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Based on the interesting Janus-type all-cis1,2,3,4,5,6-hexafluorocyclohexane (1) molecule, a novel type of excess electron compounds MF-1-MH (MF = Li, Na and K, MH = Zn, Cd and Hg) were designed theoretically. The geometric structures, electronic structures and nonlinear optical properties of MF-1-MH compounds were studied by density functional theory. Our results show that in Li-1-MH, the obvious charge transfer between Li and MH can be observed while in Na/K-1-MH, the charge transfer between Na/K and MH is negligible. Particularly, the MF-1-MH exhibit remarkable nonlinear optical (NLO) response and the first hyperpolarizability of the K-1-Zn almost achieve 1.0 × 106 au. We hope this work will further enrich the family of excess electron compounds, so that more experimental interests and efforts can be attracted to propose and synthesize new excellent NLO materials.

Here, we report an efficient endoglucanase from Aureobasidium pullulans (termed ApCel5A) was expressed in Pichia pastoris. ApCel5A shows two different enzyme activities of endoglucanase (1270 U/mg) and mannanase (31.2 U/mg). Through engineering the signal peptide and fed-batch fermentation, the enzyme activity of endoglucanase was improved to 6.63-folds, totally. Its efficient synergism with Celluclast 1.5 L, excellent tolerance to low pH (2.5), cholate and protease suggests potential application in bioresources, food and feed industries. Site-directed mutagenesis experiments present that ApCel5A residues Glu245 and Glu358 are key catalytic sites, while Asp118, Asp122, Asp198 and Asp314 play an auxiliary role. More importantly, ApCel5A display high degradation efficiency of glucan and glucomannan substrates by using tetrasaccharide contained reducing end of glucose residue as an intermediate. This study elucidated the effective methods to improve an endoglucanase expression and detailed catalytic mechanism for degradation of various substrates, which provides a new insight for endoglucanase application.

Ammonia solution has many advantages to be used for CO2 capture, while ammonia escape is a serious problem of this technology. Ammonia escape leads to absorbent loss and secondary pollution. At present, there were few relevant researches on ammonia escape coefficient. The mass transfer coefficient of ammonia escape in absorption was studied theoretically based on double film theory. The relationship between mass transfer coefficient and other variables in the absorption process is analyzed through experiments, mass transfer coefficient of ammonia escape was strongly influenced by temperature, CO2 partial pressure, gas flow rate, and L/G. Compared with previous researches, mass transfer coefficients under different conditions were obtained in this study. In the experiments, max value of mass transfer coefficient reached 0.00071 mol/(kPa × m2 × s). This research result has a certain reference value for solving the problem of ammonia escape in CO2 capture using ammonia solution, as well as the development of this technology.

In order to obtain high CO 2 absorption efficiency and low ammonia escape rate, mixed additives of piperazine and Ni(II) were used as absorbent in bubbling reactor. The effects of mixed additive on CO 2 absorption efficiency and ammonia escape rate were investigated; the performances of mixed additive in removal process were compared with that of pure ammonia solution. The proposed mechanism was analyzed by XRD and UV–visible spectrophotometer. The mixed additive has well effect on CO 2 absorption efficiency and ammonia escape reduction. The CO 2 absorption efficiency was 72% when 2 wt% ammonia solution mixed with 0.025 mol/L piperazine and 0.05 mol/L Ni(II), higher than that achieved by 3 wt% ammonia solution without additive, and the amount of ammonia loss was nearly 1/3 compared with 3 wt% pure ammonia solution. This paper provided one feasible method which is beneficial to the balance between CO 2 absorption and ammonia escape in CO 2 capture process.

Graphitic carbon nitride (g-C3N4) has been regarded as a promising photocatalyst, but it still has great limitations due to poor charge separation and low surface area. In this study, we fabricated 3D tremella-like porous carbon nitride with O and C co-doping via continuous heat treatments of bulk g-C3N4 nanosheets and uracil. The as-obtained product (CNU-10) presents unique tremella-like porous structure with a high surface area of 47.72 m2g−1. The CNU-10 sample showed considerably enhanced visible light absorption and charge separation and consequently higher photodegradation activity against organic pollutant Rhodamine B (RhB) under visible light compared with g-C3N4. O2− and h+ were proved to be the main active substances of RhB photo-degradation on CNU-10. This work offered an effective and convenient post-doping method for preparing O and C doped g-C3N4 with optimized optical/electronic properties and photocatalytic activity, which is expected to be a useful method for constructing heteroatoms-doped photocatalysts.

A fatty acid deep eutectic solvent (DES) based cloud point extraction (DES-CPE) coupled with high-performance liquid chromatography (HPLC) to determine ultraviolet absorbent (UV) in food packaging bags was presented. In this DES-CPE method, DESs prepared from medium-chain saturated fatty acids (C8-C12) and menthol are pH-dependent phase, and acid-base reactions can be carried out solely by adjusting the pH of the solution. The reaction conditions and extraction conditions, such as pH value, speed and time of vortex, selection and dosage of the extraction solvent, reaction time and temperature, effects of salt addition and centrifugation time were investigated in detail. Under optimal condition, the proposed method showed good linear range from 1 to 100μgmL−1, with good assuming regression coefficients (R2) ≥ 0.997. The limit of detection (LODs), the quantitation (LOQs), the repeatability (RSDs%) were in the range of 0.05–0.17 μgmL−1, 0.18–0.52 μgmL−1, 0.93–2.65%, respectively. The enrichment factor was 10 and the recoveries of three Ultraviolet absorbents were between 82.2% and 103.4%.