Abstract:
Azo dyes are a coloring agents having wide applications in various industries like paint, textile and paper
industries. Azo dyes released as waste materials by textile industries during cleaning process have
detrimental impacts on aquatic environment. Now a days heterogenous catalysis and adsorption studies
have been gaining much popularity worldwide due to its versatility. Presently heterogenous adsorption
mechanism of five novel azo dyes namely, Bis 3,3'-(4,4'-Diazenyldiphenylmethane)-4-
chlorobenzaldehyde, Bis 3,3'-(4,4'-Diazenyldiphenylmethane)-p-anisaldehyde, Bis 3,3'-(4,4'-
Diazenyldiphenylmethane)-naphthaldehyde, Bis 3,3'-(4,4'-Diazenyldiphenylmethane)-salicylaldehyde,
Bis 3,3'-(4,4'-Diazenyldiphenylmethane)-2,4-dihydroxybenzaldehyde with Graphene Oxide (GO) was
probed to determine adsorption prosperity on basis of experimental and computational kinetics and
thermodynamic parameters. Experimental Langmuir adsorption constant (KL) determined by UV-Vis
spectroscopy was found to be highest for Bis 3,3'-(4,4'-Diazenyldiphenylmethane)-salicylaldehyde i.e.,
3.76×109
as compared to other four azo-dyes and having more negative free energy value -54.62 kJ/mol.
Calculated electronic (EHOMO, ELUMO), kinetic (Kad), and thermodynamic parameters (ΔG, ΔH, and ΔS)
based on quantum chemical DFT approach also revealed highest adsorption of Bis 3,3'-(4,4'-
Diazenyldiphenylmethane)-salicylaldehyde with Graphene oxide (GO) due to strong deactivating –OH,
-CHO group on aromatic ring of azo-dye. Based on quantum chemical findings calculated adsorption
constant (Kad) of Bis 3,3'-(4,4'-Diazenyldiphenylmethane)-salicylaldehyde was also highest 1.93×1010
and free energy (ΔG) was -58.69 kJ/mol. It was observed that experimental results are complying with
computational results. Current research would have tremendous impact in the area of water purification
and desalination using Graphene oxide (GO) molecular sieve.
