| Summary: | Aims Chromium is one of the most important metallic pollutants in plating industry
wastewater. This toxic metal is a serious threat to human health and to the environment due
to its cumulative effects and non-degradability. This research intended to study the effects of
pH, contact time, and voltage on the degree of chromium removal from wastewater of plating
industry by using the electrocoagulation method.
Materials & Methods This laboratory research conducted from late May to late November
2012. A 1000cc reactor at laboratory scale was used that included 4 aluminum electrodes
of 90% purity, dimensions of 5 by 10cm, and thickness of 1mm, with parallel arrangement.
Synthetic chromium-bearing wastewater was prepared at the initial concentration of
50mg/l. The process is done at pH values of 3, 7, and 9, electric potentials of 20, 30, and 40
volts contact durations of 20, 40, 60, and 80 minutes.
Findings The degree of chromium reduction did not change linearly with time in the solution
and strongly depended on the pH. The efficiency of chromium removal in the samples had an
ascending trend with increases in voltage from 20 to 30 and 40 volts. The degree of chromium
removal increased at longer contact times.
Conclusion Lower pH, more contact time and higher voltages are effective factors in the
chromium removal from wastewater by coagulation method.
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