Rice Husk Cellulose-Based Adsorbent to Extract Rare Metals: Preparing and Properties

Area of Science:

• Materials Science
• Hydrometallurgy
• Environmental Chemistry

Background:

• Adsorption is crucial in rare metal hydrometallurgy.
• Sorbent quality significantly impacts adsorption efficiency.
• Developing effective sorbents for rare metals is essential.

Purpose of the Study:

• To create an activated sorbent from rice husk cellulose.
• To extract rhenium (Re) from aqueous solutions using the novel sorbent.

Main Methods:

• Rice husk cellulose was treated with NaOH and nitric acid.
• Cellulose was carbonized at 600°C and activated using physical, chemical, and combined methods.
• Characterization included IR, SEM, TA, TPD-MS, and XRD; adsorption was modeled using the Freundlich equation.

Main Results:

• Kürschner and Hoffer cellulose retained structural integrity and lacked lignin.
• The best sorbent, KHC4-600VA, exhibited superior textural properties (S=~1200 m²·g⁻¹, V=1.22 cm³·g⁻¹, R=2.05 nm).
• KHC4-600VA achieved 90% recovery of Re(VII) ions, with favorable sorption on its heterogeneous surface.

Conclusions:

• Activated cellulose derived from rice husk is a promising sorbent for rhenium extraction.
• The KHC4-600VA sorbent demonstrates high efficiency and favorable adsorption characteristics.
• This research contributes to sustainable hydrometallurgical processes for rare metals.