Removal of Malachite Green Dye from Industrial Wastewater by Using Concrete Modified with Rubber Powder

Abstract

<strong>Background:</strong> In recent years, the need for new methods of water treatment on an industrial scale in order to compensate the shortage of water resources has become imperative. Among different methods, the use of adsorption in order to remove aqueous contaminates, including synthetic dyes, has been so effective.<br /> <strong>Methods:</strong> In this research, removal of malachite green from aqueous solution by concrete modified with rubber powder has been studied. In order to achieve the maximum efficiency of malachite green removal, the impact of different parameters such as initial concentration of malachite green, pH, adsorbent dosage and contact time was studied using batch experimental method.<br /> <strong>Results:</strong> According to the results, optimum conditions of MG removal were pH of 9, initial concentration of 30 ppm, rubber powder dosage of 35% of sand weight, and contact time of 90 min. Results of compressive strength test have shown that compressive strength of concrete with 35 wt.% of rubber powder reduced 84.13% compared to simple concrete. The removal percentage of MG is 98.33% when the surface of concrete is covered by rubber powder. Experimental data corresponded with pseudo-first order equation with R²= 0.93, Langmuir and Freundlich adsorption isotherms with R²= 0.85 and 0.84, respectively. Real waste sample was used to confirm the application of concrete in ordinary conditions of wastewater basin in accordance with optimum conditions of kinetics wastewater. Elimination rate of MG happened in an optimum condition with real samples taken from industrial factory.<br /> <strong>Conclusion:</strong> Concrete modified with rubber powder has potentials for removal of MG dye from wastewater. Covering the concrete surface with rubber powder can be an innovative and useful solution for increasing the rate of elimination of pollutants and contaminants, cost reduction and accelerating the absorption process. Actually, it could be considered as one solution for managing waste rubber.