Application of magnetic microsorbents for separation, concentration and recovery of phosphate from wastewater streams

Advanced nanocomposite magnetic particles are developed and tested for the adsorptive elimination and recovery of phosphate directly from wastewater streams (PO4-P≈10mg/L). The phosphate loaded adsorbers can be extracted from the liquid phase via inexpensive low gradient magnetic separation, regenerated in a suitable solution where simultaneously phosphate desorption and concentration take place, and then reused again in multiple cycles. Laboratory experiments demonstrate the reusability of the particles in 60 consecutive adsorption/desorption cycles where under optimal reaction conditions >90% total efficiency and P-recovery can be achieved. The desorption solution can be enriched with phosphate ions through repetitive application of the same solution and used as a potential P-rich resource or alternatively serve as a source for further precipitation of a solid P-product (e.g. struvite). In addition, pilot-scale tests were performed to verify the feasibility to upscale the technology.