Low-cost zeolite X as a high-efficiency adsorbent for malachite green removal from aqueous solutions

This research investigates the preparation of a zeolite X (Z-X), its deep characterization by using various analytical techniques, and its ability in adsorbing a typical dye malachite green (MG) from aqueous solutions under wide batch experimental conditions. The physicochemical characterization reveals that Z-X is a highly crystalline and pure faujasite-type material. It has a polyhedral morphology and a well-developed texture with an enhanced surface area (313.8 m 2 · g - 1 ). Adsorption tests show that MG removal from aqueous solutions is rapid and significantly increases with increasing the solution’s pH, the MG initial concentration, and the adsorbent dose. The highest MG removal capability is evaluated to be 166.7 mg · g - 1 at a temperature of 10 °C and exceeds those of various engineered materials. Moreover, the MG removal is found to be spontaneous, exothermic, and mainly governed by physical mechanisms. The cost of adsorbent preparation and application for MG removal and Z-X regeneration is evaluated to be 9.24 USD · kg - 1 , which represents an attractive price in comparison with various available synthetic adsorbents. All these results show that Z-X can be considered a cost-effective material for the removal of dyes from industrial effluents.