Modified Bauxite for Phosphate Recovery and Recycling


This technology shows three different forms of bauxite to be effective adsorbents for phosphate ions.

  1. Mildly processed bauxite (MPB), which is essentially ball-milled raw bauxite ore,
  2. Thermally activated bauxite (TAB), which is ball-milled bauxite ore subjected to 300 C roasting, and
  3. Acid treated thermally activated bauxite (ATAB), which is ball-milled bauxite ore subjected to 300 C roasting and subsequent acid treatment using 5M HCl.
    These three different forms of bauxite are shown to adsorb phosphate in high amounts from solutions containing a range of initial phosphate concentrations, 5 ppm to 631 ppm.
    ATAB shows the highest adsorption density, demonstrating a value of 50 mg of PO4-/g ATAB at pH=6
    TAB shows an adsorption density of 25 mg PO4-/g TAB at pH=6
    There are two industry standard materials for phosphate adsorption, activated magnesia (MgO), and activated alumina (Al2O3). For comparison, activated magnesia (MgO) demonstrates an adsorption capacity of 25 mg PO4-/g at pH=6. Activated alumina (Al2O3) shows an adsorption capacity of 11 mg PO4-/g at pH=6 (reference: Journal of Environmental Chemical Engineering 5 C(2017) 3181–31893183).
    Phosphate, a finite and dwindling resource mined from phosphate rock, is a critical nutrient in modern agriculture, which is applied as fertilizer to ensure adequate plant growth. The inventors provide a cost-effective, environmentally-friendly method for recovering phosphate from agricultural runoff and other wastewater and delivering the recovered phosphate in a targeted and controlled manner to agriculture and farm sectors.


In comparison to all commonly used industrial standard adsorbents, this modified bauxite technology:

  • is cheaper
  • is more carbon friendly
  • is environmentally friendlier because of little to no chemical processing
  • has equal or better capacity for phosphate adsorption

Potential Applications:

Suggested uses include:
column-based adsorption for directed water treatment to remove phosphate loading of wastewater discharge
preloading of adsorbent pellets for controlled release of phosphate as fertilizer
incorporation into composite electrode for electrochemically-assisted phosphate removal
batch process by mixing the adsorbent, for treatment of site-specific waters for phosphate capture

Contact Information:

  • Name: Terri Sale
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  • Phone : 510-643-4219
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