Facile synthesis of la2(co3)3-diatomite composites for the continuous removal of low-concentration phosphate

Eutrophication caused by excessive phosphorus content in water is a common problem among the world. For the adsorption treatment of phosphorus wastewater, developing new adsorbent with high adsorption capacity, good selectively, and scalable synthesis is highly desired. Here, the facial synthesis of La-2(CO3)(3)-diatomite composite adsorbents is developed to achieve kilogram-scale production. With La-2(CO3)(3)center dot 8H(2)O as the active ingredient, this adsorbent exhibits high P adsorption capacity of 57.64 mg P/g (in pH = 7, 30 mg P/L solution). It also demonstrates excellent selectivity toward phosphate adsorption, capable of maintaining more than 80% of its capacity in the presence of high-concentration competing anions (up to 20 times of the phosphate molarity). The mechanism study reveals that chemical interaction and electrostatic attraction are major contributors for the phosphate adsorption, with the chemical interaction likely being the thermodynamic driving force and the electrostatic attraction affecting the adsorption kinetics. Finally, the La-2(CO3)(3)-diatomite composite adsorbent is successfully adopted in a fluidized-bed column for the continuous adsorption of low-concentration P phosphorus (2.1 mg P/L) and obtained high treatment capacity of 3940 bed volumes. These results show the promising potential of the La-2(CO3)(3)-diatomite composite adsorbent as a highly efficient phosphate adsorbent for large-scale application in water treatments. [GRAPHICS] .