Modified Natural Diatomite with Various Additives and Its Environmental Potential

Area of Science:

• Environmental Science
• Materials Science
• Geochemistry

Background:

• Chemical pollution, particularly from heavy metals, poses a significant environmental and health risk.
• Diatomite (DT) is a naturally occurring material with potential for heavy metal immobilization.
• Calcined diatomite may risk releasing heavy metals, necessitating property modification for safer application.

Purpose of the Study:

• To develop a simple, inexpensive, and improved material for heavy metal immobilization.
• To evaluate the efficacy of modifying diatomite with additives like biochar, dolomite, and bentonite.

Main Methods:

• Calcined diatomite was prepared in three grain fractions (0-1 mm, 0-0.5 mm, 5-100 µm).
• Diatomite mixtures were created using 75% diatomite and 25% additives: biochar (BC), dolomite (DL), or bentonite (BN).
• Aqueous extracts were analyzed for heavy metals (Cd, Zn, Pb, Ni) to assess immobilization efficiency and toxicity.

Main Results:

• Enrichment of calcined diatomite with biochar and dolomite significantly reduced or eliminated Cd, Zn, Pb, and Ni in aqueous extracts.
• The specific surface area and additive type were crucial for the immobilization performance.
• Mixtures of diatomite with dolomite and bentonite exhibited the lowest toxicity.

Conclusions:

• Modified diatomite, particularly with dolomite and biochar, offers an effective and less toxic solution for heavy metal immobilization.
• Utilizing locally sourced raw materials for sorbent production reduces costs and environmental impact.
• These findings support the economic viability and environmental benefits of producing high-performance sorbents from modified diatomite.