Oxygen-rich biochar from torrefaction: A versatile adsorbent for water pollution control

Area of Science:

• Environmental Chemistry
• Materials Science

Background:

• Limited understanding of torrefaction char (TC) for water pollution control compared to pyrochar (PC).
• Need for effective adsorbents for heavy metals like uranium (U(VI)) and organic dyes like methylene blue (MB).

Purpose of the Study:

• To compare the physicochemical properties and adsorption capabilities of TC and PC for U(VI) and MB.
• To investigate the influence of torrefaction atmosphere on TC performance.

Main Methods:

• Characterization of TC and PC physicochemical properties.
• Adsorption experiments to determine U(VI) and MB uptake capacities.
• Analysis of the effect of torrefaction atmosphere (N2, air) on TC.

Main Results:

• TC exhibited higher oxygen content and more oxygen-containing functional groups than PC.
• TC demonstrated significantly higher maximum adsorption capacities for U(VI) (>100 mg/g) and MB (>350 mg/g) compared to PC (56.21 and 192.67 mg/g, respectively).
• Torrefaction atmosphere influenced adsorption: N2-derived TC favored MB removal, while air-derived TC favored U(VI) removal.

Conclusions:

• Torrefaction char is a highly efficient adsorbent for U(VI) and MB, outperforming pyrochar.
• TC offers advantages of lower processing temperature and simpler preparation.
• TC presents a promising, cost-effective solution for water pollution remediation.