Economical and Technological Aspects of Copper Removal from Water Using a Geopolymer and Natural Zeolite

摘要

This study reports the efficiency of a synthesized eco-friendly geopolymer (7.5 wt% of coal fly ash incorporated into its composition) as an adsorbent for the removal of Cu(II) from an aqueous solution and a real water matrix. The results obtained were compared with a commercial natural zeolite used as an adsorbent of toxic metals in Brazil. The effect of the operating conditions on the adsorption kinetics and equilibrium were studied in a finite bath and in a fixed bed column. The adsorption kinetics curves obey the pseudo-first-order model for both materials. The geopolymer presented higher adsorption capacity than zeolite, and values for theq(max_geo)/q(max_zeo)ratio were 1.13, 1.92, and 2.56 at temperatures of 25, 40, and 55 degrees C, respectively. The isotherms obtained in the thermodynamic study are favorable and spontaneous adsorption process. The adsorption processes are endothermic. The geopolymer showed higher adsorption efficiency than the zeolite in a fixed-bed column, and even with the presence of substances in the natural water sample, the Cu(II) removal capacity of the geopolymer is 3-4 times higher than that of the zeolite. A cost analysis was also performed, the geopolymer was found to be a more economical adsorbent than the commercial zeolite.