An efficient phosphorus scavenging from aqueous solution using magnesiothermally modified bio-calcite.

Area of Science:

• Environmental Science
• Materials Science
• Green Chemistry

Background:

• Phosphorus (P) contamination in aquatic environments poses significant ecological risks.
• Developing cost-effective and sustainable sorbent materials for phosphorus removal is crucial.

Purpose of the Study:

• To synthesize and characterize novel green sorbents from waste hen eggshell for phosphorus removal.
• To evaluate the sorption performance and mechanism of modified bio-calcite materials.

Main Methods:

• Bio-calcite (BC) from eggshells was calcined to calcined bio-calcite (CBC).
• BC and CBC were further modified via magnesiothermal treatment to produce modified bio-calcite (MBC) and modified calcined bio-calcite (MCBC).
• Batch experiments were conducted to assess phosphorus sorption efficiency and kinetics.

Main Results:

• Modified bio-calcite materials exhibited enhanced porosity, surface area, and thermal stability compared to pristine BC.
• Langmuir and Freundlich models described phosphorus sorption, with highest predicted capacities for MCBC (43.33 mg/g) and MBC (35.63 mg/g).
• MBC and MCBC achieved 100% phosphorus removal up to 50 mg/L, and pseudo-second-order kinetics indicated rapid sorption, especially for MCBC (4.32 mg/g/min).

Conclusions:

• Waste hen eggshell-derived modified bio-calcite is a promising green sorbent for phosphorus removal.
• Chemisorption, involving the formation of hydroxylapatite and brushite, is the primary mechanism for phosphorus sorption.
• The study demonstrates a sustainable approach to waste valorization for environmental remediation.