Nanoporous Sponge Anchored on Graphene Produces Faster, More Efficient Wastewater Treatment

A group of scientists from the University of Vienna's Faculty of Chemistry presented a new method for creating an innovative composite material with the capacity to absorb wastewater for effective industrial pollutant treatment. Changxia Li, Freddy Kleitz, and colleagues published the study in Angewandte Chemie.

Treatment Plant Wastewater Michal Jarmoluk

Overview of The Novel Wastewater Treatment

Due to their high water solubility and lack of biodegradability, organic dyes are one of the most common harmful industrial pollutants. However, the main issue with this kind of pollution is its carcinogenic potential. Effective industrial wastewater treatment adsorbents are crucial to reducing its possible environmental harm.

The researchers developed a novel approach to design a cutting-edge composite material that is highly efficient at filtering organic pollutants from water and is made of a nanoporous, ultrathin covalent organic framework (COF) anchored on graphene to solve the issue.

First author and postdoctoral researcher Changxia Li said that there are many ways to purify water, including activated carbon filters, but there is still room for improvement in the efficiency or adsorption capacity of the applications.

According to ScienceDirect, activated carbon is a powerful adsorbent because it has a large surface area where contaminants can adhere and is a highly porous material.

Porous materials can accumulate a disproportionately large number of molecules on their surfaces during adsorption because they have a much larger total surface area than non-porous materials for the same volume.

In the new study, Freddy Kleitz's group at the Institute of Inorganic Chemistry-Functional Materials is developing new nanoporous materials.

The highly porous (COFs) is a relatively novel class of materials used in research. Apart from being porous, it is also low-density and lightweight. Their chemical bonds are created by electron pairs between atoms, which is referred to as their covalent property.

Laboratory Procedure In Developing Effective Wastewater Treatment

The scientists' aqueous model solution contained dyes ranging from 0.8 to 1.6 nanometers. The researchers developed a novel method of using water to form COF in a relatively environmentally friendly way.

As a result, they could create tiny sponges with precisely sized and shaped pores in the nanometer range and a tuned negative surface charge that attracted positively charged target molecules very specifically. Similar to how a sponge absorbs water, the experiment uses pollutants instead of water.

Pore blockage at the outer edge, particularly for large pollutant molecules, frequently prevents pollutants from entering the material's inner pores when using bulk COF powder.

ALSO READ: From Waste To Life: Researchers Found New Way Of Turning Wastewater Into Clean Organic Fertilizer

Graphene In Wastewater Treatment

According to Phys.Org, graphene is a planar sheet of sp2-bonded carbon atoms that is one atom thick and tightly packed in a honeycomb crystal lattice. It can be thought of as an atomic-scale chicken wire made of bonds between carbon atoms.

The researchers grew COF on thin-layered graphene nanosheets for this purpose, giving rise to a novel composite material with a completely porous structure. The layer of COF, which is up to two nanometers thick, and graphene, which is already a 2D layer of carbon atoms, combined to form a compact, open 3D structure. The ultrathin COF layer may expose more adsorption sites than the bulk COF powder.

On the other hand, the larger, honeycomb-like pores of the graphene network enable water to pass through the filter material. The researchers claim that the large number of adsorption sites in the ultrathin COF layer and the large pores in the graphene network enable fast and efficient wastewater treatment.

Due to the relatively low material input of graphene and the potential to reuse the composite material (after the pollutants have been washed out) as a filter, they asserted that the development is also reasonably cost-efficient.