Phosphorus recovery and resource utilization from phosphogypsum leachate via membrane-triggered adsorption and struvite crystallization approach

Abstract

Phosphorus pollution from phosphogypsum (PG) leachate has caused severe problems in the water environment and ecology. Efficient phosphate recovery and resource utilization techniques are crucial as they can aid the phosphorus pollution problem and recover the scarcity of phosphorus resources. Herein, we developed a highly efficient phosphorus recovery strategy from PG leachate by integrating the ZrO2 membrane-triggered adsorption technique with the struvite crystallization process. More than 89.23% of the phosphorus anions in the PG leachate can be recovered via membrane-triggered adsorption. With the concentrated phosphate anions washed from membrane adsorption, the phosphate anions can be further employed for struvite crystallization, and an overall phosphorus recovery efficiency of 59.36% can be achieved. The obtained fine struvite product is of high purity, with NH4MgPO4·6H2O weight ratio of up to 89.83%. The novel strategy developed here demonstrates a green and sustainable strategy toward phosphorus recovery from the PG or PG-polluted groundwater or surface water leachate, which could be applied to practical phosphorus recovery and struvite fertilizer production. The commercialization of this strategy will shed light on the emergency PG pollution control at the YangtzeRiver upstream area.