2.5 Characterizations
Scanning electron microscopy (SEM)
was performed on a Hitachi FE-SEM
SU8200 instrument (Japan). Thermogravimetric analysis (TGA) was
performed on a TGA 550 instrument (TA Instruments, USA) at 20-800°C
under N2 atmosphere using a heating rate of 20°C/min.
The FTIR spectra of the MD and OSMD samples were measured using Nicolet
iS50 FT-IR (Thermo Scientific, USA). Spectra were taken from 4000 to 400
cm−1 and the resolution of the wavenumber was 2
cm−1. XPS of raw diatomite and OSMD was carried out by
ESCALAB250Xi (Thermo Scientific, USA). The magnetization of the
immobilized enzyme was carried out by Lake Shore VSM 7307 (Lake Shore,
USA). N2 adsorption and desorption study was performed on the ASAP
2020Plus HD88 (Micromeritics, USA). Water contact angle measurement of
the samples was measured with a KRUSS drop shape analyzer DSA 100
instrument at 25°C for the support and the injecting syringe as well.