Congo red removal by lanthanum-doped bismuth ferrite nanostructures

Phase-pure lanthanum (La)-doped bismuth ferrite (La–BFO) nanostructures with La contents of 0–15% were synthesised by a wet chemical method. The structural, morphological, elemental, and optical characteristics confirmed the phase purity and granular morphology of synthesised La–BFO. Zeta potential indicated a significant increase of surface charge of La–BFO with increasing doping content. The La–BFO nanostructures were used for adsorption of anionic Congo red (CR) from aqueous solution under different physio-chemical conditions. A removal efficiency of 95% was achieved in 135 min. The experimental results suggested that the increasing doping concentration of La increased the adsorption capacity and removal efficiency due to an electrostatic interaction between negatively-charged La–BFO nanostructures and the protonated amine group of CR. The adsorption capacity was strongly influenced by the initial pH of the CR solution. • Wet chemical synthesis of phase pure lanthanum doped bismuth ferrite nanostructures. • Removal efficiency of congo red was studied under different physiological conditions. • The experimental data fitting was done by pseudo-second-order kinetics. • 94% of removal efficiency was achieved within 135 min of contact time under optimized conditions.