焦化脱硫废液中POPs的SCWO实验及动力学研究

采用连续超临界水氧化(SCWO)工业化中试装置,对某工业焦化脱硫废液中代表性的主要5种持久性有机污染物(喹啉、吲哚、吡啶、萘和联苯)进行了超临界状态下(P=28 MPa,T=380⁵30℃)的动力学研究。以COD为表征,研究5种POPs的去除率,建立了SCWO宏观动力学方程并确定相关动力学参数。结果表明,超临界状态下,当O_2过量,停留时间为30530℃)的动力学研究。以COD为表征,研究5种POPs的去除率,建立了SCWO宏观动力学方程并确定相关动力学参数。结果表明,超临界状态下,当O_2过量,停留时间为30⁹0 s时,5种POPs的去除率随着反应温度的升高和停留时间的延长而增加,去除率均在83.98%90 s时,5种POPs的去除率随着反应温度的升高和停留时间的延长而增加,去除率均在83.98%⁹9.46%之间,反应活化能Ea介于28.58899.46%之间,反应活化能Ea介于28.588⁴2.667 k J/mol之间,频率因子k0介于11.27842.667 k J/mol之间,频率因子k0介于11.278⁸6.403 s-1之间,反应级数a介于0.934 4386.403 s-1之间,反应级数a介于0.934 43¹.094 09,表明污染物分子结构影响降解效率。     

甲硫醚降解菌JLM-8的分离鉴定与降解条件优化

从制药厂的活性污泥中分离到一株能以唯一碳源和硫源降解甲硫醚的菌株JLM-8,经过生理生化测试与16S rDNA系统发育树分析鉴定为嗜麦芽寡养单胞菌(Stenotrophomonas maltophilia)。通过测定菌株的生长量、甲硫醚的降解率,利用响应面法优化最佳降解条件,并测定了该菌降解甲硫醚的动力学参数。结果表明:当接种量为25 mg·L^-1时,通过响应面法优化的最佳降解条件为温度31.3℃、pH 7.5,初始甲硫醚浓度50 mg·L^-1时最大预测降解率为98.2%,实验验证降解率为97.9%。菌株降解动力学参数最大比降解速率、半饱和系数、抑制系数分别为2.37 h^-1、143.55 mg·L^-1、51.35 mg·L^-1,临界抑制浓度为78.46 mg·L^-1。     

介质阻挡放电低温等离子体降解甲硫醚

在线-筒式反应器中,应用介质阻挡放电低温等离子体对甲硫醚的降解进行实验研究.采用BPFN型窄脉冲高压电源供电,考察了重复频率、峰值电压、初始浓度、气体流量等单因素对去除率的影响.结果表明,介质阻挡放电能够有效地去除甲硫醚废气.甲硫醚去除率随着重复频率的增加而上升,但能量利用率却降低,本实验中采用重复频率为100 Hz较合适.当气体流量为1000 mL·min-1、初始浓度为906 mg·m-3时,甲硫醚去除率可达100%,此时能量利用率为0.864 mg·kJ-1.当甲硫醚初始浓度为525 mg·L-1,气体流量由1000 mL·min-1增加至2000 mL·min-1时,甲硫醚去除率由100%降低至85.7%,但是能量利用率却由0.706 mg·kJ-1升高至1.210 mg·kJ-1.     

生物滴滤塔处理甲硫醚气体动力学模型的研究

在生物滴滤塔内描述宏观动力学,建立塔内甲硫醚的浓度分布和降解理论模型,结合实验对建立的模型进行验证,得到K_m=18.7 g·m~(-3),ν_(max)=112.1 g·m~(-3)·h~(-1)。当进气浓度为10~100 g·m~(-3)时,随进气浓度的增加出气浓度逐渐增加,甲硫醚去除率逐渐下降,随着填料高度的增加,气体浓度不断减小,模型预测结果与实验结果差值增加。在进气流量为1~15 L·min~(-1)时,随进气流量的增加,甲硫醚的去除率降低,实验与模型预测结果基本一致,进气流量增加两者误差在5%内波动。     

微波场中两种吸波材料氧化处理p-硝基酚溶液

考察了活性炭和炭化硅两种材料的吸波能力和微波辅助氧化处理p-硝基酚(PNP)溶液的情况.对活性炭固定床而言,1618 mg•L^-1 PNP溶液的微波去除率和矿化率分别为96%和91%,而炭化硅固定床上的去除率和矿化率则最高为73%和24%.3种高浓度(3540、6858 mg•L^-1和11095 mg•L^-1)PNP溶液在活性炭固定床上的微波降解率均大于98%,矿化率均高于96%.活性炭和炭化硅微波辅助氧化降解PNP的中间产物同为o-硝基酚、苯酚和苯醌.活性炭固定床微波降解PNP溶液后出水的可生化性得到明显提高.     

微波强化Fenton氧化法降解水中阴离子表面活性剂的研究

采用微波/Fenton氧化法降解水中阴离子表面活性剂十二烷基苯磺酸钠(SDBS).比较了微波辐射、Fenton氧化和微波/Fenton氧化3种方法对SDBS的降解效果;考察了H2O2与Fe2+的摩尔比、Fenton试剂投加量、微波功率、溶液pH、反应时间等因素对SDBS降解效果的影响.结果表明,微波辐射可以强化Fenton试剂对SDBS的氧化作用,明显提高SDBS的降解效率,显著缩短反应时间,并能促进SDBS的矿质化,提高TOC去除率;微波辐射与Fenton氧化对SDBS的矿质化具有明显的协同效应.微波/Fenton氧化法降解SDBS的最佳工艺条件为:pH为3,n(H2O2):n(Fe2+)为195,Fenton试剂投加量为140mmol·L-1,微波功率为500W,反应时间为10min.在此工艺条件下,SDBS和TOC去除率分别可达99%和68%.     

微波无极紫外点阵光催化氧化降解酸性蓝BGA的研究

以不规则石英片作为TiO2光催化剂的载体.与微波无极紫外灯形成点阵光催化氧化降解酸性蓝BGA.通过比较不同反应体系的处理效果,验证了微波无极紫外点阵光催化氧化法的优越性.实验结果表明,当反应时间为60 min、H2O2 投加量2 mL/L、酸性蓝BGA初始质量浓度300 mg/L、曝气量0.15 L/min时,其对酸性蓝BGA废水的TOC去除率和脱色率分别达到42.74%和90.17%.在降解的过程中它受pH影响较大,采用分段控制pH的方法,能够进一步提高脱色效果.     

微波/H2O2工艺降解水中微量硝基苯的试验研究

利用MW/H2O2高级氧化技术处理水中微量硝基苯(NB),研究了该工艺对硝基苯的去除效果,分析了微波功率、H2O2投加量、硝基苯初始质量浓度、水中普遍存在的腐植酸和碳酸氢根对MW/H2O2工艺降解硝基苯的影响.结果表明,MW/H2O2工艺在处理2L初始质量浓度为300 μg·L-1的硝基苯时效果显著,32 min后NB去除率就达88.5％,远高于单独H2O2氧化或单独的微波辐射.试验中该工艺最佳微波功率为300W,随H2O2投加量和NB初始质量浓度的增加,MW/H2O2对NB的去除率先增后减,但单位H2O2降解NB的量始终随着NB初始质量浓度的增加而增大.腐植酸对MW/H2O2氧化降解硝基苯有显著的抑制作用,但HCO3-却对硝基苯的氧化降解有一定的促进作用.     

活性炭吸附协同介质阻挡放电降解甲硫醚

采用活性炭协同介质阻挡放电技术对恶臭物甲硫醚去除进行了研究.结果表明,甲硫醚去除率随着能量密度的提高而上升.在相同能量密度下,等离子体反应器中引入活性炭可以显著提高去除率.当能量密度大于288 J·L-1时,甲硫醚去除率＞98%.甲硫醚去除率随着初始浓度和气体流量的增大而降低.本实验中,湿度显著影响甲硫醚在活性炭协同等...     

电离放电形成高浓度臭氧水溶液方法

臭氧水溶液(臭氧水)可在几秒钟内无选择致死微小生物及灭活病毒,最终将有机污染物氧化分解为CO_2、H_2O。采用强电离放电将氧离解、电离,离解电离成O、O^-、O-、O⁺、O(+、O(¹D)和O_2(a1D)和O_2(a¹Δg)等活性粒子,其中O1Δg)等活性粒子,其中O^-和O_2(a-和O_2(a¹Δg)活性粒子在强电离放电电场的放电通道中反应形成浓度高达268 mg/L O_3,之后再用强激励方法把O_3高效率溶于水中形成高浓度臭氧水。当强电离放电电场强度为96 kV/cm,放电功率为363 W,臭氧溶于水反应时间为6.2 min时,臭氧水浓度达到38.5 mg/L,将为臭氧水溶液应用提供有利基础条件。     

Computational spectroscopy and DFT investigations into nitrogen and oxygen bond breaking and bond making processes in model deNOx and deN2O reactions

Molecular DFT modeling combined with computational spectroscopy (EPR and IR) were applied for analysis of the NO bond breaking and NN and OO bond making in the context of deNO_x and deN₂O reactions. Interaction of NO, N₂O and NO₂ with cationic (transition metals) and anionic (surface O²⁻ ions) centers was explored at the molecular level. The elementary events such as reactant coordination, charge and spin redistributions, which are principal molecular constraints for efficient decomposition of the nitrogen oxides (N₂O and NO) were discussed. Particular attention was paid to dynamics of the NO bond cleavage in N₂O molecule through electron and oxygen atom transfer routes, evaluation of preferable coordination modes of NO, discrimination between inner- and outer-sphere mechanism of NN bond formation, and the influence of spin and electronic redistribution on the reaction course (spin catalysis). Owing to their simplicity and well known surface chemistry, model systems selected for studies of such processes include MoO_x/SiO₂, MgO and ZSM-5 zeolite exchanged with various transition metal ions (TMI) of different electron configuration and spin multiplicity: Mo⁵⁺ (d¹, ²D) Fe³⁺, Mn²⁺, Cr⁺ (d⁵, ⁶S), Fe²⁺ (d⁶, ⁵D), Co²⁺ (d⁷, ⁴F), Ni²⁺ (d⁸, ³F), Cu²⁺ (d⁹, ²D) and Cu⁺, Zn²⁺ (d¹⁰, ¹S).     

Vanadium peroxocomplexes as oxidation catalysts of sulfur organic compounds by hydrogen peroxide in bi-phase systems

New vanadium oxodiperoxocomplexes Bu₄N⁺[VO(O2)₂ L₂]⁻ were synthesized, where L=pyridine (1), 2-methylpyridine (2), 4-methylpyridine (3), 2-oxymethylpyridine (4). All complexes were characterized by NMR (¹H, ⁵¹V) and IR spectroscopy. The oxidation of sulfur organic compounds and diesel fuel desulfurization catalyzed by vanadium peroxocomplexes in bi-phase system was investigated in various solvents. The complexes manifested high catalytic activity and selectivity in oxidation of sulfides.     

Synthesis and characterization of the layered sodium silicate ilerite

A sodium ilerite, molar ratios 1Na₂O:8.2SiO₂:10.2H₂O, was obtained with a good crystalline structure and characterized by several NMR techniques in addition to X-ray diffraction (XRD). The X-ray pattern of the as-synthesized ilerite is in very good agreement with the structure proposed by Gies and coworkers. The narrow ²⁹Si MAS NMR signals (FWHM=0.3 ppm) indicate a good short-range order of the framework. The proton dynamics influences several ²⁹Si NMR parameters. The 16 ppm signal in the ¹H MAS NMR spectra is explained by a proton in a bridging position in the short (2.3 Å) O4–O4 bonding. The quadrupole coupling constant C_qcc=100 kHz with η=0.2 for the 16 ppm signal, which was obtained from the ²H MAS NMR spectra, confirms this explanation. ¹⁷O NMR shows also a separate signal for SiOH groups but cannot resolve the three expected lines for SiOSi. PFG NMR detects a small mobile portion of water in the ilerite, which is located probably on the external surface of the crystallites. An intracrystalline diffusion coefficient of the intercalated water molecules of the order of magnitude 10⁻¹⁵ m² s⁻¹ was obtained by NMR tracer exchange experiments.     

反气相色谱法与汉森溶解度参数软件测定原煤的三维溶解度参数

采用反气相色谱法（IGC）研究原煤在温度433.15、443.15、453.15、463.15和473.15 K时的三维溶解度参数（HSP）,并使用外推法得到原煤室温（298.15 K）时HSP的色散力分量（δ_d）、极性力分量（δ_p）、氢键力分量（δ_h）以及校正溶解度参数（δ_t）分别为δ_d=20.83（J·cm^-3）^1/2,δ_p=11.95（J·cm^-3）^1/2,δ_h=11.08（J·cm^-3）^1/2,δ_t=26.44（J·cm^-3）^1/2。同时,采用汉森三维溶解度参数软件（HSPiP）模拟原煤在室温下的HSP,得到δ_d=19.92（J·cm^-3）^1/2,δ_p=11.18（J·cm^-3）^1/2,δ_h=11.47（J·cm^-3）^1/2,δ_t=25.56（J·cm^-3）^1/2。IGC与HSPiP得出的数据一致,研究结果为煤的热力学性质研究及其溶胀剂的选择等应用提供了参考。     

醚基高铼酸盐离子液体的催化性能研究

自合成两种新型醚基高铼酸盐离子液体：1-(2-甲氧基乙基)-3-乙基咪唑高铼酸盐（[C₂2O1Im][ReO₄]）和1-(2-乙氧基乙基)-3-乙基咪唑高铼酸盐（[C₂2O2Im][ReO₄]）,并利用核磁共振氢谱/碳谱、拉曼光谱、质谱和差示扫描量热等方法表征,确定是目标产物。环氧化合物是一种化学性质活泼且易转化为其他物质的有机合成中间体,烯烃的环氧化反应是合成环氧化合物的一种重要途径,因此建立以新型醚基高铼酸盐离子液体为溶剂兼催化剂的环辛烯环氧化均相反应体系,系统研究反应温度、时间、氧化剂用量、催化剂用量及循环使用等因素的影响。结果表明,产率大于90%,反应选择性大于99%,催化剂循环5次,产率无明显下降。     

Formation of singlet molecular oxygen associated with the formation of superoxide radicals in aqueous suspensions of TiO2 photocatalysts

The production and decay of singlet molecular oxygen (¹O₂) in TiO₂ photocatalysis were investigated by monitoring its phosphorescence under various reaction conditions. First, the effects of additives such as KBr, KSCN, KI, H₂O₂, and ethanol on the amount of ¹O₂ produced by photo excitation of P25 TiO₂ were measured. The same additives were employed to investigate the effect on the amount of O₂⁻ produced. Comparison between the effects on ¹O₂ and O₂⁻ suggested that ¹O₂ is formed by the electron transfer mechanism, the reduction of molecular oxygens to O₂⁻ by photogenerated electrons and the subsequent oxidation of O₂⁻ to ¹O₂ by photogenerated holes. The formation of ¹O₂ decreased at pH < 5 and pH > 11, indicating that the intermediate O₂⁻ is stabilized at the terminal OH site of the TiO₂ surface in the pH range of 5 < pH < 11. Eighteen commercially available TiO₂ photocatalysts were compared on the formation of ¹O₂ and O₂⁻ in an aqueous suspension system. The formation of ¹O₂ was increased with decreasing size of TiO₂ particles, indicating that a large specific surface area causes a higher possibility of reduction producing O₂⁻ and then a large amount of ¹O₂ is formed. The difference in the crystal phase (rutile and anatase) did not affect the formation of ¹O₂.     

氰化尾渣矿浆电解液中铁离子的萃取富集

采用二(2-乙基己基)磷酸酯(P204)-磺化煤油萃取体系从高硫酸氰化尾渣矿浆电解液中富集铁离子,重点研究了P204浓度、相比(O/A)、振荡时间、振荡频率及温度等对Fe³⁺萃取率的影响及其萃取过程。研究表明,在P204体积分数为25%、电解液pH为1.5、温度25℃、O/A=1∶1、振荡时间10 min、振荡频率180r/min的条件下,电解液中Fe³⁺的单级萃取率可达97.73%以上,饱和萃取容量可达到21.57g/L。Fe³⁺在有机相中的萃取富集主要归因于其与P204分子结构中羟基的阳离子交换反应以及磷酰基的配位反应,形成的配合物为FeSO₄A(HA)₃与FeA₃(HA)₃。在草酸1mol/L、O/A=1∶1、振荡时间10min、振荡频率190r/min的条件下,负载有机相中Fe³⁺的单级反萃率可达82.64%以上,反萃液中铁主要以[Fe(C₂O₄)_3<...     

Study of surface reaction mechanisms by O/O and H/D isotopic exchange

Surface diffusion of active species is a general phenomenon in catalysis: rates of migration often being much higher than turnover frequencies of reaction, surface species can migrate and visit a great number of active sites in between two successive catalytic cycles. ¹⁶O/¹⁸O and H/D isotopic exchange is a very useful technique to elucidate reaction mechanisms involving mobility steps of O- and H-containing reactive species. The method is based on the measurement of the rates of exchange between gaseous ¹⁸O₂ (or D₂) and ¹⁶O species (or OH) species of the support via metal particles, small metallic clusters acting as porthole of O or H on the support. Simple kinetic models allow to calculate surface and bulk diffusivities on the oxide used as support. As a rule, a significant O mobility can only be observed above 200 °C for most oxides. Furthermore, very great differences of diffusivity (five orders of magnitude) are recorded between silica (on which OH groups are virtually immobile) and oxides like ceria exhibiting a very high oxygen mobility. Differences of diffusivity (two orders of magnitude) are much less for hydrogen than for oxygen. This method can give useful information about reactions catalyzed by metal/oxide systems in which surface diffusion can play a decisive role in the mechanism: steam reforming, water gas shift, hydrocarbon oxidation, aromatic hydrogenation, methanol synthesis, coke formation). For oxides such as Ce_xZr_1−xO₂ mixed oxides, O mobility is so high that surface and bulk mobility can no longer be distinguished. More complex kinetic models requiring computer simulation of all the steps of adsorption, desorption, diffusion and exchange simultaneously have been developed.     

Exchange and oxidation of CO on O-predosed Rh---Al2O3 and Rh---CeO2 catalysts

Exchange and oxidation of C¹⁶O were investigated at 450°C on ¹⁸O-predosed Rh and Pt catalysts supported on A1₂O₃, CeO₂ and CeO₂-Al₂O₃. In all cases, a rapid exchange of C¹⁶O with the surface can be observed. CO oxidation leads to C¹⁶O₂, C¹⁶O¹⁸O and C¹⁸O₂. Significant formation of C¹⁶O₂ is due to the relatively high ¹⁶O coverage in reaction resulting from the C¹⁶O exchange and from an exchange between O surface species and ¹⁶O internal atoms. Hydrogen is also formed via a water-gas shift reaction (CO + surface OH) in higher proportion on CeO₂-containing catalysts than on A1₂O₃. Chlorine inhibits all the reactions (exchange, oxidation and WGS) and particularly the internal exchange.