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

Existence of 2-methylpropane-2-thiol as an organosulfur and odorant compound in the soil could causes environmental problem and social dissatisfaction. In this study, remediation of this type of thiol using ultrasound is investigated. Central Composite Design (CCD) based on Response Surface Model (RSM) was used to obtain effects of the main factor (Power, sonication time and amount of water) and their interactions. Analysis of variance and Pareto analysis shows that all main factors are effective (the percentage effects of 43.30%, 30.35% and 9.62% on removal efficiency for power, sonication time and amount of water respectively). Moreover, interaction between water content and power, and sonication time and power are effective interaction (with P-values of 0.025 and 0.007 respectively). Base on experiment results and analysis of variance effects of the daylight is not significant (P-value=0.825). P-value of lack of fit (0.176) suggested model assessed as a good model and adequately fits data. Highest levels of power and sonication time (86 watt and 38 minute respectively) and water content in lower level (27 ml) in studied interval lead to maximum removal efficiency (82.83%).