Na–X Zeolite Synthesis Using the Response Surface Methodology Design of an Experimental Method for Atmospheric Water Harvesting

Abstract

Currently, obtaining clean water requires expenditures on fossil fuels and water purification costs. In recent years, due to the excessive expansion of CO2 gas, which has caused climate warming, much attention has been given to the use of renewable energy in the production of fresh water. Since air contains a significant amount of fresh water in the form of moisture, adsorption‐based atmospheric water harvesting is considered an efficient strategy for water production. In this method, at night, air humidity is adsorbed by an adsorbent material, and during the day, evaporated using solar energy and stored. Na–X zeolite has a high moisture adsorption capacity at low relative humidity (RH) due to the bonding and arrangement of tetrahedral silicate and aluminate ions. In the current research, it is aimed to optimize the synthesis conditions of Na–X zeolite materials to adsorb more moisture. The optimization is achieved via the response surface methodology method of the design of experiment. Powder with optimal properties (DOE) is obtained with a specific surface area of 688.45 m2 g−1, a total pore volume of 0.45 cm3 g−1, and an average pore diameter of 2.06 nm; this material adsorbs moisture up to 31.7% of its weight at 20% RH.