Rapid degradation of contaminated soil with 2-methylpropane-2-thiol by H sub(2)O sub(2)/KMnO sub(4 )/NaClO system: process modeling and optimization

• Published in: Asia-Pacific journal of chemical engineering 2016-09, Vol.11 (5), p.743-756
• Main Authors: Roohi, Pejman, Fatehifar, Esmaeil, Alizadeh, Reza
• Format: Article
• Language: English
• Subjects: Efficiency; Mathematical models; Optimization; Oxidation; Soil (material); Soil contamination; Soil pollution; Soil remediation
• ISSN: 1932-2135; 1932-2143
• DOI: 10.1002/apj.2006

2-Methylpropane-2-thiol is a hazardous material, and remediation of soil polluted by this contaminant with a fast method is important to study. In this study, H sub(2)O sub(2)/KMnO sub(4 )/NaClO system as a combined system is investigated for 2-methylpropane-2-thiol oxidation because of especial characteristics of each oxidation agent. Central composite design based on response surface methodology was used to obtain appropriate effects of the main factors (initial oxidant concentrations and FeSO sub(4) to soil ratio) and their interactions on the removal efficiency. Pareto analysis show that initial H sub(2)O sub(2) concentration, FeSO sub(4) to soil ratio, initial NaClO concentration, and interaction between H sub(2)O sub(2) and FeSO sub(4) are the most influential factors on 2-methylpropane-2-thiol removal efficiency (31.82%, 16.85%, 16.24%, and 8.62% respectively). P-value of lack-of-fit (0.621) indicates that suggested model adequately fits the data with high correlation coefficient (R super(2)=97.59%). Investigation of optimum condition suggests that interaction of KMnO sub(4) with H sub(2)O sub(2) drops the removal efficiency and its concentration has to be as low as possible. The concentration of other studied oxidation agents and Fe super(2+) ion must be as high as possible in the studied intervals. Verification experiment at optimum condition shows 95.71% for maximum 2-methylpropane-2-thiol removal efficiency that is a good agreement with the predicted value (94.76%).