LAUSR

Abstract Electrocoagulation (EC) dephosphorization kinetics plays an important role in design and amplification of EC reactors for phosphate removal. However, the existing EC dephosphorization kinetic models including both statistical model and adsorption model, fail to establish a direct law between the electric field characteristics and the dephosphorization process, which limit their efficient applications in practice. In this study, three classic adsorption isotherm models, i.e., Langmuir, Freundlich and Dubinin-Radushkevich model, were compared to describe the phosphorus adsorption in EC reactor. The experimental data is better fitted with Langmuir model than the other two models, indicating that adsorbed molecules are monolayered dispersed. Afterwards, an advanced EC dephosphorization kinetic model is developed by combining Faraday's law with Langmuir model. Laundry wastewater is used to illustrate the effects of current densities, plate spacing and initial phosphorus concentrations on the model parameters. Finally, the relationships among current efficiency, current density, plate spacing, initial concentration are established by using response surface methodology. Our new EC kinetic model successfully describe the phosphorus removal process of laundry wastewater, which might pave the way for the optimal design of EC reactor.