Optimization of the methodology for lead extraction from waste contaminated with heavy metals.
Environ Technol
; 31(4): 365-71, 2010 Apr 01.
Article
em En
| MEDLINE
| ID: mdl-20450110
A sequential experimental design strategy is used to optimize the extraction of lead from slag. The slag is composed mainly of iron (= 60%) and lead (= 6%), and cannot be disposed of in conventional landfill due to its high lead content. The extraction of lead is based on the complexing properties of ethylenediaminetetra-acetic acid (EDTA), the iron being masked with fluoride ions. Atomic absorption spectroscopy (AAS) has been used for monitoring iron and lead concentrations. In a first step, Plackett-Burman PB-12 experimental design was used for screening the variables and for selecting those to be used. Two central composite designs (CCDs) were then carried out to determine the optimal conditions for lead extraction. The optimized experimental conditions were established to be: contact time with the fluoride solution 30 min; particle size of slag between 150 and 600 microm; molecular concentration of fluoride solution 2.4 x 10(-3) mol and of EDTA 5 x 10(-4) mol; pH 1.5; 8 h contact time with the EDTA solution; and temperature 60 degrees C. Under these experimental conditions the lead content was reduced by 57% compared with the raw sample.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Quelantes
/
Ácido Edético
/
Gerenciamento de Resíduos
/
Resíduos Industriais
/
Chumbo
Idioma:
En
Revista:
Environ Technol
Assunto da revista:
SAUDE AMBIENTAL
/
TOXICOLOGIA
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Brasil
País de publicação:
Reino Unido