Mesoporous La-substituted nickel-cobalt ferrites synthesized via reduction method resulting in significantly enhanced adsorption properties

Mesoporous La-substituted Ni-Co ferrites, as highly efficient adsorbents for the removal of organic pollutants from water, have been synthesized through the utilization of a modified reduction method. This synthesis involves the use of NaBH 4 (as a reducing agent) and thermal treatment steps, facilitating the creation of mesoporous nanoparticles with an extensively developed surface area and enhanced adsorption properties. The structure, morphology, and textural characteristics of single-phase Ni 0.5 Co 0.5 La x Fe 2- x O 4 samples (where x = 0; 0.02; 0.04; 0.08; 0.12) have been thoroughly investigated using XRD, FTIR, SEM, BET, and TEM analysis. As the La(III) content increased, the crystallite size decreased by 65 %. The surface area of mesoporous samples increased by about 50 % for all La-doped samples and ranges from 83 to 151 m 2 /g. The introduction of La(III) ions into the NCF structure results in the formation of nanorods, elongated and spherical nanoparticles. The synthesized La-substituted ferrites' surface is positively charged, and capable of adsorbing CR dye and OTC molecules. Total surface area, as well as the surface area of the mesopores and the La(III) content, significantly impact the samples' adsorption properties. The 4La–NCF sample demonstrates the highest adsorption capacity (243 mg/g) toward Congo Red dye removal whereas the 12La–NCF possesses the highest adsorption capacity (395 mg/g) toward oxytetracycline molecules. Based on XPS studies the adsorption mechanism was chemosorption. Thus, the utilization of the reductive synthesis method in conjunction with sequential thermal treatment steps, facilitates the generation of mesoporous La-Ni-Co ferrites with a notably enlarged surface area and nanorods, leading to the formation of highly active adsorbents for water treatment. • mesoporous La-substituted nickel-cobalt ferrites have been synthesized. • a modified reductive method results in mesopore formation. • the 4La-NCF sample has shown the highest adsorption capacity for CR removal. • the 12La-NCF has exhibited the highest adsorption capacity for OTC molecules. • mesopores and La(III) content are crucial factors influencing the adsorption.