Title : Study of adsorption properties of magnetic few-layer graphene
Abstract:
Graphene derivatives are good adsorbents because they have a large specific surface area (2600 m2/g), as well as a high content of oxygen-containing groups on the surface (up to 30 wt.%), but their application is difficult because the separation of adsorbent particles from the adsorbate solution is cumbersome since the particle size is about 100 nm. This work presents a method for the preparation of few-layer graphene by self-propagating high temperature synthesis from an oxidizing agent (ammonium nitrate) and a biopolymer (cellulose), which was then used to modify with iron particles. To solve the problem of separation of sorbent particles from sorbate solution, a simple technique was developed to produce magnetic particles on the surface of few-layer graphene by Elmore chemical condensation, thanks to which it will be possible to carry out a complete separation of adsorbent particles from the pollutant solution when a magnetic field is applied. From the experiment, the obtained magnetic few-layer graphene was characterized by scanning electron microscopy, IR spectroscopy, BET specific surface area determination, and X- ray phase analysis. An organic dye, methylene blue, was used to evaluate the sorption capacity of magnetic few-layer graphene. The adsorption of methylene blue on the surface of magnetic few-layer graphene was tested as a function of the effects of increasing pH, dye concentration and process temperature. Also, adsorption models - Langmuir and Freundlich isotherms – were constructed to determine the adsorption mechanism and adsorbent morphology. The obtained magnetic few-layer graphene is superior to activated carbon in terms of adsorption capacity, and it can also be used to purify wastewater from dyes and other organic substances. It can be produced in industrial and laboratory conditions at a lower cost of equipment and reagents.
