Water treatment | Adsorption & desorption of Phosphorus ion

Phosphorus is a rare resource but, on the other hand, one of the factors of water pollution.

Discharge is regulated

Though phosphorus is a rare resource…

One of the main materials of fertilizer (NPK fertilizer)

Uneven distribution over the world

  • The top 3 producing countries(China, Morocco, and the USA) account for 71%
  • 74% of the global reserve is in one country (Morocco)
  • Japan imports 39% and 26% from China and Jordan, respectively


Fertilizer consumption is expected to be increased due to higher food demand and decreased arable area

…its discharge is regulated as one of the factors of water pollution

  • A factor of eutrophication in rivers and lakes
  • A factor of Water pollution in fish ponds
  • Discharge regulated (16mg/L(8mg/L on average of 24h)*)


*The standard emission of phosphorus is applied to only wastewater discharged, to lakes specified that phosphorus could cause significant phytoplankton multiplication by Minister of the Environment , to a sea area specified that phosphorus could cause significant marine phytoplankton multiplication by Minister of the Environment or to public water flowing in them.

International price of a phosphate rock surged during the food crisis in 2007~2008 is now stabilized but more than double of before-crisis level


Porous Alpha can reduce the cost of treatment for discharged water with phosphorus.
Our company has the patent on Production methodology of adsorption agent of Phosphorus ion, Phosphorus acid fertilizer and adsorption agent of Phosphorus ion.

Increased specific surface area of Porous Alpha by hydrothermal process realizes phosphorus ion adsorption

Before Hydrothermal process After Hydrothermal process
01-trr-main - pa-before-hydro.jpg 01-trr-main - pa-after-hydro.jpg
Specific surface area:83m2 g-1 Specific surface area: 278m2 g-1
Adsorption & precipitation of phosphorous ion
01-trr-main - pa-phosphorus-mech-formula.jpg
Soda-lime glass has the elements with which phosphorous ion is adsorbed or precipitated



Regardless of the initial concentration, the phosphorous ion is adsorbed to Porous Alpha in 1hour

01-trr-main - pa-phosphorus-mech-concentration.jpg


Porous Alpha with adsorbed phosphorus can be used as delayed release fertilizer


The dry weight of harvested tomato with a different type of phosphorus fertilizer*

01-trr-main - pa-phosphorus-mech-dry-weight.jpg


The adsorbed phosphorous can be recovered in high purity form with nitric acid and citric acid

01-trr-main - pa-phosphorus-mech-recovered.jpg

The adsorption capacity of phosphorus with Porous Alpha is drastically higher than with other materials


Existing technology to recycle phosphorus as fertilizer has issues such as limited
recoverable form of phosphorus and high running cost


As the treatment plant is simple and smaller than the others it is possible to realize with a smaller investment

We are now testing phosphorus application to the water flowing into public sewage plant

Pilot project site: Public sewage plant

Contents of the pilot project

  • Adsorption of phosphorus from water flowing into the sewage plant
  • Desorption of phosphorus
  • Evaluation of the Porous Alpha with phosphorus as fertilizer

We are now testing phosphorus application to the water flowing into public sewage plant

Phosphorus adsorption

  • Adsorption ability is the highest at approximately pH 7.0
  • Applicable initial concentration is higher than 0.8 ppm
  • Phosphate concentration in treated solution is lower than 0.2 ppm
  • It’s required to prevent the suspended solids adsorbed to Porous Alpha
    • SS should be removed in pre-treatment; or
    • Put filter to protect Porous Alpha from SS

Phosphorus recover

  • With nitric acid higher than 0.5mol/L
  • Phosphorus recovery rate: more than 80%


Nitric acid (more than 0.1mol/L) or citric acid (more than 0.05mol/L)