Application of zeolites in aquaculture industry: a review Zahra Ghasemi 1 , Iman Sourinejad 1,2 , Hossein Kazemian 1,3 and Sohrab Rohani 1 1 Department of Chemical and Biochemical Engineering, University of Western Ontario (UWO), London, ON, Canada 2 Department of Fisheries, Faculty of Marine and Atmospheric Sciences and Technologies, University of Hormozgan, Hormozgan, Iran 3 College of Science and Management, University of Northern British Columbia (UNBC), Prince George, BC, Canada Correspondence Sohrab Rohani, Department of Chemical and Biochemical Engineering, Thompson Engineering Building, Western University (UWO), 1151 Richmond Street, London, Ontario, Canada, N6A 5B9. Email: srohani@uwo.ca and Hossein Kazemian, College of Science and Management, University of Northern British Columbia (UNBC), 3333 University Way, Prince George, BC, Canada V2N 4Z9. Email: hossein.kazemian@unbc.ca; hosseinkazemian@gmail.com Received 27 September 2015; accepted 1 February 2016. Abstract Zeolites are microporous crystalline hydrated aluminosilicates, which have found various applications because of their very unique physicochemical characteristics such as ion exchange and adsorption–desorption properties. Significant progress has been made in recent years on applications of these inorganic adsorbents in different industries including agriculture, aquaculture, water and wastewater treatment, air purification and petrochemicals. This review article intends to sum- marize the published reports on the applications of natural, synthetic and modi- fied zeolites in aquaculture industry. Application of zeolitic materials for water quality improvement of fish farms and fish transportation tanks by selective cap- turing of ammonia and toxic heavy metals and zeolite application as feed additive to enhance fish growth and promote their health and nutritional parameters are the most important discussed areas. According to the technical data that are dis- cussed in this review, natural and synthetic zeolites should be considered as mate- rials with tremendous potential of applications in the aquaculture industry. Considerable amounts of research works are under way to explore other opportu- nities for application of zeolites to benefit aquaculture industry. Key words: ammonia removal, aquaculture, fish, water quality, zeolites. Introduction Most of the world’s capture fisheries are considered fully exploited or overexploited. Aquaculture plays the main role in meeting food fish demand and remains one of the fast- est-growing food producing sectors. Aquaculture provides half of all fish for human food. This share is forecasted to rise to 62% by 2030 as catches from wild capture fisheries will level off (FAO 2014). With population growth, aqua- culture will continue to expand, which means technologies with higher efficiency should be adopted to increase the production. On the other hand, due to concerns regarding detrimental impacts of aquaculture production on the envi- ronment and increased regulations on aquaculture efflu- ents, the aquaculture industry is focused on the development of new methods to minimize the toxic con- taminants in aquaculture waters in recycling systems and wastewaters of aquaculture ponds. Using eco-friendly adsorbents such as natural zeolitic minerals is considered as one of the promising approaches for treating contaminated waters and wastewaters. Schematic illustration of building a zeolite framework by means of connecting tetrahedral ½SiO 4  4 and ½AlO 4  5 via oxygen bridge to form different zeolitic structures (i.e. LTA, faujasite and sodalite) is shown in Figure 1. Zeolites are microporous crystalline hydrated alumi- nosilicates, composed of TO 4 tetrahedra (T = Si, Al) with O atoms connecting neighbouring tetrahedral. Substitution of silicon by aluminium in the zeolite framework leaves a negative framework charge that has to be neutralized by some alkali and/or alkaline earth cations (Querol et al. 2002). These cations are mobile and depending to their size and charge density are preferred by different zeolitic molec- ular sieves; therefore, they can be easily exchanged with other cations in surrounding aqueous environment. Pore size and channel shape are the structural characteristics of a given zeolitic material, which differentiates it from many other porous aluminosilicates. Zeolites have found many industrial and commercial applications because of their particular properties such as ion exchange, adsorption/des- orption and catalysis. Zeolites intercrystalline pores and channels discriminate between molecules of different size, which is known as molecular sieve characteristics. Natural and synthetic zeolites are among the most important © 2016 Wiley Publishing Asia Pty Ltd 1 Reviews in Aquaculture (2016) 0, 1–21 doi: 10.1111/raq.12148