Biosorption of Congo Red from aqueous solution by crab shell residue: a comprehensive study

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Industrial wastewater often contains persistent organic pollutants like Congo Red dye.
• Developing cost-effective and sustainable adsorbents is crucial for effective pollutant removal.
• Bio-waste materials present a viable alternative to conventional adsorbents.

Purpose of the Study:

• To investigate the efficacy of crab shell powder as an adsorbent for Congo Red removal.
• To characterize the adsorbent material and understand the adsorption mechanism.
• To determine the adsorption capacity and process kinetics.

Main Methods:

• Characterization of crab shell powder using SEM, XRD, EDS, and FT-IR.
• Adsorption experiments conducted under varying conditions.
• Analysis of equilibrium, kinetic, and thermodynamic data.
• Application of Langmuir isotherm and pseudo-second-order kinetic models.

Main Results:

• Crab shell powder possesses a rough, porous surface with functional groups attracting pollutants.
• Adsorption is a favorable, spontaneous, and endothermic physical process.
• The maximum adsorption capacity was determined to be 124.9 mg/g.
• Pseudo-second-order kinetics best described the adsorption process.

Conclusions:

• Crab shell powder is an effective and sustainable adsorbent for Congo Red removal.
• The adsorption mechanism involves monolayer coverage and physical adsorption.
• This bio-waste offers a promising solution for industrial wastewater treatment.