Fei nova nanosem 230 microscope

Propanolan titanium (Ti(OCH₂CH₂CH₃)₄) 98%, sodium selenite (Na₂SeO₃) 99%, and sodium selenate (Na₂SeO₄) 98% were purchased from Sigma-Aldrich (Germany); propan-2-ol (C₃H₇OH) was purchased from Chempur (Poland); nitric acid (HNO₃) 65% and ammonia solution (NH₃·H₂O) 30% p.a. were purchased from POCH (Poland); standard solutions (1 mg mL⁻¹): Se(IV), As(III), and As(V) were purchased from Sigma-Aldrich (Germany), and Cr(III), Cr(VI), Cu(II), Pb(II), Zn(II), and Fe(III) were purchased from Merck (Germany); re-destilated water was from Milli-Q System of Millipore (France); filters Whatman 3MM were purchased from GE Healthcare Life Sciences (United Kingdom); Certified Reference Material (CRM) of natural water, NIST 1640a, was purchased from Sigma-Aldrich (Germany).
The following equipment were used for the research: FEI Nova NanoSEM 230 microscope (FEI Company, Hillsboro, Oregon, USA), x-ray powder diffractometer (XRD) (PANalytical, The Netherlands), energy-dispersive x-ray fluorescence spectrometer (EDXRF) XDV-SD model (Helmut Fischer GmbH, Sindelfingen, Germany), energy-dispersive x-ray fluorescence spectrometer (EDXRF) Epsilon 3 model (PANalytical, Almelo, The Netherlands), and inductively coupled plasma optical emission spectrometer (ICP-OES) SpectroBlue FMS16a model (Spectro Analytical Instruments GmbH, Germany). The apparatus is described in detail in ESM.

X-ray Diffraction (XRD) Patterns of the samples were obtained with a Philips X’PERT diffractometer using Cu Kα radiation. Nitrogen adsorption-desorption isotherms were measured at −196 °C using the micrometrics ASAP 2420 sorptometer to determine textural properties. All samples were degassed at 350 °C for 16 h. The total pore volume was determined from the amount of nitrogen adsorbed at a relative pressure of 0.97. Pore size distributions were determined from the adsorption branches of isotherms using the DFT model with cylindrical geometry of the pores. Transmission electron microscopy (TEM) micrographs were taken using a JEOL 2100F electron microscope operating at 200 kV. The samples for TEM analysis were prepared by suspending a small amount of solid in ethanol. A drop of this suspension was then dispersed onto a holey carbon film on a copper grid, followed by drying at room temperature. The morphology was evaluated by scanning electron microscopy (SEM) with an FE-SEM FEI Nova NanoSEM 230 microscope with vCD detector using chromium coating.