Recovery of Indium from Sulfuric Acid Solutions by Carbon Composites Modified with Nanotubes

The laws of sorptive extraction of indium from sulfuric acid solutions by composites based on carbon-nanotube-modified activated carbons are considered. The surface of nanotubes was studied by scanning electron microscopy (SEM). The equilibrium and kinetic characteristics of the sorbents are determined. Indium sorption isotherms have convex shapes and are described by the Langmuir equation. The kinetic data were fitted by pseudo-first-order, pseudo-second-order, internal diffusion, and Elovich models. The pseudo-second-order model gave the highest correlation coefficient. Indium sorption is controlled by external diffusion. The efficiency of the carbon composites in indium extraction was verified in four sorption–desorption cycles.