Removal of Congo Red from aqueous synthetic solutions using silica gel immobilized chlorophyta hydrodictyon africanum

Abstract

A silica gel-chlorophyta hydrodictyon africanum biosorbent with improved mechanical properties was prepared and used in the removal of Congo Red (CR) from synthetic aqueous solutions. Batch sorption studies of the acidic dye showed that a maximum of 50.11 mg g -1 of the dye could be adsorbed under optimum conditions. Results show that maximum CR adsorption lie within the pH range 4-6. Above pH 6, the adsorption capacity dropped drastically to about 10.00 mg g -1 at pH 8. Kinetic data was simulated on three models and the pseudo-second order model gave a better fit with R 2 greater than 0.98. Equilibrium studies show that the adsorption of CR is best described by the Langmuir isotherm.