Development of Pistachio Shell-Based Bioadsorbents Through Pyrolysis for CO₂ Capture and H₂S Removal

Area of Science:

• Environmental Science
• Materials Science
• Chemical Engineering

Background:

• Sustainable waste management is crucial for environmental remediation.
• Biochar from agricultural waste shows promise as an adsorbent for gas pollutants.
• Pistachio shell-derived biochar is explored for CO2 and H2S capture.

Purpose of the Study:

• To produce and activate biochar from pistachio shells for CO2 and H2S adsorption.
• To investigate the impact of chemical (KOH) and physical (CO2) activation on biochar properties and adsorption performance.
• To evaluate adsorption kinetics and the influence of moisture on H2S capture.

Main Methods:

• Biochar production via pyrolysis of pistachio shells.
• Chemical activation using KOH and physical activation using CO2.
• Adsorption studies to determine CO2 and H2S uptake capacities and kinetic modeling.

Main Results:

• Chemical activation with KOH significantly increased specific surface area (531 m2/g) and microporosity.
• Chemically activated biochar achieved adsorption capacities of 87 mgCO2/g and 9.6 mgH2S/g.
• The Avrami model best described CO2 adsorption kinetics; moisture enhanced H2S capture, particularly with chemically activated biochar.

Conclusions:

• Chemically activated pistachio shell biochar is a highly effective adsorbent for CO2 and H2S.
• Enhanced microporosity and active sites contribute to superior adsorption performance.
• Moisture plays a beneficial role in H2S adsorption by facilitating dissociation on activated biochar.