Magnetic polymer composite for removal of dyes and pharmaceuticals from water: A study of involvement of different adsorption process

With the assumption that composites exhibit better absorptivity, and better stability, magnetite@chitosan composite (MNP@CT) was fabricated to evaluate its adsorptive behavior towards two different classes of pollutants: tetracycline (TTC) and Eriochrome Black-T (EBT) from wastewater. A study of its adsorptivity under identical conditions revealed higher EBT removal rates but TTC lower removal when compared to its pristine counterparts (EBT: 86%; TTC: 62%) as compared to that for MNP (EBT: 40%; TTC: 73%) and that for CT (EBT: 93%; TTC: 42%). Detailed characterization studies revealed that MNP@CT showed a dispersed nano-rod type particle with low crystallinity as compared to the highly crystalline, aggregated spherical MNP. While the surface functionality was enhanced, the particle surface area, mesoporosity, total pore volume and magnetization showed a decrease in the composite as compared to that for MNP. Thus, different adsorption processes may have been operative: high surface functionality contributing to high EBT removals whereas, lower porosity accounted for reduced uptake of TTC. A significant removal of EBT (76%) and TTC (61%) as well as >30% BOD and COD removal from simulated wastewater revealed the potential of the composite for real wastewater applications.