Selective removal of polycyclic aromatic hydrocarbons (PAHs) from soil washing effluents using biochars produced at different pyrolytic temperatures

• Published in: Bioresource technology 2014-07, Vol.163, p.193-198
• Main Authors: Li, Helian, Qu, Ronghui, Li, Chao, Guo, Weilin, Han, Xuemei, He, Fang, Ma, Yibing, Xing, Baoshan
• Format: Article
• Language: English
• Subjects: Adsorption; Biochar; Biological and medical sciences; Charcoal; Fundamental and applied biological sciences. Psychology; Hot Temperature; PAHs; Polycyclic Aromatic Hydrocarbons - isolation & purification; Selective adsorption; Soil Pollutants - isolation & purification; Soil washing effluents; Surface-Active Agents - chemistry; Surfactant recovery; Triticum aestivum
• ISSN: 0960-8524; 1873-2976
• DOI: 10.1016/j.biortech.2014.04.042

•Pyrolytic temperature influenced wheat straw-derived biochar properties.•Biochars selectively removed PAHs from effluents and recovered Triton X-100.•PAH removal and Triton X-100 loss increased with increasing pyrolytic temperature.•Selective adsorption was PAH property dependent. Wheat straw biochars produced at 400, 600 and 800°C (BC400, BC600 and BC800) were used to selectively adsorb PAHs from soil washing effluents. For soil washing effluents contained Phenanthrene (PHE), Fluoranthene (FLU), Pyrene (PYR) and Triton X-100 (TX100), biochars at 2 (for BC800) or 6gL−1 (for BC400 and BC600) can remove 71.8–98.6% of PAHs while recover more than 87% of TX100. PAH removals increase with increasing biochar dose. However, excess biochar is detrimental to the recovery of surfactant. For a specific biochar dose, PAH removal and TX100 loss increase with increasing pyrolytic temperature. For BC400 and BC600, PAH removal follows the order of PHE>FLU>PYR, while the order is reversed with PYR>FLU>PHE for BC800. Biochars have much higher sorption affinity for PAHs than for TX100. It is therefore suggested that biochar is a good alternative for selective adsorption of PAHs and recovery of TX100 in soil washing process.