Adsorption isotherms of chloroform on macroporous copolymers determined by inverse gas chromatography

The inverse gas chromatography (IGC) under finite surface coverage conditions was used for the determination of adsorption isotherms of chloroform on macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), PGME and copolymer modified with ethylene diamine, EDA, PGME-en. The specific surface areas of initial and modified copolymer samples calculated from IGC data are in fair agreement with those determined by the BET method from the low-temperature nitrogen adsorption isotherms.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Novel asymmetric polyethersulfone membranes for ultrafiltration application

Ultrafiltration has recently become popular as a promising separation method in many industrial processes covering fractionation and concentration steps in the food, pharmaceutical and biotechnology industries as much as in water and wastewater treatments. This paper presents the synthesis of novel asymmetric polyethersulfone membranes containing an interpenetrating network of poly(glycidyl methacrylate) (PGMA). In order to improve the properties and application range of membranes, the epoxy groups from PGMA are converted to amine groups by ring opening under alkaline conditions. Membranes before and after functionalization are characterized by FTIR-ATR, elememtal analysis and water permeability

Membrane-based plasmonic nanocomposites for chemical or biological sensing

One of the important applications of subwavelength plasmonic optics is sensing of chemical and biological analytes [1]. Plasmonic sensors are based on tuning of either propagating surface waves (surface plasmon polaritons, SPP) or nonpropagating (localized) ones. The adsorption of analyte modifies the surface refractive index, ensuring ultrahigh sensitivities that may exceed 10–8 refractive index units, i.e. 1 ng/cm2 (0.003 monolayer) [2]. For all plasmonic sensors it is of interest to enhance their selectivity, since their operation is based solely on refractive index sensing, i.e. different materials with similar refractive indexes cause similar outputs. In this work we propose the integration of active plasmonic part with separator (e.g. membrane or nanomembrane with nanopores) and ligand binding the targeted analyte into a single structure. This may be done by membrane nanocompositing [3], e.g. by lamination (Fig. 1a) or volume structuring/pore formation (Fig. 1b). At the same one may use built-in (nano)pores to augment the effective surface for adsorption and thus vastly increase the amount of adsorbate. For our work we chose macroporous crosslinked copolymers (MCP) which are readily formed into membranes and keep a permanent well-developed porous structure. Particularly we used glycidyl methacrylate (GMA)-based MCP. GMA has already been successfully used for heavy and precious metals adsorption and enzyme immobilization [4]. For the formation of membranes comprising GMA we selected a new method combining traditional immersion precipitation with photopolymerization and crosslinking of functional monomers [5]. Our approach may be extended to other types of chemical and bio sensors. Acknowledgment:This work has been funded by Serbian Ministry of Education and Science through the projects TR32008 and III 43009.[1] W. L. Barnes, A. Dereux, T. W. Ebbesen, Nature, 424 (2003) 824-830.[2] L. S. Jung, C. T. Campbell, T. M. Chinowsky, M. N. Mar, S. S. Yee, Langmuir, 14 (1998) 5636-5648.[3] Z. Jakšić, J. Matovic, Materials, 1 (2010) 165-200.[4] N. Miletić, Z. Vuković, A. Nastasović, K. Loos, Macromol. Biosci., 11 (2011) 1537–1543.[5] P. Radovanovic, M. Kellner, J. Matovic, R. Liska, T. Koch, J. Membrane Sci., 401-402 (2012) 254-261

Study of copper adsorption on aminofunctionalized macroporous poly(gma-co-egdma)

Macroporous crosslinked copolymer of glycidyl methacrylate and ethylene glycoldimethacrylate (PGME) was synthesized by suspension copolymerisation and modified by ring-opening reaction of epoxy groups with ethylene diamine, diethylene triamine and triethylene tetramine. The uptake of copper ions by amino-functionalized macroporous PGME from aqueous solutions was investigated in batch experiments. The equilibrium data fitted well with the Langmuir model.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

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

Makroporozni kopolimer na bazi glicidilmetakrilata funkcionalizovan sa dietilentriaminom kao sorbent tekstilne boje Reactive Black 5

In this paper, macroporous glycidyl methacrylate and ethylene glycol dimethacrylate copolymer functionalized with diethylene triamine (PGME-deta), was evaluated as Reactive Black 5 (RB5) sorbent. Batch RB5 removal from aqueous solution by PGME-deta was investigated by varying pH, contact time, sorbent dosage, initial dye concentration and temperature. The sorption is pH sensitive having maximum at pH 2 (dye removal of 85%), decreasing with the increase of pH (dye removal of 24% at pH 11) after 60 min. Sorption kinetics was fitted to chemical-reaction and particle-diffusion models (pseudo-first-, pseudo-second-order, intraparticle diffusion and Mckay models). The pseudo-second-order kinetic model accurately predicted the RB5 amount sorbed under all investigated operating conditions, while the intraparticle diffusion was the dominant rate-limiting mechanism. The diffusion mechanism was more prevalent with the decrease in temperature and the increase in concentration. The isotherm data was best fitted with the Langmuir model, indicating homogeneous distribution of active sites on PGME-deta and monolayer sorption, with the maximum sorption capacity of 353 mg g(-1). The calculated sorption rates improved with increasing temperature and an activation energy close to 40 kj mol(-1) was determined, suggesting that chemisorption was also rate-controlling.U okviru ovog rada ispitana je mogućnost korišćenja makroporoznog kopolimera glicidilmetakrilata i etilenglikoldimetakrilata funkcionalizovanog reakcijom otvaranja epoksidnih grupa sa dietilentriaminom (PGME-deta) kao sorbenta reaktivne tekstilne boje Reactive Black 5 (RB5). U šaržnim uslovima je ispitano uklanjanje RB5 iz vodenog rastvora pomoću PGME-deta, variranjem pH, vremena kontakta, mase sorbenta, početne koncentracije boje i temperature. PGME-deta je pokazao afinitet za sorpciju RB5 zbog prisustva protonovanih amino grupa koje privlače anjonske sulfonatne grupe u molekulu boje i mogućnosti stvaranja vodoničnih veza između sorbenta i sorbata. Kinetika sorpcije je analizirana pomoću četiri kinetička modela (pseudo-prvog, pseudo-drugog reda, unutarčestične difuzije i Mekej) da bi se odredilo koji model najbolje opisuje sorpciju RB5. Zapažen je izrazit uticaj pH vrednosti na sorpciju RB5, sa maksimumom na pH 2 (pri čemu je efikasnost uklanjanja boje 85%), i smanjenjem količine sorbovane boje sa povećanjem pH (količina uklonjene boje na pH 11 posle 60 min iznosi samo 24%). Izučavanjem kinetike sorpcije pokazalo se da sorpcija RB5 pomoću PGME-deta sledi kinetički model pseudo-drugog reda (PSO), sugerišući da je brzina sorpcije kontrolisana kapacitetom sorbenta i koncentracijom sorbata. Mehanizam procesa dominantno čini unutarčestična difuzija, uz manji uticaj difuzije kroz film. Ovi mehanizmi difuzije su izraženiji pri nižim temperaturama i većim koncentracijama. Langmirov model najbolje opisuje ravnotežnu izotermu, ukazujući na homogenu raspodelu aktivnih mesta na površini PGME-deta i monoslojnu sorpciju. Maksimalni sorpcioni kapacitet izračunat iz Langmirove izoterme iznosi 353 mg g-1. Zapaženo je da se brzina sorpcije povećava sa povećanjem temperature. Izračunata vrednost aktivacione energije od oko 40 kJ mol-1 potvrđuje da se radi o procesu koji dominantno kontroliše hemisorpcija

Chelating copolymers: metal sorption kinetics and reusability

Macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), PGME, was synthesized by suspension copolymerization and functionalized with diethylene triamine, PGME-deta. Kinetics for Au(III), Ag(I) and Cu(II) sorption, as well as the possibility of repeated recovery of Cu(II) ions was investigated.Physical chemistry 2008 : 9th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 24-28 September 200

Novel negatively-charged ultrafiltration membranes made by a combination of immersion precipitation and photopolymerization

Ultrafiltration (UF) membranes are currently used in industry for the concentration of proteins and other macromolecules. Performance of UF membranes is generally limited by a trade-off between permeability and selectivity [1]. However, electrically-charged ultrafiltration membranes can provide a dramatic improvement in ultrafiltration performance [2]. Novel UF membranes were made by combining traditional immersion precipitation process for making membranes with photopolymerization of the casting solution comprising polyethersulfone, glycidyl methacrylate and other reactive monomers. Negative charges were introduced either by initially using 2-acrylamido-2-methylpropane sulfonic acid as a reactive monomer, or were later created by epoxide ring opening of crosslinked glycidyl methacrylate. As shown in Fig. 1, selectivity of these membranes significantly improved as the concentration of negatively-charged groups in the membrane increased. The effects of membrane composition on the properties and separation performance of these novel UF membranes will be presented

Hexavalent chromium sorption by glycidyl methacrylate based copolymer

Macroporous crosslinked poly(glycidyl methacrylate-co-ethylene glycol dimethacrylate), PGME, was synthesized by suspension copolymerization and functionalized with diethylene triamine [PGME-deta]. Competitive sorption kinetics was studied from multicomponent Cr(VI), Cu(II), Co(II) and Cd(II) solution. Two kinetic models (the pseudo-first and the pseudo-second order) were used to determine the best-fit equation for the metals sorption by PGME-deta