Tóm tắt

A novel biochar composite impregnated with α-Fe2O3 in hierarchical porous structures (Fe(III)-ABC-20) was synthesized by means of pyrolysis combining with KOH activation using the yearly bloomed Taihu blue algae as resources. It was found that the biochar activated by KOH obtained the specific surface area of 1657.8 m2 g−1, nearlyrn92.6 times larger than that of the biochar without modification (17.9 m2 g−1). Meanwhile, abundant oxygen-containing functional groups such as eCOOH, eOH, etc. are introduced onto the surface of algae biochar. Besides, Fe(III)rnwas successfully loaded onto the porous structure of biochar from combined characterization of XRD, SEM, TEM, FTIRrnand XPS. Under the optimized operating conditions of pH at 6, Fe(III)-ABC-20 and H2O2 dosage of 0.5 g and 20 mM,rnadsorption equilibrium and Fenton-like reaction time at 20 and 60 min respectively, the biochar composite exhibitedrn98.87% removal rate of chelated nickel in electroplating wastewater. Moreover, the catalyst exerted better stabilityrnafter four repeated experiments, as which still remained 93.26% of nickel removal. Meanwhile, electrochemicalrnmeasurements revealed the presence of ligand to metal charge transfer (LMCT), indicating the promoting of Fentonlike reaction. Noticeably, degradation pathways of N,N,N′,N′-Tetrakis(2-hydroxypropyl) ethylenediamine (EDTP), onernof the main complexing agents according to the component identification using mass spectrum within electroplatingrnwastewater are proposed. EDTP might be first degraded to 2-hydroxypropanal or 2-Aminoethyl(ethyl) amine, thenrnfurther degraded to acetaldehyde or ethylene, and finally oxidized to CO2 and H2O. Therefore, the biochar compositerndeveloped here could provide a novel route for the resource utilization of blue algae and heavy metal removal inrnelectroplating wastewater containing refractory complexing agent.