Electrochemical approaches to environmental problems in the process industry

The electrochemical oxidation of aqueous sulfur dioxide: a critical review of work with respect to the hybrid sulfur cycle

Electrochemical behaviour of aqueous SO2 at Pt electrodes in acidic medium. A voltammetric and in situ Fourier transform IR study Part I. Oxidation of SO2 on Pt electrodes with sulphur-oxygen adsorbed species

The objective of this work is to develop a sustainable process for simultaneous removal of waste gases such as NO, NO2, and SO2 by an electrochemically generated Ag(I)/Ag(II) redox mediator system. High removal efficiency was achieved for NO and SO2 by the wet scrubbing method at room temperature and atmospheric pressure. This removal is achieved through oxidation and absorption by contacting the gaseous stream with redox mediator ions that offer specific or selective solubility for the solute gases to be recovered in a wet scrubber. The process parameters such as gas velocity, liquid velocity, Ag(I) concentration, and HNO3 concentration were investigated to explore the possibility of complete removal of waste gases. The Ag(I)/Ag(II)-based mediated electrochemical oxidation process proved to be quite effective for simultaneous removal of NO, NOx, and SO2 from the simulated flue gas mixtures containing NO and SO2 over a wide concentration range of 100−400 ppm. Studies were carried out with individual gas c...

Novel Process for Simultaneous Removal of NOx and SO2 from Simulated Flue Gas by Using a Sustainable Ag(I)/Ag(II) Redox Mediator

An investigation of anode materials in the anodic oxidation of sulphur dioxide in sulphuric acid solutions

A new process for removal of sulphur dioxide from waste gases is proposed consisting of both electrochemical and catalytic sulphur dioxide oxidation. In the catalytic step a part of the sulphur dioxide is oxidized by oxygen on copper producing sulphuric acid and copper sulphate. The other part is oxidized electrochemically on graphite. The cathodic reaction of this electrolysis is used for recovering the copper dissolved in the catalytic step. The basic reactions of this process have been studied experimentally in detail. It has been shown that sulphur dioxide can be electrochemically oxidized on carbon electrodes to sulphuric acid with high current efficiency. The reaction rate of the electrochemical copper deposition is increased by dissolved sulphur dioxide in the electrolyte. The catalytic oxidation of sulphur dioxide on copper has been investigated for different sulphur dioxide concentrations and temperatures. The ratio of the reaction products, sulphuric acid and copper sulphate, varies over a wide range depending on the experimental conditions.

G. Linzbach

Papers

Fundamental studies on a new concept of flue gas desulphurization