Arsenic can be removed from groundwater using a polymer gel composite
To remove arsenic from groundwater we developed a cationic polymer gel, which was impregnated with iron hydroxide. This gel composite adsorbs arsenic selectively and can be regenerated.
Arsenic is a toxic component broadly found in groundwater in the countries of almost every continent of the world. Arsenic enters the human body through drinking water and other sources such as rice, fruits, vegetables grown in arsenic contaminated water. Surprisingly, arsenic was found in high quantity in the breast milk of the mothers intaking arsenic. Consumption of arsenic over a long period makes humans suffer from chronic diseases such as skin and stomach cancer, diabetes, high blood pressure, pneumonia among children, skin lesion and others. Although researchers developed several techniques to remove arsenic from water, there is still research gap of selectively removing only arsenic components from water and necessity of a practically implementable and cost-effective solution.
Adsorption of arsenic using a polymer gel impregnated with iron hydroxide1.
A research group from Hiroshima University, Japan, developed a polymer gel, which was impregnated with Iron particles. When this gel is immersed into water and shaken, it traps arsenic in it through ion exchange. When the gel is taken out from the water, it cleanses the water by taking arsenic away, which lies in the polymer structure of the gel. This gel can be reused several times by cleaning it with saltwater. Because, in the presence of saltwater, the gel releases the arsenic by exchanging ion with sodium chloride. In a research article published in Scientific Reports, the research group proved that due to the unique preparation method of his gel, the amount iron particles in the gel was maximized. Also, the type of iron, which helps to remove maximum amount of arsenic, was confirmed in the polymer structure of the gel. This attribute helps the gel to remove high amount of arsenic. Through the arsenic adsorption mechanism, he also explained how arsenic was bound by the polymer gel structure as shown in the figure below.
Arsenic Adsorption mechanism using X-Ray Photoelectron Spectroscopy (XPS) Analysis.
This technique is easy to use for anyone and since this gel can be reused several times, the usage cost of the gel could be reduced. In future, this research group will research on the practical implementation of the gel in the contaminated water from various regions.
Link of the research article: https://www.nature.com/articles/s41598-019-48233-x
1. Safi, S. R., Gotoh, T., Iizawa, T. & Nakai, S. Development and regeneration of composite of cationic gel and iron hydroxide for adsorbing arsenic from ground water. Chemosphere 217, 808–815 (2019). https://doi.org/10.1016/j.chemosphere.2018.11.050