Enhanced Removal of Pb(II), Paracetamol and Rhodamine B from Aqueous Solutions Using Engineered Low-Cost Tea Waste-Based Magnetic Nanocomposite

The development of engineered biomass-based adsorbents capable of efficiently removing pollutants from aqueous solutions has received tremendous attention due to their cost-effectiveness and renewal potential. Herein, we report a one-pot synthesis of a low-cost magnetic composite (Fe3O4-tea) derived from waste tea and iron oxide magnetic nanoparticles and its application as nanosorbent for the removal of Pb2+, rhodamine B and paracetamol as model pollutants from aqueous solutions. The FTIR, XRD, TGA, BET, TEM and zeta potential studies confirmed the successful synthesis of Fe3O4-tea with an organic content of 54.55 wt.% and a surface area of 25.32 m(2) g(-1). The high saturation magnetization (Ms) of the composite estimated to 45.47 emu g(-1) allows for its effortless separation and recovery from wastewater solutions using a simple bar magnet. Various theoretical models were considered to study and discuss adsorption isotherms and kinetics. The equilibrium kinetics were found to follow a second-order model, regardless of the system investigated. Maximum monolayer adsorption capacities of 113.63, 92.59 and 60.24 mg g(-1) were obtained for Rhodamine B, Pb2+ and paracetamol, respectively. These values are greater than the adsorption capabilities of several conventional and magnetic sorbents reported in the literature, including activated carbon. The adsorption process mechanism was also discussed based on pH studies. The results suggest that the Fe3O4-tea adsorbent shows a great potential for effectively removing heavy metal ions and organic pollutants with a rapid uptake rate and easy magnetic separation.