Regeneration of Hexavalent Chromium from a Simulated Rinse Etching Solution Using an Electrochemical Reactor With Two Compartments Separated by a Ceramic Membrane

摘要

The performance of a batch electrochemical reactor with two compartments separated by a ceramicdiaphragm for the regeneration of Cr(VI) from a simulated rinse etching solution has been studiedunder constant cell voltage mode and in galvanostatic operation. The effect of the applied current (I)and cell voltage (U) on the Figures of Merit (fractional conversion, current efficiency, space-time yieldand specific energy consumption) for the Cr(III) to Cr(VI) electrochemical oxidation is analyzed. Asboth I and U parameters increase, the current efficiency ( for the electrochemical oxidation of Cr(III)is decreased due to the oxygen evolution side reaction, which causes an increment in the specificenergy consumption (Es). On the other hand, an increment of the values of I and U leads to greatervalues of both Cr(III) fractional conversion (X) and space-time yield ( due to the oxygen turbulence- promoting action. Comparing the results obtained under both operation modes, in galvanostaticoperation higher values of X, and coupled with lower values of Es are obtained. Hence, working ingalvanostatic operation at a relatively low applied current (1.5A) is the optimum option since theenergy consumed is quite low, the current efficiency is relatively high and the amount of Cr(VI)recovered is close to 70%.