Water Purification Using Cost Effective Material Prepared from Agricultural Waste: Kinetics, Isotherms, and Thermodynamic Studies

The usage of agricultural waste-based bio-adsorbents for the removal of environmental pollutants from water is gaining extensive attention. In this paper, carrot residue (CR) (Daucus carota L.) was used for the production of activated carbon (AC) via chemical activation with HNO₃. CR derived activated carbon (CAC) was characterized by various analytical techniques. The Brunauer–Emmett–Teller surface area was found to be 17.76 m² g⁻¹. The efficacy of this AC in adsorbing BrO₃ ⁻ from water samples was studied at time, pH, temperature, and initial BrO₃ ⁻ concentrations by batch studies. The concentration of BrO₃ ⁻ was assessed by ultra-performance liquid chromatography-mass tandem spectrometry. A maximum adsorption capacity of 16.66 mg g⁻¹ at 298 K was obtained from the Langmuir isotherms fit. The kinetic data followed closely the pseudo-first-order rate kinetic model. The thermodynamic study of BrO₃ ⁻ adsorption data showed that the adsorption was feasible, spontaneous, and endothermic in nature. The practical efficacy of CAC was performed for BrO₃ ⁻ removal from tap water as well as bottled water samples.