Study on Adsorption of Two Reactive Dyes by Natural Diatomite

摘要

The adsorption capability of diatomite to reactive dyes (reactive black K-RB and reactive golden yellow X-G) in aqueous solution was studied, and adsorption mechanism was explored from the view point of kinetics. The results show that the equilibrium adsorption capacity (qe) of each dye increases with the temperature. On the same condition, the qe of reactive black is more than reactive golden yellow. The adsorption processes follow the pseudo second–order model, and the structure, size and functional groups of dyes are important factors to adsorption reaction. The dye adsorption isotherms fit well to Freundlich and Langmuir equation. The Freundlich equation 1 between 0.3585 and 0.4411 indicates favorable adsorption. The adsorption activation energy of reactive black K-RB and reactive golden yellow X-G are 12.373 kJ/mol and 25.913 kJ/mol, respectively, which indicates that it belongs to physics adsorption. The main driving forces of adsorption are electrostatic attraction and van der waals force.