The invention discloses a method for selectively recycling
phosphorus pollutants in low-concentration
phosphorus-containing
sewage and preparing high-quality blue
iron ore and application, and belongs to the technical field of
water treatment and recycling thereof. According to the method, the low-concentration
phosphorus-containing
sewage is adsorbed by a phosphorus specific nano adsorption material HFO-201, and then the material is desorbed by adopting
sodium hydroxide and
sodium chloride with specific concentrations. The desorbed filtering material and the filtered material can be repeatedly used for adsorbing phosphorus in low-concentration
sewage. After the pH value of the filtered
desorption solution is adjusted to a certain concentration, FeCl2 with a certain concentration is added, and high-quality blue
iron ore (Fe3 (PO4) 2.8 H2O) can be generated by keeping the pH value through
sodium hydroxide under an anaerobic condition. The phosphorus product recovered by the process can be used for preparing a high-value
phosphate fertilizer and a high-energy-density
energy storage material, namely
lithium iron phosphate (LiFePO4). The HFO-201 used in the invention can realize low-concentration
phosphorus adsorption through an
ammonium group combined with a D-201 matrix and loaded HFO nanoparticles. And moreover, after alkali
desorption, the damage to the material is very low, and the material can be repeatedly used. And finally, the process of producing the high-quality blue
iron ore through phosphorus
recovery of the
desorption solution is simple and easy to operate. Through XRD, ICP and other detection, it is found that the phosphorus
recovery product is determined to be the blue iron ore, and the purity is very high. Through
economic analysis and life cycle evaluation, it can be found that the method has remarkable economical efficiency, and the influence on the environment in the production process is small.