Studies on selenite adsorption using manganese nodule leached residues

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Industrial effluents pose environmental risks due to contaminants like selenite.
• Developing efficient and cost-effective adsorbents is crucial for wastewater treatment.
• Manganese nodule leached residues (WMNLR) represent a potential low-cost adsorbent material.

Purpose of the Study:

• To investigate the efficacy of water-washed manganese nodule leached residues (WMNLR) for selenite adsorption.
• To characterize WMNLR and understand the factors influencing selenite adsorption.
• To evaluate the thermodynamic and kinetic aspects of the adsorption process for industrial effluent detoxification.

Main Methods:

• Characterization of WMNLR using XRD, FTIR, TG-DTA, BET surface area analysis, and chemical analyses.
• Systematic study of selenite adsorption as a function of time, pH, temperature, and concentrations.
• Analysis of adsorption data using thermodynamic parameters and kinetic models (second-order kinetics).

Main Results:

• WMNLR was thoroughly characterized, revealing its surface properties relevant to adsorption.
• Adsorption capacity increased with temperature, indicating an endothermic process.
• The adsorption process was found to be spontaneous and followed second-order kinetics, with a maximum capacity of 54.6 mg g⁻¹.

Conclusions:

• WMNLR is an effective adsorbent for selenite removal from aqueous solutions.
• The adsorption process is spontaneous, endothermic, and follows second-order kinetics.
• WMNLR shows significant potential for detoxifying industrial effluents containing selenite prior to environmental disposal.