STUDY OF THE BIOSORPTION OF Cd (II) AND Pb (II) USING AS ADSORBENT Nostoc sphaericum Vaucher

Abstract

The biosorption capacity of the Nostoc sphaericum Vaucher in a batch system was evaluated. The conditions were: metal concentration between 40 and 240 ppm, pH of 2 to 5; 0,13 g of dried nostoc per 50 mL of solution, to 25 °C and stirring. The concentrations of Cd (II) and Pb (II) were determined by Atomic Absorption Spectroscopy. The Langmuir model was adjusted for Pb (II) (R2 = 99,97%, p> 0,00), with qmax of 185,83 mg / g of nostoc and Kd of 0,095 L/g; however, neither of the models studied explained the results for Cd (II). It was shown that the pH is directly proportional to the biosorption capacity for Pb (II), being maxim for pH 5 (q = 37,43 mg Cd/g of nostoc). The biosorption of Cd (II) was maxim to pH 3 (q = 17,12 mg Cd / g of nostoc) without showing behavior defined pH of higher or lower than 3. The adsorption kinetics of Cd (II) and Pb (II) to a pseudo second order model was fitted (R2 = 98,38% and 99,99% respectively, p<0,05). The phytochemical screening showed the presence of saponins, reducer sugars and amino acids.