Studies on biosorbent developed from Rohu fish scales waste for defluoridation of water

ABSTRACT

Development of waste-derived biosorbent for fluoride reduction is gaining wider interest to achieve sustainable and cost-effective water treatment. Biosorbent from Rohu fish scales waste produced from the fish market is developed for defluoridation of water. The morphological characteristics of the sorbent surface were analysed by BET, SEM, and EDAX analysis. Sorption experiments were performed in batch mode to estimate the equilibrium, kinetic and thermodynamic parameters. The equilibrium analysis indicates the sorption capacity increases linearly with the concentration of adsorbate ions and follows Freundlich isotherm. Fluoride uptake capacity of 2.972 mg/g with maximum fluoride removal of 92.12% was obtained at optimum values of process parameters: adsorbate initial concentration of 5 mg/L, pH 3, agitation rate of 150 rpm, mixing period of 90 min, temperature 303 K, and dose of 6 g/L. The E value (2.236 kJ/mol) obtained from the DR isotherm suggests the physisorption mechanism for fluoride sorption. The kinetic study indicates that fluoride sorption follows the second-order kinetic model. Thermodynamic parameters ∆H = −14.72 kJ/mol and ∆S = 0.049 kJ/mol which indicates the spontaneous and exothermic sorption nature of adsorption for fluoride reduction using fish scales sorbent. The reuse and regeneration of the exhausted Rohu fish scales sorbent was performed with 0.1 N NaOH to explore the possibility of reuse and found that it could be effectively reused up to six cycles with about 80% regeneration. The study to check practical applicability of defluoridation of field water using Rohu fish scales adsorbent indicates the adsorbent significantly reduced the fluoride.

KEYWORDS:

• Fish scales waste
• defluoridation
• regeneration
• adsorption
• kinetics and isotherms
• thermodynamics

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability statement

Due to the nature of this research, participants of this study did not agree for their data to be shared publicly, So supporting data is not available. The research is did not receieve any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Additional information

Funding

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