Quanta 3d feg microscope

The samples were shaken using a laboratory shaker type 357 of constant vibration speed (180 rpm) (Elpin Plus, Lubawa, Poland). The pH was measured using a pH meter, CPI-505, with a glass electrode (Elmetron, Zabrze, Poland). The concentrations of Cu(II), Zn(II), Mn(II) and Fe(III) complexes with EDDS in the filtrate were determined using the spectrometer ICP-OES of 720 ES type (Varian Inc., Palo Alto, CA, USA). The sample introduction system was equipped with a glass Conikal^® nebulizer, cyclonic double pass spray chamber and three-channel peristaltic pump. The optimal operating parameters used for determination of the studied elements by the ICP-OES technique are as follows: power, 1200 W; plasma argon gas flow rate, 15 dm³/min; auxiliary argon gas flow rate, 2.25 dm³/min; nebulizer argon gas flow rate, 0.2 dm³/min; pump rate, 12 rpm; analytical wavelengths: 327.395 nm for Cu, 213.857 nm for Zn, 257.610 nm for Mn and 259.940 nm for Fe. Scanning electron microscopy images were obtained using the Quanta 3D FEG microscope with the EDS/EBSD system (FEI). Fourier transform infrared spectra of hydrogels were recorded by the attenuated total reflectance technique (FTIR-ATR), and measurements were made using a FTIR Carry 630 spectrometer (Agilent Technologies, Santa Clara, CA, USA).

To evaluate the diameter of pores in the dialysis membrane, we applied Environmental Scanning Electron Microscopy (ESEM). A fragment of the dialysis membrane (1 × 1 (cm)) was placed on the SEM sample holder and the subsequent ESEM measurements were performed using the SEM Quanta 3D FEG microscope (FEI Company, Hillsboro, OR, USA) in use by the Department of Solid State Physics (Institute of Physics Jagiellonian University, Kraków, Poland). The ESEM images were collected by a Low-Vacuum Secondary Electron Detector (LVED) using an electron beam of 20 keV energy. During the measurement, the specimen was kept at 130 (Pa) of water vapor at room temperature.