Effects of dissolved organic matter on phosphorus recovery via hydroxyapatite crystallization: New insights based on induction time

Recovery of phosphorus from sewage can help establish a new phosphorus cycle and hydroxyapatite (HAP) crystalli-zation is a promising way. HAP crystallization is an amorphous calcium phosphate (ACP) mediated process, and its in-duction time reflects the rate of HAP nucleation, and seriously affects the efficiency of phosphorus recovery. In this study, the effects of different types of dissolved organic matter (DOM) on the induction time and phosphorus recovery performance of ACP-mediated HAP phosphorus recovery were studied, and the mechanism was analyzed by X-Ray Diffraction, Fourier transform infrared spectroscopy, and scanning electron micrograph with energy dispersive spec-trometry. The results show that DOM greatly prolongs the induction time of ACP-mediated HAP crystallization and leads to an increase in the yield of microcrystals, thus leading to a decrease in phosphorus recovery efficiency. DOM inhibits ACP-mediated HAP crystallization by complexing lattice ions and occupying active growth sites on the crystal surface. Pre-removal of DOM can not only improve the speed and efficiency of phosphorus recovery by the HAP crys-tallization process but also improve product quality.

Automated summary

This study investigated the effects of different types of dissolved organic matter on the induction time and phosphorus recovery performance of HAP crystallization, demonstrating that DOM significantly prolongs the induction time and decreases phosphorus recovery efficiency.