Study of different chemical activatings on obtaining activated carbon from Hymenaea courbaril L shell for cadmium (II) removal

the use of zncl2, h3po4, h2so4, hno3 and hcl for algarrobo fruit shell activation (hymenaea courbaril l) permitted to evaluate and compare the adsorptive capacity of the corresponding carbons prepared. the precursor was impregnated with the chemical agents mentioned, separately and it was pyrolized at 500°c in each case. the superficial characteristics of the activated carbons prepared were determined through the brunnauer-emmet-teller (sbet) conventional method, obtaining adsorption isotherms of n2 at 77k and were compared to those of the norit-a (cac) commercial activated carbon. the balance determination at liquid phase of the process was carried out by using cadmium (ii) solutions in load essays at initial concentrations (co) of 25, 50 and 100 mg/l during 1 h contact time. the cadmium (ii) balance concentration was determined by flame atomic adsorption spectrophotometry (eaa). the activated carbons with h3po4 and zncl2 presented specific superficial area values (sbet) of 1262 and 968 m2/g, respectively. the freundlich and langmuir models were applied to the experimental results. the isotherms showed better adsorption conditions at solutions with a cadmium (ii) co of 25 mg/l for all the carbons prepared. the correlation coefficient values (r2) and the adsorption constant kf for activated carbon with h3po4 fit freundlich？s model better