Structural studies of marine exoskeletons: redox mechanisms observed in the Cu-supported CaCO3 surfaces tudied by EPR.
Electron Paramagnetic Resonance (EPR), optical and infrared (IR) spectral studies have been performed on the pure and Cu-adsorbed exoskeletons of marine environment. The EPR spectrum of exoskeletons at room temperature exhibits a sharp signal at g approximately 1.9970. The possible redox mechanisms have been noticed on heating these exoskeletons in which the low spin Mn(3+) reduces to Mn(2+). The optical absorption spectra also give the evidence of the presence of Mn(3+) ions. The effects of thermal sintering on the EPR spectra have been studied and discussed in detail. The Cu-adsorbed samples clearly showed the adsorption of the Cu(2+) ions over CaCO(3) and the redox mechanism in these samples have been monitored by EPR.
Linga Raju
C H
CH
Department of Physics, Sri Venkateswara University, Tirupati 517 502, India.
Narasimhulu
K V
KV
Gopal
N O
NO
Rao
J L
JL
Reddy
B C V
BC
D000818:Animals; D002119:Calcium Carbonate / Q000737:chemistry*; D003300:Copper; D003445:Crustacea / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D008974:Mollusca / Q000737:chemistry*; D010084:Oxidation-Reduction; D012623:Seawater; D013055:Spectrophotometry, Infrared / Q000379:methods
D003300:Copper; D002119:Calcium Carbonate