Modified lead dioxide for organic wastewater treatment: Physicochemical properties and electrocatalytic activity

Abstract

An investigation on lead dioxide electrodeposition from methane­sul­fonate electrolytes additionally containing Ni²⁺ is reported. It is shown that the lead dioxide electrodes micromodified by nickel have different physico­chem­ical properties vs. nonmodified PbO₂-anodes, that are formed during the depo­sition. The electrocatalytical reactivity of the electrodes involved in com­par­ison to both the oxygen evolution, as well as to the electrooxidation of 2,4-
-dichlorophenoxyacetic (2,4-D) acid is investigated. The processes of electro­chemical oxidation of 2,4-D on various materials occur qualitatively with the same mechanism and differ only in the reaction rate. It is shown that the Ni-PbO₂-anode possesses the highest electrocatalytic activity: the destruction rate of 2,4-D on it increases 1.5 times in comparison with the unmodified lead diox­ide. The chemical oxygen demand (COD) of a 0.4 mM solution of 2,4-D, det­ermined by the dichromate method, is 90.0 mg dm^-3 which is 94 % of the theor­etical value.