Sulfate removal from wastewater by mixed oxide-LDH: Equilibrium,kinetic and thermodynamic studies

The removal of sulfate from effluent is carried out by adsorption using a mixed oxide of magnesium and aluminum obtained after calcination of a layered double hydroxide. this work requires the control and optimization of various parameters such as the effect of contact time,ph,adsorbent dose and sulfate initial concentration. the removal of sulfate from effluent is a rapid process. in fact,in the ambient temperature (25°c),the adsorption equilibrium is reached after 60 min. the adsorption capacity for the uptake of sulfate from effluent at 25°c is 840mg/g. it is found that the adsorption kinetics is best described by the pseudo-second order model. adsorption isotherms of sulfate are well fitted by freundlich isotherm equation. the effect of temperature on the adsorption process of sulfate is also studied and the thermodynamic parameters are determined. the use of the mixed oxide is very interesting as an adsorbent. it allows the treatment of waste liquid and the regeneration of a ldh phase which can be used as precursor.