3D Printable Material Could Remove Pollutants from Air and Water

Every year, millions of tons of dyes and other compounds, many of them toxic, are discharged in industrial waste, posing a threat to the environment and human health. These compounds must be removed from wastewater in treatment plants; allowing them into natural waterways would be disastrous. Many different approaches have been taken to removing these chemicals from the water, with the most common being the use of activated carbon to absorb the compounds. Activated carbon, however, is an expensive natural resource to produce and to regenerate, and its use is often limited due to cost and other issues including end-of-life disposal.

Lower-cost alternatives to activated carbon are being sought, and one possibility may be a 3D printable material developed by a group of Italian researchers. The hybrid material is synthesized from solid wastes and a naturally abundant polymer, and can cut down wastes in air and wastewater with more success than activated carbon.

The research has been published in a paper entitled “A New Porous Hybrid Material Derived From Silica Fume and Alginate for Sustainable Pollutants Reduction,” which you can read here.

“This paper shows the simple synthesis of a new porous hybrid material, obtained by using low cost and by-product materials,” said lead author Dr. Elza Bontempi from the University of Brescia. “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.”

New porous material, before (a) and 15 min after (b) the exposition to exhaust fume of a diesel car.

The researchers combined a naturally abundant raw material called sodium alginate – a polysaccharide which can be extracted from seaweed and algae, and is the commonly used gelling agent for inkjet bioprinting – with silica fume, a high-volume industrial byproduct of ferrosilicon or silicon metal alloy processing, to produce a green adsorbent that is superior to activated carbon.

“The article reports preliminary results about the new material’s capability to capture particulate matter,” said Dr. Bontempi. “It can also be used for wastewater remediation. In particular, its ability to replace activated carbon is demonstrated.”

Taking advantage of alginate’s gelling properties, the researchers combined it with baking soda to consolidate the material. They then tested its effect on wastewater pollution, using methylene blue dye as a model pollutant. The material adsorbed and removed the dye, even at high concentrations, with 94 percent efficiency. Compared with activated carbon, production of the hybrid material consumed less energy and left a much lower carbon footprint. It also demonstrated capabilities for trapping diesel exhaust fume particulate matter.

The versatile material can be applied as a coating, sprayed, brushed, or 3D printed. This means that it could be used as a particulate-removing building surface covering, as well as to design water filtration units.

New porous hybrid material obtained by direct foaming: sample not treated (a), sample treated with thermal treatment at 400°C (b), extrusion (c), 3D printing (d), deposited by spray (e), or by brush (f).

“Finally, the possibility to shape the material by 3D printing highlights its high versatility and opens new possibilities,” the researchers stated. “For example, filters, components with specific dimensions and geometries or replacement parts can be easily designed and manufactured and integrated in the plant. Indeed, 3D printing allows to realize personalized designed components, that may be not available on the market, or that may have high production costs, and require time to be delivered.”

Authors of the paper include Alessandra Zanoletti, Ivano Vassura, Elisa Venturini, Matteo Monai, Tiziano Montini, Stefania Federici, Annalisa Zacco, Laura Treccani and Elza Bontempi.

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