Experimental and theoretical study using DFT method for the competitive adsorption of two cationic dyes from wastewaters

• Published in: Applied surface science 2016-12, Vol.390, p.311-319
• Main Authors: Regti, Abdelmajid, Ayouchia, Hicham Ben El, Laamari, My Rachid, Stiriba, Salah Eddine, Anane, Hafid, Haddad, Mohammadine El
• Format: Article
• Language: English
• Subjects: Adsorption; Binary systems; Carbon from medlar; Cationic dyes; Competition; DFT-derived indices; Electrophilicity; Mathematical models; Nitrogen atoms; Parameters; Sulfur; Surface chemistry
• ISSN: 0169-4332; 1873-5584
• DOI: 10.1016/j.apsusc.2016.08.059

[Display omitted] •The adsorption efficiency increases with increasing pH, thus more negatively charged surface was available.•Monolayer adsorption and homogeneous adsorbent surface.•The experimental and theoretical data are in good agreement showing that MB has ability to accept electrons allowing more adsorption than BY28 dye. The adsorption of cationic dyes, Basic Yellow (BY28) and Methylene Blue (MB) on a new activated carbon from medlar species were studied in both single and binary system. Some experimental parameters, namely, pH, amount of adsorbent and contact time are studied. Quantum chemical results indicate that the adsorption efficiency was directly related to the dye electrophilicity power. Some theorical parameters were calculated and proved that MB is more electrophilic than BY28, than greatest interaction with surface sites. Kinetic study showed that the adsorption follows the pseudo-second-order model and Freundlich was the best model to describe the phenomenon in the single and binary system. According to the local reactivity results using Parr functions, the sulphur and nitrogen atoms will be the main adsorption sites.