International Journal of Applied Engineering Research ISSN 0973-4562 Volume 15, Number 7 (2020) pp. 730-734 © Research India Publications. http://www.ripublication.com 730 A Review of Natural Zeolites and Their Applications: Environmental and Industrial Perspectives Gilar Wisnu Hardi, Muhammad Artha Jabatsudewa Maras, Yori Rachmia Riva, and Siti Fauziyah Rahman* Program Study of Biomedical Engineering, Department of Electrical Engineering, Faculty of Engineering, Universitas Indonesia, Kampus UI Depok 16424, Indonesia,. Abstract Unique and outstanding physical and chemical properties of zeolite materials make them extremely useful in a variety of applications, including agronomy, ecology, manufacturing, and industrial processes. Zeolites are crystalline hydrated aluminosilicates with physical and chemical properties, including loss and adsorb water and other molecules that act as molecular sieves and substitution of their constituent cations without any structural change. In this review, we summarize the main uses of zeolites in environmental and industrial perspectives, including zeolite as pollutant removal, construction, and catalyst. 1. INTRODUCTION Cronstedt (1756) created the term "zeolite" from the Greek with means "to boil" and "stone", for minerals that remove water when heated [1]. Zeolites have alkali and alkaline earth cations with crystalline hydrated aluminosilicate, open, three- dimensional structure. This is also able to reversibly lose and gain water and exchange extraframework cations, even without altering the structure of crystal. The broad structural cavities and the inlet channels contain water molecules, which form spheres of hydration around exchangeable cations [2]. The general formula for natural zeolites is (Li, Na, K)a(Mg, Ca, Sr, Ba)d[Al(a+2d)Sin-(a+2d)O2n]·mH2O where the part of the square brackets reflects the framework atoms and the part of the extraframework atoms outside the square brackets is cations plus water molecules [1]. Once dehydrated (or "activated"), a zeolitic phase can readsorb not only water, but also gases, vapors, and fluids, particularly if their molecules are polar [1]. Many zeolites naturally occur in volcanic lava flux cavities as mineral and are mined extensively all over the world. Other zeolites are synthetic and for commercial uses or produced for researchers [3]. Zeolites are presented in the hardened lava either during diagenesis due to active geothermal systems in high heat flow areas, during the burial metamorphism of the lava pile, or hydrothermal alteration of the continental basalts [3]. Due to their unique properties, zeolites are used in a variety of applications worldwide. This paper aims to give review regarding the implementation of natural zeolites, especially in the environmental and industrial perspectives. 2. CLASSIFICATION OF NATURAL ZEOLITE Based on the framework structure of the natural zeolites, Gottardi and Galli classified natural zeolites into seven groups [1, 4]. Figure 1 shows the classification and type of natural zeolites. Figure 1: Classification of Zeolite