Synergistic removal of tetracycline and copper (II) by in-situ B-Fe/Ni nanocomposite—A novel and an environmentally sustainable green nanomaterial
Geetha Gopal, Natarajan Chandrasekaran, Amitava Mukherjee
Abstract
Since both antibiotics and heavy metals are regular entities in aquatic environments nowadays, finding an effective strategy for simultaneous removal of both the contaminants has gained importance. In this work clay supported Fe/Ni (B-Fe/Ni) nanocomposite was prepared through an in-situ green synthesis approach and characterized by SEM-EDX, FTIR, XRD, and XPS to confirm the size, surface functional groups, and elemental composition of the composite. The adsorbent was then utilized for simultaneous removal of TC and Cu2+ from aqueous solutions in single and binary modes. In a single system, the B-Fe/Ni (sorbent dosage 1000 mg/L, pH7, TC conc. 60 mg/L, and Cu conc. 1 mg/L) removed 96% and 83% of TC and Cu2+, respectively, while in a binary mode more than 90% of TC and 80% of Cu2+ were removed. This enhanced adsorption efficiency is attributed to the complex formation through TC–Cu2+ bridging and greater affinity of the adsorbent for the TC–Cu2+ complex than TC or Cu2+ individually. TC and Cu2+ were adsorbed to the surface of B-Fe/Ni, and Fe0 in B-Fe/Ni reduced Cu2+ to Cu0 and degraded TC to the smaller molecules. The existence of Fe (II) and Fe (III) in the B-Fe/Ni complexed with the amide of TC and Cu(II) which was confirmed by XPS and FTIR analysis. The reusability study revealed that the TC and Cu2+ removal efficiency was above 60% for TC and 50% for Cu2+ till the third cycle, and validation with the real water samples confirmed above 75% TC and Cu2+ removal. The residual toxicity of B-Fe/Ni interacted TC-Cu2+ solution in freshwater Scenedesmus sp. was significantly lower compared to the untreated one, indicating that the process effectively reduced the environmental toxicity of the pollutants.