Ultrasonic treated dried turmeric leaves powder as biosorbent for enhanced removal of lead from aqueous solutions

ABSTRACT

The present investigation was targeted to remove toxic heavy metal lead (Pb(II)) from synthetic solution with ultra-sonicated turmeric leaves powder (UTLP) as sorbent. The responsible functional groups for adsorption of Pb(II) onto UTLP were investigated using Fourier Transform Infrared (FTIR) spectroscopy, and the adsorption was confirmed by Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray spectroscopy (EDS) analysis. The Central Composite Design (CCD) method was used to scrutinise the effective parameters. Based on the optimisation results, the maximum % biosorption (97.36) of Pb(II) was attained under optimum conditions of pH: 4.92, biosorbent dosage (BD): 0.44 g and initial solution concentration (ISC): 37.93 mg/L. The experimental findings were fitted with Langmuir and Freundlich and Temkin isotherms. Sequel to isotherm data, the Freundlich model gave good fit with R² = 0.99 and a maximum adsorption capacity of 36.49 mg/g. The pseudo-second-order model was found to be the most significant for kinetic data analysis. The thermodynamic parameters such as Gibb’s energy change (∆G⁰), enthalpy change (∆H⁰) and entropy change (∆S⁰) were estimated, and it was found that the process was spontaneous and endothermic in nature. Furthermore, the desorption study was conducted with 0.1 N HNO₃ to estimate the ease of regeneration behaviour of UTLP. Conclusively, the results revealed that UTLP is prominent and cheap biosorbent for removal of Pb(II) from aqueous medium.

KEYWORDS:

• Lead
• polymer
• optimisation
• kinetics
• desorption

Acknowledgments

The authors are very much grateful to Vignan’s Foundation for Science, Technology and Research for providing facilities to carry out the current research towards successful completion.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors.