Recovery of Phosphorus from Incineration Ash of Chicken Droppings by Citric Acid Leaching Followed by Adsorption Using a Porous Resin Containing Hydrated Zirconium Oxide Powder

An efficient leaching method using citric acid solutions was investigated for the recovery of phosphorus from incineration ash of chicken droppings (IACD). The IACD samples before and after leaching were characterized by energy dispersive X-ray spectroscopy, X-ray diffraction analysis, and infrared spectroscopy. Optimum leaching was achieved using 3% citric acid at a liquid–solid ratio of 0.2 cm3/mg. The leached phosphorus was quantitatively adsorbed on READF-(PG), a commercially available microporous resin containing hydrated zirconium oxide in the pores. Phosphorus adsorption is proposed to occur via anion exchange between the hydroxyl groups of the hydrated zirconium oxide in the resin and the phosphate anions in the aqueous solution. More than 98% of the phosphorus adsorbed on the READF-(PG) resin was successfully desorbed using a NaOH solution. Thus, citric acid leaching followed by adsorption on a READF-(PG) resin is a promising technique for the recovery of phosphorus from IACD.