Adsorption of Safranine-T dye using a waste-based zeolite: Optimization, kinetic and isothermal study.

[Display omitted] • A waste-based Linde Type-A (LTA) zeolite successfully used to remove a cationic dye. • A Composite Central Rotational Design (CCRD) allowed the determination of optimal zeolite dosage and agitation rate. • Efficient removal of Safranine-T dye (>98 %) from colored aqueous solutions. • Nearly quantitative removal achieved with very short contact times. • High potential of aluminum waste-based LTA zeolites for treating textile wastewaters. The global issue of water resource pollution due to wastewater containing dyes is a significant environmental concern. The proper treatment of these harmful wastewaters is a great challenge due to their characteristic structural complexity and low biodegradability. The present work reports the application of a Linde Type-A (LTA) zeolite synthesized from a hazardous aluminum waste as an adsorbent to remediate Safranine-T dye from aqueous solutions. The optimal experimental conditions (agitation rate and zeolite dosage of 147 rpm and 21.5 g/L, respectively) were determined through a central composite rotational design (CCRD), and enabled a removal efficiency of 98.12 % of the textile dye. The model that showed the best fit to the experimental data and better explained the adsorption mechanism, according to the isothermal studies, was the Sips model. The kinetics followed the pseudo-first order model and revealed that Safranine-T dye removal was achieved in a contact time of just one minute. The waste-based LTA zeolite exhibited highly promising adsorbent properties with an efficient and extremely fast adsorption capacity. Its use as a treatment agent for dye-contaminated wastewater can significantly contribute to sustainability and the circular economy. [ABSTRACT FROM AUTHOR]