Synthesis, modification, and porous properties of new glycidyl methacrylate copolymers

Synthesis, Characterization and Application of a New Functionalized Polymeric Sorbent Based on Alkenylphoshine Oxide

A novel phosphorus-containing sorbent (CyP(Ph)4-DVB) was prepared by copolymerizing divinylbenzene (DVB) with bis α,β-unsaturated phosphorylated cyclohexene (CyP(Ph)4). ATR-FT-IR indicated that the phosphinoyl group was introduced into the sorbent structure. The thermal properties of the sorbent were investigated using a differential scanning calorimeter (DSC), which revealed that (CyP(Ph)4-DVB) is more stable than poly(DVB). The CyP(Ph)4-DVB was applied for cationic dye removal, such as C.I. Basic Yellow 2 (BY2) and C.I. Basic Blue 3 (BB3). Batch adsorption tests suggested that the Freundlich isotherm model seemed to be the better one for the description of equilibrium sorption data at equilibrium, rather than the Langmuir or Temkin models. The Freundlich constants concerning the adsorption capacity of CyP(Ph)4-DVB, k_F, were calculated as 14.2 mg^1-1/nL^1/n/g for BY2 and 53.7 mg^1-1/nL^1/n/g for BB3.

Application of Functionalized DVB-co-GMA Polymeric Microspheres in the Enhanced Sorption Process of Hazardous Dyes from Dyeing Baths

Intensive development of many industries, including textile, paper, plastic or food, generate huge amounts of wastewaters containing not only toxic dyes but also harmful auxiliaries such as salts, acid, bases, surfactants, oxidants, heavy metal ions. The search for effective pollutant adsorbents is a huge challenge for scientists. Synthesis of divinylbenzene copolymer with glycidyl methacrylate functionalized with triethylenetetramine (DVB-co-GMA-TETA) resin was performed and the obtained microspheres were evaluated as a potential adsorbent for acid dye removal from dyeing effluents. The sorption capacities were equal to 142.4 mg/g for C.I. Acid Green 16 (AG16), 172 mg/g for C.I. Acid Violet 1 (AV1) and 216.3 mg/g for C.I. Acid Red 18 (AR18). Non-linear fitting of the Freundlich isotherm to experimental data was confirmed rather than the Langmuir, Temkin and Dubinin-Radushkevich. The kinetic studies revealed that intraparticle diffusion is the rate-limiting step during dye adsorption. Auxiliaries such as Na₂SO₄ (5–25 g/L), CH₃COOH (0.25–1.5 g/L) and anionic surfactant (0.1–0.5 g/L) present in the dyeing baths enhance the dye adsorption by the resin in most cases. Regeneration of DVB-co-GMA-TETA is possible using 1 M NaCl-50% v/v CH₃OH.

Peculiar Properties of Mesoporous Synthetic Carbon/Graphene Phase Composites and their Effect on Supercapacitive Performance

Composites of mesoporous synthetic carbon and the graphene phase were synthesized in aqueous suspension by employing dispersive interactions of both phases. The resulting carbon-based materials were further heat treated in air at 350 °C. The composites and their components were characterized by using adsorption of nitrogen, potentiometric titration, thermal analysis-mass spectrometry, X-ray photoelectron spectroscopy, SEM, high-resolution TEM, and XRD. Then, they were tested as supercapacitors in three-electrode cells and under visible-light irradiation. The composites and the initial carbon share exactly the same pore-size distributions, but they exhibit significant differences in their surface chemistry, wettability, and conductivity. This allowed us to determine the extent of their effects on their capacitive/pseudocapacitive performance. The results showed that features other than the textural properties can increase the capacitive performance by more than 100 %. The synergistic properties of the composites and their sulfur functional group related photoactivity were linked to chemical interactions between the nanoporous carbon phase and graphite oxide during the formation of the composite.

An efficient method for the immobilization of inulinase using new types of polymers containing epoxy groups

New glycidyl methacrylate copolymers containing different numbers of epoxy groups were synthesized and used to develop effective procedures for inulinase immobilization. The beneficial characteristics of the carriers included a high degree of crosslinking, stability at ambient temperature, an appropriate surface, and the presence of reactive epoxy groups. Some factors affecting the efficiency of immobilization of crude inulinase, including the kind and amount of carrier, the number of epoxy groups, as well as buffer pH and buffer concentration were examined. The yield of immobilization of this enzyme on the investigated type of microspheres was higher than on the commercial carrier, Eupergit^® C. After immobilization, the optimum temperature for inulinase activity shifted from 55 to 45 °C, whereas the optimum pH = 5 remained unchanged. The basic parameters of inulin hydrolysis were examined, and the possibility of applying the obtained biocatalyst in continuous conditions was tested. Inulin at a concentration of 0.5 % (w/v) was almost completely hydrolyzed to fructose (in a yield of 98 %) at a flow rate of 0.1 mL/min. A tenfold increase in the speed of flow resulted in an increase in the yield of oligosaccharides (DP2-DP6) up to ~41 % in the overall hydrolysate, as analysed by HPLC-RID and LC-ESI/MS. These results indicate that two forms of inulinase, an exo- and an endo-acting enzyme, were immobilized on our carrier. The enzyme showed good operational stability in a packed column over 28 days. There were no significant decreases in the efficiency of continuous hydrolysis during this time (about 17.4 % in comparison to its initial value).