Adsorption-Regeneration Process for Removing Dimethoate and Recovering Phosphorus with Three-Dimensional Hierarchically Porous Carbon

Abstract

Phosphorus shortage and pollution are two significant societal and environmental problems for human beings. Thus, this study presents a novel process to efficiently recover phosphorus from dimethoate-containing wastewater on the basis of a three-dimensional hierarchically porous carbon (3D HPC ) material. The shape and size of the 3D HPC can be easily controlled by using polyurethane sponges as templates. The 3D HPC absorbed more than 80% of dimethoate at the initial concentration of 100 mg·L −1 . A total of 90.8% of the absorbed dimethoate was desorbed and mineralized to phosphate by cathodic regeneration employing 3D HPC as cathode in alkaline solution, combined with UV radiation and ozonation. The adsorption capacity and dimethoate-to-phosphate conversion efficiency remained 94.5% and 103.6%, respectively, after seven adsorption-regeneration cycles. Moreover, our study of the co-existing substances showed that they slightly competed with dimethoate. The recovery efficiency of phosphate in the regeneration solution reached 99.8% simply by adding CaCl 2 to form calcium phosphate precipitation.

Keywords: Adsorption； Regeneration； Organophosphorus； Phosphorus recovery； Cathode