Optimization of Multi-Cathode Membrane Electrolysers for the Indirect Electrochemical Reduction of Indigo

In order to color cellulose fibers with vat or sulfur dyes, large amounts of nonregenerable reducing agents are usually required. In this paper, the authors present the use of indirect electrochemical reduction, thus, offering economic and ecological advantages. Multi-cathode cells are used to overcome low cell current and a further increase in cell current is achieved by using three-dimensional flow-through electrodes.