Magdalena Sobiesiak

Functionalization of Carbon and Silica Gel by Phosphoric Acid

Functionalization of polymer-based carbon (SCS-3) and silica gel (SG60) by phosphoric acid at 800°C was investigated. It was shown that heat treatment of carbon and silica gel in the presence of phosphoric acid at 800°C provides a way of functionalizing materials with phosphorus-containing surface groups. Functionalization of the finished carbon occurs as a surface reaction while destruction of the silica gel structure was observed. Functionalization with phosphoric acid creates new acid surface groups — phosphorus-containing and oxygen-containing in the case of carbon and only phosphorus-containing in the case of silica gel. Enhancement of the amount of acid surface groups by functionalization improves the metal-ion binding properties of both carbon and silica gel.

Chemical composition of plasma treated polyimide microspheres

Abstract Synthetic carbon microspheres for chromatography were obtained from porous copolymer of 4,4′-bis(maleimidodiphenyl)methane (BM) and divinylbenzene (DVB) using arc discharge argon plasma treatment. Chemical structure of the obtained material was determined by elemental analysis, scanning electron microscopy with X-ray detector, acid and base titrations, and atomic absorption spectroscopy. The results suggest that the carbon microspheres contain copper coming from the plasma reactor electrodes. To remove it two complexion agents were used: EDTA and 20% HNO3. Copper can be removed from the surface using these methods. The other amount was permanently built into internal structure of the microspheres.

Preparation of lignin-containing porous microspheres through the copolymerization of lignin acrylate derivatives with styrene and divinylbenzene

Abstract A novel method for synthesizing microspheres from lignin or lignin acrylate derivatives through copolymerization with styrene (St) and divinylbenzene (DVB) has been developed. The copolymers were obtained by the emulsion-suspension polymerization with a constant molar ratio of DVB to St of 1:1 (w/w) and different amounts of lignin or its derivatives. The morphologies of the obtained materials were examined by scanning electron microscopy. Two types of lignin modifications were performed to introduce vinyl groups into the lignin molecules: modification with acrylic acid and modification with epichlorohydrin plus acrylic acid. The course of modification was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy. The thermal stability and degradation behavior of the obtained microspheres were investigated by thermogravimetric analysis, and the pore structure was characterized via nitrogen sorption experiments. Owing to the presence of specific functional groups and the well-developed pore structure, the obtained Lignin-St-DVB microspheres may have potential application as specific sorbents for the removal of phenolic pollutants from water, as demonstrated by the solid-phase extraction technique.

Comparison of heterogeneous pore models QSDFT and 2D-NLDFT and computer programs ASiQwin and SAIEUS for calculation of pore size distribution

The pore size distributions (PSD) of selected carbons were calculated from their nitrogen adsorption isotherms using both the QSDFT model implemented in ASiQwin version 3.0 software (Quantachrome Instruments) and 2D-NLDFT model implemented in SAIEUS software (Micromeritics). The results showed that both the QSDFT and the 2D-NLDFT methods give similar PSDs despite the different methods for accounting for the heterogeneity of the carbon adsorbent. The characteristic features of the methods and software were discussed and possible improvements were proposed.

Phosphoric Acid and Steam as Activation Agents for Carbonized Porous Polymer Surfaces

Carbon sorbents derived from the copolymer of 4,4′-bis(maleimidodiphenyl)methane and divinylbenzene are described. The influence of phosphoric acid treatment and the type of carrier gas used in the carbonization process were studied. Solid-phase extraction experiments were conducted to determine their impact on the sorption properties of these new sorbents. The recoveries and breakthrough volumes for phenolic compounds preconcentrated from water were studied.

Characteristics of thermal behavior of photoluminescent copolymers studied by the TG/DTG/FTIR coupled method

Thermal properties of the photoluminescent copolymers, naphthalene-2,7-diol dimethacrylate derivatives, are presented in this paper. The materials were synthesized by bulk copolymerization of 2,7-(2-hydroxy-3-methacryloyloxypropoxy)naphthalene (2,7-NAF.DM) with four popular vinyl monomers: 2-hydroxyethyl methacrylate (HEMA), butyl acrylate (BA), divinylbenzene (DVB) and styrene (ST). As an initiator, the α,α′-azoiso-bis-butyronitrile was used. Thermal stabilities and degradation behaviors of the obtained copolymers were studied by means of the differential scanning calorimetry and thermogravimetric (TG/DTG, in air and in helium atmosphere) analyses. Gases evolved during the thermal treatment were monitored using the TG-FTIR coupled method. The presented copolymers can have potential application as luminophores, protective coatings or fiber-optical sensors.

Synthesis and characterization of organic–inorganic hybrid microspheres

This study presents the synthesis of hybrid microspheres based on monomers of various chemical nature. As organic compounds, styrene and 1,4-divinylbenzene were used, whereas triethoxyvinylsilane (TEVS) was applied as an inorganic one. Four different systems with the increasing quantity of TEVS were studied. Then inorganic parts of TEVS were removed with aqueous solution of NaOH. Structure of the new materials was confirmed by FTIR-ATR, EDX–SEM and TGA analyses. Thermal resistance of the copolymers was assessed using the TG–DTG system. The synthesized hybrid materials exhibited highly developed porous structure that was confirmed from the low-temperature nitrogen adsorption data. The prepared materials were tested as sorbents for removing organic compounds from aqueous solutions using the SPE technique.

Assessment of the structural evolution of polyimide-derived carbons obtained by phosphoric acid activation using Fourier transform infrared and Raman spectroscopy:

Two series of carbons obtained by carbonization of porous copolymer of 4,4′-bis(maleimidodiphenyl) methane (50 mol%) and divinylbenzene (50 mol%) with and without phosphoric acid (impregnation ratio 1.1) at temperatures 400–1000℃. The carbons were characterized using elemental analysis, nitrogen adsorption, potentiometric titration, Fourier transform infrared and Raman spectroscopy. It has been shown that phosphoric acid causes structural and chemical changes in polyimide copolymer as compared to thermally treated carbons. Structural changes: phosphoric acid promotes transformation of polyimide copolymer to carbon structure at lower temperatures as compared to thermally treated carbons. Phosphoric acid is responsible for formation of highly developed micro/mesoporous structure that is different from that of thermally treated carbons. Chemical changes: phosphoric acid causes elimination of hydrogen and nitrogen, introduction of phosphorus and oxygen as phosphate-like structure. Significant amount of phosphorus imparts acid properties to carbon.

SPE of Phenols on New Amine - Based Copolymers

Porous microspheres, copolymers: bis [4(2-hydroxy-3-methacryloyloxypropoxy)-phenysulfide (BES.DM) and glycidyl methacrylate (GMA) have been prepared by suspension-emulsion polymerization. The copolymer (BES.DM+GMA) including reactive epoxide rings was modified with three amines: butylenediamine (BDA), diethylenetriamine (DETA), triethylenetetramine (TETA). Next, attachment of HCO3- species to the primary amine groups took place.The prepared porous polymers were used as adsorbents in off-line SPE experiments. A mixture of phenol (PH), 2-chlorophenol (ChP), 2,4-dichlorophenol (DChP) and 2,4,6-trichlorophenol (TChP) as testing compounds was applied.Depending on the way of chemical modification, the prepared adsorbents possessed diverse sorption properties towards the testing compounds. Competition of the phenolic compounds for active sites presented on the polymer surface was observed. The most effective in water purification process were polymers possessing both amine and bicarbonate groups. The best recovery results were obtained for 2,4-dichlorophenol.