Konjac glucomannan-based aerogels with excellent thermal stability and flame retardancy for thermal insulation application.

Biomass aerogels are a promising kind of environment-friendly thermal insulation material. However, the flammability, poor water resistance, and thermal instability of biomass aerogels limit their applications. Herein, freeze-drying and thermal imidization were used to create konjac glucomannan (KGM), boron nitride (BN), and polyimide (PI)-based aerogels with a semi-interpenetrating network structure. The introduction of BN was beneficial to improve the mechanical properties and thermal stability of aerogels. The imidization process of PI improved the hydrophobicity, mechanical property, and flame retardancy of the aerogels. The synergistic effect of PI and BN reduced the peak heat release rate and total heat release rate of KGM-based aerogel by 55.8 % and 35 %, respectively, and endowed aerogel with good self-extinguishing performance. Moreover, the results of thermal conductivity and infrared thermal imaging demonstrated that the aerogels had excellent thermal insulation properties, and could effectively manage thermal energy over a wide range of temperatures. This study provides a simple method for the preparation of heat-insulating aerogel with high fire safety, which has broad application prospects in the field of energy saving and emission reduction.

Efficient treatment of palladium from wastewater by acrolein cross-linked chitosan hydrogels: Adsorption, kinetics, and mechanisms.

Herein we present a study on the preparation and properties of a hydrogel adsorbent for treatment of wasted palladium souring from actial petrochemical industrial wastewater. Chitosan was used as the raw material and acrolein as the cross-linking agent for the hydrogel (A/CS). The adsorption behaviors of the hydrogel for Pd(II) ions were characterized and analyzed. The effect of pH, temperature, adsorption kinetics, and thermodynamics were investigated. Langmuir models were employed to describe the adsorption isotherms, while the pseudo-second-order equation was applied to describe the adsorption kinetics. The experimental results demonstrated that the adsorption was a monolayer chemical adsorption, and the adsorption capacity was found to reach 505.05 mg/g under optimal conditions. In addition, FT-IR and XPS analyses, combined with MS calculations confirmed that chelation and electrostatic attraction were dominated in the adsorption process. Overall, the development of this hydrogel adsorbent will provide a practical approach to the treatment of industrial wastewater containing palladium and have great potential for practical applications.

Diazotization-Enabled Deaminative Late-Stage Functionalization of Primary Sulfonamides.

We, for the first time, disclosed a simple and efficient strategy for the late-stage functionalization of primary sulfonamides by diazotization, leading to sulfonyl chlorides, sulfonates, and complex sulfonamides. This protocol obviates the requirement for the prefunctionalization of sulfonamides. Its applicability is exemplified by the late-stage functionalization of sulfonamide-type drugs.

Synthesis and Micellization of Carbosilane Sulfonate Surfactants with Short Alkyl Chains.

Carbosilane surfactants, consisting of carbosilane as a hydrophobic group linked to hydrophilic groups, are one kind of silicone surfactants. In this paper, a series of carbosilane sulfonate surfactants with short alkyl chains (Cn-Si2C-SO3Na (n = 1-6)), Me-Si2C-SO3Na, Et-Si2C-SO3Na, Pr-Si2C-SO3Na, Bu-Si2C-SO3Na, Pen-Si2C-SO3Na, and Hex-Si2C-SO3Na, were prepared and characterized by 29 Si NMR, 1H NMR, and FT-IR spectroscopies. The influence of the alkyl chain length on their micellization was studied using surface tension, dynamic light scattering, conductivity, and transmission electron microscopy. The CMC value decreases with increasing length of the short alkyl group. The γCMC value of Cn-Si2C-SO3Na (n = 1-6) increases as the alkyl chain increases from methyl to propyl, while the γCMC value gradually decreases as the alkyl chain increases from propyl to hexyl. The larger and rigid tetramethyldicarbosilane group functioned synergistically with a short alkyl chain, resulting in carbosilane sulfonate surfactants adsorbing at the air/water interface with a rugby ball shape; accordingly, the Amin values of the investigated carbosilane sulfonate surfactants increase with increasing length of the alkyl chain. The micellization process of carbosilane sulfonate surfactants is enthalpy-driven at lower temperatures and entropy-driven at high temperatures. The ΔHm0 values became more negative and ΔSm0 values more positive as the alkyl chain length increased. Aggregates in the range of 10-800 nm were observed for Cn-Si2C-SO3Na (n = 1-6) in an aqueous solution, and the hydrodynamic diameter (Dh) decreased with increasing length of the short alkyl group.

Rigidity-Dependent Emission: Inspired Selection of an ATP-Specific Polyvalent Hydrogen Binding-Lighted Fluorophore for Intracellular Amplified Imaging.

ATP, a small molecule with high intracellular concentration (mM level), provides a fuel to power signal amplification, which is meaningful for biosensing. However, traditional ATP-powered amplification is based on ATP/aptamer recognition, which is susceptible to the complex biological microenvironment (e.g., nuclease). In this work, we communicate a signaling manner termed as ATP-specific polyvalent hydrogen binding (APHB), which is mimetic to ATP/aptamer binding but can avoid interference from biomolecules. The key in APHB is a functional fluorophore that can selectively bind with ATP via polyvalent hydrogen, and the fluorescence was lighted with the changes of the molecular structure from flexibility to rigidity. By designing, synthesizing, and screening a series of compounds, we successfully obtained an ATP-specific binding-lighted fluorophore (ABF). Experimental verification and a complex analogue demonstrated that two melamine brackets in the ABF dominate the polyvalent hydrogen binding between the ABF and ATP. Then, to achieve amplification biosensing, fibroblast activation protein (FAP) in activated hepatic stellate cells was taken as a model target, and a nanobeacon consisting of an ABF, a quencher, and an FAP-activated polymer shell was constructed. Benefiting from the ATP-powered amplification, the FAP was sensitively detected and imaged, and the potential relationship between differentiation of hepatocytes and FAP concentration was first revealed, highlighting the great potential of APHB-mediated signaling for intracellular sensing.

Selective adsorption and separation of methylene blue by facily preparable xanthan gum/amantadine composites.

In this work, xanthan gum-based composites were successfully graft-modified by amantadine (XG-Fe3+/AM) with higher adsorption capacity and selectivity on recycling cationic dye (methylene blue, MB) from aqueous solution. The adsorption equilibrium of MB could be achieved approximately within 5 min when the initial concentration was 100 mg/L, and the maximum adsorption capacity was up to 565 mg/g. After 5 desorption-regeneration cycles, the removal rate of XG-Fe3+/AM for MB could still be as high as 95 % with slight decrement. Additionally, the effects of pH, contact time, temperature and initial dye concentration on the adsorption performance of MB were systematically examined. Furthermore, the adsorbent was characterized by FT-IR, BET and XPS analysis. In mixed anionic and cationic dyes, the adsorption selectivity of XG-Fe3+/AM on MB in the mixture of MB and methyl orange (MO) reached up to 99.69 %. Molecular dynamics simulation revealed that the trend of adsorption energy for dyes was in good agreement of the experimental order of adsorption capacities and molecular sizes among seven anionic and cationic dyes based on molecular matching effect and electrostatic interaction. Therefore, XG-Fe3+/AM is an eco-friendly, facile-synthesis and high-selectivity adsorbent, which remove cationic dyes in multi-component systems through electrostatic interaction and molecular matching effect.

Efficient selective recycle of acid blue 93 by NaOH activated acrolein/chitosan adsorbent via size-matching effect.

Here we report an efficient strategy to separate and recycle acid blue 93 (AB93) from mixed anionic dyes selectively within sodium hydroxide activated A/CS adsorbent (N-A/CS). This work broke the common sense that the larger the specific surface area, the better the adsorption property is, which provided an alternative strategy to separate dyes. The adsorption equilibrium of AB93 could be achieved approximately within 1-2 min, and the maximum adsorption capacity was up to 2500 mg/g. Besides, it can be activated continuously and reused at least 15 times. In mixed anionic dyes, the adsorption selectivity of N-A/CS on AB93 in the mixture of AB93 and acid fuschin (AF) reached up to 99.7 %. Molecular dynamics simulation revealed that the trend of adsorption energy for dyes qualifies well with the experimental order of adsorption capacities and molecular sizes among five anionic dyes based on molecular matching effect. Thus, N-A/CS is a low-cost, easily-preparable, significantly-effective-and-reusable adsorbent, providing a promising "size-matching" strategy to adsorb multi-component dye systems.

Efficiently ion-enhanced adsorption of anion dyes by acrolein crosslinked polyethylenimine/chitosan hydrogel with excellent recycling stability.

A novel adsorbent acrolein crosslinked polyethylenimine/chitosan hydrogel (A-PEI/CS) was developed with excellent recycling stability and ion-enhanced effect on removing anionic dye (acid blue 93, AB93) from aquatic environment. For AB93, A-PEI/CS was such an adsorbent with the characteristics of high adsorption capacity up to 1212.4 mg/g and continuous recyle ability of more than 15 times. After 15 desorption-regeneration cycles, the removal rate of A-PEI/CS for AB93 could still be as high as 96 % with imperceptibly downward trend. In addition, the addition of salts (KCl, NaCl and CaCl2) could promote the adsorption of A-PEI/CS, and the removal rate would be enhanced with increasing concentration of the salt. The effects of pH (2-7), contact time (30-600 min), temperature (30-50 °C) on the adsorption performance of A-PEI/CS were systematically examined. Furthermore, the physicochemical properties of the adsorbent were analyzed by FT-IR, XPS and zeta potential. The adsorption mechanism can be explained by electrostatic interaction, hydrogen bond interaction, chemical interaction. Intriguing to note that, the adsorption energy of adsorbents was investigated by molecular simulation, and the low pH and common salt environment can promote the adsorption effect, indicating that the prepared adsorbent has excellent application value in the treatment of practical high-salinity wastewater.

Synthesis of ZnO nanoparticle-anchored biochar composites for the selective removal of perrhenate, a surrogate for pertechnetate, from radioactive effluents.

Pertechnetate (TcO4-) is a component of low-activity waste (LAW) fractions of legacy nuclear waste, and the adsorption removal of TcO4- from LAW effluents would greatly benefit the site remediation process. However, available adsorbent materials lack the desired combination of low cost, radiolytic stability, and high selectivity. In this study, a ZnO nanoparticle-anchored biochar composite (ZBC) was fabricated and applied to potentially separate TcO4- from radioactive effluents. The as-synthesized material exhibited γ radiation resistance and superhydrophobicity, with a strong sorption capacity of 25,916 mg/kg for perrhenate (ReO4-), which was used in this study as a surrogate for radioactive pertechnetate (TcO4-). Additionally, the selectivity for ReO4- exceeded that for the competing ions I-, NO2-, NO3-, SO42-, PO43-, Cu2+, Fe3+, Al3+, and UO22+. These unique features show that ZBC is capable of selectively removing ReO4- from Hanford LAW melter off-gas scrubber simulant effluent. This selectivity stems from the synergistic effects of both the superhydrophobic surface of the sorbent and the inherent nature of sorbates. Furthermore, density functional theory (DFT) calculations indicated that ReO4- can form stable complexes on both the (100) and (002) planes of ZnO, of which, the (002) complexes have greater stability. Electron transfer from ReO4- on (002) was greater than that on (100). These phenomena may be because (002) has a lower surface energy than (100). Partial density of state (PDOS) analysis further confirms that ReO4- is chemisorbed on ZBC, which agrees with the findings of the Elovich kinetic model. This work provides a feasible pathway for scale-up to produce high-efficiency and cost-effective biosorbents for the removal of radionuclides.

Synergistic Effect of Segregated Pd and Au Nanoparticles on Semiconducting SiC for Efficient Photocatalytic Hydrogenation of Nitroarenes.

Efficient catalytic hydrogenation of nitroarenes to anilines with molecular hydrogen at room temperature is still a challenge. In this study, this transformation was achieved by using a photocatalyst of SiC-supported segregated Pd and Au nanoparticles. Under visible-light irradiation, the nitrobenzene hydrogenation reached a turnover frequency as high as 1715 h-1 at 25 °C and 0.1 MPa of H2 pressure. This exceptional catalytic activity is attributed to a synergistic effect of Pd and Au nanoparticles on the semiconducting SiC, which is different from the known electronic or ensemble effects in Pd-Au catalysts. This kind of synergism originates from the plasmonic electron injection of Au and the Mott-Schottky contact at the interface between Pd and SiC. This three-component system changes the electronic structures of the SiC surface and produces more active sites to accommodate the active hydrogen that spills over from the surface of Pd. These active hydrogen species have weaker interactions with the SiC surface and thus are more mobile than on an inert support, resulting in an ease in reacting with the N═O bonds in nitrobenzene absorbed on SiC to produce aniline.

Selective adsorption and recycle of Cu2+ from aqueous solution by modified sugarcane bagasse under dynamic condition.

Tetraethylenepentamine modified sugarcane bagasse was prepared and applied to test its feasibility in removing and recovering Cu2+ from wastewater under dynamic condition. Results showed that the Cu2+ could be selectively absorbed from wastewater by the modified SCB fixed bed column. To understand the adsorption mechanism, Cd2+ had been selected as the model interfering ion to investigate how co-ions influence the adsorption of Cu2+ on the sorbent. It was observed that the adsorption capacity of the sorbent for Cu2+ (0.26 mmol g-1) was significantly higher than that of Cd2+ (0.03 mmol g-1), even when the Cd2+ initial concentration was 100 times higher than that of Cu2+ in the binary system. This finding indicated that the presence of Cd2+ in the solution exerted negligible influence on the adsorption of Cu2+ on the modified SCB. The selectivity of the modified sorbent was further confirmed in the Cu/Cd/Mg/Pb/K quinary system. Further analysis to dynamic adsorption experiment illustrated that, due to the presence of amine groups, the modified SCB showed strong coordination ability to Cu2+, which allowed the other adsorbed ions (e.g., Cd2+) desorbed. This high adsorption selectivity toward Cu2+ suggested that this prepared sorbent would be a promising candidate for removing and recovering Cu2+ from wastewater.

Au Sub-Nanoclusters on TiO2 toward Highly Efficient and Selective Electrocatalyst for N2 Conversion to NH3 at Ambient Conditions.

As the NN bond in N2 is one of the strongest bonds in chemistry, the fixation of N2 to ammonia is a kinetically complex and energetically challenging reaction and, up to now, its synthesis is still heavily relying on energy and capital intensive Haber-Bosch process (150-350 atm, 350-550 °C), wherein the input of H2 and energy are largely derived from fossil fuels and thus result in large amount of CO2 emission. In this paper, it is demonstrated that by using Au sub-nanoclusters (≈0.5 nm ) embedded on TiO2 (Au loading is 1.542 wt%), the electrocatalytic N2 reduction reaction (NRR) is indeed possible at ambient condition. Unexpectedly, NRR with very high and stable production yield (NH3 : 21.4 µg h-1 mg-1cat. , Faradaic efficiency: 8.11%) and good selectivity is achieved at -0.2 V versus RHE, which is much higher than that of the best results for N2 fixation under ambient conditions, and even comparable to the yield and activation energy under high temperatures and/or pressures. As isolated precious metal active centers dispersed onto oxide supports provide a well-defined system, the special structure of atomic Au cluster would promote other important reactions besides NRR for water splitting, fuel cells, and other electrochemical devices.

[Modeling of thermal degradation of linarin during concentration process].

Ganmaoling granule, with annual sale of over one billion yuan, is the first brand of domestic cold medicine sales. As the only traditonal Chinese medicine（TCM） quality control indicator of Ganmaoling granule, linarin is thermally unstable. Its content will be changed significantly during the production process, which would then affect the quality of the finished product. In this paper, the law of degradation of linarin was investigated. The experimental results showed that degradation reaction of linarin belongs to the first reaction characteristics. The effective methods to reduce the loss of linarin would be realized fortunately by strictly controlling the heating temperature or shortening the heating time.

[Study on balance of process of alcohol precipitation of ganmaoling granules].

Ganmaoling granule is the first brand of domestic cold medicine sales, but its preparation method and process control parameters are relatively rough. Therefore it is urgent to upgrade the technologies of large varieties of traditional Chinese medicine (TCM). This paper focused on the balance between the remove of impurity and the retention of linarin during the process of alcohol precipitation of Ganmaoling granules. The effects of four factors on the process were investigated via single factor experiments. The results showed that the precipitating period, the initial ethanol concentration and the final ethanol concentration had a great effect on retention of linarin while the initial density of the extract has not. Similarly, the initial ethanol concentration, the final ethanol concentration and the initial extract density have a great effect on the yield of dry extract while the time of alcohol precipitation has not. The parameters of alcohol precipitation of Ganmaoling granules were optimized as 16 h of precipitating period, 95% ethanol as the initial reagent, 70% of the final ethanol concentration, and 1.10 of the initial extract density.

[On-line monitoring of extraction of coldrine by near-infrared spectrum].

Extraction of the four Chinese herbals is the beginning step of the production process of coldrine granules and influences on drug quality significantly. In this paper, the on-line near infrared spectrum was collected during the extraction process of coldrine and then pre-processed by the first derivative. Partial least square regression (PLSR) model was developed for the quantity indicators of linarin, chlorogenic acid and solid content, according to results of both HPLC and weight-loss as reference methods. The correlation coefficient, root mean square error of cross-validation (RMSECV), root mean square error of calibration (RMSEC) and root mean square error of prediction (RMSEP) were used to optimize model parameters and confirm their performance. Correlation coefficients of three quality control indicator models reached more than 0.95.Values of RMSEC of linarin, chloroenic acid and solid content were 0.010 4, 0.009 34 and 0.055 5, respectively. And the values of RMSEP were 0.009 47, 0.142 and 0.008 42, respectively. The models, built on-line analyze data, revealed that the correlation coefficients of predicted values and measured values were greater than 0.97 and values of RSEP of linarin, chloroenic acid and solid content were 8.14%, 8.17% and 9.86%, respectively. The results showed that the NIR method could achieve the on-line detection and real-time monitoring of multi-indexes during the extraction process of coldrine. The technology could be used for drug quality control in the process of practical production, reducing the batch differences and ensuring pharmaceutical quality stability. In addition, it could provide real-time production data for subsequent product quality backtracking.

[Study on main pharmacodynamics and underlying mechanisms of 999 Ganmaoling].

To observe synergistic effects of 999 Ganmaoling (GML) and its Chinese/Western materia medica (CMM and WMM) on pharmacodynamic action and to study underlying mechanisms, their anti-inflammatory, antipyretic effects were compared by assaying the increased capillary permeability induced by glacial acetic acid in mice, ear swelling induced by Xylene in mice, non-specific pleurisy induced by carrageenan in rats, and yeast induced fever in rats. Crystal violet (CV) and microbial activity (XTT) assay were used to evaluate the inhibition of GML and its CMM and WMM on KPN biofilm formation, and scanning electron microscopy (SEM) was applied for observing KPN biofilm morphology changes. The results showed that compared with control group, GML could reduce exudation amount of Evans-Blue and the degree of Ear swelling significantly, and CMM and WMM have no significant effects. The concentration of TNF-α and IL-1ß of rat pleural effusion in GML, CMM and WMM group decreased significantly. The concentration of TNF-α, IL-1ß and IL-8 in GML group, TNF-α, IL-8 in WMM group and IL-8 in CMM in rats serum decreased significantly. The body temperature in rats decreased significantly in GML and WMM group after 4-8 h of administration. CMM group showed no significant difference in rat body temperature compare with control. Compared with control group, GML (55-13.75 g•L⁻¹) could inhibit KPN biofilm formation and reduce number of viable cells in the KPN biofilm. CMM (45-22.5 g•L⁻¹) and WMM (10 g•L⁻¹) could also inhibit KPN biofilm formation and reduce number of viable cells (P<0.01). Result of SEM also showed that GML (55 g•L⁻¹) and its CMM (45 g•L⁻¹) and WMM (10 g•L⁻¹) could interfere the bacterial arrangement of KPN biofilm and extracellular matrix. GML and its CMM & WMM could inhibit the formation of KPN biofilm, CMM & WMM in GML showed synergism and complementation in inhibit KPN biofilm. Results showed that GML had obvious anti-inflammatory and antipyretic effects and could destruct KPN mature biofilm. WMM and CMM showed obvious synergistic effect against inflammation and inhibition of KPN biofilm formation and reduction of number of viable cells but no same effects against fever.

[Study on toxicity of 999 Ganmaoling grain and influence of diet on hepatic toxicity].

This paper was aimed to compare the acute toxicity of 999 Ganmaoling grain and its different ingredients, and investigate the influence of routine diet on the hepatic toxicity induced by Ganmaoling in mice, so as to provide experimental basis for the clinical safety evaluation. Mice were given a single dose of Ganmaoling grain or its different ingredients respectively by gavage, and then observed for 14 days. LD50 values of Ganmaoling grain or its chemical ingredient and the maximal tolerated dose of its herb ingredient were determined. Mice were divided into starvation and diet group, a single dose of Ganmaoling grain was administered by gavage. LD50 values were estimated after 14 day observation. Mice were divided into starvation and diet group. At the same time,control group was set up for each. A single dose of Ganmaoling grain was given. Serum biochemical indexes were detected, liver weight index was calculated and liver tissue morphological change was observed after 6 h. LD50 values were 4.42, 0.64 g•kg⁻¹ for Ganmaoling grain group and chemical ingredient group, respectively. The maximal tolerated dose of the herb ingredient group was close to 24.24 g•kg⁻¹. The toxic symptom was basically similar in the Ganmaoling grain and the chemical ingredient group. The body weight and food intake were decreased to a certain extent in both groups. There were pathological changes of liver and heart tissue in some of the surviving animals. The animals in the Ganmaoling grain group exhibited a lighter toxicity and recovered faster than that in the chemical ingredient group. LD50 values of Ganmaoling grain were 2.56, 6.93 g•kg⁻¹ for starvation and diet group respectively. TD50 values were 1.29, 6.31 g•kg⁻¹ for starvation and diet group respectively. The toxicity of 999 Ganmaoling was less, which may be related to the reduction of toxicity after the combination of herb and chemical ingredients. Compared with starvation group, the values of LD50 and TD50 of diet group was significantly increased, and toxicity was decreased. From the point of view of safety, it is safer to use Ganmaoling in the absence of hunger or after meal. The above tests provide experimental basis for the clinical safety use of Ganmaoling.

A low cost, green method to synthesize GaN nanowires.

The synthesis of gallium nitride nanowires (GaN NWs) by plasma enhanced chemical vapor deposition (PECVD) are successfully demonstrated in this work. The simple and green synthesis route is to introduce gallium oxide (Ga2O3) and nitrogen (N2) for the growth of nanowires. The prepared GaN nanowires have a single crystalline wurtzite structure, which the length of some nanowires is up to 20 µm, with a maximum diameter about 140 nm. The morphology and quantity of the nanowires can be modulated by the growth substrate and process parameters. In addition, the photoluminescence and field emission properties of the prepared GaN nanowires have been investigated, which were found to be largely affected by their structures. This work renders an environmentally benign strategy and a facile approach for controllable structures on nanodevice.

ZIF-8 derived graphene-based nitrogen-doped porous carbon sheets as highly efficient and durable oxygen reduction electrocatalysts.

Nitrogen-doped carbon (NC) materials have been proposed as next-generation oxygen reduction reaction (ORR) catalysts to significantly improve scalability and reduce costs, but these alternatives usually exhibit low activity and/or gradual deactivation during use. Here, we develop new 2D sandwich-like zeolitic imidazolate framework (ZIF) derived graphene-based nitrogen-doped porous carbon sheets (GNPCSs) obtained by in situ growing ZIF on graphene oxide (GO). Compared to commercial Pt/C catalyst, the GNPCSs show comparable onset potential, higher current density, and especially an excellent tolerance to methanol and superior durability in the ORR. Those properties might be attributed to a synergistic effect between NC and graphene with regard to structure and composition. Furthermore, higher open-circuit voltage and power density are obtained in direct methanol fuel cells.

Bandgap engineering and manipulating electronic and optical properties of ZnO nanowires by uniaxial strain.

Bandgap engineering is a common practice for tuning semiconductors for desired physical properties. Although possible strain effects in semiconductors have been investigated for over a half-century, a profound understanding of their influence on energy bands, especially for large elastic strain remains unclear. In this study, a systematic investigation of the transport properties of n-type [0001] ZnO nanowires was performed at room temperature using the in situ scanning tunnelling microscope-transmission electron microscope technique which shows that the transport properties vary with the applied external uniaxial strain. It has been found that the resistance of ZnO nanowires decreases continuously with increasing compressive strain, but increases under increased tensile strain, suggesting piezo-resistive characteristics. A series of near-band-edge emissions were measured and the corresponding variations of bandgaps were obtained during the application of tensile strain of individual ZnO nanowires via cathodoluminescence spectroscopy. From this, a relationship between the changes of energy bandgap and the transport properties, both induced by uniaxial strain, is built.