Adsorption of Ammonia from Aqueous Solutions by Using Activated Iron Scraps Particles

Ammonia contamination in aquatic environments has become a major ecological and health concern.This study investigates the use of industrial iron waste, a low-cost and readily available material, as an adsorbent for removing ammonia from polluted water.Laboratory experiments were conducted to evaluate the effects of four key parameters: solution pH, contact time, adsorbent dosage, and initial ammonium concentration.Optimization was performed using Response Surface Methodology (RSM) in Design-Expert 7.1.6,and ANOVA confirmed that all variables significantly influenced adsorption efficiency.Surface characterization before and after activation revealed physicochemical enhancements.Adsorption equilibrium data were fitted to Langmuir and Freundlich isotherms.The Langmuir model showed a superior fit (R = 0.97), indicating monolayer adsorption with a maximum capacity of 13.6 mg/g, while Freundlich results (R = 0.94) also supported favorable multilayer adsorption.The study achieved high removal efficiencies of up to 94% under optimized conditions, underscoring the potential of industrial iron waste as an effective and sustainable adsorbent.Its low cost, ease of activation, and local abundance make it a promising candidate for scalable water treatment applications, particularly in resource-constrained areas.