The contribution of the pH on the bio-removal of heavy metals is evaluated from two points of view: the metallicion, by means of use of ions with the same charge, and that of the biosorbent, using several natural biosorbents on the adsorption of a common metal. The results show a strong pH effect in the metallic ion's aqueous chemistry, dueto a complex chemical speciation dominated by aquo and hydroxo-complexes, which is partially conditioned by the own cation's acidity. The characteristically functional groups, present on the adsorbent's surface, are also subject to pH effect, because of the strong competence with exchangeable ions (H3O+ ) for the ionizables active centers. lt has been experimentally proved the preference of the studied biosorbents for Cd +2 ion rather than Zn +2 , being the algae Lessonia trabeculata, polyalginaterich algae, in its both varieties, non and cross...

The contribution of the pH on the bio-removal of heavy metals is evaluated from two points of view: the metallicion, by means of use of ions with the same charge, and that of the biosorbent, using several natural biosorbents on the adsorption of a common metal. The results show a strong pH effect in the metallic ion's aqueous chemistry, dueto a complex chemical speciation dominated by aquo and hydroxo-complexes, which is partially conditioned by the own cation's acidity. The characteristically functional groups, present on the adsorbent's surface, are also subject to pH effect, because of the strong competence with exchangeable ions (H3O+ ) for the ionizables active centers. lt has been experimentally proved the preference of the studied biosorbents for Cd +2 ion rather than Zn +2 , being the algae Lessonia trabeculata, polyalginaterich algae, in its both varieties, non and cross...

The contribution of the pH on the bio-removal of heavy metals is evaluated from two points of view: the metallicion, by means of use of ions with the same charge, and that of the biosorbent, using several natural biosorbents on the adsorption of a common metal. The results show a strong pH effect in the metallic ion's aqueous chemistry, dueto a complex chemical speciation dominated by aquo and hydroxo-complexes, which is partially conditioned by the own cation's acidity. The characteristically functional groups, present on the adsorbent's surface, are also subject to pH effect, because of the strong competence with exchangeable ions (H3O+ ) for the ionizables active centers. lt has been experimentally proved the preference of the studied biosorbents for Cd +2 ion rather than Zn +2 , being the algae Lessonia trabeculata, polyalginaterich algae, in its both varieties, non and cross...

Antibiotics and pharmaceutical products have become emergent contaminants in residual waters due to the inefficient commercialization and distribution. This study proposes the use of waste materials from tea leaves of chamomile (CM), green tea (GT) and peppermint (PM) and their chemical modifications: carboxylation, sulfonation and thiolation as adsorbents of Penicillin G. The tea samples were treated with sustainable chemical reactions in aqueous media and minimal reagent consumption. The adsorbents and their chemical modifications were characterized by instrumental techniques. All the adsorbents reported constant thermal stability and only small morphological changes on their surfaces. The adsorption tests demonstrated a strong influence of the acidity on the elimination of the antibiotic, mostly at the level of the chemistry of the added functional groups, mainly through dipole-dipole...