Phosphates in wastewater at elevated concentrations cause eutrophication of water\nbodies and their removal from treated wastewater is essential before effluents are discharged to the\nenvironment. Phosphates are predominately removed during wastewater treatment by chemical\nprecipitation which is usually expensive and has a significant environmental footprint. The purpose\nof this study was to investigate the effectiveness of waste recycled bricks as adsorbent for phosphate\nremoval during wastewater treatment. The kinetics, isotherms, and thermodynamics of adsorption\nwere investigated to establish the mechanisms of adsorption. The results showed that adsorption\ncapacities increased with an increase in contact time, adsorbent dosage, and initial phosphate\nconcentration. The kinetic study indicated that adsorption was governed by several mechanisms with\nvarious processes dominating different stages of the adsorption. The adsorption process was better\nrepresented by the pseudo-second-order kinetics and the Langmuir isotherm adequately described\nthe adsorption of phosphates onto brick particles with a maximum adsorption capacity of 5.35 mg/g.\nThe thermodynamic studies showed that the adsorption process was exothermic and proceeded\nspontaneously, demonstrating that waste bricks can be used as a sustainable alternative for the\neffective removal of phosphates from wastewater.
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