Research on nanocomposite materials for industrial waste treatment
Dr. Lu Thi Mong Thy (Ho Chi Minh City University of Food Industry) has researched to synthesize magnetic metal oxide nanomaterials, based on Graphene oxide, which can be applied in the treatment of heavy metals and toxic pigments in wastewater.
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Currently, industrial waste is a serious threat to the environment. In particular, waste from factories of many industries, such as metallurgy, plating, paint, batteries, tanning, textile dyeing, chemicals, ... contains a lot of toxic substances. Especially, the concentration of heavy metal ions (arsenic, lead, nickel, copper, manganese, ...), and organic pigments (methylene, red congo, ..) in the water environment is at an alarming level as well as causing serious consequences for the environment. Therefore, the removal of heavy metals and organic pigments from polluted water is one of the necessary issues today.
Many methods have been applied to treat water contaminated with heavy metal ions and organic pigments such as, membrane filtration, adsorption, oxidation, coagulation, ion exchange, biodegradation, etc. Recently, graphene oxide (GO) is one of the carbon nanostructured materials, thanks to its high adsorption capacity and large specific surface area. GO materials are well dispersed in aqueous medium, able to bind metal ions, colorants in solution, and are considered as potential adsorbents. In particular, GO has great advantages in removing heavy metals and colorants from aqueous solutions.
However, GO sheets tend to stack on top of each other, reducing the mechanical strength and contact area, limiting the adsorption capacity. At the same time, GO is nano-sized, so it is difficult to recover after use. Therefore, the solution of synthesizing nanocomposite materials based on GO combined with magnetic oxide to increase recovery and reuse is studied by Dr. Lu Thi Mong Thy.
Accordingly, two types of nanocomposite materials Fe3O4/GO and MnFe2O4/GO were successfully synthesized by TS Thy by simple co-precipitation method with Fenton catalyst. The composites have distribution of oxide nanoparticles with small, uniform size from 10 - 25 nm, easy to recover, and reuse by external magnetic field (magnet). The material retains its high magnetic ability and is stable during adsorbent application.
The study also found the suitable ratio of Fe3O4/GO and MnFe2O4/GO to adsorb each heavy metal and colorant in water. The ability to recover and reuse materials with high recovery and reuse efficiency (more than 70%). In particular, Fe3O4/GO with higher magnetism is capable of adsorbing methylene blue organic pigment (MB), while MnFe2O4/GO mainly adsorbs heavy metals, such as lead, arsenic, nickel,...Set of parameters optimal adsorption conditions of these materials, creating a basis for consulting, applied to wastewater treatment units.