Efficient Lead Pb(II) Removal with Chemically Modified Nostoc commune Biomass

Area of Science:

• Environmental Science
• Materials Science
• Biotechnology

Background:

• Heavy metal pollution, particularly lead (Pb(II)), poses significant risks to aquatic ecosystems and human health.
• Conventional methods for lead removal often involve high costs and generate secondary waste.
• Development of efficient, cost-effective, and sustainable biosorbents is crucial for environmental remediation.

Purpose of the Study:

• To prepare and characterize a novel biosorbent from chemically modified Nostoc commune (NCM) cyanobacteria.
• To evaluate the efficacy of NCM for the removal of lead (Pb(II)) from aqueous solutions.
• To investigate the adsorption mechanism, kinetics, thermodynamics, and reusability of the NCM biosorbent.

Main Methods:

• Preparation and chemical modification of Nostoc commune (NC) cyanobacteria using NaOH to form NCM.
• Characterization of NCM using FTIR, SEM/EDX, and point of zero charge (pHPZC) measurements.
• Batch adsorption experiments to determine optimal conditions (pH, biomass dose) and evaluate Pb(II) removal efficiency, adsorption kinetics, and isotherms.

Main Results:

• NCM exhibited a high adsorption capacity for Pb(II) (qe = 384.6 mg g−1), surpassing many reported biosorbents.
• Optimal adsorption was achieved at pH 4.5-5.5 with a biomass dose of 0.5 g L−1.
• Adsorption followed Freundlich isotherm and pseudo-2nd order kinetics, indicating chemisorption on heterogeneous surfaces. The process was exothermic, feasible, and spontaneous. NCM showed high regeneration efficiency (up to 4 cycles) and effective removal from real wastewater.

Conclusions:

• Chemically modified Nostoc commune (NCM) is a highly effective and reusable biosorbent for lead removal from aqueous media.
• The adsorption mechanism involves chemisorption on heterogeneous surfaces, driven by favorable thermodynamic conditions.
• NCM presents a promising sustainable solution for treating lead-contaminated water and industrial wastewater.