Abstract: There are mass of phosphorus in stone coal acid leaching solution which will affect the subsequent vanadium extraction process and the purity of V₂O₅，which could make the product unqualified.Research on phosphorus removal from acid leaching solution by an environmentally friendly desalination technology-capacitive deionization (CDI) was uconducted.The effect of operational parameters on the phosphorus removal and the adsorption mechanism of phosphorus were investigated.The results show that 63.28% phosphorus and only 1.30% vanadium could be removed under the optimum conditions of 2.0 V charging voltage，flow rate of 25 mL/min，pH of 0.75 and the distance between polar plates of 9 mm.CDI has good separation performance of phosphorus from the stone coal acid leaching solution.The calculation by Medusa software and the FTIR analysis showed the phosphorus in stone coal acid leaching solution was adsorbed by electrode in forms of H₂PO^-₄ and PO^3-₄.Meanwhile，the adsorption process included both physical adsorption and chemical adsorption.

Key words: CDI, Vanadium-containing acid leaching solution, Phosphorus removal, Medusa, FTIR