PCDD/F adsorption enhancement over nitrogen-doped biochar: A DFT-D study.

Area of Science:

• Environmental Chemistry
• Materials Science
• Computational Chemistry

Background:

• Polychlorinated dibenzo-p-dioxins/furans (PCDD/F) pose significant environmental and health risks.
• Controlling PCDD/F emissions is crucial, with 2,3,4,7,8-pentachlorodibenzo-p-furan (PeCDF) being a key contributor to toxicity.
• Biochar is explored as a potential adsorbent for PCDD/F, but its efficiency can be improved.

Purpose of the Study:

• To investigate how different nitrogen (N) species enhance the adsorption of 2,3,4,7,8-PeCDF on biochar.
• To provide insights for designing tailored carbon materials for industrial PCDD/F emission control.
• To elucidate the interaction mechanisms between N-doped biochar and PeCDF.

Main Methods:

• Systematic computational investigations using density functional theory (DFT) calculations.
• Analysis of adsorption energy and interaction distances for pristine and N-doped biochar.
• Comparison of adsorption performance with different N doping types (graphitic, pyridinic, pyrrolic) and content.

Main Results:

• Pristine biochar adsorbs 2,3,4,7,8-PeCDF via π-π electron donor-acceptor (EDA) interactions.
• Nitrogen doping significantly enhances PeCDF adsorption on biochar compared to pristine biochar.
• Pyrrolic N-doped biochar exhibits the strongest adsorption, with higher adsorption energy and shorter interaction distance than graphitic and pyridinic N doping.
• Enhanced adsorption is attributed to improved π-π EDA and electrostatic interactions.
• The type of N doping species is more influential than doping content, with pyrrolic N being most efficient.

Conclusions:

• Pyrrolic N-doped biochar is highly effective for adsorbing 2,3,4,7,8-PeCDF, offering superior performance over other N-doped variants.
• The study provides crucial understanding for the application of N-doped biochar in industrial PCDD/F removal.
• N-doping, particularly with pyrrolic N, enhances adsorption capacity and offers a promising strategy for environmental remediation.