Jec 530

The fungi were cultivated on 9 mm, circular cover glasses (Agar Scientific Ltd., Stansted, UK) in Petri dishes (as described above) for a week. After this time, cultures were gently washed with a fresh culture medium and fixed for 30 min with a mixture of 4% formaldehyde (158127, Sigma-Aldrich, St. Louis, MO, USA) and 2% glutaraldehyde (01909, Polysciences, Inc., Warrington, FL, USA) in 0.1 M cacodylic buffer (15540.02, Serva Electrophoresis GmbH, Heidelberg, Germany). Next, the specimens were washed three times with a 0.1 M cacodylic buffer and dehydrated with increasing ethanol concentrations (POCH, Gliwice, Poland). Finally, they were transferred to 1:1 (v:v) mixture of ethanol:acetone followed by incubation in dehydrated acetone (POCH, Gliwice, Poland) and drying at a critical point (CPD E3000, Quorum Technologies, Lewes, UK). The dried samples (still on cover glasses) were adhered to microscope holders and sputter coated with ~10 nm layer of gold (JFC-1100E, JEOL, Tokyo, Japan). The specimens were imaged using a JEOL JSM5410 scanning electron microscope (JEOL, Tokyo, Japan). Similar samples coated with carbon (JEC-530, JEOL, Tokyo, Japan) were observed using Hitachi S-4700 FEG scanning (Institute of Geology of the Jagiellonian University in Kraków, Poland).

The images were taken using an Axio Imager.M1m optical microscope (Zeiss, Jena, Germany) and a JSM-6610LV scanning electron microscope (JEOL Ltd., Akishima, Japan) after sputtering the samples with carbon using an automatic coating machine JEC-530 (JEOL Ltd., Akishima, Japan). In addition, the dry matter content was measured in both suspensions. Particle size analysis by laser diffraction was carried out using a particle size analyser Mastersizer 2000 (Malvern Instruments Ltd., Malvern, UK). The specific surface areas of schwertmannite A (SCH_A) and schwertmannite B (SCH_B) were determined using FlowSorb 2300 apparatus (Micromeritics Instruments Corp, Norcross, GA, USA). The density of schwertmannite sorbents was performed using a pycnometer. The isoelectric point (pH_iep) was determined by electrophoretic zeta potential measurements using a Zetasizer 2000 (Malvern Instruments Ltd., Malvern, UK). FT-IR measurements of the obtained schwertmannite sorbents were performed with a Vertex 70/70V spectrometer (Brucker, Billerica, MA, USA).