Activated carbon loaded with Ni-Co-S nanoparticle for superior adsorption capacity of antibiotics and dye from wastewater: Kinetics and isotherms

Abstract

Activated carbon (AC) was synthesized using inexpensive rice husk and was subsequently loaded with Ni-Co-S (NCS) nanoparticle by a simple and efficient method with very high adsorption capacity. The NCS nanoparticles were well incorporated on the AC surface via the reactions of metal precursors with thioacetamide at low temperatures. The complete formation and distribution of NCS nanoparticles on the surface of AC have been analyzed and explained via different analytical techniques such as XRD, FESEM, EDX, HRTEM, and XPS. The thermal stability of activated carbon loaded with Ni-Co-S nanoparticle (AC-NCS) was increased, and the size of NCS nanoparticle was decreased upon using the AC. Further, the adsorption property was investigated through adsorption kinetics, adsorption isotherms, and thermodynamics parameters. The maximum adsorption capacity (Qmax) of adsorbent was displayed as 2825.67 mg g−1 for Congo red, 962.21 mg g−1 for tetracycline, and 744.70 mg g−1 for ciprofloxacin. Moreover, the importance and role of the AC were examined by a comparative adsorption study with and without the loading of NCS nanoparticle. The adsorption capacities of AC-NCS was substantially enhanced for the dye and antibiotics in comparison to the unloaded AC and NCS. The adsorption studies confirmed that adsorption of adsorbates takes place via the formation of hydrogen bonding, π-π interactions and metal coordination between adsorbent and pollutants. Recyclability test and adsorption of pollutants in synthetic effluents illustrated the sustainability of AC-NCS adsorbent. Overall results suggested that AC-NCS is a prominent adsorbent for efficient removal of both dye and antibiotics present in the polluted water.