Magnetic composites from minerals: study of the iron phases in clay and diatomite using Mössbauer spectroscopy, magnetic measurements and XRD

High sucrolytic activity by invertase immobilized onto magnetic diatomaceous earth nanoparticles

“…The XRD analysis and Mössbauer spectroscopy supported the presence of only magnetite, as iron phase, and DE in the magnetic composite. A good magnetic response and superparamagnetic behavior were also observed for the mDE composite [18] . These features are very important for the magnetic bio-separation technology because the magnetite has a better response against an external magnetic field applied when compared with others iron oxides (maghemite – γ-Fe 2 O 3 , and hematite – α-Fe 2 O 3 ).…”

“…In this work, mDE nanoparticles (12 nm) were synthesized by co-precipitation method as proposed by Cabrera et al [18] . The XRD analysis and Mössbauer spectroscopy supported the presence of only magnetite, as iron phase, and DE in the magnetic composite.…”

“…Magnetic DE nanoparticles (grain size around of 12 nm) were synthesized as reported by Cabrera et al [18] . Briefly, 5 mL of iron solutions (0.6 mol L −1 FeCl 2 ·4H 2 O and 1.1 mol L −1 FeCl 3 ·6H 2 O) were added to DE preparation (2.0% w/v).…”

“…Magnetic diatomaceous earth (mDE) has been explored in magnetic bio-separation technology [13] , [14] , [15] , [16] , [17] . However, these applications do not include enzyme immobilization that was firstly employed for invertase in our lab [18] .…”

Magnetic Bio-Derivatives: Preparation and Their Uses in Biotechnology

“…Cabrera et al [36] proposed two magnetic composites as a matrix to immobilize invertase via covalent bonding. For this, clay minerals such as montmorillonite (MMT) and diatomaceous earth (DE) were used as a nonmagnetic component.…”