铜铝复合氧化物的制备及催化甲醛降解反应

利用柠檬酸与氢氧化铜、氢氧化铝的酸碱反应制备柠檬酸铜铝复合盐，经500℃热分解制备出了铜铝均匀分布的铜铝复合氧化物。复合氧化物的结构及元素分布采用X射线衍射仪、X射线光电子能谱仪及透射电子显微镜-能谱联用技术进行了表征。以30%过氧化氢溶液为氧化剂，以铜铝复合氧化物为催化剂催化水中甲醛的降解，在25℃、过氧化氢浓度为80μmol/mL、甲醛浓度为0.998 mg/mL，通过分光光度法测定剩余甲醛含量并计算甲醛降解率为95.3%。通过加入自由基捕捉剂叔丁醇验证了该反应机理为自由基反应。实验考察了甲醛浓度、催化剂浓度、过氧化氢浓度及酸碱度对甲醛降解效果的影响。实验发现当甲醛浓度小于0.998 mg/mL，催化剂浓度为16 g/L，过氧化氢浓度为80μmol/mL,25℃，在pH=5～9范围内，甲醛降解率均在90%以上。     

静电纺丝法制备空气过滤膜及应用

详细阐述了静电纺丝技术以及静电纺空气过滤膜材料的性能。提出了静电纺制备空气过滤材料存在的工艺问题及改进方法。综述了静电纺制备纳米纤维过滤材料及其复合改性研究进展。最后总结了静电纺空气过滤材料的应用。     

香芹酚/明胶/聚乙烯醇纤维膜的制备 及其抗氧化性能

为了实现香芹酚（CAR）的缓释，减缓食品的氧化变质进程，以可降解聚合物明胶（GEL）和聚乙烯醇（PVA）为基材，CAR为抗氧化剂，采用静电纺丝法制备香芹酚/明胶/聚乙烯醇复合纤维膜（CAR/GEL/PVA纤维膜）。通过SEM、FTIR、XRD对纤维膜的结构进行表征，并测定了纤维膜的抗氧化活性、缓释性能和橄榄油的过氧化值；考察了CAR添加量（以溶液中GEL的质量为基准）对纤维膜结构和性能的影响。结果表明：随着CAR添加量的增加，纺丝溶液的黏度增加，电导率下降，所制备的纤维膜形貌由直径较小且分布均匀转变为直径较大且分布不均匀，从而影响纤维膜的力学性能、抗氧化性能和缓释效果。Ritger-peppas和Weibull模型能较好地拟合缓释过程，其相关系数接近于1，释放规律遵循Fickian扩散机制，且当CAR添加量为5%时，纤维膜的缓释效果最佳。高CAR添加量的CAR/GEL/PVA纤维膜能在油脂类食物中缓慢释放，具有较强的抗氧化活性。在48 h时，CAR添加量为20%的纤维膜的DPPH自由基清除率为82.4%，比未添加CAR纤维膜提升了50.4%，可以有效降低橄榄油的过氧化值。     

静电纺纳米纤维复合梯度型空气过滤材料的研究进展

概述了静电纺纳米纤维及其复合梯度过滤材料的特性,详述了国内静电纺纳米纤维复合梯度型空气过滤材料的制备、过滤模型理论及数值模拟等研究进展。基于不同纤维层过滤不同粗细颗粒物,每一层纤维网发挥各自独特作用,可采用多种结构和折叠结构复合,增大过滤面积,制备多层梯度的静电纺纳米纤维复合滤材,使滤材具有高效低阻、容尘量大、使用寿命长等特点,是未来空气滤材的重点研发方向;同时应加强过滤模型设计与数值模拟研究,通过滤材的应用数据不断修正模型,促进滤材性能的改进。     

负载活性组分的核壳结构纤维膜的制备及性能

采用同轴静电纺丝技术制备了用于伤口修复的核壳结构纳米纤维膜,将蛛丝蛋白(Ss)和美洲大蠊提取物(PAE)分别负载于纳米纤维的壳层与核层.采用SEM和TEM对纳米纤维膜的形貌进行了表征,结果显示,纤维具有明显的核壳结构,且随着Ss含量的增加,纤维直径从350 nm降至280 nm,核层直径由120 nm升至140 nm,壳层厚度由115 nm降至70 nm;FTIR结果证明Ss已成功负载到纤维膜中.纤维膜的物理性能测定实验表明,制备的纳米纤维膜拉伸强度可达4.3 MPa,溶胀率可达150％,水蒸气透过率可达1834 g/(m2·24 h),水接触角减小到32.7°.药物释放实验结果显示,7 d内药物释放可达77％;考察了纳米纤维膜的生物相容性,相较于未负载Ss的纳米纤维膜,Ss含量为20％的纤维膜的细胞增殖率提高了25％.     

钡铁氧体粉体及其复合电纺纤维的制备

通过化学共沉淀法制备了磁铅石型钡铁氧体粉体,采用激光粒度仪、扫描电子显微镜（SEM）和X-射线衍射仪（XRD）等对其进行表征测试,并采用微波网络分析仪对该粉体的吸波性能进行了初步研究。分别将化学共沉淀法制备的钡铁氧体粉体以及粒径为纳米级的钡铁氧体粉体与聚乙烯吡咯烷酮（PVP）共混后静电纺丝,通过调节钡铁氧体粉体的加入方式及其分散状态等条件,探索最佳纺丝状态,制备出了负载钡铁氧体粒子的电纺纤维毡,采用扫描电子显微镜（SEM）观测了纤维形貌。     

静电纺丝纳米纤维膜空气过滤研究进展

静电纺丝纳米纤维膜具有高比表面积、孔径小、孔隙率高、纤维均一性好等优点,在空气过滤及个体防护等领域表现出巨大的应用潜力.总结了近年来国内外关于静电纺丝法制备高效低阻和功能化(抗菌、可降解、疏水和耐高温)新型空气过滤材料的最新研究成果,分析和讨论了现有研究中存在的问题,并对未来的发展方向进行了展望.     

聚乳酸复合空气过滤材料的制备及性能研究

以分子质量为7万的聚乳酸（PIA）为原料,分别用不同的溶剂制得两种纺丝液,并采用静电纺丝法将其分别纺在水刺无纺布和熔喷无纺布上,采用TSI8130仪器对阻力和效率进行测试,比较两者的过滤性能。结果表明：当纳米纤维膜厚度为2mm左右时,水刺非织造布与纳米纤维的复合材料过滤效率从近乎0提高到45．88％,当纳米材料厚度为1mm左右时,提高到26．12％;熔喷非织造布分别与1mm和2mm厚度的纳米纤维膜复合后过滤效率分别提高了23．7％和24．6％,但缺点是过滤阻力提高。     

Iron-chromium-molybdenum oxide catalysts for methanol oxidation

The activity and selectivity of a precipitated iron-chromium-molybdenum oxide catalyst (Mo/(Fe + Cr) = 2.5/(0.5 + 0.5)) towards methanol mild oxidation have been studied by a flow-circulation method. Commensurable activity and selectivity with those of the industrial Fe₂ (MoO₄)₃-MoO₃ catalysts as well as an enhanced stability have been found. The Mössbauer spectra of fresh and tested catalysts show that during the catalytic reaction a partial reduction occurs and a steady state composition differing from the initial one is formed.     

室内甲醛催化氧化脱除的研究进展

综述了国内外采用氧化技术治理室内甲醛污染的最新研究进展.分析了目前各种脱除甲醛技术的缺陷,提出采用催化氧化方法脱除甲醛;介绍了光催化氧化装置的原理、效果及其改性研究;对采用多相催化氧化脱除室内甲醛的研究做了详尽的阐述;最后介绍了在室内甲醛脱除中催化氧化同其他方法的一些复合技术.通过对室内甲醛催化氧化脱除的分析,从甲醛脱除效果和能耗的角度看,低温催化氧化是一种脱除室内甲醛可行有效的方法.     

过氧化氢氧化苯酚铜锰复合氧化物催化剂的制备

采用固相法制备了新型催化剂铜锰复合氧化物催化剂。利用高效液相色谱法对苯酚过氧化氢氧化反应产物进行分析,以苯酚转化率和苯二酚收率为评价指标,对催化剂进行了评价。结果表明,催化剂性能随铜与锰物质的量比、焙烧温度、焙烧时间和研磨时间等因素的增大呈先升高再降低的趋势,并与络合剂的还原性有关。确定最佳工艺条件为:室温下,按锰与铜物质的量比1:2将Cu_2(OH)_2CO_3、MnCO_3和适量H_2C_2O_4·2H_2O混匀,置于研钵匀速研磨10 min,马弗炉400℃焙烧2 h。最佳条件下,苯酚转化率为63.7%,苯二酚收率为59.1%。     

Effects of NO and solids on the oxidation of methane to formaldehyde

The selective oxidation of methane has been studied both in the presence and absence of solids (inert or catalysts) with and without NO added, at 1 bar of total pressure. NO enhances the yield to formaldehyde, while the solids favor its decomposition. These results, together with abundant literature data, show a maximum for formaldehyde yield of about 4.0%.     

甲醇氧化制甲醛铁钼催化剂研究

采用共沉淀法制备了不同Mo与Fe原子比的甲醇氧化制甲醛催化剂,在常压固定床反应器上对催化剂进行活性评价,采用BET、XRD和TEM对制备的催化剂进行表征。结果表明, Mo与Fe原子比为2.2~2.8时,催化剂具有较好的活性,(400~450) ℃焙烧的催化剂具有良好的比表面积、适宜的孔容和孔径,形成了较为稳定的MoO₃和Fe2(MoO₄)₃晶相,使催化剂具有更高的活性和选择性。对甲醇氧化制甲醛反应进行研究,结果表明,在反应温度(265~315) ℃,空速(8 500~13 000) h^-1时,甲醇转化率>98%,甲醛收率>93%, 500 h长周期考核,催化剂表现出良好的活性和稳定性。     

甲醛催化氧化反应机理的研究进展

催化氧化技术具有环境友好、节省能源、操作简单等优点,在治理室内甲醛污染方面显示出非常有潜力的应用前景。本文综述了近年来甲醛催化氧化反应机理的研究进展,阐述了在甲醛催化氧化过程中,氧的活化、可能产生的反应中间体以及反应路径。重点介绍了贵金属催化剂（Au、Pt、Pd 和Ag）和过渡金属（Mn、Co和Ce等）氧化物催化剂在甲醛氧化反应过程中,不同金属种类、载体性质和添加剂等对反应机理的影响。介绍了已经商业化的除甲醛产品所采用的反应机理。最后,指出了甲醛催化氧化反应机理存在的问题并对其未来研究发展方向进行了展望。     

复合氧化物催化剂催化氧化甲苯性能

以γ-Al2O3为催化剂载体,铜、锰为活性组分,稀土元素铈为助催化剂,采用浸渍法制备复合氧化物催化剂5%Cu/γ-Al2O3、5%Mn/γ-Al2O3、5%Cu-5%Mn/γ-Al2O3和5%Cu-5%Mn-1.6%Ce/γ-Al2O3,并考察其催化氧化甲苯性能。研究表明,复合氧化物催化剂催化氧化甲苯具有显著的效果,5%Cu-5%Mn/γ-Al2O3催化剂和5%Cu-5%Mn-1.6%Ce/γ-Al2O3催化剂表现出良好的低温活性和催化性能,对甲苯的完全燃烧温度分别为340℃和285℃。采用SEM和BET对催化剂进行表征,结果表明,催化剂的催化活性与活性组分在催化剂表面的分散度和催化剂的孔结构相关。     

Design composite oxide supported Pt catalyst for catalytic wet air oxidation of ammonia with a high concentration in chloride system

Massive discharge of ammonia nitrogen wastewater not only causes eutrophication of the water body but also has a toxic effect on humans and living things. How to deal with ammonia nitrogen wastewater is a crucial topic for researchers. Here, a novel catalyst of Pt@Ti–Si where platinum was supported on a composite oxide of titanium oxide (TiO₂) and silicon oxide (SiO₂) via a one-pot method was successfully synthesized for catalytic wet air oxidation (CWAO) of ammonia with a high concentration (more than 2000 ppm). Due to the improved specific surface area of SiO₂ and the excellent acid-base resistance of TiO₂, the prepared composite oxide-supported platinum catalyst has excellent catalytic performance and good stability for CWAO with a high concentration of ammonia. At 200 °C and the O₂ pressure of 2 MPa for 2 h, the 1%Pt@Ti10–Si1 catalyst has a 96.32% conversion of 2470 ppm ammonia and 97.15% selectivity to N₂ and has good catalytic performance even after five cycles. Under the same reaction conditions, when the chloride concentration in the system is 3000–10000 ppm, the CWAO reaction can be inhibited at an early stage and promote conversion and selectivity at a later stage. The results show that the catalyst has good tolerance to chloride ions, and the treated ammonia nitrogen wastewater can be used for subsequent biochemical processes. Therefore, the developed novel catalyst in this study is effective for the CWAO of highly concentrated ammonia and has potential industrial application value.     

Advances on transition metal oxides catalysts for formaldehyde oxidation: A review

This article highlights recent advances in the development of transition metal-based catalysts for formaldehyde oxidation, particularly the enhancement of their catalytic activity for low-temperature oxidation. Various factors that enhance low-temperature activity are reviewed, such as morphology and tunnel structures, synthesis methods, specific surface area, amount and type of active surface oxygen species, oxidation state, and density of active sites are discussed. In addition, catalyst immobilization for practical air purification, reaction mechanism of formaldehyde oxidation, and the reaction parameters affecting the overall efficiency of the reaction are also reviewed.     

Transient experiments on the selective oxidation of methane to formaldehyde over V2O5/SiO2 studied in the temporal-analysis-of-products reactor

Methane oxidation to formaldehyde was studied over a vanadium oxide catalyst supported on silica at 630 °C using the technique known as temporal analysis of products with sequential pulsing of methane and oxygen. This work shows that methane interacts very weakly and oxygen very strongly with the catalyst surface and it is concluded that the initial activation of methane involves an adsorbed oxygen species. Methyl radicals formed in the first step subsequently extract lattice oxygen to yield formaldehyde.