活性炭的预处理对CeO2/AC催化剂NH3选择性催化还原NOx性能的影响

为了改善活性炭(AC)负载的CeO_2基催化剂的脱硝性能,采用空气热氧化或硝酸对活性炭进行预处理,考察了预处理方式对其负载的CeO_2基催化剂氨选择性催化还原(NH_3-SCR)NO_x反应性能的影响。对预处理后的活性炭及其负载的CeO_2基催化剂进行了红外光谱(FTIR)、NH_3程序升温脱附(NH_3-TPD)、N_2吸附-脱附、X射线衍射(XRD)及H_2-TPR等表征。结果表明:硝酸预处理显著增加了活性炭表面含氧官能团、增强了表面酸性,提高了其负载的CeO_2基催化剂的氧化还原性能,促进了催化剂表面NH_3的吸附和活化,使催化剂表现催化优异的NH_3-SCR脱硝性能。该催化剂对NO_x的起燃温度和完全转化温度分别为75℃和190℃,显著优于空气热氧化处理的活性炭制备的催化剂,但H_2O易导致催化剂活性下降。

NH_3·H_2O皂化二-(2-乙基己基)磷酸微乳液体系的溶水过程研究

研究了NH3·H2 O皂化二 - (2 -乙基己基 )磷酸微乳液体系增溶水过程微观结构的转变 ,测定了增溶水过程电导率和粘度的变化 ,以及在一定溶水量时电导率和温度的关系 。

Mechanistic Study on the Monofunctional Binding of Hydrolysis Products of Non-planar Heterocyclic Complexes Trans-[PtCl_2NH_3(piperidine)] and Trans-[PtCl_2(piperidine)_2] to DNA Purine Bases

The monofunctional substitution reactions between trans-[PtCl（H2O）（NH3）（pip）]＋,trans-[Pt（H2O）2（NH3）（pip）]2＋,trans-[PtCl（H2O）（pip）2]＋,trans-[Pt（H2O）2（pip）2]2＋ （pip = piperidine） and adenine/guanine nucleotides are explored by using B3LYP hybrid functional and IEF-PCM salvation models. For the trans-[Pt（H2O）2（NH3）（pip）]2＋ and trans-[PtCl（H2O）（NH3）（pip）]＋ complexes,the computed barrier heights in aqueous solution are 13.5/13.5 and 11.6/11.6 kcal/mol from trans-Pt-chloroaqua complex to trans/cis-monoadduct for adenine and guanine,and the corresponding values are 20.7/20.7 and 18.8/18.8 kcal/mol from trans-Pt-diaqua complex to trans/cis-monoadduct for adenine and guanine,respectively. For trans-[PtCl（H2O）（pip）2]＋ and trans-[Pt（H2O）2（pip）2]2＋,the corresponding values are 21.5/21.3 and 19.4/19.4 kcal/mol,and 26.0/26.0 and 20.7/20.8 kal/mol for adenine and guanine,respectively. Our calculations demonstrate that the barrier heights of chloroaqua are lower than the corresponding values of diaqua for adenine and guanine. In addition,the free energies of activation for guanine in aqueous solution are all smaller than that for adenine,which predicts a preference of 1.9 kcal/mol when trans-[PtCl（H2O）（NH3）（pip）]＋ and trans-[Pt（H2O）2（NH3）（pip）]2＋ are the active agents and ～1.9 and ～ 5.3 kcal/mol when trans-[PtCl（H2O）（pip）2]＋ and trans-[Pt（H2O）2（pip）2]2＋ are the active agents,respectively. For the reaction of trans-Pt-chloroaqua （or diaqua） to cis-monoadduct,we obtain the same transition-state structure as from the reaction of trans-Pt-chloroaqua （or diaqua） to trans-monoadduct,which seems that the trans-Pt-chloroaqua （or diaqua） complex can generate trans-or cis-monoadduct via the same transition-state.

g-C_(3)N_(4)/Ce-W-Ti催化剂SCR脱硝性能及热解动力学

利用水热共沉淀法构筑铈钨钛复合氧化物催化剂,探讨类石墨相氮化碳(g-C_(3)N_(4))对其SCR脱硝性能的影响,并研究非等温条件下Ce/W/Ti活性组分对g-C_(3)N_(4)热分解的作用规律,得到其热解活化能。研究结果表明:当三聚氰胺和硫酸钛质量比为4∶1时,可促使铈钨钛复合氧化物中形成g-C_(3)N_(4),提高了其SCR脱硝性能;且CeWTiO_(z)-Mel_(4)催化剂单位质量Ce/W/Ti活性组分单位时间NO(x)转化率远高于CeWTiO_(z)和CeWTiO_(z)-Mel_(2),几乎是3倍;掺杂的g-C_(3)N_(4)与Ce/W/Ti活性组分之间存在协同效应,但Ce/W/Ti活性组分会催化g-C_(3)N_(4)热分解;随着g-C_(3)N_(4)的热分解,Ce/W/Ti活性组分的催化分解作用增强,对g-C_(3)N_(4)热分解活化能降低更有效。

Electrospun gelatin/chitosan nanofibers containing curcumin for multifunctional food packaging

Recently,food grade nanofiber-based materials have received growing attentions in food packaging.In this work,novel active and intelligent packaging nanofibers based on gelatin/chitosan with curcumin(GA/CS/CUR)were developed via electrospinning technique.Effects of the incorporation of CUR content(0.1%-0.3%,m/m)on the microstructure and functional properties of the electrospun nanofibers were investigated.Morphological studies using scanning electron microscopy indicated that loading CUR can affect the average diameter of nanofiber mats,which remained around 160-180 nm.The addition of an appropriate level CUR(0.2%,m/m)led to a stronger intermolecular interaction,and thus enhanced the thermal stability and tensile strength of the obtained nanofibers.Meanwhile,the incorporation of CUR significantly improved antioxidant activity and the antimicrobial activity of GA/CS/CUR nanofibers.Moreover,the sensitivity of nanofibers to ammonia results indicated that GA/CS nanofibers containing 0.2%CUR(GA/CS/CURⅡ)presented high sensitivity of colorimetric behavior to ammonia(within 3 min).These results suggest GA/CS/CURⅡnanofibers has great potential as a multifunctional packaging to protect and monitor the freshness of proteinrich animal foods,such as meat and seafood.

Improvement of low-temperature catalytic activity over hierarchical Fe-Beta catalysts for selective catalytic reduction of NO_x with NH_3

Hierarchical Fe-Beta obtained by hydrothermal synthesis exhibited higher low-temperature NH_3-SCR activity than conventional Fe-Beta. In order to identify the main factors leading to the difference in catalytic activity, we investigated the pore structure, acidity and Fe sites of the hierarchical Fe-Beta and conventional Fe-Beta. The enhanced activity of hierarchical Fe-Beta was mainly due to the increase of the quantity of active Fe species. NH_3-TPD and DRIFTS results of NH_3 adsorption clearly verified that hierarchical Fe-Beta had more Lewis acid sites, which is beneficial to the adsorption and activation of NH_3. The H_2-TPR, UV–vis DRS, and EPR results confirmed that the hierarchical Fe-Beta had more isolated active Fe species, which may be associated with that the hierarchical structure introduced more structural defects as ion-exchange sites. Based on the analysis of kinetics experiments and the abovementioned characterizations, it can be concluded that the improvement of NH_3-SCR activity was not due to an intrinsic effect of the specific structural characteristics, but was related to more Fe active sites and better dispersion of Fe species in the hierarchical Fe-Beta.

Influence of NH_3-treating temperature on visible light photocatalytic activity of N-doped P_(25)-TiO_2

The influence of NH3-treating temperature on the visible light photocatalytic activity of N-doped P25-TiO2 as well as the relationship between the surface composition structure of TiO2 and its visible light photocatalytic activity were investigated.The results showed that N-doped P25-TiO2 treated at 600℃ had the highest activity.The structure of P25-TiO2 was converted from anatase to rutile at 700℃.Moreover,no N-doping was detected at the surface of P25-TiO2.There was no simply linear relationship between the visible light photocatalytic activity and the concentration of doped nitrogen,and visible light absorption.The visible light photocatalytic activity of N-doped P25-TiO2 was mainly influenced by the synergistic action of the following factors:(i) the formation of the single-electron-trapped oxygen vacancies(denoted as Vo);(ii) the doped nitrogen on the surface of TiO2;(iii) the anatase TiO2 structure.

SO_2在含氮沥青基活性炭纤维上的脱除 Ⅰ含氮沥青基活性炭纤维的脱硫能力研究

由水和氨混合物活化制得的不同比表面积及氮含量的含氮沥青基活性炭纤维［ＰＡＣＦ（ＮＨ３）］在Ｏ２和Ｈ２Ｏ存在下脱除ＳＯ２的能力进行了研究。ＸＰＳ结果表明，ＰＡＣＦ（ＮＨ３）表面的含氮官能团主要为类吡咯氮、类吡啶氮及铵盐，它们的主要作用是增强对水的吸附。当比表面积相近，氮含量增加时或者氮含量相近，比表面积增大时，均导致ＰＡＣＦ（ＮＨ３）的脱硫能力增强，这与ＰＡＣＦ（ＮＨ３）对水的吸附量增加有关。

准噶尔盆地地层活化水的成因与油气藏关系

精选并研究了准噶尔盆地252个活化水样,发现矿化度大、活化系数高、处于活化早期状态的NaHCO3水分布在克拉玛依油田九区—乌尔禾油田—风城油田—玛湖油田一带,同时地层水中微量元素硼(B)、铵(NH+4)、有机氮的含量呈现异常高值分布。这一带正是准噶尔盆地主要的“地幔上涌区”和大断裂通过区。盆地东部另一“地幔上涌区”的五彩湾油区一带,也有较多活化水出现。过去评价地下环境的封闭性只靠CaCl2型水的“变质系数(rNa/rCl)”,现在对NaHCO3型水所在的环境也可评价其封闭性;有活化水的存在,可望找到油气藏;并可以推测有否轻质油藏、判断油气藏的相对形成期。

不同氮源对结瘤小麦植株生长及其固氮活性的影响

用Ｎｉｔｒｏ苜蓿根瘤菌（Ｍｅｄｉｃａｇｏｓｐ．）诱导小麦结瘤并研究不同氮源对植株生长和结瘤的影响．研究表明，在一定浓度范围内，ＮＯ３－和ＮＨ４＋均能促进植株生长和类根瘤的形成，植株干重的增加与培养基中ＮＯ３－的减少量呈正相关，该种类根瘤具有一定的固氮活性．

磁性铁基氧化物SCR脱硝催化剂的改性研究

为获得脱硝性能良好的铁基催化剂,采用微波辅助柠檬酸溶胶凝胶法一步制备新型磁性铁基SCR脱硝催化剂,考察铈钨助剂对其SCR脱硝性能的优化,并研究了煅烧温度和柠檬酸添加量对催化剂脱硝性能的影响。结果表明:微波辅助柠檬酸溶胶凝胶法可快速得到新型磁性铁铈钨复合氧化物催化剂;铈掺杂可提高催化剂SCR脱硝性能,当铈掺杂摩尔比由0.05增至0.20,催化剂脱硝效率先增大后减小;钨掺杂也可提高催化剂SCR脱硝性能,随着钨掺杂摩尔比由0.025增至0.10,催化剂脱硝效率先升高后降低;合适的铈、钨掺杂摩尔比为n(Fe)∶n(Ce)∶n(W)=0.85∶0.10∶0.05。当煅烧温度由400℃升至600℃或柠檬酸/金属阳离子摩尔比由0.25增至0.10时,Fe_(0.85)Ce_(0.10)W_(0.05)Oz催化剂脱硝效率均先增大后减小,合适的煅烧温度与柠檬酸/金属阳离子摩尔比分别为500℃和0.50。

亚低温与硝铵配比对番茄幼苗渗透调节物质及抗氧化酶活性的影响

【目的】探索亚低温及不同硝铵配比对番茄幼苗渗透调节物质及抗氧化酶活性的影响,为通过合理施肥调控番茄抵御亚低温危害提供参考。【方法】以番茄为材料,采用温室水培的方法,对比研究了常温(15~25℃)和亚低温(8~15℃)下营养液中NO-3-N/NH+4-N比例分别为100/0,75/25,50/50,25/75和0/100时对温室番茄幼苗抗寒性的影响。【结果】与常温条件相比,亚低温使番茄幼苗叶片O-·2产生速率、丙二醛(MDA)含量、脯氨酸含量、超氧化物歧化酶(SOD)活性升高;使番茄植株叶片可溶性蛋白含量和过氧化氢酶(CAT)、过氧化物酶(POD)活性降低。不论在亚低温还是在常温下,NO-3-N/NH+4-N比例为75/25时植株的抗寒性最强,此后随NH+4-N比例的增大抗寒性减弱。【结论】亚低温条件下,NO-3-N/NH+4-N比例为75/25时最有利于提高番茄植株的抗寒性。

不同退化程度对高寒草甸土壤无机氮及脲酶活性的影响

以东祁连山围封草地(FG)、轻度退化草地(LD)、中度退化草地(MD)、重度退化草地(HD)4种类型高寒草甸为研究对象,分别在春季、夏季和冬季采集各类型高寒草地0~10cm、10~20cm和20~30cm土层的土壤样品,研究了土壤的无机氮总量、铵态氮(NH_4^+-N)、硝态氮(NO_3^--N)含量及土壤脲酶活性,以明确不同退化程度对高寒草甸土壤无机氮和脲酶活性特征及其季节动态的影响。结果表明,草地退化对表层土壤的无机氮总量影响较大,春季和夏季3种不同退化程度高寒草地土壤无机氮总量均显著升高,春季LD、MD和HD分别比FG升高了39.9%、28.9%和68.4%,夏季分别升高了19.1%、28.7%和33.6%,但冬季却显著降低,LD、MD和HD分别比FG降低了20.4%、27.2%和47.4%。土壤无机氮形态的研究结果表明草地退化对土壤无机氮形态的效应存在季节差异,草地退化导致春季表层土壤铵态氮含量升高,而对硝态氮含量影响不大,从而导致土壤无机氮总量升高,而夏季情况正好相反,草地退化对夏季表层土壤的铵态氮含量影响不大,而硝态氮含量升高,同样导致土壤无机氮总量升高。草地退化对脲酶活性的影响同样存在季节差异,相比FG,春季LD和MD的表层土壤脲酶活性显著提高,HD下降,而夏季和冬季随着退化程度的加剧,脲酶活性均表现出逐渐升高的趋势,表明轻度和中度退化加快了春季高寒草甸土壤氮素的转化,增加了土壤无机氮的供应能力。

利用含砷氧化锌尘制备活性氧化锌

用 NH3- (NH4) 2 SO4溶液浸取处理含砷氧化锌尘 ,可彻底清除砷 ,制备出合格的活性氧化锌。对于含砷质量分数为 1%～ 2 %的原料 ,产品中所含砷质量分数可降至 0 .0 0 0 5 %以下。该方法具有除砷彻底、不易产生二次污染的优点 ,为含砷氧化锌尘的综合利用提供了一种新方法。

硝酸铵气溶胶挥发动力学

研究了单分散ＮＨ４ＮＯ３干气溶胶在流动反应器内的挥发动力学．结果表明，挥发反应符合零级反应，凝聚反应符合二级反应．ＮＨ４ＮＯ３气溶胶计算粒径为０．６５μｍ，计算数浓度为８０—１２０个／ｃｍ３时，挥发和凝聚反应的表观活化能分别为２８１．７９ｋＪ／ｍｏｌ和９７．５４ｋＪ／ｍｏｌ，表观速率常数的指数前因子分别为６．８１×１０４７μｌ·ｍ－３·ｍｉｎ－１（ｐｐｂｖ·ｍｉｎ－１）和１．１３×１０１４μｌ－１·ｍ３·ｍｉｎ－１（ｐｐｂｖ－１·ｍｉｎ－１）．说明ＮＨ４ＮＯ３气溶胶的挥发受化学反应控制．

Effect of preparation methods on the performance of CuFe-SSZ-13 catalysts for selective catalytic reduction of NO_x with NH_3

CuFe-SSZ-13 catalyst showed excellent performance in the selective catalytic reduction of NO_x with NH_3(NH_3-SCR) for diesel engine exhaust purification. To investigate the effect of preparation methods on NH_3-SCR performance, Fe was loaded into one-pot synthesized Cu-SSZ-13 catalysts through solid-state ion-exchange(SSIE), homogeneous deposition precipitation(HDP) and liquid ion-exchange(IE), respectively. Three CuFe-SSZ-13 catalysts showed similar SO_2 resistance, which was better than that of Cu-SSZ-13. The improvement was attributed to the protection of Fe species. Hydrothermal stability of three CuFe-SSZ-13 catalysts was significantly different, which was attributed to the state of active species caused by different preparation methods. Compared with the other two catalysts, more active species existed inside the zeolite pores of CuFe-SSZ-13 SSIE. During hydrothermal aging, the aggregation of these active species in the pores caused the collapse of catalyst structure, ultimately leading to the deactivation of CuFe-SSZ-13 SSIE. In contrast, Fe species was dispersed better on the surface over CuFe-SSZ-13 IE, enhancing the hydrothermal stability of catalysts. Consequently, Fe loading effectively improved the resistance of SO_2 and H_2O over Cu-SSZ-13. For CuFe-SSZ-13, large amounts of active species located inside the zeolite pores are not beneficial for the hydrothermal stability.

海水盐度对完全混合活性污泥法氨氮去除率的影响研究

采用完全混合活性污泥法研究了大生活用海水进入城市污水系统后 ,海水盐度对曝气池中NH3—N去除率的影响 ,同时研究了不同海水盐度下 ,温度、pH值的变化对NH3—N去除率的影响。实验结果表明 ,污水中海水占 1 2 %时 ,对曝气池中NH3—N的去除率无太大影响 ;但是当提高到 2 4 %时 ,NH3—N去除率有所降低 ;海水盐度达 36%时 ,NH3—N去除率明显降低。温度的升高 ,有利于去除NH3—N ,尤其是高海水盐度下 ,温度的影响更为明显。海水存在时 ,脱除氨态氮的最适宜pH值为 8 0～ 8 5。

化学反应速度及活化能测定实验研究

针对化学反应速度及活化能测定实验中经常遇到的困难 ,分析了实验失败的主要原因 ,是由于固体 (NH4) 2 S2 O8试剂中含有少量水而引起的 ,提出了用Na2 SO3 及以痕量碘加速过量Na2 SO3

Promotional mechanism of activity of CeEuMnO_(x) ternary oxide for low temperature SCR of NO_(x)

Due to strong synergistic effect of the elements,a series of XEuMnO_(x) ternary oxides(X=Ce,Ni,Co,Sb,Sn,Mo) were synthesized by one-pot co-precipitation method,and composite components were identified and optimized to maintain high activity and superior SO_(2)and H_(2)O endurance in selective catalytic reduction of NO_(x)with NH_(3)(NH_(3)-SCR).NO_(x)conversion of CeEuMnO_(x) ternary oxide catalysts attains more than 90% at 100-250℃,and finally achieves 74%under existence of 50×10^(-6)SO_(2) and 10 vol% H_(2)O at 230℃.The facile electron transfer through redox cycle of Mn^(3+)+Ce^(4+)■Mn4++Ce^(3+) and enhanced oxygen mobility can promote formation of more Mn species in high oxidation state and chemisorbed oxygen,accelerating oxidation of NO and the adsorbed NO_(2) formed can facilitate"fast SCR"reaction to improve low-temperature activity.In situ diffuse reflectance infrared Fourier transform spectroscopy(DRIFTS)study reveals that addition of Ce to EuMnO_(x)catalyst boosts adsorption of NH_(3)and NO_(x)species.NH_(3)species are activated as crucial intermediate(NH_(2))to promote NH_(3)-SCR reaction.This research provides a novel material for practical deNO_(x)application of stationary source combustion flue gas in the future.

One-pot synthesis of Fe/Cu-SSZ-13 catalyst and its highly efficient performance for the selective catalytic reduction of nitrogen oxide with ammonia

Series of Fe/Cu-SSZ-13 catalysts with different Fe loading content were synthesized by simple one-pot strategy.The obtained catalysts were subjected to selective catalytic reduction(SCR)of NO x with NH 3 and were characterized by various techniques.The results show that Fe 0.63/Cu 1.50-SSZ-13 catalyst with proper Fe content exhibits excellent catalytic activity with widest operation temperature window from 160 to 580℃,excellent hydrothermal stability as well as good resistance to sulfur poisoning when compared with Cu-SSZ-13,signifying its great potential for practical applications.Further characterizations reveal that the synthesized Fe/Cu-SSZ-13 catalysts present typical chabazite(CHA)structure with good crystallinity,while isolated Cu^2+and monomeric Fe 3+are revealed as the predominant copper and iron species.At low temperatures,isolated Cu^2+species act as primary active sites for SCR reaction,while monomeric Fe^3+species provide sufficient active sites for sustain the SCR activity at high temperature.Moreover,Fe over doping would lead to the damage of zeolite structure,destruction of isolated Cu^2+site,as well as the formation of highly oxidizing Fe2O3,thus causing deterioration of catalytic performances.