Synthesis and Characterization of Engineered Nanobiochar for Enhanced Removal of Excess Fluoride in Water

Abstract

Fluoride contamination in groundwater poses serious public health risks in many developing regions. This study reports the synthesis, characterization, and application of hydrochloric acid (HCl)-engineered corncob-derived nanobiochar for fluoride removal from aqueous solutions. Corncobs were pyrolyzed at 550 °C to produce biochar, mechanically milled to nanoscale dimensions, and chemically activated using 1M HCl. The engineered nanobiochar was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy (SEM), X-ray Diffraction (XRD), and Brunauer–Emmett–Teller (BET) surface area analysis. Batch adsorption experiments were conducted to evaluate the effects of adsorbent dosage, initial fluoride concentration, pH, and contact time. Optimal fluoride removal (80–90%) was achieved at a dosage of 0.8 g L⁻¹, initial fluoride concentration of 6 mg L⁻¹, pH 2, and contact time of 60 minutes. The enhanced performance was attributed to increased surface area, nanoscale porosity, and the introduction of oxygen-containing functional groups following HCl treatment. The results demonstrate that engineered corncob nanobiochar is a low-cost, sustainable, and effective adsorbent for fluoride removal, with strong potential for application in fluoride-endemic regions.