Title: Removal of ionic metals from wastewaters of COD determinations

 

Author: Sérgio Alberto Cruz Monteiro De Morais; Maria Aurora Soares da Silva; Maria Isabel Viana Limpo Serra; Maria Isabel Branco Martins; Cristina Maria Fernandes Deler Alvim de Matos; M.G.F. Sales

 

Addresses:
TRELAB/Instituto Superior de Engenharia do Porto, Departamento de Engenharia Química, R. Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal
TRELAB/Instituto Superior de Engenharia do Porto, Departamento de Engenharia Química, R. Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal
TRELAB/Instituto Superior de Engenharia do Porto, Departamento de Engenharia Química, R. Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal
TRELAB/Instituto Superior de Engenharia do Porto, Departamento de Engenharia Química, R. Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal
TRELAB/Instituto Superior de Engenharia do Porto, Departamento de Engenharia Química, R. Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal
TRELAB/Instituto Superior de Engenharia do Porto, Departamento de Engenharia Química, R. Dr. António Bernardino de Almeida, 431, 4200-072 Porto, Portugal

 

Journal: Int. J. of Environment and Waste Management, 2012 Vol.10, No.2/3, pp.177 - 189

 

Abstract: Chemical Oxygen Demand (COD) determinations generate highly disruptive waste streams with chromium, mercury and silver. These should follow specific waste management approaches in search of environmental and economical benefits, for which this work reports simple chemical procedures allowing toxic metal removal. Chromium(VI) is reduced to chromium(III) and total chromium is precipitated with sodium hydroxide. Silver is precipitated with chloride and mercury with iodide. Enhanced reduction of mercury levels is achieved by adsorption to activated carbon. Treated wastewaters have Cr, Ag and Hg levels of 225, 410 and 2.25 ppb, respectively, and the purity of the produced solids is always >80%.

 

Keywords: COD; chemical oxygen demand; laboratory waste; waste management; chemistry laboratories; ionic metals; wastewater treatment; toxic metals; metal removal; chromium; mercury; silver.

 

DOI: http://dx.doi.org/10.1504/IJEWM.2012.048364

 

Available online 01 Aug 2012

 

 

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