Mathematical modeling and optimization of sonication remediationof soil polluted with 2-methylpropane-2-thiol

The existence of 2-methylpropane-2-thiol as an organosulfur and odorant compoundin the soil could cause environmental problems and public discontent. In this study,the remediation of this type of thiol using ultrasound was investigated. A centralcomposite design (CCD) based on the response surface model (RSM) was used toinvestigate the effects of the main factors (power, sonication time, and amount ofwater) and their interactions on removal efficiency. The analysis of variance (ANOVA)and Pareto analysis showed that the percentage effects were 43.30%, 30.35% and9.62% on removal efficiency for power, sonication time and amount of water,respectively. This indicated that all the main factors were effective. Moreover, theinteraction between water content and power as well as sonication time and powerwere effective on removal efficiency with P-values of 0.025 and 0.007, respectively.Base on experiment results and the ANOVA table, the impact of daylight was notsignificant (P-value=0.825). The P-value of lack of fit (0.176) proved that thesuggested model adequately fits the data. The highest levels of power and sonicationtime (86 watts and 38 minutes respectively) and a lower level of water content (27ml) in the studied interval resulted in maximum removal efficiency (82.83%).

Keywords:

2-methylpropane-2-thiol , Mathematical modeling , Optimization , Soil remediation , Sonication