Carboxylic acid-based fuel mediated sustainable one-pot fabrication of CaFe2O4 with enhanced adsorptive elimination of hazardous dye

Abstract

The present work successfully demonstrated the morphological variation of CaFe₂O₄ (CFO) concerning various fuels (carboxylic acid groups contain compounds) using a one-step combustion technique. The SEM analysis of the CFO suggests the formation of sharp-edge rocky crystals to highly agglomerated porous clumps concerning the role of fuel. The x-ray diffraction analysis suggests that all samples of CFO are nanocrystalline orthorhombic structure constituted <50 nm. The BET and EDX analysis discloses that CFO s surface area and element composition is highly depend on the fuel molecule (reducer). The CFO performs efficacious in the adsorptive removal of hazardous dye Acid Fuchsin (AF) from an aqueous medium in a slightly acidic environment (pH 6). The AF removal was engaged with the batch adsorption method and optimized the process’s essential parameters (amount of adsorbent, initial AF concentration, and time) were optimized to achieve the utmost efficiency. The AF adsorption was well described by the Langmuir isotherm with outstanding adsorption capacity in the order of CFO-OA (Oxalic acid) (866) < CFO-TA (Tartaric acid) (1063) < CFO-CA (Citric acid) (1504) < CFO-MA (Malonic acid) (1656 mg/g). The adsorption energies were estimated from the Dubinin-Radushkevich model, indicating that adsorption occurs via the chemical process. The pseudo-second-order (PSO) kinetic model was better at explaining the uptake of AF, and the Intraparticle diffusion model indicated that pore diffusion was the rate-controlling step. The reusability test shows that the CFO has high efficiency up to five regeneration cycles. Thus, the work suggests that CFO could be an eco-friendly, cost-effective alternative adsorbent for wastewater treatment.