Removal of Orthophosphates in Simulated Municipal Wastewater by Adsorption using Activated Carbon from Banana (Musa acuminata balbisiana) Pith Impregnated with Ca2+ from Eggshells

Phosphate pollution in municipal wastewater is a critical environmental issue due to its contribution to eutrophication and associated public health risks. This study investigates the efficacy of activated carbon derived from Saba banana pith, both impregnated with calcium ions (Ca2+) from eggshells (ABPC) and without impregnation (ABP), as adsorbents for the removal of orthophosphate. Characterization of the surface morphology revealed that ABPC exhibited a greater porosity compared to ABP, providing a higher density of active sites for phosphate adsorption. The optimal pH for orthophosphate removal was pH 6 for ABP, achieving a removal efficiency of 38.23 %, and pH 9 for ABPC, with a removal efficiency of 91.11 %. Using an adsorbent dosage of 0.5 g, ABP achieved a maximum phosphate removal efficiency of 37.64 %, while ABPC reached 91.18 %. Adsorption isotherm analysis indicated that the Langmuir model best described the adsorption behavior for both ABP and ABPC, suggesting monolayer adsorption onto a surface with uniform binding sites. Kinetic analysis indicated that the adsorption process aligns with the pseudo-second-order model, suggesting that chemisorption governs the rate-limiting step. The findings demonstrate that ABPC is a highly effective adsorbent for orthophosphate removal, achieving performance levels that meet the guidelines established by DAO 2021-19 for environmental discharge. This study underscores the potential of utilizing biowaste-derived activated carbon for phosphate remediation in wastewater treatment.