Adsorption and purification of phosphorus from eutrophication water by nano-sized goethite modified anion exchange resin

Abstract

The purpose of this study was to explore an improved phosphate adsorption material to optimize its application in the removal of inorganic phosphorus from eutrophic water. In this paper, a composite method of nano-hydroxyl iron (FeOOH) and anion exchange resin D-201 was proposed. FeOOH@D-201 composite resin was initially obtained by dispersing nano-hydroxyl iron in anion exchange resin D-201. Then, batch adsorption experiments were carried out to evaluate the improvement by comparing the phosphate adsorption capacity of FeOOH@D-201 and pure D-201. The quasi-second-order kinetic model and Langmuir adsorption isotherm model were fitted to analyze the adsorption process and mechanism of the composite resin. The results showed that the maximum phosphate adsorption capacity of FeOOH@D-201 composite resin was 132.1 mg/g, which was 46% higher than that of pure D-201, and broken through the limitations of conventional anion exchange resin in the removal of inorganic phosphorus. The model fitting results showed that the adsorption process was in good agreement with the quasi-second-order kinetic model and Langmuir model, and it was inferred that the adsorption mechanism was mainly electrostatic attraction and coordination. After five acetic acid desorption and adsorption regeneration cycles of FeOOH@D-201, the phosphate removal ability of the adsorbent remained above 70.4%, which confirmed the good regeneration performance of the composite resin.

Keywords

• nano-hydroxyl iron
• anion exchange resin
• phosphorus removal by adsorption