Although graphene-based substances are a potential adsorbent, their performance in the removal of pharmaceutical contaminants has been restricted due to the deterioration induced by aggregation and the lack of control over their porosity and dimensions. . An article published in the journal Advanced Sustainable Systems reported the formation of a unique graphene material supported with high porosity composite foam to combat aggregation.
New graphene-based foam compound as a highly reactive filter medium for the efficient removal of Gemfibrozil from (residual) water. Image credit: 3DStach / Shutterstock.com
Increasing the contribution of pharmaceuticals to the EC
Pharmaceuticals are among the most prominent emerging contaminants (ECs) in water systems. They can cause serious environmental consequences along with possible health problems.
To successfully eradicate ECs from processed wastewater streams, drinking water and effluent purification facilities must adopt appropriate tertiary treatment methods.
Adsorption: the method of choice for water treatment
Adsorption is considered a technology with great potential in water treatment. It is a reliable and less expensive approach compared to reverse osmosis, oxidation, microfiltration, ultrafiltration, and ion exchange, among others.
The most obvious advantages of using adsorption for wastewater treatment are the simplicity of the procedure, an abundant supply of various types of adsorbent materials, the cost-effectiveness and the ability to remove most types of contaminants such as biological , inorganic / organic or insoluble / soluble.
Unfortunately, the adsorbent approach to water treatment has certain practical limitations, most notably a shortage of high-capacity adsorbent materials for a wide variety of ECs. Graphene-based substances surpassed many other potential adsorbent materials explored, demonstrating encouraging effectiveness in this regard.
Pros and cons of graphene-based materials
Graphene and graphene oxide (GO) have a high propensity to adsorb natural pollutants due to their large specific innate area (relative to many different carbonaceous substances), wettability, monolayer architecture, and a surface adorned with oxygen-containing functional groups (OCFG).
Despite optimum adsorption performance and the constant reuse of porous graphene (PG) to a variety of emerging contaminants, the problems of isolating these graphene-based materials (GBM) out of water, along with their restricted reuse, they limit their realistic implementations on a large scale. water treatment.
Another important impediment to its use is the agglomeration between its sheets. Stacking allows this agglomeration to restore graphene-based material to its base material (graphite).
Schematic diagram for column filter configuration (left) and a photo of the 40 mm ID adsorption column filter (right). © Khalil, AM, Han, L. et al. (2022).
Preparation of foams for the supporting graphene
Functionalization by surface modification is believed to be a useful method for preparing foams to treat effluent. Various strategies have recently been used to improve the adsorption efficiency of diatomaceous earth foams. Unfortunately, the procedures were quite complicated and resulted in a significant amount of greenhouse gas emissions.
Boron nitride (BN) has a number of exceptional qualities, such as superior thermal and chemical stability and excellent wear resistance; as a result, it is used in high temperature environments and in other industries.
Demonstration of the physical properties of the foam (lightness and strength): a) foam as it is prepared placed on plant leaves, and b) foam material that supports a standard cylindrical weight of about 1340 times its own weight © Khalil, AM, Han, L. et al. (2022).
Important results of the study
In this study, reduced porous GO nanofilms were effectively anchored to tape-shaped BN foam to treat gemfibrozil-contaminated water (GEM) in batch testing and column research.
Graphene-based foam outperformed its graphene-based competitors such as GO, PG and nanograph platelets (NGP) in terms of gemfibrozil adsorption kinetics, with an extraction efficiency of 90 percent in just five minutes.
In terms of longevity, BN foam-backed graphene-based nanomaterials showed consistent consistency in the extraction of gemfibrozil drugs when recycled for numerous rounds with no significant absorption losses. In addition, the foam material showed exceptional characteristics, such as lightness with a porosity of more than 98 percent, as well as excellent strength, with the ability to withstand 1300-1400 times its own weight.
In filtering activities, the foam-filled adsorbent column filter outperformed sonic porous graphene nanosheets based on sand filters that handled aqueous gemfibrozil mixtures. To mimic the results of the test for the removal of emerging contaminants within the GO / BNF filter material, a 1-D solute transport computational framework was developed.
Conclusions
Proper construction and verification of the fixed bed system depends largely on the choice of a suitable porous medium, which may be the material of the filled column or the material of the sensitive area, as well as the precise experimental measurement of the characteristics of advection-dispersion-retardation. .
Reinforced graphene-based composite foam for filtration purposes would be an important step in water and effluent filtration technologies. These results imply that high-porosity foam-reinforced graphene nanomaterial filters with shorter interaction times and longer feed periods to treat water and effluents could be easily manufactured.
Reference
Khalil, AM, Han, L. et al. (2022). New graphene-based foam compound as a highly reactive filter medium for the efficient removal of Gemfibrozil from (residual) water. Advanced sustainable systems. Available at: https://doi.org/10.1002/adsu.202200016
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