Electrocoagulation has been suggested to be a promising alternative
to chemical coagulation for removing various pollutants
from freshwaters and wastewaters [1–3]. Sacrificial metal anodes
or cathodes produce metal ions or metal hydroxides into solution.
Metal cations and hydroxides interact with pollutants by several
mechanisms, including charge neutralization, precipitation, and
enmeshment. Pollutants can be removed from water by electroflotation,
which can occur simultaneously with electrocoagulation, or
by sedimentation, or filtration. Electroflotation is caused by
micrometer-sized bubbles (15–23 lm diameter), which are produced
on the cathode surface [4]. Other mechanisms that may affect
pollution removal are electromigration of ions towards
electrodes and reduction of metals on the cathode surface. These
reactions, as well as well-known advantages and disadvantages
and applications of electrocoagulation, are presented in review
articles [1–3,5,6].
It is well known that aluminum in the electrocoagulation process
can be dissolved from aluminum anodes and cathode electrodes.
Aluminum dissolves from anodes according to simple
electrochemical reaction Eq. (1) and forms hydroxides in water