A review on activation methods of date seeds for removal of pollutants from water

Abstract

There has been an increase in nitrate levels in water bodies, posing a significant environmental and public health problem due to runoff from agriculture and the discharge of industrial effluents. Adsorption using low-cost adsorbents, such as agricultural wastes, is a cost-effective and efficient process. Among available agricultural wastes, date seeds have attracted significant attention due to their characteristics, including high carbon content, a highly reactive surface, and porous nature. This review critically examines the various activation techniques available to enhance adsorption efficiency. Physical (thermal, steam, and carbon dioxide) and chemical (acid, base, and salt impregnation) activation methods are examined in detail, with emphasis on parameters such as pore evolution, surface area, and functional group development. The review also discusses the operational conditions that influence nitrate adsorption, the efficiency of activated date seed adsorbents, and the mechanisms involved in the adsorption process. The review further examines the effects of adsorption parameters (pH, contact time, adsorbent dose, temperature, and initial nitrate concentration) on activated carbon adsorption. The results demonstrate the potency of activated date seeds as a green, economical, and eco-friendly material for water treatment applications.