3D Printed Graphene-Based Capacitive Deionization for Efficient Phosphorus Recovery from Wastewater

Phosphorus resources are non-renewable strategic resources. Sewage phosphorus recovery is an important measure to achieve sustainable use of phosphorus resources. The low phosphorus content and coexisting ion interference in sewage are the core bottlenecks for achieving efficient phosphorus recovery. This project uses the capacitive deionization technology (CDI) and the selective phosphorus adsorption principle to establish a CDI-assisted electrocoagulation-enhanced sewage deep treatment and phosphorus recovery technology based on 3D-printed three-dimensional graphene-based capacitor electrodes. The graphene-based 3D printing ink is developed to construct controllable three-dimensional high-capacitance adsorption electrode materials; iron-based MOFs are used for screening and electrode loading to achieve high-selectivity adsorption of phosphate ions; the construction relationship between the three-dimensional structure of the electrode accurately constructed by 3D printing and the effective exposure of the phosphorus selective adsorption core and the phosphorus selective adsorption efficiency is clarified; the influence mechanism of the electrode pore construction method on the effective utilization of the electrode surface interface and the phosphate ion mass transfer process inside the electrode is explored; the electrochemical regulation strategy of the capacitive electrode on the adsorption and desorption process of phosphate ions is established to obtain the most economical sewage phosphorus adsorption-concentration efficiency; the differences in the phosphorus precipitation components and effective phosphorus content in the electrocoagulation phosphorus recovery process under different water quality conditions are examined, and the economic and operational stability of the CDI-assisted electrocoagulation phosphorus recovery technology is evaluated. The successful implementation of this project will establish new technologies and principles for efficient sewage phosphorus recovery.