Identification of the Physicochemical Factors Involved in the Dye Separation via Methionine-Functionalized Mesoporous Carbons

Synthetic dyes in the wastewater from different industries have adverse effects on human and animal health and cause disturbance of the environmental equilibrium. Functional porous materials have provided significant progress in the removal of dyes from wastewater using adsorption methods. Yet, the correlation and deeper understanding of the physicochemical properties of the porous materials and the dye remains a great challenge. Although ordered mesoporous carbons (OMCs) have unique beneficial features for dye separation, such as high surface area, uniform pore size, good mechanical and thermal stability, so far no report explores OMCs for selective dye adsorption from mixtures. Herein, OMCs of different morphologies and structures are synthesized via nanocasting and modification with methionine amino acid as new adsorbents for rhodamine B and sunset yellow FCF dyes. The results confirm that the obtained carbon materials have a significantly better affinity to rhodamine B than to sunset yellow FCF, which is related to the presence of a high number of acidic functional groups on their surface. In addition, the morphology of materials plays also an important role in the adsorption process. Carbon spheres with wrinkled walls are more efficient in the removal of both dyes than carbon particles with worm-like shapes.