Uv vis spekol 1300

The studies of tetracycline immobilization onto semi-IPNs were carried out in a static system as follows. An amount of 0.1 g of semi-IPN with a known moisture was placed in Erlenmeyer flasks. Over the semi-IPN, 10 mL tetracycline solutions with concentrations between 0.25 and 1 mg/mL were added under gentle stirring (160 rpm., Thermostated Shaker Bath, Memmert, M00/M01, Schwabach, Germany) at different temperatures (298, 308 and 313 K) for different time intervals (10–100 min). After the specified period of time, the semi-IPN was removed quantitatively from the tetracycline solution by centrifugation at 1000 rpm for 10 min. The concentration of tetracycline in the supernatant solution before and after adsorption was determined using a UV–VIS Spectrophotometer (UV–VIS SPEKOL 1300, Analytik Jena, Jena, Germany) at a wavelength of 276 nm using a previously plotted calibration curve. The quantities of tetracycline adsorbed at any time, q_t (mg/g) and at equilibrium, q_e (mg/g) were calculated as follow: $$q_t=\frac{C_{01}-C_t}{W}·V$$
$$q_e=\frac{C_{01}-C_e}{W}·V$$
where: C₀₁—initial concentration of tetracycline solution (mg/mL); C_t–concentration of tetracycline at any time (mg/mL); C_e—concentration of tetracycline at equilibrium (mg/mL); V—volume of drug solution (mL); and W—amount of semi-IPNs (g).

Sorption experiments were conducted using glass bottles containing 0.1 g of the sorbents and 20 mL solution of metal ions or dyes, with an initial pH of about 6, initial concentration of metal ions of 300 mg/L and initial concentration of the dye solutions of 3 × 10⁻⁵ M. The glass bottles were placed on a slow-moving platform shaker (LCD Digital Linear Shaker, SK-L330-Pro, DLAB Scientific Inc., Los Angeles, CA, USA) for 5–6 h. The concentrations of metal ions in the solution, before and after sorption, were analyzed using an atomic adsorption spectrometer (AAS) (ContrAA 800 Spectrometer Analytik Jena, Jena, Germany). The concentration of dyes, before and after sorption, was determined using a UV–Vis spectrophotometer (UV–Vis SPEKOL 1300, Analytik Jena, Jena, Germany), based on the calibration curves determined at the specific wavelength of 497 nm for CR and 597 nm for DR15. The sorption capacity (SC) of the hydrogel beads was calculated with Equations (2) and (3).

where Cs = sorbed concentration of ions or dyes [g/L], V = volume of the sorption solution and m = weight of used sample [g].

where Cs = sorbed concentration of ions after 360 min (mol Me/g hydrogel beads), and M = active sites (AS) of hydrogel beads (mol AS/g hydrogel beads).