Magnetic porous biochar with nanostructure surface derived from penicillin fermentation dregs pyrolysis with K2FeO4 activation: Characterization and application in penicillin adsorption.

Magnetic porous biochars (MCHCl, MCHAc) with nanostructure on surfaces were prepared from penicillin fermentation dregs by pyrolysis with K2FeO4 activation and used in penicillin adsorption. MCHCl and MCHAc had high BET surface areas of 672 and 735 m2/g, respectively; mainly be attributed to the activation of K2FeO4 as well as acid pickling. Saturation magnetizations of MCHCl and MCHAc were 75.29 and 42.45 emu/g, respectively; the magnetism was mainly derived from the Fe3O4 and Fe3C in magnetic biochars. MCHCl had nano sticks of ~ 80 nm and MCHAc had petal-like slice of ~ 30 nm on surfaces. The maximum adsorption capacities of penicillin on MCHCl and MCHAc were 196 and 322 mg/g at 308 K, respectively. The adsorptions of penicillin on MCHCl and MCHAc were consistent with pseudo primary kinetics and the Langmuir adsorption isotherm model, and thermodynamic analysis indicated that the adsorption mechanism included physical and chemical adsorption.