Pyrolysis of Biomass Wastes to N-Doped Biochar-Stabilized Co Nanoparticles for Efficient Pollutant Degradation Via Peroxymonosulfate Activation

Abstract

Lignocellulosic biomass wastes can be considered as renewable and abundantly available resources, but it is a big challenge to convert them into valuable products via environmentally friendly and cost-effective approaches. Herein, a facile twostep hydrothermal-pyrolysis method is developed to fully convert the lignocellulosic biomass wastes into N-doped biochar-stabilized Co nanoparticles (Co−N/biochar) and bio-oil enriched with valueadded small compounds. The as-synthesized Co−N/biochar, with uniform N doping and well-dispersed Co nanoparticles, presents favorable activities for activating peroxymonosulfate (PMS) to degrade refractory organic contaminants. The underlying PMS activation and pollutant degradation mechanism is illuminated with free radical quenching experiments and an electron paramagnetic resonance analysis. The nonradical pathway is demonstrated to be dominant in the pollutant degradation with the PMS/Co−N/ biochar system. The singlet oxygen ( 1 O 2 ) generated from PMS activation is identified as the main contribution species for the pollutant degradation process. This work will provide a new approach to fully convert the biomass wastes into bio-oil and functional biochar materials with prominent activities.

MnO2 Nanosheet Nets on Carbon Fiber as Fixed Catalysts for a Highly Efficient, Nonradical Fenton-like Process in Wastewater Refractory Pollutant Treatment

“…This indicates that the Mn species participated in the activation of PMS, consistent with previous studies suggesting that the Mn 4+ /Mn 3+ redox pair can activate PMS to generate ROSs. 2,46,65,66 In Figure 5i, the ratios of lattice oxygen (Mn-O-Mn), adsorbed hydroxyl (Mn-OH), and O V s were found to change during the degradation of TC. The ratio of Mn-O-Mn decreased to 49.5%, while the ratio of O V increased to 23.1%.…”

“…Remarkably, the 3D-MNSN-CF/PMS system exhibited excellent catalytic performance across a wide pH range from 2 to 11, demonstrating its adaptability to various wastewater environments in practical applications. 46,47 Furthermore, the influence of coexisting ions and NOM, including SO 4 2− , Cl − , H 2 PO 4 − , HCO 3 − , and humic acid (HA), was examined (Figure 4b−f). The addition of Cl − enhanced the degradation rate of TC, achieving a k value of 0.55 min −1 at a concentration of 100 mM Cl − .…”

Outlook on Single Atom Catalysts for Persulfate-Based Advanced Oxidation

“…The electronegativities of these elements follow the order: O (χ O = 3.44) > N (χ N = 3.04) > S (χ O = 2.58) > C (χ C = 2.55) > P (χ P = 2.19) > B (χ B = 2.04). Consequently, these atoms can either donate or withdraw electrons from SACs, exerting either synergistic or antagonistic effects. − For example, O-, N-, S-, and B-doping were found to enhance persulfate activation by enhancing the persulfate ion adsorption via Lewis acid–base bonding, faster electron transfer, and/or a combination of these effects. − P-doping instead might scavenge SO 4 •– or • OH, resulting in inhibition of the catalyst activity. , In all these cases, careful synthesis and characterization with changing dopant concentrations and controlled spatial distribution appear as prerequisites for further advancing the discussion on the kinetic benefits.…”

Real-Time Emission, Chemical Properties, and Dynamic Evolution Mechanism of Volatile Organic Compounds during Co-Pyrolysis of Rice Straw and Semi-Bituminous Coal

“…12 Moreover, numerous reactions occur involving the destruction and reorganization of structures during co-pyrolysis of biomass and coal. 16,17 The thermogravimetric characteristics and reaction mechanism of coal and biomass co-pyrolysis are more complicated than those of the single pyrolysis processes of coal or biomass. A synergistic effect is believed to occur during coal and biomass co-pyrolysis, but the characteristics and internal mechanism of this synergistic effect are still unclear.…”

“…For example, the direct co-combustion of coal and biomass is not practical in either industrial boilers or other facilities, due to problems including formation of striated flows, lower combustion and heating transfer efficiencies, increased risks of corrosion, and ash deposition . Moreover, numerous reactions occur involving the destruction and reorganization of structures during co-pyrolysis of biomass and coal. , The thermogravimetric characteristics and reaction mechanism of coal and biomass co-pyrolysis are more complicated than those of the single pyrolysis processes of coal or biomass. A synergistic effect is believed to occur during coal and biomass co-pyrolysis, but the characteristics and internal mechanism of this synergistic effect are still unclear.…”