Green Synthesis of Copper Nanoparticles Using Tea Leaves Extract to Remove Ciprofloxacin (CIP) from Aqueous Media

Abstract

     In the present investigation, the synthesis of copper nanoparticles from green tea was attempted and investigated for its capacity to adsorb drugs (Ciprofloxacin). The copper nanoparticles (Cu-NPs) were characterized by different techniques of analysis such as scanning electron microscopy (SEM) images, atomic force microscope (AFM),  blumenauer-emmer-teller (BET), fourier transform infrared (FTIR) spectroscopy, and zeta potentials techniques. Cu-NPs lie in the mesoporous material category with a diameter in the range of 2-50 nm. The aqueous solution was investigated for the removal of ciprofloxacin (CIP) with green tea-synthesized Cu-NPs. The results showed that ciprofloxacin efficiency depends on initial pH (2.5-10), CIP (2mg/L-15mg / L) dose, temperature (20 ° C-50 ° C); time (0-180 min) and Cu-NP dose (0.1g /L-1g /L). Spherical nanoparticles with an average size of 47nm and a surface area of 1.6562m²/g were synthesized. The batch experiment showed that 92% of CIP 0.01 mg/L were removed at a maximum adsorbent dose of 0.75 g/L, pH 4, 180 min, and an initial 1:1 rate (w / w) of CIP: Cu-NPs. Kinetic adsorption models and ciprofloxacin removal mechanisms were examined. The kinetic analysis showed that adsorption is a physical adsorption system with activation energy of 0.8409 kJ.mol^-1. A pseudo-first-order model is preferred for the kinetic removal after the physically diffusing process due to the low activation energy of 13.221kJ.mol^-1. On the other hand, Langmuir, Freundlich, Temkin, and Dubinin isotherm models were also studied; the equilibrium data were best fitted with Langmuir and Dubinin isotherm models with maximum adsorption capacity of 5.5279, and 1.1069 mg/g, respectively. The thermodynamic values of ∆G⁰ were -0.0166, -0.0691, -4.1084, and -0.7014 kJ/mol at 20, 30, 40, and 50 ° C, respectively. The values of ΔH⁰ and ΔS⁰ were 18.8603 kJ/mol and 0.0652kJ/mol.k, respectively. These values showed spontaneous and endothermic sorption. The presence of the CIP concentration in aqueous media was identified by UV-analysis.