Journal of Environmental Biology

Effective and sustainable fluoride removal from aqueous solutions using chemically functionalized biochar and pellet based column system

M.M. Girkar^1,2, S.P. Shukla¹*, S. Kumar¹, K. Kumar¹, V.S. Bharti¹, G.R. Bhuvaneshwari³, S.S. Gangan⁴, S.W. Belsare² and S.N. Kunjir⁵     

¹Aquatic Environment & Health Management Division, ICAR-Central Institute of Fisheries Education, Mumbai- 400 061, India

²Department of Aquatic Environment Management, Maharashtra Animal and Fishery Sciences University, Nagpur, 440 001, India

³Mariculture Division, ICAR-CMFRI, Vizhinjam Regional Centre, Thiruvananthapuram-695 001, India

⁴Department of Fisheries Resource Management, Taraporevala Marine Biological Research Station, Mumbai- 400 051, India

⁵Department of Fisheries Extension, Economics & Statistics, Maharashtra Animal and Fishery Sciences University, Nagpur-440 001, India

Received: 25 January 2025                   Revised: 23 April 2025                   Accepted: 15 October 2025

*Corresponding Author Email : spshukla@cife.edu.in                  *ORCiD: https://orcid.org/0000-0002-8908-8701

Abstract

Aim: This study aims to assess the fluoride-removal performance of a unique column-bed prototype designed for water treatment.

Methodology: In batch and column study, the efficacy of the adsorbent chemically functionalized sugarcane bagasse biochar (FSB) in fluoride removal (water spiked with sodium fluoride) was examined under diverse conditions. The adsorption process was analyzed by the Langmuir and Freundlich isotherms, while the kinetics was examined using the pseudo-first and pseudo-second-order models. The column bed, prepared from low-cost pellets of Plaster of Paris, bagasse filaments, and FSB, was tested under varying flow rates, bed heights, and electric charges.

Results: Optimal fluoride removal (78.6%) was achieved at 60 min contact, 150 mg 100 ml^-1 adsorbent, 5.0 mg l^-1 fluoride, 120 rpm agitation, and pH 5.0. Adsorption followed the Freundlich model and pseudo-second-order kinetics, indicating chemisorption, while column studies showed improved removal with increased bed height and lower flow velocity.

Interpretation: This study introduces a novel column-bed reactor design for fluoride removal, employing pelleted FSB packing material as a unique approach to enhance efficiency.

Key words: Adsorption, Chemically functionalized biochar, Column study, Fluoride, Sugarcane bagasse

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