Recycled niobium felt as an efficient three-dimensional electrode for electrolytic metal ion removal

An electrolytic process for the removal of lead from aqueous solutions usin g a flow-through cell with a recycled niobium felt is proposed. The operati onal conditions for the reactor were optimised as a function of the solutio n how rate and the electrolytic removal of Pb(II) was used to characterise the mass transport properties of the niobium felt electrode. The three-dime nsional cathode was made from continuous niobium tips resulting from niobiu m ingots machining. The performance and figures of merit of the niobium fel t were studied using different flow rates. In the experiments lead concentr ation dropped from 50 mg l(-1) to 0.5 mg l(-1) (99% removal) in electrolysi s time ranging from 94 to 150 min, depending on the flow rate. Dimensionles s Sherwood and Reynolds numbers were correlated to characterise the mass tr ansport properties of the niobium felt, and they were fitted to the equatio n Sh = 22.9(Re)(0.43)(Se)(0.33). (C) 2000 Elsevier Science Ltd. Ali rights reserved.