Water treatment

Adsorption & desorption of Phosphorus ion


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

Though phosphorus is a rare resource…

One of main materials of fertilizer (NPK fertilizer)

Uneven distribution over the world

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

  • Factor of eutrophication in rivers and lakes
  • Factor of Water pollution in fish ponds
  • Discharge regulated (16mg/L(8mg/L in 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

Phosphorus adsorption & recovery decrease environmental burden and utilize rare resource

Porous Alpha can reduce the cost of treatment for discharged water with phosphorus
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

Specific surface area:83m2 g-1

After Hydrothermal process

Specific surface area : 278m2 g-1)

Adsorption & precipitation of phosphorous ion

Soda-lime glass has the elements with which phosphorous ion is adsorbed or precipitated

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

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

Dry weight of harvested tomato with different type of phosphorus fertilizer*

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


Adsorption capacity of phosphorus with Porus Alpha is drastically higher than others


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 smaller investment

Case Study

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

Pilot project site: Public sewage plant

Contents of pilot project

・Adsorption of phosphorus from water flowing into sewage plant

・Desorption of phosphorus

・Evaluation of the Porous Alpha with phosphorus as fertilizer


Specification and applied conditions for phosphorus adsorption, recovery and usage as fertiliser

Phosphorus adsorption

・Adsorption ability is the highest 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)