ADSORPTION BEHAVIOR OF SOLID WASTE OF LEATHER MANUFACTURE
The adsorption behavior of chrome-containing and tannins-containing solid waste originated from leather manufacture was investigated. The experimental results indicated that the chrome-containing leather waste could substantially adsorb acid dyes and direct dyes.However it was ineffective for the adsorption of alkali dyes.The adsorption equilibrium of chrome-containing leather waste to acid dyes and direct dyes could be described by the Langmuir equation and the pseudo-second-order rate model gave perfect fitting to the adsorption kinetics.The tannins-containing leather waste exhibited high adsorption capacities to Au 3+、U 6+、Th 4+ and Hg 2+.However the adsorption equilibrium of metal ions on the tannins-containing leather waste could not be described by single equation.The adsorption equilibrium of Cu 2+、U 6+、Pb 2+ and Hg 2+ could be described by the Freundlich equation, while that of Au 3+ and Th 4+ could be described by the Langmuir equation.These facts implied that the different adsorption mechanisms might be involved in the adsorption processes of metal ions on the tannins-containing leather waste. The pseudo-second-order rate model also gave perfect fitting to the adsorption rate data of metal ions on the tannins-containing leather waste. The adsorption column of chrome-containing leather waste could be easily regenerated after adsorption of dyes. Similarly, the adsorption column of tannins-containing leather waste could be also easily regenerated after adsorption of metal ions except Au 3+. The change of adsorption behavior of the regenerated columns was not considerable, which indicated the potential value of a using solid waste of leather processing in environmental protection.