ABSTRACT
In the present work the cobalt ferrite nanospheres (CFO NS) were prepared via one-step, templatefree solvothermal method and used as a magnetic adsorbent of chromium(VI) ions. The synthesized materials were characterized by X-ray powder diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM) and vibrating sample magnetometry (VSM). The XRD results confirmed the cubic spinel structure of CFO NS while the SEM revealed sphere-like morphology with diameters of the CFO NS in the range of 100-300 nm. TEM images showed that each NS is composed of smaller CFO nanoparticles with size around 7-8 nm. The magnetic measurements revealed ferromagnetic character of CFO nanospheres with the maximum saturation magnetization and coercivity of 75 emu/g and 677 Oe, respectively. The synthetized CFO NS were tested as an adsorption material for removal of chromium(VI) ions from aqueous solution. The obtained removal efficiency is in the range from 38 to 88%. The results suggest that the adsorption capacity of CFO NS strongly depends on conditions of the solvothermal synthesis.
ABSTRACT
Cell wall isolated from pea roots was used to separate and characterize two fractions possessing class III peroxidase activity: (i) ionically bound proteins and (ii) covalently bound proteins. Modified SDS-PAGE separated peroxidase isoforms by their apparent molecular weights: four bands of 56, 46, 44, and 41kDa were found in the ionically bound fraction (iPOD) and one band (70kDa) was resolved after treatment of the cell wall with cellulase and pectinase (cPOD). Isoelectric focusing (IEF) patterns for iPODs and cPODs were significantly different: five iPODs with highly cationic pI (9.5-9.2) were detected, whereas the nine cPODs were anionic with pI values between pH 3.7 and 5. iPODs and cPODs showed rather specific substrate affinity and different sensitivity to inhibitors, heat, and deglycosylation treatments. Peroxidase and oxidase activities and their IEF patterns for both fractions were determined in different zones along the root and in roots of different ages. New iPODs with pI 9.34 and 9.5 were induced with root growth, while the activity of cPODs was more related to the formation of the cell wall in non-elongating tissue. Treatment with auxin that inhibits root growth led to suppression of iPOD and induction of cPOD. A similar effect was obtained with the widely used elicitor, chitosan, which also induced cPODs with pI 5.3 and 5.7, which may be specifically related to pathogen defence. The differences reported here between biochemical properties of cPOD and iPOD and their differential induction during development and under specific treatments implicate that they are involved in specific and different physiological processes.
