The influences of different temperatures and sewage treatment processes on the pyrolysis of sludge obtained from three municipal wastewater plants in Shenyang, China, were studied in a fixed-bed reactor. To clarify nitrogen transformation mechanisms, the functional forms of sewage sludge nitrogen (SS-N) were evaluated through X-ray photoelectron spectroscopy; the NO x precursor was identified with a spectrophotometric method. The results show that nitrogen present in sludge in forms of protein N (P-N), pyridine N (N-6), pyrrole N (N-5), quaternary N, and nitrogen oxides (N-X); P-N and N-6 account for approximately 80% of the total nitrogen in raw sludge samples (SS-Raw). NH 3 is the main product of P-N conversion during sludge pyrolysis; the majority of N-6 tends to be converted into HCN at 400−600 °C. The N-6 removal rate is closely linked to the type and origin of municipal sludge that originates from different sewage treatment processes as well as the various stages of the microbial growth curve. The anaerobic process facilitates the removal of N-6 from chars and its conversion to HCN. SS-Raw does not contain N-X; an increase in the temperature increases the amount of bound N-X in the SS-N fraction. This N-X mainly originates from the conversion of heterocyclic N (N-6 and/or N-5). The transformation routes of fuel nitrogen during sludge pyrolysis are discussed as well.

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Transparent polyimides derived from ester-containing dianhydrides with different electron affinities were synthesis and the different properties caused by different ester linkages were well investigated.

Strong and tough structural materials are a challenging materials engineering problem that has drawn considerable attention among the materials community. Here we demonstrate that ternary supramolecular ensembles of cellulose nanocrystals-polyvinyl alcohol-glucose by evaporation-induced corporative assembly achieved simultaneous enhancement on the stiffness and toughness with the Young’s modulus of 13 GPa at the work-of-fracture of 1.1 MJ·m–3. Compositional alteration led to stiff and tough ternary ensembles with the Young’s modulus up to 14.7 GPa and the toughness up to 12.1 MJ·m–3, respectively. Concurrent enhancement in the stiffness and toughness was owing to the multiscale deformation involving weak interactions and helicoidal organization, leading to more efficient energy dissipation. The freestanding transparent films of the ternary ensembles exhibited dynamic selective reflection of left-handed circularly polarized light in response to mechanical and chemical stimuli. The combination of the mechanical, chemical, and sustainability-linked advantages with the stimuli-responsive selective reflection of circularly polarized light renders the ternary ensembles promising potentials as an implant for remote monitoring of mechanical strain and as a camouflaging material for security applications.

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A composite catalyst for the selective catalytic reduction (SCR) of NO with NH is investigated, in which the rare earth (RE, including La, Ce, Pr, and Nd) is doped into manganese oxides supported on activated semi-coke (MnO/ASC) via hydrothermal method at the molar ratio of Mn:RE = 1:5. It is evidenced that the addition of RE at a rather low molar ratio can enhance the catalytic activity of MnO/ASC. The catalyst with a Mn:Ce molar ratio of 10:1 yields an over 90% NO removal efficiency in the temperature range of 150-250 °C. An approximate 100% NO conversion and 95% N selectivity are achieved at about 200 °C. The catalysts are characterized by N physisorption, X-ray powder diffraction (XRD), scanning electron microscope (SEM), hydrogen temperature-programmed reduction (H-TPR) and X-ray photoelectron spectroscopy (XPS). The results indicated that the Ce additive is conducive to the NO adsorption and then accelerates the SCR reaction due to the formation of more chemisorbed oxygen (O), which is favored during the oxidation of NH and NO. Moreover, the in situ diffused reflectance infrared Fourier transform spectroscopy (DRIFTS) results confirm that the Ce additive on MnO/ASC catalyst could provide more active Brønsted acid sites, which eventually contributes to the SCR reaction. The generation of ad-NH and nitrite species is proved to play the crucial role in the promotional effect of RE addition.