Synthesis of Co3O4@SiO2 Core/Shell-Nylon 6 Magnetic Nanocomposite as an Adsorbent for Removal of Congo Red from Wastewater

In this paper, a Co3O4@SiO2 core-shell magnetic nanoparticle-nylon-6 (CSMN6) was synthesized for the first time and used for the elimination of Congo red dye from wastewater samples. The morphology and the structure of the prepared CSMN6 were studied completely and its adsorption behavior vs. Congo red dye has been investigated. The sorption performance was evaluated using batch studies at room temperature, at varying operating conditions such as solution pH, sorbent dosage, initial dye concentration and contact time. It has been found that the Elovich kinetics model and Langmuir isotherm can describe this process adequately and a maximum adsorption rate of 138.9 mg g(-1) is obtained which may be illustrated by homogeneous physical and chemical adsorption of Congo red on the surface of the adsorbent. Through this process of adsorption with the adsorbent dose of 1.4 g l(-1), more than 86% of the Congo red dye from a solution with the concentration of 50 mg L-1 was eliminated. The saturation magnetization of CSMN6 was 7.8 emu g(-1) and shows paramagnetic properties and could be isolated from the environment using an exterior magnet. The higher temperature was more suitable for the elimination of the Congo red dye. Also, intraparticle rate constant computed for Congo red was 4.87 mg g(-1) min(-1/2) that indicates higher tendency of CSMN6 to remove Congo red from aqueous solutions. The used CSMN6 can be recovered simply by using ethanol and utilized again for eliminating Congo red dye from contaminated water. In these reusing processes, a high yield of 76% may be obtained up to 5 recovery cycles. These results demonstrate that CSMN6 is a considerable candidate for water treatment processes with high effective and repeatable performance.