Participation of H_2O_2 in Enhancement of Cold Chilling by Salicylic Acid in Banana Seedlings

The possible physiological mechanism of enhancement of cold tolerance by salicylic acid (SA) in banana seedlings ( Musa acuminata cv. Williams 8188) was explored. Measurements of leakage electrolyte after 2 d of recovery at 30/22 ℃ (day/night) following 3 d of cold stress at 7 ℃ showed that pretreatment with hydroponic solution containing SA 0.3-0.9 mmol/L as foliar spray under normal growth conditions (30/22 ℃) could significantly enhance cold tolerance of banana plants. The highest enhancing effect of SA occurred at 0.5 mmol/L and it showed the lowest leakage rate of electrolyte or smaller leaf wilting area after 2 d of recovery at normal temperature from 3 d of 7 ℃ or 5 ℃ cold stress. Higher concentrations (≥2.5 mmol/L) of SA, however, caused more electrolyte leakage, indicating that they aggravated chilling damage. Enhanced cold tolerance by SA could be related to H 2O 2 metabolism. Compared with water_treated seedlings (control), SA 0.5 mmol/L treatment inhibited activities of catalase (CAT) and ascorbate peroxidase (APX), increased peroxidase (POX) activity, but did not affect the activity of superoxide dismutase (SOD) under normal growth conditions, and these changes might lead to an accumulation of H 2O 2, whereas SA pretreatment enhanced the activities of CAT and APX, and reduced the increase in productions of H 2O 2 and thiobarbituric acid_reaction substances (TBARS) during subsequent 7 ℃ cold stress and recovery periods. Exogenous H 2O 2 treatments (1.5 -2.5 mmol/L) also increased cold tolerance of banana seedlings. Furthermore, pretreatment of banana seedlings with dimethylthiourea (a trap for H 2O 2) significantly inhibited cold tolerance induced by SA. These results suggested that endogenous H 2O 2 may be required for SA_enhanced cold tolerance. The significance of the interaction of SA, H 2O 2 and H 2O 2_metabolizing enzymes during cold stress has been discussed.

Activation of Plasma Membrane NADPH Oxidase and Generation of H_2O_2 Mediate the Induction of PAL Activity and Saponin Synthesis byEndogenous Elicitor in Suspension-Cultured Cells of Panax ginseng

Endogenous elicitor, termed cellulase-degraded cell wall (CDW), was prepared from the cell wall of suspension-cultured ginseng (Panax ginseng C.A. Meyer) cells via cellulase degradation. CDW activated the NADPH oxidase activity of isolated plasma membranes and stimulated in vivo H2O2 generation in ginseng cell suspensions. CDW also increased the activity of phenylalanine ammonia lyase (PAL), expression of a P. ginseng squalene epoxidase (sqe) gene and saponin synthesis. NADPH oxidase inhibitors inhibited both in vitro NADPH oxidase activity and in vivo H2O2 generation. Induction of PAL activity, saponin synthesis and sqe gene expression were all inhibited by such inhibitor treatments and reduced by incubation with catalase and HA scavengers. These data indicate that activation of NADPH oxidase and generation of H2O2 are essential signalling events mediating defence responses induced by the endogenous elicitor(s) present in CDW.

构建双通道路径增强iCOF/Bi_(2)O_(3)S型异质结在纯水体系中光催化合成H2O2性能

太阳能光催化技术是一种绿色、经济、可持续的制备H_(2)O_(2)方法,被认为是取代传统蒽醌法最有前景的策略。然而,由于有限的光捕获能力、快速的光生载流子复合以及氧化还原能力不足等问题,单一组分光催化剂表现出温和的光催化活性。并且,在光催化合成H_(2)O_(2)反应系统中需要额外添加牺牲剂。在这项研究中,我们通过光沉积法将Bi_(2)O_(3)(BO)纳米颗粒负载于离子型有机共价框架材料(iCOF)纳米纤维上,构建一种S型异质结用于双通道路径光催化合成H_(2)O_(2)。在纯水体系中,在iCOF表面负载10 wt%BO时,复合催化剂iCOF/BO10表现出最高的H_(2)O_(2)产率,达到了9.76 mmol·g^(-1)·h^(-1)(在420 nm处的量子效率为5.5%)。这一性能分别是纯iCOF的2.2倍,纯BO的5.6倍。原位表征技术(包括原位X射线光电子能谱、DFT理论计算、活性物种捕获实验以及原位漫反射红外傅里叶变换光谱)揭示该S型异质结不仅能促进光生载流子的分离和增强光吸收能力,而且能实现氧化还原能力最大化,使得反应体系同时通过间接2e^(-)氧气还原反应和4e^(-)水氧化反应双通道路径产生H_(2)O_(2)。此外,4e^(-)水氧化反应生成的O_(2)能够通过间接2e^(-)氧气还原反应加快H_(2)O_(2)生成的反应动力学,实现光催化H_(2)O_(2)的全合成。该项工作为开发新颖催化剂实现高效光催化合成H2O_(2)提供了独特的见解。

C6H10S2O联合Nano-CaCO3对铅染毒小鼠海马学习记忆功能的影响

评价 C6H10S2O联合Nano-CaCO3对铅染毒小鼠的海马学习记忆功能产生的影响,以指导铅染毒相关问题的处理。方法 选择齐齐哈尔医学院动物实验中心提供的20-30g 健康雌性 KM 小鼠,健康清洁级,分为正常对照组、模型对照组、C6H10S2O 组、Nano-CaCO3组、联合治疗组,其中后四组均为铅染毒模型。五组的饲养条件相同,方法 /剂量建立铅染毒模型,提供对应治疗方法,通过评估体质量与血液中铅元素含量、NO含量和ACHE活力、水迷宫、新物体识别测量的结果,判断治疗效果。结果 与空白对照组比较,模型对照组的体质量显著降低(P<0.05),血铅含量显著增加(P<0.05);与模型对照组比较,C6H10S2O组和联合治疗组小鼠的体质量显著提高(P<0.05),而血铅含量仅在联合治疗组显著减少(P<0.05);其他三组的体质量和血铅含量均无统计学差异(P>0.05)。与模型对照组比较,联合治疗组的跨越隐匿平台次数和平台象限游泳路程显著增加(P<0.05);与Nano-CaCO3组比较,联合治疗组的跨越隐匿平台次数和平台象限游泳路程也显著增加(P<0.05)。五组在NO含量和ACHE活力、认知指数方面的对比,差异均不存在统计学意义(P>0.05)。结论 C6H10S2O联合Nano-CaCO3可以减少铅含量,提高体质量,对空间学习能力有一定影响,但对认知能力、学习记忆能力不存在显著影响。

A dendritic Cu/Cu_(2)O structure with high curvature enables rapid and efficient reduction of carbon dioxide to C_(2) in an H-cell

Electrocatalytic reduction of CO_(2)(CO_(2)RR)to multicarbon products is an efficient approach for ad-dressing the energy crisis and achieving carbon neutrality.In H-cells,achieving high-current C_(2)products is challenging because of the inefficient mass transfer of the catalyst and the presence of the hydrogen evolution reaction(HER).In this study,dendritic Cu/Cu_(2)O with abundant Cu^(0)/Cu^(+)interfaces and numerous dendritic curves was synthesized in a CO_(2)atmosphere,resulting in the high selectivity and current density of the C_(2)products.Dendritic Cu/Cu_(2)O achieved a C_(2)Faradaic efficiency of 69.8%and a C_(2)partial current density of 129.5 mA cm^(-2)in an H-cell.Finite element simulations showed that a dendritic structure with a high curvature generates a strong electric field,leading to a localized CO_(2)concentration.Additionally,DRT analysis showed that a dendritic struc-ture with a high curvature actively adsorbed the surrounding high concentration of CO_(2),enhancing the mass transfer rate and achieving a high current density.During the experiment,the impact of the electronic structure on the performance of the catalyst was investigated by varying the atomic ratio of Cu^(0)/Cu^(+) on the catalyst surface,which resulted in improved ethylene selectivity.Under the optimal atomic ratio of Cu^(0)/Cu^(+),the charge transfer resistance was minimized,and the desorption rate of the intermediates was low,favoring C_(2) generation.Density functional theory calculations indicated that the Cu^(0)/Cu^(+) interfaces exhibited a lower Gibbs free energy for the rate-determining step,enhancing C_(2)H_(4) formation.The Cu/Cu_(2)O catalyst also exhibited a low Cu d-band center,which enhanced the adsorption stability of *CO on the surface and facilitated C_(2)formation.This observa-tion explained the higher yield of C_(2) products at the Cu^(0)/Cu^(+) interface than that of H_(2) under rapid mass transfer.The results of the net present value model showed that the H-cell holds promising industrial prospects,contingent upon it being a catalyst with both high selectivity and high current density.This approach of integrating the structure and composition provides new insights for ad-vancing the CO_(2)RR towards high-current C_(2) products.

Synergistic degradation of phenols by bimetallic CuO-Co_3O_4@γ-Al_2O_3 catalyst in H_2O_2/HCO_3^- system

The development of new catalytic techniques for wastewater treatment has long attracted much attention from industrial and academic communities.However,because of catalyst leaching during degradation,catalysts can be short lived,and therefore expensive,and unsuitable for use in wastewater treatment.In this work,we developed a bimetallic CuO-Co3O4@γ-Al2O3 catalyst for phenol degradation with bicarbonate-activated H2O2.The weakly basic environment provided by the bicarbonate buffer greatly suppresses leaching of active Cu and Co metal ions from the catalyst.X-ray diffraction and X-ray photoelectron spectroscopy results showed interactions between Cu and Co ions in the CuO-Co3O4@γ-Al2O3 catalyst,and these improve the catalytic activity in phenol degradation.Mechanistic studies using different radical scavengers showed that superoxide and hydroxyl radicals both played significant roles in phenol degradation,whereas singlet oxygen was less important.

Preparation of N‐vacancy‐doped g‐C_3N_4 with outstanding photocatalytic H_2O_2 production ability by dielectric barrier discharge plasma treatment

Dielectric barrier discharge（DBD） plasma is considered to be a promising method to synthesize solid catalysts. In this work, DBD plasma was used to synthesize a nitrogen‐vacancy‐doped g‐C3N4 catalyst in situ for the first time. X‐ray diffraction, N2 adsorption, ultraviolet–visible spectroscopy, scanning electron microscopy, transmission electron microscopy, X‐ray photoelectron spectrosco‐py, electrochemical impedance spectroscopy, electron paramagnetic resonance, O2 tempera‐ture‐programmed desorption, and photoluminescence were used to characterize the obtained cat‐alysts. The photocatalytic H2O2 production ability of the as‐prepared catalyst was investigated. The results show that plasma treatment influences the morphology, structure, and optical properties of the as‐prepared catalyst. Nitrogen vacancies are active centers, which can adsorb reactant oxygen molecules, trap photoelectrons, and promote the transfer of photoelectrons from the catalyst to the adsorbed oxygen molecules for the subsequent reduction reaction. This work provides a new strat‐egy for synthesizing g‐C3N4‐based catalysts.

Degradation of Nitrobenzene-Containing Wastewater with O_3 and H_2O_2 by High Gravity Technology

Nitrobenzene-containing industrial wastewater was degraded in the presence of ozone coupled with H2O2 by high gravity technology. The effect of high gravity factor, H2O2 concentration, pH value, liquid flow-rate, and reaction time on the efficiency for removal of nitrobenzene was investigated. The experimental results show that the high gravity technology enhances the ozone utilization efficiency with O3/H202 showing synergistic effect. The degradation efficiency in terms of the COD removal rate and nitrobenzene removal rate reached 45.8% and 50.4%, respectively, under the following reaction conditions, viz.： a high gravity factor of 66.54, a pH value of 9, a H2O2/O3 molar ratio of 1：1, a liquid flow rate of 140 L/h, an ozone concentration of 40 rag/L, a H2O2 multiple dosing mode of 6 mL/h, and a reaction time of 4 h. Compared with the performance of conventional stirred aeration mixers, the high gravity technology could increase the COD and nitrobenzene removal rate related with the nitrobenzene-containing wastewater by 22.9% and 23.3%, respectively.

Advanced treatment of oil recovery wastewater from polymer flooding by UV/H_2O_2/O_3 and fine filtration

In order to purify oil recovery wastewater from polymer flooding （ORWPF） in tertiary oil recovery in oil fields, advanced treatment of UV/H2O2/O3 and fine filtration were investigated. The experimental results showed that polyacrylamide and oil remaining in ORWPF after the conventional treatment process could be effectively removed by UV/H2O2/O3 process. Fine filtration gave a high performance in eliminating suspended solids. The treated ORWPF can meet the quality requirement of the wastewater-bearing polymer injection in oilfield and be safely re-injected into oil reservoirs for oil recovery.

Nitric acid pressure leaching of limonitic laterite ores:Regeneration of HNO3 and simultaneous synthesis of fibrous CaSO4·2H2O by-products

An innovative technology,nitric acid pressure leaching of limonitic laterite ores,was proposed by our research team.The HNO3 regeneration is considerable significance for the improvement of the proposed technology and its commercial application,but it has not been systematically investigated.Herein,regenerating HNO3 from Ca(NO3)2 solution with low-cost H2SO4,and simultaneous synthesis of fibrous CaSO4·2H2O by-products were studied.As a theoretical basis,the solubility of CaSO4·2H2O in HNO3 medium is studied.It is concluded that the solubility of CaSO4·2H2O increases with increasing temperature or increasing HNO3 concentration,which has considerable guiding significance for the subsequent experimental research and analysis.Then,the effects of various factors on the residual Ca^2+ concentration of filtrate,the regenerated HNO3 concentration and the morphology of synthesized products are investigated using ICP-AES and SEM.And the effect mechanism is also analyzed.The results indicate the regenerated HNO3 concentration reaches 116 g/L with the residual Ca^2+ concentration being 9.7 g/L at the optimum conditions.Moreover,fibrous CaSO4·2H2O by-products with high aspect ratios(length,406.32μm;diameter,14.71μm;aspect ratio,27.62)can be simultaneously synthesized.

A simple and efficient synthesis of 2-substituted benzothiazoles catalyzed by H_2O_2/HCl

A simple and efficient procedure for the synthesis of substituted benzothiazoles through condensation of 2-aminothiophenol with aromatic aldehydes in the presence of H2O2/HCl system in ethanol at room temperature is described. The target compounds have been characterized by ^1H NMR, ^13C NMR, IR and MS. Short reaction time, easy and quick isolation of the products, and excellent yields are the main advantages of this procedure.

Selective and mild oxidation of sulfides to sulfoxides by H_2O_2 using DBUH-Br_3 as catalyst

DBUH-Br_3 catalyzed selective conversion of sulfides to sulfoxides in the presence of H_2O_2 as oxidizing agent is described.The reaction was performed selectively at room temperature and relatively short reaction times.

Contacted Ion Pairs in Aqueous CuCl2 by the Combination of Ratio Spectra, Difference Spectra, Second Order Difference Spectra in the UV-Visible Spectra

The microstructure of aqueous CuCl2 has been studied through lots of technologies for many years; however, it remains a controversial subject. In this study, a new spectroscopic method has been proposed to analyze the UV-visible spectra of thin fihn of CuCl2/H2O solutions at different concentrations. This method is the combination of ratio spectra, difference spectra and second order difference spectra. By using this method, two new bands at -230 and -380 nm are obviously observed. The bands are assigned as the contacted ion pairs [CuCl3（H2O）n]- or [CuCl4（H2O）n]2-, which demonstrates that ion pairs exist in the CuCl2/H2O solution. Such finding agrees with the recent theoretical spectra obtained by time-dependent density functional theory. Furthermore, the populations of the contacted ion pairs are discussed. This study not only offers the direct spectroscopic evidence of [CuCl3（H2O）n]- or [CuCl4（H2O）n]2- in aqueous CuCl2, but also suggests that the spec- troscopic analysis method is powerful to extract the weak bands in a strong overlapping spectrum.

Recovery of magnetite from FeSO_4·7H_2O waste slag by co-precipitation method with calcium hydroxide as precipitant

Proper utilization of the FeSO4·7H2O waste slag generated from TiO2 industry is an urgent need, and Fe3O4 particles are currently being widely used in the wastewater flocculation field. In this work, magnetite was recovered from ferrous sulphate by a novel co-precipitation method with calcium hydroxide as the precipitant. Under optimum conditions, the obtained spherical magnetite particles are well crystallized with a Fe304 purity of 88.78%, but apt to aggregate with a median particle size of 1.83 μm. Magnetic measurement reveals the obtained Fe304 particles are soft magnetic with a saturation magnetization of 81.73 A-m2/kg. In addition, a highly crystallized gypsum co-product is obtained in blocky or irregular shape. Predictably, this study would provide additional opportunities for future application of low-cost Fe3O4 particles in water treatment field.

Photocatalytic performance of TiO_2 catalysts modified by H_3PW_(12)O_(40), ZrO_2 and CeO_2

The binary composite photo-catalysts CeO2/ZiO2, ZrO2/ZiO2 and the ternary composite photo-catalysts H3PW12040-CeO2/TiO2, H3PW12O40-ZrO2/TiO2 were prepared by sol-gel method. The catalysts were characterized by thermogravimetric-differential thermal analysis （TG-DTA）, scanning electron microscopy （SEM） and X-ray diffraction （XRD）. The photocatalytic elimination of methanol was used as model reaction to evaluate the photocatalytic activity of the composite catalysts under ultraviolet light irradiation. The effects of doped content, activation temperature, time, initial concentration of methanol and gas flow rate on the catalytic activity were investigated. The results showed that after doping a certain amount of CeO2 and ZrO2, crystallization process of TiO2 was restrained, particles of catalysts are smaller and more uniform. Doping ZrO2 not only significantly improved the catalytic activity, but also increased thermal stability. Doping H3PW12O40 alSO enhanced the catalytic activity. The catalytic activities of binary and ternary composite photocatalysts were significantly higher than un-doped TiO2. The dynamics law of photocatalytic reaction over the binary CeO2/TiO2 and ZrO2/TiO2 catalysts has been studied. The activation energy 15.627 and 15.631 kJ/mol and pre-exponential factors 0.5176 and 0.9899 s^-1 over each corresponding catalyst were obtained. This reaction accords to the first order dynamics law.

Prospect of vapor phase catalytic H2O2 production by oxidation of water

Vapor phase catalytic hydrogen peroxide production by oxidation of water is possible by coupling the reaction with oxidation of an organic sacrificial reductant. It is potentially a safer process than direct synthesis from H2 and O2. Based on mechanistic information available mostly for liquid phase catalytic processes, feasible reaction mechanisms for such coupled reactions are proposed based on which desirable catalyst properties are identified. It is found that the surface-adsorbed oxygen bond is an important parameter for identifying desirable catalysts. Thermodynamics can be used to identify the types of organic oxidation reactions that can couple with water oxidation such that H2O2 formation becomes thermodynamically favorable. Reactions such as epoxidation of alkenes and selective oxidation of alkanes to alcohols cannot provide sufficient thermodynamic driving force, whereas oxidation of alcohols to aldehydes and to acids can. Finally, further research is suggested to identify catalytic properties important for H2O2 decomposition and for coupling selective oxidation of organic compounds to oxidation of H2O in order to facilitate development of H2O2 production coupled with selective organic oxidation.

Degradation of Microcystin-RR by Combination of UV/H_2O_2 Technique

The experiments were performed to investigate the degradation of microcystins in order to assess the effectiveness and feasibility of UV/H2O2 system for the disinfection of water polluted by microcystins. The influence factors such as H2O2, pH and UV light intensities were investigated respectively. Degradation of microcystin-RR （MC-RR） could be fitted by either the pseudo-first-order or second-order rate equations. This homogenous system could significantly enhance the degradation rate due to the synergetic effect between UV and H2O2. The degradation mainly followed the mechanism of direct photolysis and .OH oxidation reactions. Experimental results showed that 94.83% of MC-RR was removed under optimal experimental conditions and the UV/H2O2 system provided an alternative to promote the removal of microcystins in drinking water supplies.

Reforming of Methane by CO2 over Bimetallic Ni-Mn/γ-Al2O3 Catalyst

γ-Al2O3 supported Ni-Mn bimetallic catalysts for CO2 reforming of methane were prepared by impregnation method. The reforming reactions were conducted at 500-700℃ and atmospheric pressure using CO2/CH4/N2 with feed ratio of 17/17/2, at total flow rate of 36 mL/min. The catalytic performance was assessed through CH4 and CO2 conversions, synthesis gas ratio （H2/CO） and long term stability. Catalytic activity and stability tests revealed that addition of Mn improved catalytic performance and led to higher stability of bimetallic catalysts which presented better coke suppression than monometallic catalyst. In this work, the optimum loading of Mn which exhibited the most stable performance and least coke deposition was 0.5wt%. The fresh and spent catalysts were characterized by various techniques such as Brunauer-Emmett-Teller, the temperature programmed desorption CO2- TPD, thermogravimetric analysis, X-ray diffraction, scanning electron microscope, EDX, and infrared spectroscopy.

Dissolved Silica Adsorbed onto MnO_2 in Catalyzing the Decomposition of H_2O_2: Molecular Structural Rearrangement Revealed by FTIR,SEM-EDX and XRD

It has been generally unclear over the mechanism of inhibitory influence of silicate on structural rearrangement or solely physical adsorption onto manganese dioxide （MnO2） about the decomposition of hydrogen peroxide （H2O2）. Consequently, several experiments were carried out by using MnO2 as a catalyst for the decomposition of H2O2 in a concentration series under certain concentrations of silicates. The silicates were analyzed by using a molybdenum blue colorimetric method. The results showed that the determination of silicates was inhibited by H2O2, whose inhibitory effect was greatly increased by increasing its concentration, but not limited by pH. SEM-EDX （scanning electron microscopy-energy dispersive x-ray spectrometry） results showed that the adsorption of silicates onto the surface of MnO2 was not purely via a structural rearrangement, with increasing Mn atoms protruding on the outer surface by covering oxygen and silicon atoms. XRD （X-ray diffraction） and FTIR （Fourier transform infrared） spectra results further revealed no significant total crystal structural changes in MnO2 after the adsorption of silicates, but only a small shift of 0.21° at 2e from 56.36° to 56.15° , and a FTIR vibration showed at around 1 050 cm-1. The results, therefore, showed that silicate adsorption onto MnO2 took place via both surface adsorption and structural rearrangement by interfacial reaction.

Reactive adsorption desulfurization coupling aromatization on Ni/ZnO-Zn_6Al_2O_9 prepared by Zn_xAl_y(OH)_2(CO_3)_z·x H_2O precursor for FCC gasoline

Aiming to improve the reactive adsorption desulfurization（RADS） performances of Ni/Zn O adsorbents,ZnxAly（OH）2（CO3）z·x H2 O precursor is synthesized by coprecipitation of Zn2＋,AlO-2,and CO2-3; the Zn OZn6Al2O9 composite oxides are obtained by the calcination of ZnxAly（OH）2（CO3）z·x H2 O precursor,and the Ni/Zn O-Zn6Al2O9（6.0 wt% Ni O） adsorbents are prepared by wetness impregnation method. The phase,acid strength,acid type and quantity,morphology,and thermal properties were characterized by X-ray diffraction,temperature-programmed desorption of ammonia,pyridine-adsorbed infrared spectrum,high-resolution transmission electron microscopy,and Thermo Gravimetry-Derivative Thermo Gravimetry（TG-DTG）,respectively. The breakthrough sulfur capacities of six adsorbents are between 34.2 and 47.9 mg/gcat. The kinetic studies indicated that the active energy of RADS（49.4 k J/mol） could reach nano-sized Zn O,the particle size of is about 12.0 nm. All the excellent RADS performances can be due to the high SBET. Also,there are some extents of aromatization reactions that occur,which can be contributed to the B？nsted acid rooted in Zn6Al2O9 composite oxide,and the octane number of products can be preserved well.