Organic pollutants removal by phosphoric acid modified biochar from residue of Inonotus obliquus

Herbal medicine is used widely, and the residues increase rapidly. Biochar preparation from the residues is a potential way to treat wastes with wastes. Inonotus obliquus (IO) is a natural porous fungus and is famous for its hypoglycemic effect. The residues of Inonotus obliquus (IOR) are potential raw materials for biochar because of their porous structure. P-IORBC and Zn-IORBC, activated by H3PO4 and ZnCl2 respectively, were prepared from IOR. The distinct properties of P-IORBC and Zn-IORBC were shown in the study. P-IORBC was optimized by response surface method (RSM), and the optimized parameters of P-IORBC preparation were 166 min (pyrolysis time), 374 °C (pyrolysis temperature), and 3.91 (the mass ratio of H3PO4 to IOR). The actual methylene blue (MB) adsorption (951.56 mg/g) was near the predicted value (971.00 mg/g), indicating the reliability of the response surface model. Zn-IORBC has a larger pore volume and pore size, while P-IORBC has a larger specific surface area. The specific surface areas of Zn-IORBC and P-IORBC were 1676.78 and 2014.51 m2/g, respectively. Compared to Zn-IORBC, the pyrolysis temperature of P-IORBC was reduced from 547 °C to 374 °C. The tetracycline (TC) adsorption for P-IORBC and Zn-IORBC was 1515.46 mg/g and 1033.66 mg/g. P-IORBC was more effective at the adsorption of cationic dyes than Zn-IORBC. In general, P-IORBC had more potential due to its high yield and environmentally friendly characteristics. The data provides a reference for biochar preparation from residues of herbal medicine.