Equilibrium and Kinetic Studies of Silver(I) Preconcentration on Synthetic Sorbents

A new synthetic sorbent (S₁) was obtained based on a copolymer of styrene with maleic anhydride and norsulfazole (S) with subsequent modification by the reagent 4,4'-(ethane-1,2-diylbis(azanylidene))bis(pentan-2-one). The structure of the sorbent S was studied by IR and UV spectrometry. The sorption of Ag(I) ions on the sorbents S and S₁ was studied. The influence of various parameters on the sorption process was studied, i.e., pH, contact time, and initial concentration of the metal ion. The results of the conducted studies were presented by various models of adsorption isotherms and kinetic models. According to the results of the studies, sorption is best characterized by the Langmuir model and the pseudo-second-order kinetic model. The maximum static sorption capacity was 420.08 mg/g for sorbent S and 577.24 mg/g for sorbent S₁. For adsorption studies, a solution of Ag(I) of a concentration of 2 × 10^–3 M was used in the work. Static sorption studies were carried out at room temperature. At the final stage, the process of the desorption of the absorbed silver ions was carried out. For this purpose, mineral (HNO₃) and organic (CH₃COOH) acids were used in the concentration range 0.5–2.0 M. Synthetic sorbents S and S₁ were used to extract silver(I) from mushrooms. The results have shown that the modification of the chelating adsorbent with the reagent 4,4'-(ethane-1,2-diylbis(azanylidene))bis(pentan-2-one) was accompanied by an increase in the sorption capacity, i.e., a simultaneous increase in the efficiency of Ag(I) ion extraction by the obtained synthetic sorption material. Comparative characteristics of the maximum adsorption capacities q_max of various adsorbents with respect to Ag(I) showed that the adsorbents S and S₁ have higher sorption capacity.