Implementation of Magnetic Nanostructured Adsorbents for Heavy Metals Separation from Textile Wastewater

In the framework of sustainability, water shortages and water pollution are two important aspects to be considered. Proposing efficient and low-impact technologies is of paramount importance to promote circular economies associated with the use of water in the industrial context, especially in the textile industry. In this work, the application of a set of magnetic nanostructured adsorbents (MNAs) to cleanse metal ions from textile wastewaters was studied and analyzed. MNAs were generated with a low-cost process, involving iron (II/III) salts (e.g., chlorides), sodium or ammonium hydroxide solutions, and graphene oxide, obtained from graphite by a modified Hummers' method at room temperature. The shape and the size were studied with transmission electron microscopy. Adsorbents were tested with different metal ions (e.g., copper, chromium (III), and nickel). Metal ion concentrations were analyzed by means of inductively coupled plasma optical emission spectroscopy (ICP-OES), and adsorption isotherms were characterized. From the results, the MNAs exhibited the capability of removing metal ions up to a yield of 99% for Cr3+, 94.7% for Cu2+, and 91.4% for Ni2+, along with adsorption loads up to 4.56 mg/g of MNAs.