Nickel Hyperaccumulator Biochar as a Ni-Adsorbent and Enhanced Bio-ore

Area of Science:

• Environmental Science
• Biotechnology
• Materials Science

Background:

• Growing demand for nickel necessitates innovative extraction methods.
• Agromining utilizes metal-accumulating plants (hyperaccumulators) to produce bio-ore.
• Biochar can adsorb nickel from wastewater, offering a remediation strategy.

Purpose of the Study:

• To investigate the potential of biochar derived from the nickel-hyperaccumulating plant Odontarrhena chalcidica (syn. Alyssum murale) as a nickel adsorbent.
• To characterize nickel concentration in O. chalcidica biomass and resultant biochars produced at varying pyrolysis temperatures.
• To evaluate the nickel adsorption capacity of O. chalcidica biochar.

Main Methods:

• Cultivation of O. chalcidica on soils with varied nickel concentrations.
• Characterization of plant biomass and biochars synthesized at different pyrolysis temperatures.
• Nickel batch adsorption experiments to determine biochar adsorption capacity.

Main Results:

• Nickel concentration in O. chalcidica increased with soil nickel content, reaching a limit of approximately 23 g Ni kg−1 dry weight.
• Pyrolysis concentrated nickel in biochar, with higher temperatures yielding increased nickel concentrations (max. 87 g Ni kg−1) and surface areas (max. 103 m2/g).
• O. chalcidica biochar demonstrated nickel adsorption performance comparable to established high-performing adsorbents.

Conclusions:

• Biochar synthesized from O. chalcidica biomass is an effective nickel adsorbent.
• This process can yield a nickel-enhanced bio-ore with exceptionally high nickel content, surpassing that of conventional nickel ores.
• The study highlights a sustainable approach for nickel recovery and wastewater remediation.