Green and large-scale production of ammonia:Laser-driven pyrolysis of nitrogen-enriched biomass

As a vital chemical,ammonia(NH3)plays an irreplaceable role in many fields such as chemical synthesis and energy storage.Green renewable biomass can be converted into biofuels,but its nitrogen resources are underused throughout.Laser-driven pyrolysis is envisaged to debuts as a bridge to connect them to realize the direct conversion from nitrogen-rich biomass into ammonia.The pulsed laser-induced local-transient thermal effect recognized the biological nitrogen resources conversion,such as cheap and plentiful yeasts,to small gaseous molecules and achieved spectacular ammonia production rate up to 260.4 mg/h,an order of magnitude higher performance than thermochemical ammonia synthesis.Simultaneously,the tiny hot point generated by a low-energy laser(20W)guarantees the whole ammonia synthesis reaction systemis in amild environment of low temperature and normal pressure.Additionally,the remaining solid residue after laser-driven pyrolysis also can be further exploited as a highly active catalyst for electrocatalytic nitrate reduction reaction(NIRR).

Experimental comparison between aircraft fuel tank inerting processes using NEA and MIG

Fuel tank inerting technologies are able to reduce the fire risk by injection of inert gas into the ullage or fuel, the former called ullage washing and the latter fuel scrubbing. The Green On-Board Inert Gas Generation System（GOBIGGS） is a novel technology based on flameless catalytic combustion, and owning to its simple structure and high inerting efficiency, it has received a lot of attentions. The inert gas in the GOBIGGS is mainly comprised of CO2, N2, and O2（hereinafter, Mixed Inert Gas（MIG））, while that in the On-Board Inert Gas Generation System（OBIGGS）, which is one of the most widely used fuel tank inerting technologies, is NitrogenEnriched Air（NEA）. The solubility of CO2 is nearly 20 times higher than that of N2 in jet fuels,so the inerting capability and performance are definitely disparate if the inert gas is selected as NEA or MIG. An inerting test bench was constructed to compare the inerting capabilities between NEA and MIG. Experimental results reveal that, if ullage washing is adopted, the variations of oxygen concentrations on the ullage and in the fuel are nearly identical no matter the inert gas is NEA or MIG. However, the ullage and dissolved oxygen concentrations of MIG scrubbing are always higher than those of NEA scrubbing.

Nitrogen-doped biochars as adsorbents for mitigation of heavy metals and organics from water:a review

Mitigation of toxic contaminants from wastewater is crucial to the safety and sustainability of the aquatic ecosystem and human health.There is a pressing need to find economical and efficient technologies for municipal,agricultural,aquacultural,and industrial wastewater treatment.Nitrogen-doped biochar,which is synthesized from waste biomass,is shown to exhibit good adsorptive performance towards harmful aqueous contaminants,including heavy metals and organic chemicals.Incor-porating nitrogen into the biochar matrix changes the overall electronic structure of biochar,which favors the interaction of N-doped biochar with contaminants.In this review,we start the discussion with the preparation techniques and raw materials used for the production of N-doped biochar,along with its structural attributes.Next,the adsorption of heavy metals and organic pollutants on N-doped biochars is systematically discussed.The adsorption mechanisms of contaminant removal by N-doped biochar are also clearly explained.Further,mathematical analyses of adsorption,crucial to the quantification of adsorption,process design,and understanding of the mechanics of the process,are reviewed.Furthermore,the influence of environmental parameters on the adsorption process and the reusability of N-doped biochars are critically evaluated.Finally,future research trends for the design and development of application-specific preparation of N-doped biochars for wastewater treatment are suggested.