Solar Energy Materials & Solar Cells 92 (2008) 291–297
Electrocoagulation of a synthetic textile efﬂuent powered by
photovoltaic energy without batteries: Direct connection behaviour
David Valero, Juan M. Ortiz, Eduardo Expo
sito, Vicente Montiel
, Antonio Aldaz
Grupo de Electroquı
mica Aplicada y Electrocata
lisis, Departamento de Quı
sica, Instituto Universitario de Electroquı
Universidad de Alicante, Ap 99, Alicante 03080, Spain
Received 24 July 2007; accepted 5 September 2007
Available online 5 November 2007
The feasibility of the use of an electrocoagulation system (EC) directly powered by a photovoltaic (PV) array has been demonstrated.
The model pollutant used was a reactive textile dye Remazol Red RB 133. It has been proved that PV array conﬁguration is a factor of
great inﬂuence on the use of the generated power. The optimum PV array conﬁguration must be reshaped depending on the
instantaneous solar irradiation. A useful and effective methodology to adjust the EC–PV system operation conditions depending on solar
irradiation has been proposed. The current ﬂow ratio, J
, is established as the control parameter.
r 2007 Elsevier B.V. All rights reserved.
Keywords: Electrocoagulation; Photovoltaic energy; Renewable energy; Efﬂuent decolourization
For the last two decades, developed countries have
assisted to a progressive rise of social concern about
environmental impact caused by industry. This fact has
been translated in a progressive toughening of the
legislation in the matter of efﬂuents, and the search of
‘‘greener’’ methods and processes, not only more effective
and less polluting, but also less water consuming or
capable of its reusing. This question is helping to develop
new and more effective technologies for water recovery
At the main industrial processes, with suitable control
and analysis of the environment, the majority of waste-
water produced by industrial activity can be treated by
biological puriﬁcation plants. Nevertheless, textile industry
efﬂuents present two main problems: on one hand, they
have high COD values and, on the other hand, they
contain organic compounds like phenols, dyes, tensoac-
tives, etc., some of them very toxic and prevent their direct
treatment in a biological plant. To solve this problem some
combinations of physical–chemical techniques have been
tested, as chemical coagulation followed by sedimentation
and absorption, ozonization and oxidation processes.
However, they have a high cost and new and better
methods have been searched [1–4].
Electrocoagulation (EC) is an electrochemical technique
closely related to chemical coagulation, which involves the
supply of an electric current to a sacriﬁcial anode (made of
aluminium or iron), placed into a process tank. Because of
current pass, aluminium ions, which act as a coagulant, are
generated. Simultaneously, organic matter can be electro-
oxidized directly, on the anode surface, or indirectly by
mediated reagents electrogenerated on anode surface. Gas
bubbles, which help for ﬂotation of the ﬂoccules, are also
produced. The generated sludge is subsequently separated
by ﬁltration. The advantage of EC over chemical coagula-
tion is that the amount of chemicals needed is minima,
so that the cost for the treatment is lower than for chemical
process and the salinity of waters is not increased.
EC has been used for the treatment of different industrial
wastewaters like meat industry efﬂuents, aqueous suspen-
sions containing kaolinite, bentonite, ultra ﬁne particles,
ARTICLE IN PRESS
0927-0248/$ - see front matter r 2007 Elsevier B.V. All rights reserved.
Corresponding author. Tel.: +34 96590 3536; fax: +34 96590 3537.
E-mail address: Vicente.Montiel@ua.es (V. Montiel).