Removal of polystyrene microplastics from wastewater by Ti–Al electrode electrocoagulation under pulse current: Efficiency and mechanism

As microplastic pollution in aquatic ecosystems continues to rise, research on wastewater treatment methods designed to address microplastics has gained significant attention. To reduce the power consumption of electrocoagulation, this study presents an approach using Ti–Al electrode under pulsed current conditions to address polystyrene (PS) microplastic contamination in wastewater. After selecting the appropriate electrode materials and shapes, we conducted a comprehensive investigation into the effects of various operational parameters—such as initial solution pH, electrolyte concentration, current density, pulse frequency, and pulse duty cycle—on PS removal efficiency. Under optimal conditions (electrode spacing of 1 cm, current density of 4 A·m −2 , pulse duty cycle of 40%, pulse frequency of 500 Hz, initial solution pH of 7, and electrolyte concentration of 0.05 mol·L −1 ), the removal efficiency of PS reached 93.24%, with a power consumption of 0.00977 kWh·mg −1 . Analysis of the resulting flocs revealed that free radicals generated during the electrocoagulation process disrupted the microplastic surfaces and facilitated the formation of Ti and Al flocs, which ultimately removed the microplastics through a combination of adsorption, electro-neutralization, and capture mechanisms. This study demonstrates the effectiveness of Ti electrode electrocoagulation for treating microplastic-laden wastewater and provides valuable insights for advancing microplastic treatment technologies. Practitioner Points Using pulse current electrocoagulation to remove polystyrene microplastics from wastewater. Titanium electrodes outperforms traditional electrodes ()in terms of efficiency and energy consumption. The mechanism for removing polystyrene microplastics using titanium electrodes in pulse current electrocoagulation was proposed. Titanium electrode electrocoagulation is effective in removing microplastics from wastewater and provides a reference for actual wastewater treatment. Graphical Titanium complexes such as Ti 4+ , Ti 3+ , Ti (OH) 2 + , and Ti (OH) 3 + generate during the electrocoagulation process, while alongside aluminum complexes like Al 3+ , Al (OH) 2+ , and Al (OH) 2 + generate. These positively charged species engage in charge neutralization with negatively charged microplastic particles. In addition, [Ti (OH) 4 ] n and [Al (OH) 3 ] n flocculants remove polystyrene particles via adsorption, net trapping, and rolling actions owing to their increased surface functional groups and larger specific surface area.