Banana Peel Powder as an Effective Multilayer Adsorbent of Ammonium Ions

The recovery of ammonium ions or ammonia from wastewater using bioadsorbents offers an attractive sustainable route to nitrogen reuse and environmental remediation. In this work, we have studied the ability of banana peel powder (BNPP) for adsorption of ammonium ions. The prepared BNPP was characterized by Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy-dispersive X-ray spectroscopy, and thermogravimetric analysis. Structural and morphological features of BNPP were connected to the observed NH<inf>4</inf>⁺adsorption. The adsorption kinetics was found to fulfil pseudo-first-order and pseudo-second-order models while adsorption isotherms were fit adequately by Langmuir and Freundlich models. Accordingly, the adsorption of NH<inf>4</inf>⁺on BNPP is predominantly controlled by physical adsorption that enables chemisorption in a time-bound manner. The maximum adsorption capacity of BNPP was 34.48 mg/g and is superior to several prominent biomass candidates that have been reported for adsorption of NH<inf>4</inf>⁺. BNPP was also deployed on artificial urine, and the results suggest that it is an attractive bioadsorbent for harvesting nitrogen from liquid waste.