Preparation of mixed oxide surface and its characteristics toward adsorption of textile dyes

Abstract

Mixed oxides samples of copper and cobalt were prepared by the reactions of ammonium carbonate and the metal nitrates from aqueous solutions followed by calcinating at 650 "c. Similar process was also adopted to get the copper oxide and cobalt oxides separately. The individual oxides and the mixed oxide were characterized by a wide range of experimental techniques viz., Energy Dispersion X-ray (EDX),UV-Vis and IR spectroscopy, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM). Elemental analysis showed the presence of copper, cobalt and oxygen in the mixed oxide with a composition of CUDACOO.4002. UV-Vis and lR spectroscopic studies yielded useful information on the structure of the matrices studied. IR spectral analysis of the samples provided useful information on the identification of the compounds. From the spectra the band characteristics of copper oxide, cobalt oxide and MMO confirmed the presence of the components in each substrate. X-ray scattering patterns of the oxides and MMO oxide indicating the crystalline nahtre of the substrates. Surface morphology obtained by SEM shows the surface of copper oxide and cobalt oxides are sphere-shaped and granular respectively. The sizes of the particles ranged from nm to pm leveL While SEM observation for the MMOsurface seems to consist of agglomerates. MMO were studied to examine the surface capacity; and doing so it was used as an adsorbent for promoting the degradation of textile dyestuffs. In that case, methylene blue (MB) and procion red (PR)were attempted on the l\.1MOsurface. The adsorption data showed that both the MBand PR dyes can be adsorbed on the mixed oxide surface. But the extent of PR adsorption is much higher than MB, suggesting the present MMO a precise adsorbent for the PR removal. The adsorption processes were also foUowed by studying the isotherm of the adsorption on l\.1MO. The study showed very consistent consequences. Photolysis of dyestuffs was carried out as well. The extent of dye removal under photolysis was found to be nearly identical to that observed without photolysis, suggesting that the high surface performance of the MMO is achievable without external force like photolysis.