New low-cost material to reduce air, water pollution

Scientists have developed a new low-cost and sustainable material that may displace activated carbon as the preferred choice for reducing waste-water and air pollution.

The material, described in the journal Frontiers in Chemistry, is synthesised inexpensively from solid wastes and a naturally abundant polymer.

It could cut down pollutants in air and waste-water with more success than activated carbon, the current gold standard adsorbent, researchers said.

This paper shows the simple synthesis of a new porous hybrid material, obtained by using low cost and by-product materials," said Elza Bontempi from the University of Brescia in Italy.

"The material was designed on the basis of The European Commission's request to develop an affordable, sustainable and innovative design-driven material solution that can reduce the concentration of particulate matter in urban areas," said Bontempi.

Activated carbon is the most common adsorbent used to reduce both atmospheric and wastewater pollution - but is expensive to produce and regenerate.

The challenge has been to find an economical alternative.

Researchers combined a naturally abundant raw material, sodium alginate (a polysaccharide that can be extracted from seaweed and algae) with a high-volume industrial by-product, silica fume to produce a "green" adsorbent that is better than activated carbon.

"The article reports preliminary results about the new material's capability to capture particulate matter," said Bontempi.

"It can also be used for waste-water remediation. In particular, its ability to replace activated carbon is demonstrated," she said.

The synthesis method is simple and easy to scale up, researchers said.

Taking advantage of the gelling properties of alginate, they combined it with the decomposition of food-grade sodium-bicarbonate (baking soda) to consolidate the material.

Testing of waste-water pollution was performed using methylene blue dye as a model pollutant.

The hybrid material adsorbed and removed the dye, even at high concentrations, with 94 per cent efficiency, researchers said.