Competitive adsorption of Cu2+ and Ni2+ on Luffaacutangula modified Tetraethoxysilane (LAP-TS) from the aqueous solution: Thermodynamic and isotherm studies

• The Luffa Actangula Peels was modified with Tetraethoxy silane for the removal of Cu2+ and Ni2+ ions.
• It shows maximum adsorption capacity of 12 mg g−1 at 120 min and 303 K for both the metal ion.
• The LAP-TS was best fitted by Langmuir Isotherm for Cu2+ ion with 22.05 mg g−1(qm) and Ni2+ ions was best fitted by Freundlich isotherm with 22.71 mg g−1 monolayer adsorption capacity. It follows pseudo 2nd kinetics.

Luffa Actangula Peels modified with Tetraethoxysilane (LAP-TS) was evaluated for the removal of Cu2+ and Ni2+ ions from the aqueous solution. The presence of functional groups like –CH and –CO3, –C–O groups on the surface of the peel and surface morphology were characterized by FTIR, EDX and SEM. The LAP-TS shows equilibrium adsorption capacity of 12 mg g−1 at pH 5.0 for Cu2+ ion and 12 mg g−1 at pH 7.0 for Ni2+ ion in 120 min at 303 K temperature. In case of Cu2+ ion it is best fitted by Langmuir Isotherm showing monolayer adsorption capacity of 22.056 mg g−1 whereas in case of Ni2+ it is best fitted by Freundlich Isotherm with multilayer adsorption capacity of 22.716 mg g−1 and higher regression coefficient n single metal adsorption system the adsorption efficiency removal of LAP-TS towards Cu2+(95%) were more than Ni2+(80%) ions, whereas in case of binary system it was about 96%, which increases at higher concentration at pH 5.0. The adsorption of Cu2+ and Ni2+ ions were thermodynamically spontaneous, Endothermic in nature with randomness at solid/liquid solution interface in both the cases. The adsorption of Cu2+ and Ni2+ follows pseudosecond order kinetics showing chemisorption interaction and intraparticle diffusion is the main rate determining step.