Competitive heavy metal adsorption on pinecone shells: Mathematical modelling of fixed-bed column and surface...

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Industrial effluents pose significant environmental risks due to heavy metal contamination.
• Effective and sustainable methods for heavy metal removal are crucial for environmental protection.
• Biosorbents offer a cost-effective and eco-friendly alternative to conventional wastewater treatment methods.

Purpose of the Study:

• To evaluate pinecone shells as a biosorbent for removing multiple heavy metal ions from aqueous solutions in a fixed-bed column.
• To investigate the influence of operational parameters on biosorption efficiency.
• To understand the adsorption mechanism and assess the regeneration potential of the biosorbent.

Main Methods:

• Fixed-bed column experiments were conducted using pinecone shells as the biosorbent.
• Influent concentration, bed height, and flow rate were varied to optimize removal efficiency.
• Adsorption data was analyzed using the Sips model to elucidate the adsorption mechanism.
• Fourier Transform Infrared (FTIR) and X-ray Diffraction (XRD) were used for characterization.
• Regeneration studies were performed using hydrochloric acid solutions.

Main Results:

• Pinecone shells demonstrated high adsorption capacities for lead (Pb(II)) at 66 mg/g and copper (Cu(II)) at 11.1 mg/g.
• The Sips model accurately described breakthrough data, indicating a surface complexation mechanism.
• The metal uptake sequence in multimetal solutions was Pb(II) > Cu(II) > Cadmium (Cd(II)).
• Carboxyl and hydroxyl functional groups on pinecone shells were identified as key interaction sites.
• The biosorbent showed effective regeneration capabilities with hydrochloric acid.

Conclusions:

• Pinecone shells are a cost-effective and efficient biosorbent for removing toxic heavy metals from industrial wastewater.
• The fixed-bed column system utilizing pinecone shells is applicable for real-world environmental remediation.
• Surface complexation is the primary mechanism for heavy metal adsorption by pinecone shells.
• Regeneration of the biosorbent enhances its economic viability and sustainability for wastewater treatment.