Optimization of two-step bioleaching of spent petroleum refinery catalyst by Acidithiobacillus thiooxidans using response surface methodology.
J Environ Sci Health A Tox Hazard Subst Environ Eng
; 49(14): 1740-53, 2014.
Article
in En
| MEDLINE
| ID: mdl-25320861
A central composite design (CCD) combined with response surface methodology (RSM) was employed for maximizing bioleaching yields of metals (Al, Mo, Ni, and V) from as-received spent refinery catalyst using Acidithiobacillus thiooxidans. Three independent variables, namely initial pH, sulfur concentration, and pulp density were investigated. The pH was found to be the most influential parameter with leaching yields of metals varying inversely with pH. Analysis of variance (ANOVA) of the quadratic model indicated that the predicted values were in good agreement with experimental data. Under optimized conditions of 1.0% pulp density, 1.5% sulfur and pH 1.5, about 93% Ni, 44% Al, 34% Mo, and 94% V was leached from the spent refinery catalyst. Among all the metals, V had the highest maximum rate of leaching (Vmax) according to the Michaelis-Menten equation. The results of the study suggested that two-step bioleaching is efficient in leaching of metals from spent refinery catalyst. Moreover, the process can be conducted with as received spent refinery catalyst, thus making the process cost effective for large-scale applications.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Acidithiobacillus thiooxidans
/
Petroleum
/
Environmental Restoration and Remediation
/
Industrial Waste
Type of study:
Prognostic_studies
Language:
En
Journal:
J Environ Sci Health A Tox Hazard Subst Environ Eng
Journal subject:
TOXICOLOGIA
Year:
2014
Document type:
Article
Affiliation country:
Corea del Sur
Country of publication:
Reino Unido