Related Experiment Video
Updated: May 22, 2026

Exfoliation of Egyptian Blue and Han Blue, Two Alkali Earth Copper Silicate-based Pigments
Published on: April 24, 2014
Oxidative decolorization of methylene blue by leached sea-nodule residues generated by the reduction-roasting
P K Satapathy1, N S Randhawa, N N Das
1P.G. Department of Chemistry, North Orissa University, Baripada- 757 003, Orissa, India.
Abstract:
The leached residue, generated after selective extraction of Cu, Ni and Co by reductive-roasting ammoniacal leaching of sea nodules, was characterized by various physicochemical methods. The finely divided residue, containing mainly manganese carbonate/silicates and manganese (III, IV) (hydr)oxides along with iron oxides, showed a lower surface area (66.3 m2 g(-1)) than that of the parent sea nodule (130 m2 g(-1)). The catalytic efficiency of water-washed sea nodule residue (WSNR) was evaluated taking oxidative decolorization of methylene blue (MB) as the test reaction. The extent of decolorization was decreased with increase in pH but increased in the presence of H2O2 or NaCl. Decolorization of MB occurred in two consecutive steps; the rate constant of the first step was -10 times higher than that of the second step. The formation of a surface precursor complex between WSNR and MB at a rate-limiting step, followed by electron transfer from MB to the active metal centre of WSNR and release of product(s), was proposed as the decolorization process.
Related Concept Videos
Microbial Leaching
Metabolism of Chemolithotrophs
Preparation of Amines: Reduction of Oximes and Nitro Compounds
Though catalytic hydrogenation can reduce nitrobenzenes, the reduction is nonselective in the presence of other functional groups. For instance, if nitrobenzene contains an aldehyde group,...
Microbes and Other Elemental Cycles
Bioremediation
Qualitative Analysis
For instance, group IV...

