Competitive Bioadsorption of Pb+2 and Cu+2 Ions by Caryocar coriaceum WITTM. Barks

Several environmental impacts are associated with the improper disposal of toxic metals in the environment. The bioadsorption stands out for being a cheap and easy-to-operate technique for remove those contaminants in wastewaters. When existing more than one contaminant present in the wastewater, the adsorptive study becomes complex, since there is competition between these species for the available active sites of the adsorbent. Therefore, this work aimed to study and compare the removal of Pb+2 and Cu+2 ions in aqueous solutions, both on mono- and multielementary systems, through the application of the bioadsorption technique using as the adsorbent the residues of the Caryocar coriaceum WITTM. barks. Characterization techniques like SEM-EDS, XRD, FTIR, and pH(PZC) were used to study the adsorbent. The results showed that all the systems follow the pseudo-second-order model, and the diffusing process was chemissoption associated with ions change. Langmuir model presented a better fit than Freundlich model. The maximum adsorptive capacity (mg g(-1)) obtained, for the multielementary systems, was 47.6 for Pb+2 and 20.4 for Cu+2. It was found that there was an inhibitory effect between Cu+2 and Pb+2, which resulted in a reduction of q(max) values by approximately 37%, for Cu+2, and 55%, for Pb+2, compared to the monoelementary system, however, enabling the simultaneous removal of both contaminants, optimizing process time, and reflecting systems with real conditions. As a conclusion, it was found that the bark of Caryocar coriaceum WITTM. showed good adsorptive results compared to the literature and that it could be used as a adsorbent for solutions containing dissolved Pb+2 and Cu+2, for both mono- and multielemental systems.