Adsorption of basic dye from wastewater using raw and activated red mud

Area of Science:

• Environmental Chemistry
• Materials Science
• Industrial Chemistry

Background:

• Red mud is a major industrial waste from bauxite processing.
• Effective and low-cost adsorbents are needed for industrial wastewater treatment.
• Methylene blue is a common model pollutant in dye-contaminated water.

Purpose of the Study:

• To investigate the potential of treated red mud as an adsorbent for methylene blue removal.
• To optimize adsorption conditions and understand the adsorption mechanism.
• To evaluate the adsorption isotherm and kinetic models for methylene blue adsorption onto red mud.

Main Methods:

• Red mud was chemically and thermally treated.
• Batch adsorption experiments were conducted varying contact time, adsorbent dose, pH, temperature, and initial dye concentration.
• Adsorption data were fitted to Freundlich, Temkin, and Dubinin-Radushkevich isotherm models.
• Adsorption kinetics were analyzed using pseudo-first order, pseudo-second order, intraparticle diffusion, and Elovich models.

Main Results:

• Treated red mud demonstrated effective methylene blue adsorption from aqueous solutions.
• The Dubinin-Radushkevich model best described the adsorption isotherm data.
• The pseudo-second order kinetic model provided the best fit for the adsorption rate data.
• Adsorption was influenced by contact time, adsorbent dose, pH, temperature, and initial dye concentration.

Conclusions:

• Treated red mud is a promising, inexpensive adsorbent for methylene blue removal.
• The adsorption process follows pseudo-second order kinetics and is best described by the Dubinin-Radushkevich isotherm.
• Red mud offers a sustainable solution for treating dye-contaminated industrial wastewater.