Excited State Charge Transfer Coupled Double Proton Transfer Reaction of 7-Azaindole Derivatives in Methanol: A Theoretical Study

Excited state charge transfer coupled excited state double proton transfer (ESCT/ESDPT) reaction in methanol (MeOH) for 3-cyano-7-azaindole(3-CNAI), 5-cyano-7-azaindole(5-CNAI), and 3,5-dicyano-7-azaindole(3,5-CNAI) were investigated using time-dependent density functional theory (TDDFT) method for the first time. The intermolecular hydrogen bonds of 3-CNAI-MeOH, 5-CNAI-MeOH, and 3,5-CNAI-MeOH complexes are demonstrated to be strengthened in the excited state and weakened in tautomer excited state, which indicates that reverse proton transfer reaction is not easy to take place. Due to the formation of intermolecular hydrogen bond, the absorption and excited state fluorescence spectra of the above three complexes are red-shifted in comparison with those of isolated molecules. The tautomer excited state fluorescence spectra that are induced by ESDPT reaction are also red-shifted relative to the excited state fluorescence for the above complexes. In addition, the sites where cyano group absorbed on 7-azaindole induces a large discrepancy of electron density distribution in excited state. Frontier molecular orbitals reflect that HOMO and LUMO orbitals of proton transfer PT-3-CNAI-MeOH, PT-5-CNAI-MeOH, and PT-3,5-CNAI-MeOH complexes are different with HOMO and LUMO orbitals of 3-CNAI-MeOH, 5-CNAI-MeOH, and 3,5-CNAI-MeOH complexes, respectively

High Rate Nitrogen Removal in an Alum Sludge-Based Intermittent Aeration Constructed Wetland

A new development on treatment wetland technology for the purpose of achieving high rate nitrogen removal from high strength wastewater has been made in this study. The laboratory scale alum sludge-based intermittent aeration constructed wetland (AlS-IACW) was integrated with predenitrification, intermittent aeration, and step-feeding strategies. Results obtained from 280 days of operation have demonstrated extraordinary nitrogen removal performance with mean total nitrogen (TN) removal efficiency of 90% under high N loading rate (NLR) of 46.7 g N m^–2 d^–1. This performance was a substantial improvement compared to the reported TN removal performance in literature. Most significantly, partial nitrification and simultaneous nitrification denitrification (SND) via nitrite was found to be the main nitrogen conversion pathways in the AlS-IACW system under high dissolved oxygen concentrations (3–6 mg L^–1) without specific control. SND under high dissolved oxygen (DO) brings high nitrogen conversion rates. Partial nitrification and SND via nitrite can significantly reduce the demand for organic carbon compared with full nitrification and denitrification via nitrate (up to 40%). Overall, these mechanisms allow the system to maintaining efficient and high rate TN removal even under carbon limiting conditions

XRD data and structural parameters of all LDHs samples.

<p>XRD data and structural parameters of all LDHs samples.</p

IR spectra of the synthesized LDHs.

<p>A: S-Ni_0.1MgAl, B: S-Ni_0.1MgAl-Nd, C: S-Ni_0.1MgAl-Ce and D: S-Ni_0.1MgAl-La.</p

Rylene and Rylene Diimides: Comparison of Theoretical and Experimental Results and Prediction for High-Rylene Derivatives

Low rylene (R) and rylene diimides (RD) are important organic semiconductors and dyes. High R and RD with larger conjugated cores show different properties compared with their low counterparts. Herein, absorption spectra, frontier molecular orbitals, band gaps, inner-sphere reorganization energy (λ_i), ionization potential, electron affinity, and atomic charge population of 20 rylene compounds were calculated by the density functional theory method. The theoretical results agree well with experimental ones. We predict some unusual properties of some high rylene derivatives that are unknown compounds due to synthetic difficulties. The lowest unoccupied molecular orbital energy levels of RD compounds change slightly, from −3.61 to −3.79 eV, which makes them strong electron acceptors. The band gaps narrow with the size increase of conjugated cores, which makes high rylene derivatives near-infrared dyes. The rising highest occupied molecular orbital energy levels of high rylene derivatives makes them unstable in the air. The λ_i falls with the size increase of the conjugated core, and the size of RD-4 or R-4 is big enough for the small λ_i to favor charge transport. The charge population analysis indicates R and RD have different charge distribution under the effect of electron-withdrawing imide groups, which contributes to distinct properties

SEM images of the fractured surface for the composites.

<p>A: S-Ni_0.1MgAl-La/EVA, B: S-Ni_0.1MgAl-Ce/EVA, C: S-Ni_0.1MgAl-Nd/EVA and D: S-Ni_0.1MgAl/EVA.</p

Glycerol Production from Undetoxified Lignocellulose Hydrolysate by a Multiresistant Engineered Candida glycerinogenes

Glycerol is an important platform compound with multidisciplinary applications, and glycerol production using low-cost sugar cane bagasse hydrolysate is promising. Candida glycerinogenes, an industrial yeast strain known for its high glycerol production capability, has been found to thrive in bagasse hydrolysate obtained through a simple treatment without detoxification. The engineered C. glycerinogenes exhibited significant resistance to furfural, acetic acid, and 3,4-dimethylbenzaldehyde within undetoxified hydrolysates. To further enhance glycerol production, genetic modifications were made to Candida glycerinogenes to enhance the utilization of xylose. Fermentation of undetoxified bagasse hydrolysate by CgS45 resulted in a glycerol titer of 40.3 g/L and a yield of 40.4%. This process required only 1 kg of bagasse to produce 93.5 g of glycerol. This is the first report of glycerol production using lignocellulose, which presents a new way for environmentally friendly industrial production of glycerol

TEM images of the synthesized LDHs.

<p>A: S-Ni_0.1MgAl, B: S-Ni_0.1MgAl-Nd, C: S-Ni_0.1MgAl-Ce and D: S-Ni_0.1MgAl-La.</p

XRD patterns of the synthesized LDHs.

<p>A: S-Ni_0.1MgAl, B: S-Ni_0.1MgAl-Nd, C: S-Ni_0.1MgAl-Ce and D: S-Ni_0.1MgAl-La.</p

Contact angle images of the synthesized LDHs.

<p>A: S-Ni_0.1MgAl, B: S-Ni_0.1MgAl-Nd, C: S-Ni_0.1MgAl-Ce and D: S-Ni_0.1MgAl-La.</p