Enhancing Restoration of Arid Mining Area Using Lignite-Based Superabsorbent Gel

Area of Science:

• Materials Science
• Environmental Science
• Polymer Chemistry

Background:

• Arid mining areas face severe ecological degradation and soil salinization.
• Effective soil conditioners are crucial for ecological restoration in arid regions.
• Lignite humic residue (LHR) offers a low-cost, functional additive for soil improvement.

Purpose of the Study:

• To design and synthesize a high-performance superabsorbent gel for ecological restoration in arid mining areas.
• To enhance the water absorption capacity and mechanical strength of superabsorbent polymers using LHR.
• To evaluate the material's effectiveness in improving soil properties and supporting plant growth in saline conditions.

Main Methods:

• Solution polymerization of acrylic acid (AA) and acrylamide (AM) monomers.
• Incorporation of lignite humic residue (LHR) as a functional additive.
• Crosslinking using N,N'-methylene-bisacrylamide (MBA) and initiation with ammonium persulphate (APS).

Main Results:

• The synthesized LHR-AA-AM gel exhibited high water absorption (522 g·g⁻¹ in distilled water, 65.5 g·g⁻¹ in 0.9% NaCl solution).
• The superabsorbent gel maintained over 81.8% of its capacity after five reabsorption cycles.
• Field trials demonstrated significant improvement in vegetation coverage in treated mining areas.

Conclusions:

• The LHR-based superabsorbent gel is an efficient and economical material for ecological restoration of arid, saline-alkali lands.
• The gel improves soil water retention, enhances the soil microenvironment, and increases plant salt tolerance.
• This technology offers a promising, soil-replacement-free solution for revegetation in degraded arid regions.