Modified Bauxite for Phosphate Recovery and Recycling

Tech ID: 32498 / UC Case 2022-017-0

Brief Description

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.

Suggested uses

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


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

Related Materials

Learn About UC TechAlerts - Save Searches and receive new technology matches


  • Gadgil, Ashok J.

Other Information

Categorized As