removal of microplastics from synthetic wastewater via sonoelectrocoagulation process: modeling and optimization by central composite design

Wastewater treatment plants are an important pathway for microplastics (mps) to enter the environment. in recent decades, hybrid treatment technologies such as sono-electrocoagulation have been used to treat various types of wastewater. this study aimed to remove polypropylene microplastics from synthetic wastewater by sono-electrocoagulation process using central composite design. the central composite design was utilized to investigate the relationship among four independent variables including the number of mps (0.003-0.03 mps/l), sodium sulfate concentration (180-9000 mol/l), voltage (1-15 v) and reaction time (20-180 min) on the efficiency of polypropylene microplastic. design expert 13 software and central composite design method were used to design and analyze the experiments and results. the optimum number of concentration of mps, sodium sulfate concentration, voltage, and reaction time were found to be 6343.36 mps/l, 0.0181924 mol/l, 10.0356 v, and 62.21 min, respectively. in optimal conditions, polypropylene removal was found to be %90.34. central composite design proposed a quadratic model for this process. adequacy of the model using lack of fit statistical tests values, p-values, and f-values was checked, yielding the values of were 1.76, 0.0001 ˂, 19.51, respectively. the r2, r2 adjusted, r2 predicted values which were 0.9367, 0.8776, 0.6959, respectively. considering the proper removal efficiency, the sono-electrocoagulation process can be used to remove microplastics.