The use of waste green tea leaves (TV) with particle diameter 30 and 40 of the Tyler series, on the removal of the dyes basic yellow 57 (AM 57), basic blue 99 (AZB 99) and acid red 18 was investigated from aqueous solutions at room temperature by intermittent desorption experiments. The parameters evaluated in the adsorption capacity were: pH, mass of adsorbent, the concentration of dye adsorption rate and ionic strength, supported by the FTIR, SEM, EDX and TGA analysis. The results are analyzed using mathematical models of Langmuir, Freundlich, Temkin, Dubinin- Radushkevich and Redlich -Peterson. The results show that the adsorption is given by a mixed mechanism. The determined parameters show a high affinity of the adsorbent with AZ 99 with a maximum adsorption capacity of 287.2 mg g- 1, followed with by AM 57 120 mg g -1 and the RA 18 with 58 mg g- 1 elucidating the potential use of t...

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...