. Non-functionalized and amino-functionalized nanocomposites exhibited superparamagnetic behavior at 300 K, with a saturation magnetization of 5.0 emu/g and 2.9 emu/g, respectively. TEM analysis of the magnetic nanocomposite has shown that magnetic nanoparticles were homogeneously dispersed in the polymer matrix. It was demonstrated that incorporation of magnetic nanoparticles enhanced the thermal stability of the magnetic nanocomposite in comparison to the initial non-magnetic macroporous copolymer

Electrochemical Behavior of H3pw12o40/Acid-Activated Bentonite Powders

Electrochemical behavior of 12-tungstophosphoric acid (HPW)/acid-activated bentonite (AAB) powders with various loadings of HPW was investigated. The physicochemical properties of the prepared powders were examined by X-ray powder diffraction, nitrogen adsorption-desorption isotherms, atomic force microscopy and cyclic voltammetry measurements. The results indicated that the prepared powders are composed mainly of oriented domains of large rock blocks, probably resulting from a preferable deposition of bentonite particles having a face-to-face interaction. The particles had a mainly disordered mesoporous structure with a pore volume that varied according to the pore size in the range of 2-50 nm. In addition, the particles had crystallite size between 4.9 and 9.0 nm. The electrocatalytic activities of prepared HPW/AAB electrodes were studied in the oxidation of NO2- and the results revealed that the electrodes possessed relatively higher nitrite oxidation currents than AAB electrode. The best electroactivity was observed for HPW3/AAB electrode (AAB + + 20 wt % HPW) and the limit of detection (3 sigma) was determined as 8 mu M

Textural properties of macroporous acid modified montmorillonite nanocomposites

Macroporous crosslinked copolymer, poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) and its nanocomposites with acid modified montmorillonite (WA) were synthesized by radical suspension copolymerization. Nanocomposites were obtained by introducing various amounts of WA into the reaction system. Textural properties of synthesized samples were analyzed by mercury intrusion porosimetry. The synthesized nanocomposites have significantly higher specific surface area in comparison to the copolymer. Total pore volume and the most dominant pore diameter decrease with incorporation of acid modified montmorillonite in copolymer matrix.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Sinteza, svojstva i primena umreženih makroporoznih kopolimera na bazi metakrilata

In this paper, the results obtained during extensive research on the synthesis, properties and application of cross linked copolymers, performed at the Faculty of Technology and Metallurgy (Department of Physical Chemistry and Electrochemistry) and at the IChTM (Center for Catalysis and Chemical Engineering and Center for Chemistry) are summarized. According to the obtained results, changes in the composition of the inert component and the content, type and amount of the crosslinking agent, as well as the type of copolymerization reaction, all strongly influence the porosity parameters of the synthesized macroporous copolymers. Also, it was shown that the synthesized copolymers of glycidyl methacrylate, GMA, and ethylene glycol dimethacrylate, EGDMA, modified with ethylene diamine can be used for the selective sorption of gold and platinum from mixed solutions containing copper, cobalt and nickel ions.U okviru ovoga rada prikazani su rezultati dobijeni u toku višegodišnjeg izučavanja sinteze, svojstava i primene makroporoznih umreženih kopolimera na bazi metakrilata, koja su obavljena pri Katedri za fizičku hemiju i elektrohemiju Tehnološko-metalurškog fakulteta u Beogradu, Centra za katalizu i hemijsko inženjerstvo i Centra za hemiju Instituta za hemiju, tehnologiju i metalurgiju u Beogradu. Pokazano je da se izmenom sastava i udela inertne komponente, vrste i udela umreživača, kao i načina izvođenja reakcije kopolimerizacije može bitno uticati na parametre porozne strukture sintetizovanih umreženih makroporoznih kopolimera i na taj način njihova svojstva prilagoditi različitim potrebama. Pokazano je takođe da se sintetizovani kopolimeri glicidilmetakrilata i etilenglikoldimetakrilata obrađeni sa etilendiaminom mogu uspešno koristiti za selektivno izdvajanje platine iz mešanih rastvora sa jonima bakra, kobalta i nikla

Sorption of different phenol derivatives on a functionalized macroporous nanocomposite of poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) and acid modified bentonite

Macroporous nanocomposite of poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate) and acid modified bentonite was prepared by radical suspension copolymerization. Nanocomposite was functionalized with diethylenetriamine (DETA), by ring-opening reaction of the pendant epoxy groups. Functionalization was performed in order to enable phenol derivatives sorption. This new, not sufficiently investigated material, with developed porous structure was denoted CP-S-A-DETA. In this study, the influence of temperature on 4-nitrophenol (4NP) sorption on CP-S-A-DETA was investigated. The chemisorption was estimated as dominant process since activation energy of sorption of 4NP of 54.8 kJ mol(-1) was obtained. After determining the optimal sorption conditions for 4NP, the sorption of 2-nitrophenol (2NP) and 2-chloro-4-nitrophenol (2Cl4NP) on CP-S-A-DETA was investigated with respect to pH, initial concentration and contact time. The 2NP sorption was seldom tested, while according to our knowledge, the 2Cl4NP sorption was not investigated. The isotherm data were best fitted with Langmuir model, while the sorption dynamics obeyed the pseudo-second-order kinetic model for all derivatives

Parcijalno hidrogenovanje jestivih ulja - sinteza i verifikacija katalizatora na bazi nikla

Developed in the late 1800s as a butter substitute, margarine is made with vegetable oils. Margarine was created by a scientist from Provence (France) Hippolyte Mege-Mouries, in response to an offer by the Emperor Louis Napoleon III. To formulate his entry, Mege-Mouries used margaric acid, a fatty acid component isolated in 1813 by Michael Chevreul and named because of the lustrous pearly drops that reminded him of the Greek word for pearl - margarites.Parcijalna hidrogenacija jestivih biljnih ulja je veoma važna operacija u industriji biljnih masti i ulja. Katalizator koji se uobičajeno upotrebljava u industrijskom procesu parcijalne hidrogenaciji biljnih ulja je nikl nanešen na silikatni nosač. Izbor i hemijska sinteza niklovog katalizatora, postupak nanošenja nikla i promotora na nosač i aktivacija katalizatora su od vitalnog značaja za dobijanje visoko-aktivnog hidrogenacionog katalizatora. Niklov katalizator, nanešen na domaći prirodni silikat (dijatomejska zemlja) sintetizovan je precipitacionom metodom sa NaaCOs. Aktivnost sintetizovanog katalizatora je testirana na pilot postrojenju (5 kg) i u industrijskom reaktoru kapaciteta 5 tona. Dobijena aktivnost sintetizovanog katalizatora potvrđena je i na "scale-up" nivou sa faktorom 1000

Thermodynamcis of molybdenum adsorption onto porous copolymer

Macroporous glycidyl methacrylate and ethylene glycol dimethacrylate copolymer functionalized with diethylene triamine, PGME-deta, was tested as molybdate ion adsorbent from aqueous solutions. Kinetics of Mo(VI) sorption was investigated in batch static experiments, in the temperature range 298-343 K. The temperature rise promotes Mo(VI) removal, with the maximum experimental adsorption capacity of 585 mg g-1 at 343 K. Thermodynamic parameters revealed spontaneous and endothermic nature of Mo(VI) adsorption onto PGME-deta.Physical chemistry 2012 : 11th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 201

Optimizacija i standardizacija autohtone tehnologije pirotskog kačkavalja sa zaštitom oznake porekla

Based on results of performed investigations and analysis of existing conditions relating to technological process in production of kachkaval, we propose the following: To determine the causes of disturbed secretion in case of cows and sheep, investigate the mechanism of proteolytic activity and explain the origin (endogenous or exogenous); Goat milk should be delivered to dairies separately; control of temperature and relative humidity in departments for maturing and drying of cheese; introduction of whey and water separation; in that case, butter can be produced from separated cream. In order to successfully realize project it is also necessary to investigate location of the dairy in Dojkinci in relation to raw material status in different seasons of the year, and take certain measures for improvement of hygienic condition of milk throughout entire technological process: milking, delivering to dairies, storage, transport, etc.; obligatory introduction of basic routine milk analysis when delivered to dairies (volume, acidity, etc.); Introduction of technological log - diary for certain phases of production of kachkaval is also necessary. Finally, subsequent to standardization of entire technological process activities related to obtaining of brand name for such product with determined geographical origin are of great importance.Stara planina spada u red najpoznatijih stočarskih regiona Srbije. Tokom istorije ovom planinom su prolazila nebrojena stada ovaca i gajilo se mnogo goveda. Zahvaljujući toj činjenici, koja je rezultat izvanrednih prirodnih uslova za bavljenje stočarstvom, javili su se i postali poznati širom sveta proizvodi kao: pirotski kačkavalj, pirotsko jagnje i pirotski ćilim. Posle vekovima uspešnog stočarstva Stare planine, poslednih decenija XX veka krenuo je ne zadrživ proces stagnacije, što je praćeno ne samo smanjenjem proizvodnje i redukcijom broja seoskog stanovništa već i odumiranjem pojedinih sela. Da paradoks bude veći tražnja za proizvodima sa ovog područja pre svega kačkavalja ne prestaje i biva sve veća. Promene u pogledu privrednog razvoja naše zemlje koje su u toku osvetlile su zaboravljenu Staru planinu i pirotski kačkavalj, jer se shvatilo da Srbija može ponuditi svetskom tržištu baš te, već poznate specijalitete sa prirodno ne zagađenih područja. Da bi se to i desilo bilo je neophodno započeti projekat koji će na naučnim osnovama omogućiti sagledavanje potencijala i pokazati pravi put za aktiviranje resursa. Ovim projektom se planiraju sledeće najvažnije aktivnosti: -Utvrđivanje mogućnosti proizvodnje stočne hrane i način ishrane ovaca i goveda i predlog mera za njihovo poboljšanje. -Ispitivanje proizvodnog potencijala populacija ovaca i goveda i predlog mera za unapređenje proizvodnje mleka. -Snimanje tradicionalne tehnologije proizvodnje kačkavalja i standardizacija svih procesa od prijema mleka do zrenja sira. -Na osnovu standardizacije proizvodnje kačkavalja i ispitivanja svih važnih osobina dobiće se robna marka i prepoznatljive karakteristike novog proizvoda koji će biti uveden u sistem za dobijanje oznake geografskog porekla

Modification of porous structure of Ca- smectit, copolymer of glycidilmethacrylate and their composite

Smektitna glina iz domaćeg ležišta „Bogovina“, je modifikovana sa različitim koncentracijama HCl kiseline (1,5 - 7,5M). Rendgeno-difrakcionom analizom je utvrđeno prisustvo minerala smektita i pratećih minerala kvarca, kalcita, ilita i feldspata. Na osnovu rezultata hemijske analize, infracrvene spektroskopije (IC), termogravimetrijske ( TG) analize utvrđeno je da u ispitivanim uzorcima dolazi do izmene katjona već pri koncentraciji HCl od 1,5 M. Pri modifikaciji smektita sa kiselinom koncentracije 3 M pored katjonske izmene Na+, Ca2+ sa H+dolazi do delimičnog narušavanja oktaedarskih slojeva u strukturi smektita. Uzorci modifikovani kiselinom veće koncentracije pored navedenih promena imaju i povećanu količinu prisutne amorfne faze. Modifikacija strukture uzoraka smektita različitim koncentracijama HCl kiseline utiče na promenu zapremine makro, mezo i mikro pora. Suspenzionom kopolimerizacijom su sintetisani porozni kopolimeri poli(GMA-co-EGDMA) pri različitom odnosu monomera glicidilmetakrilata (GMA) i etilenglikoldimetakrilata (EGDMA) u prisustvu inicijatora radikalne kopolimerizacije azobisizobutironitrila (AIBN) i inertne komponente. Ispitan je uticaj različitih vrsta i udela umreživača kao i udela alifatskih alkohola u inertnoj komponenti na poroznu strukturu kopolimera. Pri sintezi kompozita korišćena je kopolimerna matrica sa odnosom GMA i umreživača EGDMA 60/40 i inertnom komponentom koja predstavlja smešu cikloheksanola i tetradekanola u odnosu 4:1, uz dodatak nemodifikovanog smektita i smektita modifikovanog 3 M HCl. Utvrđeno da je stepen ugradnje nemodifikovanog smektita u kopolimernu matricu znatno manji, dok je ugradnja kiselo modifikovanog smektita skoro 2 puta efikasnija. SEM analizom su ispitana morfološka svojstva kompozita. Pokazano je da se samo u slučaju kompozita sa smektitom modifikovanim kiselinom dobijaju čestice koje su iste veličine kao i kopolimerne, sa razvijenom makroporoznom strukturom. Utvrđeno je da kompozit sa kiselim smektitom znatno poboljšava termičku stabilnost kopolimera. Makroporozna struktura kompozita je određena Hg-porozimetrijom i dobijeni rezultati pokazuju povećanje specifične površine i pomeranje raspodele veličine pora ka manjim prečnicima pora.Local smectite clay from „Bogovina“ was modified with HCl acid having different concentrations (1.5 – 7.5 M). The X-ray diffraction analysis confirmed the presence of smectite and impurities like quartz, calcite, illite and feldspar. According to results of chemical analysis, infrared (IR) spectroscopy and thermogravimetric (TG) analaysis it was confirmed that the cation exchange already occurred at 1.5 M HCl. Smectite modification with 3 M HCl beside cation exchange of Na+, Ca2+ with H+ lead to partial derogation of octahedral layers of smectite structure. Samples modified with higher acid concentrations beside all mention changes also had increased amount of amorphous phase. The modifications in smectite structure with different HCl concentrations caused change in macro, meso i micro pore volume. Porous copolymers poly(GMA-co-EGDMA) with different ratios of GMA and EGDMA monomers were synthesized by suspension copolymerization in a presence of the azobisisobytironitrile (AIBN) as an initiator, and inert component. The influence of type of and amount of cross-linker as well as the ratios of aliphatic alcohols in the inert component on porous structure of copolymer were investigated. The copolymer matrix with monomer GMA and EGDMA ratio 60/40 and inert componet (mixture of cyclohexanol and tetradecanol 4:1) were used for synthesis of the composite together with either unmodified smectite or smectite modified with 3 M HCl. It was established that the degree of incorporation of unmodified smectite into copolymer matrix is rather low, while the incorporation of acid modified smectite is approx. twice more efficient. SEM analysis revealed morphological properties of composite. It was shown that only particles of composite with acid modified smectite were within the same range as the copolymer particles with developed macroporous structure. It was confirmed that composite with acid modified smectite significantly enhanced thermal stability of copolymer. Macroporous structure composite established by Hg-porosimetry and the obtained results indicated increase in specific surface area and shift in the distribution of pore diameter size toward lower pore diameters