Phosphate Removal with pH-Responsive Calcium Carbonate Nanoparticles

Increasing use and excessive release of phosphate cause eutrophication. In this work, calcium carbonate nanoparticles were produced and modified to remove phosphate from water. The calcium carbonate nanoparticles were synthesized through wet carbonation with polyethylene glycol and sodium dodecyl sulfate added to limit particle size. Iron was incorporated into the calcium carbonate nanoparticles to improve phosphate removal. The BET surface area of CaCO3 was significantly improved after Fe incorporation. Phosphate removal was enhanced from 50 to 90 % within minutes. More importantly, the adsorption behavior of CaCO3-Fe was different from that of the pH-responsive CaCO3 material. Phosphate adsorption was reduced in alkaline solution due to the decreased positive surface charge of CaCO3-Fe for interaction with phosphate.

Automated summary

This study successfully improved the removal of phosphate by producing and modifying calcium carbonate nanoparticles. The incorporation of iron increased the surface area of CaCO3, resulting in significantly enhanced phosphate removal. CaCO3-Fe exhibited different adsorption behavior for phosphate compared to traditional pH-responsive materials.