Ultrasound assisted batch operation for the adsorption of hexavalent chromium onto engineered nanobiocomposite

The study demonstrates the comparative retention characteristics of chromium from aqueous environment on iron(III) cellulose nanocomposite bead under conventional (C-ads) and ultrasound assisted (U-ads) batch adsorption operation. Optimization of process parameters was achieved varying pH, contact/sonication time, initial Cr(VI) concentration, adsorbent dose at fixed solution temperature. Equilibrium was achieved within 5 h and 30 min of contact time in C-ads and U-ads respectively. Langmuir isotherm is found suitable in C-ads while Temkin in U-ads. Both the operation is aided by change in negative free energy, positive enthalpy and entropy. Ultrasound assisted adsorption is much favorable in terms of efficiency, feasibility, spontaneity and randomness. Both the operations follow more the second order than the first order kinetic model. The pore diffusion prevails more in case of U-ads while the surface adsorption in C-ads.