Algal Foams Applied in Fixed-Bed Process for Lead(II) Removal Using Recirculation or One-Pass Modes

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Brown algae incorporation into biopolymer materials for metal sorption is established.
• Direct utilization of algal biomass for foam preparation represents a novel approach.

Purpose of the Study:

• To prepare and evaluate porous foams from algal biomass (AB) and alginate for lead(II) (Pb(II)) sorption.
• To investigate the performance of these foams in both batch (recirculation) and continuous (one-pass fixed-bed) systems.
• To assess foam reusability and the impact of competing ions (Cu(II)) on Pb(II) removal.

Main Methods:

• Ionotropic gelation was used to prepare macroporous foam discs from AB (Laminaria digitata) and alginate.
• Sorption isotherms (Langmuir) and kinetics (pseudo-second order) were determined in recirculation mode.
• Fixed-bed column studies (one-pass mode) evaluated flow rate, feed concentration, and bed height effects.
• Regeneration cycles and binary metal ion (Pb(II)/Cu(II)) competition were analyzed.

Main Results:

• Both AB and alginate foams exhibited good Pb(II) sorption, fitting Langmuir isotherms and pseudo-second order kinetics.
• Foams demonstrated feasibility for reuse over 9 cycles with minimal mass loss.
• In one-pass mode, AB foams showed less sensitivity to flow rate compared to alginate foams.
• Foams preferred Pb(II) over Cu(II) but lacked complete selectivity in binary solutions.

Conclusions:

• Directly prepared algal biomass foams are effective sorbents for Pb(II) removal.
• The developed foams offer a reusable and potentially scalable solution for metal ion remediation.
• Algal biomass foams present a promising alternative to alginate foams for water treatment applications.