Facile H2O2 Hydrothermal Synthesis of Bimodal Mesoporous Silica MCM-48 Spheres

The ordered bimodal mesoporous silica MCM-48 spheres were facile synthesized by mild- temperature post-synthesis H2O2 hydrothermal treatment of as-synthesized MCM-48. The results showed that H2O2 is indispensable for simultaneously removing organic templates and forming ordered bimodal mesoporous silica MCM-48 spheres. The bimodal mesoporous MCM-48 was characterized by X-ray diffraction, transmission electron micrographs, FT-IR, and N2 adsorption-desorption, and a possible mechanism was proposed for the formation of bimodal mesoporous MCM-48.

Heterogeneous interfacial engineering of Pd/TiO2 with controllable carbon content for improved direct synthesis efficiency of H2O2

Series of heterogeneous interfacial engineered TiO2(C-TiO2) with controllable carbon content were facilely synthesized by incipient-wet impregnation using glucose and subsequent thermal carbonization. The obtained C-TiO2 were used as catalytic supports to load Pd nanoparticles for H2 O2 direct synthesis from H2 and O2. The as-prepared samples were systematically studied by transmission electron microscopy(TEM), X-ray photoelectron spectroscopy(XPS), air isothermal microcalorimeter, temperature-programmed reduction of H2(H2-TPR), and so on. The catalytic results showed that H2 O2 productivity and H2O2 selectivity of Pd/C-TiO2 firstly rose with increasing carbon content and then declined. Pd/C-TiO2 catalyst with 1.89 wt% of carbon content showed the best catalytic performance that had 61.2% of selectivity and 2192 mmol H2O2/g Pd/h of productivity, which were significantly better than those of pristine Pd/TiO2(45.2% and 1827 mmol H2O2/g Pd/h). Various characterization results displayed that the carbon species were heterogeneously dispersed on TiO2 surface. Moreover, no obvious geometric transformation in supports and Pd nanoparticles were observed among different catalysts. The superficial hydrophobicity of Pd/C-TiO2 was gradually promoted with increasing carbon content, which led to the corresponding decrease in adsorption energy of H2O2 with catalysts. According to structure-performance relationship analyses, the heterogeneous interfacial engineering of carbon could maintain the interaction of Pd nanoparticles with TiO2 and simultaneously accelerate the H2O2 desorption. Both factors further determined the excellent H2O2 direct synthesis performance of Pd/C-TiO2.

Mg（OH）2对松木CTMP H2O2漂白的影响

探讨了Mg（OH）2部分取代NaOH对马尾松CTMPH2O2漂白的影响。实验结果表明，随着Mg（OH）2用量的增加，漂后浆料白度逐步降低，但漂后残余H2O2明显增加，返黄值下降。减小Mg（OH）：颗粒的尺寸，可提高漂后浆料的白度和残余H2O2。Mg（OH）2取代25％的NaOH时，漂后浆料白度变化不大，但漂白浆得率、不透明度、松厚度和抗张指数均有所提高。

Xanthate interaction and flotation separation of H2O2-treated chalcopyrite and pyrite

This study investigated the effects of H2O2 treatment on xanthate interaction and flotation separation of chalcopyrite and pyrite by making use of a series of laboratory flotation experiments and surface analysis techniques.Flotation test results showed that H2O2 treatment influenced the flotation behaviors of the two minerals;however,flotation of pyrite was depressed more significantly than that of the chalcopyrite.Under well-controlled H2O2 concentration,the selective separation of chalcopyrite from pyrite was realized at pH 9.0,at which the recovery of chalcopyrite was over 84%and that of pyrite was less than 24%.Zeta potential,UV-visible and IR spectrum measurements revealed that the collector interacted differently with the two minerals after H2O2 treatment,and the surface of chalcopyrite adsorbed much greater amount of xanthate than that of the pyrite.IR and XPS analyses showed that the H2O2 treatment significantly changed the surface properties of pyrite to very hydrophilic species that inhibited the adsorption of collector and thus depressed the floatability of pyrite.While,the surface of chalcopyrite remained mildly inert to H2O2,as a result,the adsorption of xanthate and its oxidation to dixanthogen were very effective,which enhanced the flotation of chalcopyrite.

Gene expression profile of hypertrophic chondrocytes treated with H2O2:A Preliminary investigation

Objective To identify the osteogenesis genes whose expression is altered in hypertrophic chondrocytes treated with H2 O2.Methods Murine chondrogenitor cells(ATDC5) were differentiated into hypertrophic chondrocytes by InsulinTransferrin-Selenium(ITS) treatment, and then treated with H2 O2. Suitable conditions(concentration, time) were determined by using the MTT assay. After total RNA isolation and cD NA synthesis, the levels of 84 genes were determined using the PCR array, whereas quantitative RT-PCR was carried out to validate the PCR array data. Results We identified 9 up-regulated genes and 12 down-regulated genes, encoding proteins with various functions, such as collagen proteins, transcription factors, proteins involved in skeletal development and bone mineral metabolism, as well as cell adhesion molecules. Quantitative RT-PCR confirmed the altered expression of 5 down-regulated genes(Smad2, Smad4, transforming growth factor β receptor 1, transforming growth factor β receptor 3, and matrix metalloproteinase 10). Conclusions H2 O2 significantly changed the expression of several genes involved in a variety of biological functions. Because of the link between oxidative damage and Kashin-Beck disease, these genes may also be involved in the deep-zone necrosis of the cartilage observed in Kashin-Beck disease.

Design of hierarchical, three-dimensional free-standing single-atom electrode for H2O2 production in acidic media

Electrochemical reduction of molecular O2 to hydrogen peroxide(H2O2)offers a promising solution for water purification and environmental remediation.Here,we design a hierarchical free-standing single-Co-atom(with Co-N4 coordination)electrode for oxygen reduction reaction(ORR)via a two-electron pathway to make H2O2 in acidic media.The current density of the single-Co-atom electrode reached 51 mA/cm2 at 0.1 V vs reversible hydrogen electrode,lasting for more than 10 hours of continuous operation with H2O2 selectivity greater than 80%.Toward practical application,the single-Co-atom electrode was directly used to assemble an electrochemical cell to produce H2O2 at a rate of 676 mol/kgcat/h with a cell voltage of about 1.6 V.

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.

Oxidative Desulfurization of DBT with H2O2 over 3DOM H3PW12O40/Al2O3 Catalyst

A series of heteropoly acid (HPA) based Al2O3 catalysts with three-dimensional ordered (3DOM) structure were synthesized by colloidal crystal template method.Interconnected macropores (250 nm) could be clearly observed by scanning electron microscope (SEM) and transmission electron microscope (TEM).Mesopores could be detected by N2 adsorption-desorption isotherms which further confirmed the 3DOM structural characteristics of catalyst.Moreover,Keggin-type HPW was highly dispersed in the Al2O3 framework,which suggested by powder X-ray diffraction (XRD) and Fourier transform infrared spectra (FT-IR) results.The oxidation desulfurization (ODS) performance of 3DOM H3PW12O40/Al2O3 of refractory sulphur compounds was evaluated in the presence of hydrogen peroxide.It oxidized 98.5% of dibenzothiophene (DBT) into corresponding sulfone within 3 h,which exhibited superior ODS performance than corresponding mesoporous and microporous H3PW12O40/Al2O3 catalyst.The enhancement of ODS efficiency is related to the improvement of mass transfer of DBT in the pore channel resulting from the interconnected 3DOM structure.Furthermore,the as-prepared catalyst still demonstrates outstanding cycle performance after 6 runs,which could be easily recovered from the model fuel.

Study on Performance and Influencing Factors of H2O2 Production by Bioelectrochemical System

This study used a bioelectrochemical system (BES) to produce H2O2.Seven cycles after the addition of microorganisms,the BES started successfully and entered a stable operation period.During stable operation,the voltage was 581 mV,the COD removal efficiency at the anode was 85.39%,and the H 2O 2 mass concentration at the cathode was 0.5%.After the addition of 10% of graphite particles in the reaction chamber,the H2O2 production increased by 13%.After loading Pt-containing carbon black catalyst on the cathode,the H2O2 production increased by 34%.The mass concentration of H2O2 was 0.67% under the optimum process conditions of a cathode loaded with Pt-containing carbon black catalyst,pH=7,and dissolved oxygen of 8 mg/L.

几种落叶果树H2O2含量变化与自然休眠关系的研究

以设施栽培中常见的几种核果类果树品种和两个葡萄品种为试材 ,分析了芽休眠期间H2 O2 含量变化动态 ,并探讨了温度、生长调节剂及化学破眠物质对H2 O2 含量影响的效应。结果表明 :休眠期间 ,不同树种 (品种 )芽内H2 O2 含量存在差异 ,基本趋势是晚熟品种高于早熟品种 ,花芽高于叶芽 ,但葡萄品种相反 ,早熟的‘京秀’高于晚熟的‘巨峰’ ;休眠期芽内H2 O2 含量基本呈稳步上升后急剧下降的趋势 ,不同品种急剧下降的时间略有差别 ,且与自然休眠解除的时间相吻合。低温 ( 5℃ )处理显著增加了芽中H2 O2 含量 ,中温 ( 1 0℃ )使H2 O2 含量略有增加 ,而高温 ( 2 0℃ )却导致H2 O2 含量降低。休眠前期 5 0mg·L-1ABA处理显著提高了芽中H2 O2 含量 ,而 1 0 0mg·L-1的GA3 和 6 BA处理有减少H2 O2 含量的趋势 ,但二者差异不明显。热带地区常用的化学破眠物质对芽H2 O2 的影响因树种 (品种 )、使用时期不同而异 ,硫脲、KNO3 前期使用对核果类果树影响明显 ,CaCN2 对核果类无明显效应 ,但对葡萄品种作用显著。果树芽H2 O2含量的动态变化表明 ,H2 O2 可能是低温解除自然休眠的原因。

外源H2O2处理对燕麦种子活力的影响

试验以燕麦种子为材料,通过不同浓度H_2O_2(0,0.24,0.48,0.96,1.92和3.84 mol·L^(-1))处理0(CK),3,6,9和12 h后,分析其发芽率(G_p),发芽指数(G_i),平均发芽时间(MGT)及幼苗活力指数(SVI)的变化,以探讨外源H_2O_2处理对种子活力的影响。结果表明,高浓度的H_2O_2处理降低了燕麦种子的G_p、G_i及SVI,且提高了其MGT。H_2O_2浓度、处理时间及两者之间的交互作用对燕麦种子G_p、G_i、MGT和SVI的影响差异极显著。浓度为3.84 mol·L-1的H_2O_2处理12 h后,燕麦种子G_p、G_i和SVI最小,而其MGT则最大。这表明H_2O_2浓度越高,处理时间越长,燕麦种子活力的丧失就越严重。因此,高浓度H_2O_2处理造成的脂质过氧化损伤可能是导致种子活力丧失的主要原因,在农牧业生产中外源H_2O_2预处理的应用要谨慎。

H2O2引发的UV／Fenton苯酚光催化降解

研究了H2O2引发光催化降解方法对废水中微量苯酚的去除效果,应用传感技术分析了降解过程中H2O2浓度变化,及其H2O2引发光催化降解苯酚的机理,考察了影响苯酚光催化降解的因素,确定了最佳降解试验条件为:H2O20.075～0.30mmol/L,Fe3+0.1～0.15mmol/L,pH值4～5.在此条件下,苯酚初始浓度为50mg/L的含酚废水反应2h,苯酚降解率达到95%,矿化去除率达77%.

H2O2在TiO2可见光催化反应中的作用机理

以锐钛矿、金红石及混晶TiO2作光催化剂,研究了H2O2在TiO2可见光催化反应过程中的作用机理。结果表明,H2O2在TiO2表面活性位吸附后可拓宽TiO2的光吸收范围至可见光区;通过对反应体系的荧光光谱分析显示,金红石型TiO2在H2O2存在条件下,经可见光激发可持续稳定产生羟基自由基·OH。光催化实验表明,往反应体系中加入H2O2后,3种光催化剂均能可见光催化降解苯酚,且金红石型TiO2显示出最高的催化活性,反应120min对苯酚的降解率达80%;在TiO2可见光催化反应过程中,由锐钛矿型TiO2经一系列复杂反应产生H2O2,生成的H2O2虽只是一中间产物,但对污染物的可见光催化降解起决定性作用。

用H2O2/Fe^3＋处理高浓度含甲醛废水的研究

研究采用H2O2/Fe3+催化氧化处理高浓度含甲醛废水,探讨了双氧水和催化剂投加量、反应pH及反应温度等操作条件对处理效果的影响,并通过酸溶解回用失活催化剂。结果表明,较优的操作条件为:H2O2/COD(质量比)=2.2~2.6,Fe3+/H2O2(摩尔比)=0.048~0.058,反应pH1.80~2.68,反应温度50℃,反应时间40 min;在上述操作条件下,甲醛去除率达到99%以上,COD去除率达到85%以上。失活的催化剂可通过稀酸溶解后循环使用,其效果与三价铁盐作催化剂的基本相同。采用H2O2/Fe3+处理含甲醛废水具有比采用H2O2/Fe2+较优的效果。

外源H2O2对水稻幼苗抗寒性的调节作用(英文)

在常温下用不同浓度的外源H2O2(0～20mmol·L-1)预处理水稻幼苗,再进行12h6℃低温胁迫,根据幼苗相对含水量和质膜相对透性筛选最佳外源H2O2处理浓度,并分析最佳外源H2O2浓度下幼苗的渗透调节物质和活性氧相关指标的变化.结果表明:(1)0～8mmol·L-1H2O2预处理可以增加水稻幼苗的相对含水量,降低其质膜相对透性,并以4mmol·L-1H2O2的效果最佳.(2)低温胁迫后,与对照组相比,4mmol·L-1外源H2O2预处理降低了水稻幼苗萎蔫程度,并使其总呼吸速率、交替途径容量都有增加,同时还抑制了丙二醛的含量,增加了可溶性糖、可溶性蛋白质和脯氨酸的含量.(3)外源H2O2预处理对水稻幼苗的内源H2O2含量以及O2-·产生速率没有显著影响.研究发现,外源H2O2可以通过提高呼吸速率、降低脂质过氧化程度、增加碳氮代谢来有效增强水稻幼苗的抗寒性,它可能以一种独立于内源活性氧系统之外的方式发挥作用.

机械浆H2O2漂白中MgSO4、DTPA和Na2SiO3的作用

从防止H_2O_2分解角度对MgSO_4、DTPA和Na_2SiO_3的适宜用量进行了探讨,对3种漂白助剂在机械浆H_2O_2漂白中的作用进行了比较,同时对DTPA预处理对H_2O_2漂白的效果进行了评价。在含有过渡金属离子的碱性H_2O_2溶液中,3种助剂适宜用量分别为:MgSO_4为0.05%～0.1%,DTPA为0.1%～0.5%,Na_2SiO_3为0.5%～3.0%。Na_2SiO_3的使用效果明显好于DTPA。两段H_2O_2漂白的正交实验表明,在影响机械浆H_2O_2漂白的3种助剂中,Na_2SiO_3是最显著的影响因素,其次是DTPA。对机械浆进行DTPA预处理可以改善H_2O_2漂白效果,增加残余H_2O_2和降低浆料的返黄值。DTPA预处理的适宜用量为0.3%～0.5%。

粉煤灰增强超声/H2O2降解左氧氟沙星的实验研究

研究粉煤灰对超声/H2O2体系降解左氧氟沙星的增强效果,考察了粉煤灰添加量、H2O2浓度、溶液初始pH值、左氧氟沙星初始浓度等对降解效果的影响.结果表明,与单独超声,H2O2氧化,超声/H2O2,超声/粉煤灰,粉煤灰/H2O2氧化相比,粉煤灰有效增强了超声/H2O2体系对左氧氟沙星的降解,降解反应符合一级反应动力学.粉煤灰添加量为1.5g/L,H2O2浓度为15.0mmol/L,pH=7.16,超声功率325W,左氧氟沙星初始浓度20mg/L,反应160min,左氧氟沙星的去除率达到99.12%,TOC去除率为17.37%.利用荧光探针法对不同体系产生的·OH浓度进行了分析比较,粉煤灰作为非均相催化剂,主要在于发生类Fenton反应.采用HPLC/MS/MS方法对3种反应产物进行了分析,结果表明左氧氟沙星主要是通过喹诺酮环失去-C2,哌嗪环去亚甲基化以及·OH进攻喹诺酮环发生降解.

牡丹花蕊醇提物对H2O2诱导HUVEC细胞损伤的保护作用

采用高效液相色谱分析牡丹花蕊醇提物的主要成分,并通过H2O2诱导HUVEC细胞建立损伤模型,研究牡丹花蕊醇提物对其保护作用。结果表明:牡丹花蕊醇提物主要成分为芦丁、槲皮素和芍药苷3种单体,含量分别为44.25%,15.50%,17.00%;牡丹花蕊醇提物能够降低细胞及其培养液中MDA含量,提高细胞内SOD和GPX活性以及GSH的含量。牡丹花蕊醇提物能够提高HUVEC细胞的抗氧化能力。