Adsorption of Vanadium (V) on Amorphous and Modified Silica

Abstract

In this work, we investigate V(V) sorption on amorphous and modified silica. Silicon dioxide was obtained from the metallurgical slag. The impact of modification on vanadium sorption was studied. The surface was modified with hydrazides (HDs) and dimethylhydrazides (DMHDs) of the tertiary carbonic Versatic acids CH3R1R2CC(O)OH of the C10–19 fractions. The optimal sorption conditions on the unmodified sorbent were pH 4, 1 h, and 40 °C. The sorption capacity of V(V) ions increased with surface modification. For modified sorbents, the range of action shifted to a more acidic area (2.0–3.0), where the HV10O285− polyanion formed a complex with N′,N′-dimethylhydrazide groups. When studying the kinetics of the V(V) sorption process on silica samples, the optimum time of adsorption equilibrium establishment (10 min) and reaction mechanism were determined. The sorption process was significantly accelerated by surface modification. The vanadium sorption process is described by pseudo-second-order kinetics. The study of adsorption isotherms revealed that the vanadium sorption isotherm corresponds to the Langmuir equation. The differences in the extraction of vanadium ions are explained by different sorption mechanisms, which are associated with the variety of vanadium forms in the solution.