Newly developed ion exchange resin with iron oxide to remove arsenic from drinking water

04-Oct-08

Specialty chemicals group LANXESS has developed Lewatit FO36, an innovative hybrid adsorber consisting of a combination of a polymeric anion exchange resin and an iron oxide with a goethite structure that can reliably remove arsenic from drinking water. The iron oxide is distributed in the pores of the weakly basic ion exchange resin in a layer a few nanometers thick by a special production process. This fine, highly reactive iron oxide layer can selectively adsorb the arsenic. Unlike the other anionic components of water such as chloride, nitrate, sulfate and carbonate, only arsenic has high affinity to the iron oxide surface, and is the only substance to be adsorbed. Although Lewatit FO36 was designed by the Ion Exchange Resins business unit primarily for adsorbing arsenic, it can also be used for adsorbing other trace impurities. The combination of ion exchange resin and iron oxide has various advantages from a mechanical and hydraulic point of view. The plastic matrix of the ion exchange resin gives the material high mechanical stability and allows the specific shaping of the particles. LANXESS has thus succeeded in producing a non-dusting, free-flowing bulk material with a uniform bead size (monodispersity). When used as a filtration agent, the product has the big advantage of a uniform structure, allowing the liquid to pass evenly through all the beads, excluding the formation of dead corners and ensuring a highly homogeneous flow. The amount of pumping energy required to operate the unit is also reduced by the homogenous form of the channels between the beads. Health studies show that the arsenic absorbed by the human body through the long-term consumption of contaminated drinking water has the potential to cause cancer or skin problems, even in concentrations of just a few ppb (parts per billion).