[Transformation Regularity of Nitrogen in Aqueous Product Derived from Hydrothermal Liquefaction of Sewage Sludge in Subcritical Water].

Hydrothermal liquefaction in subcritical water is a potential way to treat sewage sludge as a resource rather than a waste. This study focused on the transformation regularity of nitrogen in aqueous product which was derived from hydrothermal liquefaction of sewage sludge under different operating conditions. Results showed, within the studied temperature scope and time span, the concentration of total nitrogen (TN) fluctuated in the range of 2867.62 mg x L(-1) to 4171.30 mg x L(-1). The two major exiting formation of nitrogen in aqueous product was ammonia nitrogen (NH4+ -N) and organic nitrogen (Org-N). NH4+ -N possessed 54.6%-90.7% of TN, while Org-N possessed 7.4%-44.5%. The concentration of nitrate nitrogen (NO- -N) was far more less than NH4+ -N and Org-N. Temperature had a great influence on the transformation regularity of nitrogen. Both the concentration of TN and Org-N increased accordingly to the increase of reaction temperature. With the reaction time prolonging, the concentration of TN and Org-N increased, while the concentration of NH4+ -N increased first, then became stationary, and then decreased slightly.

Synthesis of benzimidazoles containing pyrazole group and quantum chemistry calculation of their spectroscopic properties and electronic structure.

Five benzimidazole compounds containing pyrazole group were synthesized via one-step reaction of o-phenylenediamine and 1-arylpyrazole-4-carbaldehyde in ethanol under mild conditions. The composition and structure of resultant benzimidazole compounds were analyzed by means of elemental analysis, mass spectrometry, (1)H-nuclear magnetic resonance spectroscopy and X-ray single crystal diffraction. The ultraviolet-visible light spectra and fluorescent spectra of the products were measured. Their ground-state (S(0)) equilibrium geometries and vibrational frequencies were determined based on B3LYP method, and their first excited-state (S(1)) geometries were fully optimized based on 6-31G (d, p) basis set of TD-B3LYP method. Besides, the spectroscopic properties of the products were computed based on cc-pVTZ basis set of TD-B3LYP method and compared with corresponding experimental data. It has been found that benzimidazole compounds containing pyrazole group can be readily synthesized in a high yield via one-step reaction of o-phenylenediamine and 1-arylpyrazole-4-carbaldehyde in ethanol solvent. The fluorescence properties of the five synthesized compounds are closely related to their molecular structure; and their computed fluorescence spectra well correspond to their experimental values. Moreover, they have stable structure and strong fluorescence, showing potential application in time-resolved fluoroimmunoassay and DNA probe.

Ab initio characterization of size dependence of electronic spectra for linear anionic carbon clusters C(n) (-) (n = 4-17).

In this article, we determine the ground-state equilibrium geometries of the linear anionic carbon clusters C n- (n = 4-17) by means of the density functional theory B3LYP, CAM-B3LYP, and coupled cluster CCSD(T) calculations, as well as their electronic spectra obtained by the multireference second-order perturbation theory CASPT2 method. These studies indicate that these linear anions possess doublet ²∏(g) or ²∏(u) ground state, and the even-numbered clusters are generally acetylenic, whereas the odd-numbered ones are essentially cumulenic. The energy differences, electron affinities, and incremental binding energies of C n- chains all exhibit a notable tread of parity alternation, with n-even chains being more stable than n-odd ones. In addition, the predicted vertical excitation energies from the ground state to four low-lying excited states are in reasonably good agreement with the available experimental observations, and the calculations for the higher excited electronic transitions can provide accurate information for the experimentalists and spectroscopists. Interestingly, the absorption wavelengths of the 1²∏(u/g) ← X²∏(g/u) transitions of the n-even clusters show a nonlinear trend of exponential growth, whereas those of the n-odd counterparts are found to obey a linear relationship as a function of the chain size, as shown experimentally. Moreover, the absorption wavelengths of the transitions to the higher excited states of C n- series have the similar linear size dependence as well.

[Organic phosphorus mineralization in the sediments under the impact of pH and temperature].

In the simulation, Bowman-Cole modified organic phosphorus fractionation system was used for the analysis of pH and temperature impact on organic phosphorus mineralization. The results showed that when pH were 6.5, 7.5 and 8.5, organic phosphorus (TOP) accounted for 31.71%-41.73%, 30.85%-43.29% and 27.25%-56.31% of total phosphorus (TP) in the sediments respectively. Alkalescent environment accelerated the process of organic phosphorus mineralization which slowed down when environment was neutral. When temperatures were 15 degrees C, 25 degrees C and 35 degrees C, TOP accounted for 29.07%-46. 62%, 27.81%-46.62% and 34.56%-46.62% of TP respectively. The process of organic phosphorus mineralization increased with temperature in the first 10 days but decreased in the following 20 days. Under acidic and high temperature environment, labile organic phosphorus (LOP) has a strong influence on the water quality because of the simultaneous processes of transformations from nonlabile organic phosphorus (NOP) to moderately labile organic phosphorus (MLOP) and from MLOP to LOP.

[Organic phosphorus forms in the sediments in the downstream channel of North Canal River watershed].

Bowman-Cole modified organic phosphorus fractionation system was used for the analysis of the phosphorus (P) forms in the sediments in North Canal River. The results showed that the average concentrations variation of total phosphorus (TP), and total organic phosphorus (TOP) in the sediments were 654.9-1285.4 mg x kg(-1) and 241.6-501.1 mg x kg(-1), respectively. TOP accounted for 34.08%-41.86% of TP which was much higher than other regions. The vertical distribution of OP forms changed greatly with the depth in the sediments. Labile organic P (LOP) increased at first (0-10 cm depth) but decreased gradually (10-40 cm). On the contrary, moderately labile organic P (MLOP) showed a degressive trend and nonlabile organic P (NOP) was no change with the depth. MLOP was the major part of TOP which was about 39.03%-85.72% of TOP, and was much higher than LOP (7.73%-24.13%) and NOP (10.14%-35.64%). The dynamic of MLOP in the sediments should be attended because it's easy to transform to LOP resulting in a strong influence on the water quality.

[Study of solanesol adsorbed on platinum electrode by surface enhanced Raman scattering].

The normal Raman spectrum (RRS) of solanesol molecules and surface enhanced raman scattering (SERS) of these molecules adsorbted on Pt electrode surface are reported in this paper. By comparison that the results show that the molecules of solanesol is adsorbed on the Pt surface through the C=C bond. The large difference between RRS and SERS demonstrates that the interaction between the molecules and Pt surface is rather strong and this interaction leads to a large disturbance to the molecules structure of solanesol.