Coupling magnetite and goethite nanoparticles with sorbent materials for olive mill wastewater remediation

This work aimed at treating OMW by developing an environmentally friendly and cost-effective media capable of removing phenolic compounds upon the interaction between magnetic nanoparticles and sorbent material such as zeolite. Magnetite (Fe3O4) and goethite (FeO(OH)) nanoparticles were prepared using the microemulsion method by using dimethylene-1,2-bis (dodecyl dimethyl ammonium bromide) (CTAB) as a surfactant. The prepared nanoparticles had magnetic properties. X-Ray Diffraction (XRD), and Transmission Electron Microscope (TEM) were used for the structural and morphological characterization. The average crystalline sizes for magnetite and goethite obtained from TEM were 7–16 and 5–14 nm, respectively. The nanocomposite media of magnetite and goethite with zeolite were prepared via coupling natural Jordanian zeolite with magnetic nanoparticles using two approaches; mixing and coating. The adsorption process of phenolic compounds was analyzed by the direct photometric method after treating real samples with nanocomposite media at different conditions. In the batch experiment, the optimum conditions were percent of media to OMW 3%, contact time 3 days, pH of 5, and room temperature. Results revealed that the percent removal of phenolic compounds was 79% and 80% for magnetite/zeolite and goethite/zeolite, respectively using the mixing approach, while with coating approach of magnetite/zeolite, the percentage removal was 75%. A significant improvement of % removal from 61 to 93% was observed with the new composite media of granular activated carbon (GAC) with various percentages to the (Fe3O4, FeO(OH)/zeolite) even at pH of 3.