Phosphate adsorption study employing a synthesized activated carbon derived from banana pseudostem

In recent years, the application of biomass sources as precursors for various materials has been employed as an alternative for waste reuse. The banana pseudostem, being a lignocellulosic residue generated in huge quantities, has been studied for its reuse possibilities. The use of this biomaterial as a pyrolyzed and activated adsorbent compound is a promising application in wastewater treatment. Phosphorus (P), as a macronutrient, must have its concentration controlled in water bodies, as it contributes to the eutrophication process and causes environmental impact, demanding effective control of its release and removal in wastewater. Although some studies have already applied the banana pseudostem in wastewater treatment, its use for phosphorus removal is still scarce. Therefore, this work aimed to produce and characterize the banana pseudostem activated carbon (BPAC) under specific conditions at 600°C for 90 minutes, through chemical activation with zinc chloride at a ratio of 3:1. The results showed a surface area of 996 m² g-1, and the kinetic and adsorption isotherm tests revealed an equilibrium time of 16 hours and a maximum P adsorption capacity of 11.82 mg L-1, respectively. The pseudo-first order kinetics model were better fitted to experimental results, and for the isotherm at 18°C, the Langmuir was better fitted. The pH at the point of zero charge resulted in a value of 7.20, indicating that phosphorus adsorption is better favored near neutrality.