Treatment of chromium electroplating effluents by chemical and electrochemical coagulation proess
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2020-09-10 21:23
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DERMENTZIS, Konstantinos I.. Treatment of chromium electroplating effluents by chemical and electrochemical coagulation proess. In: Ecological and environmental chemistry : - 2017, Ed. 6, 2-3 martie 2017, Chișinău. Chisinau, Republic of Moldova: Academy of Sciences of Moldova, 2017, Ediția 6, p. 130.
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Ecological and environmental chemistry
Ediția 6, 2017
Conferința "Ecological and environmental chemistry 2017"
6, Chișinău, Moldova, 2-3 martie 2017

Treatment of chromium electroplating effluents by chemical and electrochemical coagulation proess


Pag. 130-130

Dermentzis Konstantinos I.
 
Eastern Macedonia and Thrace Institute of Technology
 
Disponibil în IBN: 13 martie 2019


Rezumat

Heavy metals, such as chromium are of considerable concern because they are non-biodegradable, highly toxic and probably carcinogen. Chromium is released into the environment from electroplating, anodizing, chromating, metal finishing, tannery, dyeing and fertilizer industries. Waste streams from electroplating units may contain up to 500 mg/lit Cr (VI), which, according to environmental regulations worldwide must be controlled to an acceptable level before being discharged to the environment. The permissible limit for Cr (VI) is 0.5 mg L-1 in effluent discharge to sewage systems. In this work the removal of hexavalent chromium from industrial electroplating effluents was studied using both, the classical chemical coagulation with addition of the coagulant FeCl36H2O and the electrochemical coagulation treatment (electrocoagulation) with electrodissolution of sacrificial iron anode. Complete and efficient removal of chromium was achieved by both methods. The parameters affecting the chemical coagulation process are: solution pH, coagulant concentration and time of processing with optimal conditions pH 11 and coagulant concentration 500 mg/L. The initial chromium concentration of 300 mg/L Cr(VI) in the treated wastewater decreased by 99.9 % in 30 min of processing time. The parameters affecting the electrocoagulation process are: solution pH, applied current density and time of electroprocessing. The electrocoagulation treatment of the same wastewater sample brought about also complete and efficient removal of the initial chromium concentration by 99.9 % at the optimum current density of 10 mA/cm2, pH = 4 and 20 minutes of electroprocessing time. The overall cost of the chemical method was calculated to 1.03 € per m3 and of the electrochemical to 0.69 € per m3 of treated wastewater.

Cuvinte-cheie
chemical coagulation, electrocoagulation, electroplating effluent, hexavalent chromium