Study on Vanadium (V) Hydrolysis at the different ionic strength

Vanadium is one of the most valuable elements which are used in chemistry, biochemistry,metallurgy, pharmacy, medicine, electrical energy storage with high performance and as acatalyst in biological system and industry. It is a ubiquitous metal and exists in soil, fossil,water, air and living organisms. In sea water, vanadium exists mainly in the form of H2VO4-[1].Vanadium has many oxidation states and it is important for organisms in some animals andgreen plants [2]. Vanadate in the range 1 < pH < 10 and the constant ionic strength werestudied with VNMR and potentiometric methods [3]. Gharib et al [4] studied vanadium (V)hydrolysis in the range of 0.1 < I < 1 mol dm-3 with a combination of potentiometric andspectrophotometric techniques. In the present research, the hydrolysis of vanadium (V) inaqueous solution in the range of 2 < pH < 12 at 25±0.5˚C and in the range of NaCl 0.5 ≤ I ≤3 was measured by the potentiometric method. Calculations showed that in pH ≤ 2, VO2+species exist, in 2 ≤ pH ≤ 8, H2VO4- species exist and in 8 ≤ pH ≤ 12, HVO42- species exist.The hydrolysis constant for different species are showed that in Table 1.