Ograniczanie wyników

Czasopisma help
Autorzy help
Lata help
Preferencje help
Widoczny [Schowaj] Abstrakt
Liczba wyników

Znaleziono wyników: 52

Liczba wyników na stronie
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników

Wyniki wyszukiwania

Wyszukiwano:
w słowach kluczowych:  aqueous solution
help Sortuj według:

help Ogranicz wyniki do:
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
Structural parameters of retrograded amylose chains in aqueous solution were determined by means of a comparative analysis with glucose solutions stored under the same conditions and the same specific volume. Viscosimetric and Polarimetrie measurements were carried out in glucose and amylose (from potato) solutions during storage, within the same concentration range of 0.005-0.02 (g/cm3), and with a fixed low concentration of a polymer complexing agent (5 10 -5 g/cm3), added as a polymer chain stiffener. From the ratio of limit viscosity numbers obtained for polysaccharide and monosaccharide solutions, the average asymmetric parameter of rigid amylose chain was calculated, value of which points to a significant length expansion of retrograded α-D-glucopyranose coil. Measurements of the concentration dependence of the optical rotatory dispersion in retrograded amylose and its monomer unit solutions were used to determine the degree of coiling into helix of polysaccharide in aqueous solution.
Enteromorpha prolifera green algae is the main species that causes green tide in China’s Yellow Sea. To effectively realize the resourceful utilization of this biomass, batch experiments were carried out to investigate factors that impact the Acid Bordeaux B (ABB) absorption of E. prolifera powder, such as exposure time, pH, adsorbent dose, and oscillation frequency. The dye adsorption onto adsorbent was confirmed by Fourier transform infrared spectroscopy (FTIR). Results showed that amide, hydroxy, carboxylate, and C-O groups were involved in the adsorption process. The treatment conditions for dye concentration of 100 mg·L⁻¹ were optimized: contact time 60 min, pH value 4 to 9, water temperature 303 to 313 K, adsorbent dosage 0.25 g·L⁻¹ and oscillation frequency 150 rpm. Equilibrium data were analyzed by using the Freundlich and Langmuir models. The data fit well in both models. The maximum equilibrium adsorption capacity calculated by the Langmuir equation was 1,111.11-3,333.33 mg·g⁻¹. To clarify the sorption kinetic, the fitness of the Pseudofirst- order model, the Pseudo-second-order model, and the intra-particle diffusion model were tested, showing that the pseudo-second order model was suitable to describe the adsorption process. The sorption process was complex, and both the boundary of liquid film and intra-particle diffusion contributed to the rate-determining step. Thermodynamic parameters (e.g. ΔG⁰, ΔH⁰, and ΔS⁰) were calculated, which implied the exothermic and spontaneous nature of biosorption as well as the type of adsorption (physisorption). Results illustrate that the removal ratio from the wastewater with 100 mg·L⁻¹ ABB reached 90.86%, indicating that E. prolifera could be a potential biosorbent used for the removal of ABB from industrial effluents.
The functionalized mesoporous’ potential ability of binding heavy metals using different templates, namely cetyltrimethylammonium (CTAB) (adsorbent A) and triblock copolymer (Pluronic P123, EO20PO70EO2O, Mav = 5800) (adsorbent B), was evaluated. The synthesized materials were characterized by powder X-ray diffraction (XRD), nitrogen gas sorption, FT-IR and solid-state ¹³C and ²⁹Si NMR spectroscopy and thermogravimetry (TGA) measurements. In the adsorption experiment, the effects of several variables (stirring time, pH and presence of other metals in the medium) were studied. On the basis of these results, it was observed that the adsorption capacities were higher for adsorbent B than adsorbent A. The results also confirmed that the ureido group (CO-NH₂) has a good affect of binding metal ion.
Metodą elektroforezy bibułowej rozdzielano różne formy selenu. Wyznaczono ruchliwość jonów SeO32- i SeO42-. Wykazano znaczne zróżnicowanie występujących form selenu w badanych roztworach wodnych. Stwierdzono niższą ruchliwość jonu SeO42-.
 Some surfactants widely used as additives in food, pharmaceuticals, and cosmetic formulations are susceptible to peroxidation resulting in accumulation of hydroperoxides (HP). Our investigation was aimed to study the possible influence of different surfactants on the proportionality and reproducibility of the ferrous oxidation-xylenol orange method developed originally for the determination of hydroperoxides. We also attempted to apply this method to determine hydroperoxides produced radiolytically in surfactant molecules. From our preliminary studies we conclude that the method can be applied for determination of hydroperoxides in systems containing non-ionic or anionic surfactants provided careful calibration is performed for each surfactant.
Our paper presents biological Cr(VI) removal from water solution by applying a clean fungi culture, namely Aspergillus niger. The growth of the organism and removal of chromium(VI) were done in water solution of various chromium(VI) contents and at optimal pH value. During 14 days of incubation, samples of 5 ml each were collected daily to determinate chromium(VI) contents in solution. Then the efficiency of this biological removal was also specified. The Cr(VI) removal process may occur via reduction, biosorption, or bioaccumulation pathways. To determine which pathway may be used in the study the Cr(III) contents were also determined in the samples as well chromium contents in ooze after mycelium irrigating and in mycelium.
Pierwsza strona wyników Pięć stron wyników wstecz Poprzednia strona wyników Strona / 3 Następna strona wyników Pięć stron wyników wprzód Ostatnia strona wyników
JavaScript jest wyłączony w Twojej przeglądarce internetowej. Włącz go, a następnie odśwież stronę, aby móc w pełni z niej korzystać.