Natural and Modified Zeolites as Adsorbents for Nitrogen and Phosphorus Control in Eutrophic Freshwater Bodies: A Comprehensive Review on Freshwater Applications of the Last 10 Years

Abstract

Eutrophication of freshwater bodies is primarily caused by excessive nitrogen and phosphorus, resulting in significant environmental challenges, including harmful algal blooms and hypoxia. This review examines the potential for natural and modified zeolites to act as adsorbents and regulate nutrient concentrations in eutrophic freshwater ecosystems, excluding applications for wastewater or industrial water effluents. Natural zeolites are effective adsorbents of ammonium, whereas modified zeolites (with aluminum, iron, calcium, and many others) have been noted to have enhanced phosphate adsorption and a higher overall nutrient removal efficiency. The application of modified zeolites for controlling eutrophication in freshwater bodies has proven to have high efficiency in adsorbing nitrogen and phosphorus, resulting in reduced nutrient release from sediments and improved water quality in shallow lakes and reservoirs. This review describes the adsorption mechanisms and modification methods, with an appreciation for the multifunctional role of zeolites in nutrient immobilization and capping sediments. Finally, it presents the potential to use zeolite-based materials in eutrophic freshwater restoration through sustainable circular economy approaches. Zeolite materials present ample environmental applications for cost-effective and targeted mitigation approaches to freshwater eutrophication.