Effects of Ca2+ initial concentration on Cu2+ selective adsorption from aqueous solution by modified sugarcane bagasse under batch and column condition

Tetraethylenepentamine (TEPA) modified sugarcane bagasse (SCB), as a potential biosorbent to selective removal of Cu2+ from high calcium-containing wastewater, was prepared and characterised. Adsorption performances of the modified SCB toward Cu2+ were investigated, and effects of Ca2+ under different initial concentration on Cu2+ adsorption were carried out under both batch and dynamic conditions. Results showed that adsorption isotherm of Cu2+ on modified SCB fitted Sip isotherm model well, and the optimum pH range for Cu2+ adsorption was from 4.0 to 6.0. Dynamic adsorption of Cu2+ on the modified SCB fixed-bed column showed a typical S shape breakthrough curve, which could be predicted well by Bohart-Adams model. Competitive adsorption results in the binary system showed that molar ratio of Cu2+ and Ca2+ adsorbed on the modified SCB was 36.0:1, 15.0:1, 10.7:1, 7.8:1, 6.6:1 and 4.7:1 at of initial concentration ratio of these two metal ions 1:25 1:50 and 1:100 under batch condition, while that was 110:1, 41.7:1, 32.5:1, 27.0:1, 20.9:1 and 16:1 under dynamic condition. Operating at dynamic condition was better than batch condition for Cu2+ selective removal by the modified SCB. Wastewater treatment results showed that the TEPA modified SCB fixed-bed column could recycle Cu2+ from high calcium-containing aqueous solution, and it had great potential in practical application.