脱硫脱硝后V2O5/AC在含NH3气氛中的再生及硫资源化的耦合过程研究

V2O5/AC具有很好的烟气同时脱硫脱硝能力,脱硫过程包括其对烟气中SO2的吸附、吸附饱和后SO2从其上的脱附（再生）及脱附出SO2的资源化。考察了同时脱硫脱硝后的V2O5/AC在含NH3气氛中的再生和硫资源化的耦合过程。研究了NH3注入量、再生温度、再生时间和尾气循环流量对再生效率、硫回收率及二次脱硫脱硝活性的影响。结果表明,再生温度和再生时间主要影响SO2的脱附,因而影响再生效率和二次脱硫脱硝活性;NH3注入量不影响SO2的脱附,但明显影响硫回收率和二次脱硫脱硝活性;尾气循环模式是提高硫回收率的重要方法,但在研究的条件下循环流量对再生效率、硫回收率和二次脱硫脱硝活性的影响不大。     

Ceramic Filter Balls Loaded with α-Fe2O3 and Their Application to NH3-N Wastewater Treatment

Hydrolysis reaction of Fe(NO₃)₃ at a high temperature in the presence of urea as the homogeneous precipitant was studied. With the prepared ceramic filter balls loaded with α-Fe₂O₃ after high temperature calcination, the loading of α-Fe₂O₃ on the porous ceramic filter balls from Fe(NO₃)₃ solutions of different concentrations and mechanical stability of the loaded α-Fe₂O₃ were studied. The product was characterized using XRD and SEM. Adsorption experiments were conducted to evaluate the performance of the product in adsorbing NH₃-N. It turned out that the specific surface area of the ceramic filter balls loaded with α-Fe₂O₃ had increased to 36.5387 m²/g from original 4.6127 m²/g. When the concentration of Fe(NO₃)₃ was 0.40 mol/L, the loading of α-Fe₂O₃ on the ceramic filter balls accounted for 8.4% of the total mass of the adsorbent and α-Fe₂O₃ was adsorbed on the filter balls very well. The adsorption isotherm of NH₃-N on the ceramic filter ball adsorbent loaded with α-Fe₂O₃ was of Langmuir type. The saturated adsorption capacity was 3.33 mg/L, and the adsorption constant K was 0.1873. NH₃-N was adsorbed by α-Fe₂O₃ more easily, which was a kind of specific adsorption.     

Electrochemical Oxidation of Ammonia on Ir Anode in Potential Fixed Electrochemical Sensor

Ir catalyst possesses a good electrocatalytic activity and selectivity for the oxidation of NH3 and/or NH4OH at Ir anode in the potential fixed electrochemical sensor with the neutral solution. Owing to the same electrochemical behavior of NH3 and NH4OH in a NaClO4 solution, NH4OH can be used instead of NH3 for the experimental convenience. It was found that the potential of the oxidation peak of NH4OH at the Ir/GC electrode in NaClO4 solutions is at about 0.85 V, and the current density of the oxidation peak of NH4OH is linearly proportional to the concentration of NHaOH. The electrocatalytic oxidation of NH4OH is diffusion-controlled. Especially, Ir has no electrocatalytic activity for the CO oxidation, illustrating that CO does not interfere in the measurement of NH4OH and the potential fixed electrochemical NH3 sensor with the neutral solution, and the anodic Ir catalyst possesses a good selectivity. Therefore, Ir may have practical application in the potential fixed electrochemical NH3 sensor with the neutral solution.     

NH4+ Charge Carrier Coordinated H-Bonded Organic Small Molecule for Fast and Superstable Rechargeable Zinc Batteries

Organic small molecules as high-capacity cathodes for Zn-organic batteries have inspired numerous interests, but are trapped by their easy-dissolution in electrolytes. Here we knit ultrastable lock-and-key hydrogen-bonding networks between 2, 7-dinitropyrene-4, 5, 9, 10-tetraone (DNPT) and NH₄⁺ charge carrier. DNPT with octuple-active carbonyl/nitro centers (H-bond acceptor) are redox-exclusively accessible for flexible tetrahedral NH₄⁺ ions (H-bond donator) but exclude larger and rigid Zn²⁺, due to a lower activation energy (0.14 vs. 0.31 eV). NH₄⁺ coordinated H-bonding chemistry conquers the stability barrier of DNPT in electrolyte, and gives fast diffusion kinetics of non-metallic charge carrier. A stable two-step 4e⁻ NH₄⁺ coordination with DNPT cathode harvests a high capacity (320 mAh g⁻¹), a high-rate capability (50 A g⁻¹) and an ultralong life (60,000 cycles). This finding points to a new paradigm for H-bond stabilized organic small molecules to design advanced zinc batteries.     

导电玻璃上室温沉积钛膜及TiO2纳米管阵列的制备与表征

在掺氟的杂nO2(FTO)导电玻璃衬底上采用射频磁控溅射的方法室温沉积纯Ti薄膜, 以NH4F/甘油为电解液, 经电化学阳极氧化得到结构有序、微米级的TiO2纳米管阵列/FTO复合结构, 并通过场发射扫描电子显微镜(FESEM)、X射线衍射(XRD)以及光电化学的方法对纳米管阵列进行了表征. 研究表明, 在氩气气压为0.5 Pa, 功率为150 W, 时间为0.5 h条件下在导电玻璃上室温沉积获得钛膜的结构为晶带T型组织, 表面均匀性好且致密度较高; 在电压为30 V下, 随着阳极氧化时间从1 h延长至3 h, 纳米管的管径从50 nm增加到75 nm, 纳米管的长度从750 nm增至1100 nm后减至800 nm, 管壁由平滑变为波纹状; 随氧化电压的升高, 纳米管管径逐渐增大, 而表面覆盖物逐渐减少, 可通过在稀的HF溶液(0.05%(w, 质量分数))中超声清洗去除; 此外, 瞬态光电流测试表明结晶的电极表现出更好的光电转换性能, 紫外光照射下能促进TiO2光生载流子有效分离, 在热处理温度为450 ℃时, 具有较高的光电化学性能.     

以ZrO2-TiO2为载体的整体式锰基催化剂应用于低温NH3-SCR反应

以MnO2为活性组分, Fe2O3为助剂, 制备了以TiO2及ZrO2-TiO2为载体的整体式催化剂. 考察了它们在不同温度焙烧后应用于富氧条件下, NH3选择性催化还原(NH3-SCR)氮氧化物的低温反应性能和高温稳定性. 用X射线衍射(XRD)实验、比表面积测定(BET)、储氧性能测定(OSC)及程序升温还原(H2-TPR)等方法对催化剂进行了表征. 结果表明, 以ZrO2-TiO2为载体的催化剂具有很好的高温热稳定性, 并具有较高的比表面积和储氧能力, 同时具有较强的氧化能力. 催化剂的活性测试结果表明, 以ZrO2-TiO2为载体的整体式锰基催化剂明显地提高了NH3-SCR反应的低温活性, 具有良好的应用前景.     

不同分子筛负载锰铈催化剂的低温NH_3-SCR脱硝性能

分别以β、ZSM-5和USY分子筛为载体,采用浸渍法制备了锰铈催化剂,对其低温NH_3-SCR反应性能进行了评价,并采用XRD、BET、NH_3-TPD、H_2-TPR以及XPS对催化剂进行了表征。结果表明,三种分子筛负载的锰铈催化剂均具有较好的低温NH_3-SCR反应活性,其中,Mn-Ce/USY的催化性能最好,在107℃时NOx转化率可达到90%。负载锰铈后催化剂的比表面积和孔体积均有所下降;活性组分MnOx主要以无定型态分布于催化剂表面,且在ZSM-5上检测到聚集的CeO_2。催化剂表面弱酸对低温NH3-SCR反应起主要作用,催化剂表面上活性组分的表面浓度和氧化态明显不同,较高的Mn~(4+)/Mn~(3+)原子比和吸附氧表面浓度对提高催化剂的低温NH3-SCR反应活性有利。     

Adsorption and Decomposition of NH3 on Ni/Pt(111) and Ni/WC(001) Surfaces: A First-Principles Study

Density functional theory was used to study the NH₃ behavior on Ni monolayer covered Pt(111) and WC(001). The electronic structure of the surfaces, and the adsorption and decomposition of NH₃ were calculated and compared. Ni atoms in the monolayer behave different from that in Ni(111). More dz2 electrons of Ni in monolayer covered systems were shifted to other regions compared to Ni(111), charge density depletion on this orbital is crucial to NH₃ adsorption. NH₃ binds more stable on Ni/Pt(111) and Ni/WC(001) than on Ni(111), the energy barriers of the first N-H bond scission were evidently lower on Ni/Pt(111) and Ni/WC(001) than on Ni(111), these are significant to NH₃ decomposition. N recombination is the rate-limiting step, high reaction barrier implies that N₂ is produced only at high temperatures. Although WC has similar properties to Pt, differences of the electronic structure and catalytic activities are observed for Ni/Pt(111) and Ni/WC(001), the energy barrier for the rate-determined step increases on Ni/WC(001) instead of decreasing on Ni/Pt(111) when compared to Ni(111). To design cheaper and better catalysts, reducing the N recombination barrier by modifying Ni/WC(001) is a critical question to be solved.     

超高效液相色谱-串联质谱法测定斑马鱼性腺中13种类固醇激素

建立了超高效液相色谱-串联质谱测定雌性斑马鱼性腺中13种类固醇激素的分析方法。雌鱼性腺分别经预冷的乙腈、乙酸乙酯浸提后,氨基(NH2)、亲水-亲脂平衡介质(HLB)固相萃取柱富集净化,ACQUITY UPLCBEH C18色谱柱进行梯度分离。采用多反应监测模式扫描,基质匹配外标法定量。研究了不同提取溶剂对13种类固醇激素的提取效果,考察了固相萃取柱的净化效果,并对斑马鱼性腺进行类固醇激素加标回收率实验,结果表明,13种分析物的平均加标回收率为74.8%~127.0%,相对标准偏差为3.9%~15.8%,方法检出限为0.006~0.300μg/kg。该方法简便、准确、灵敏,可应用于斑马鱼性腺类固醇激素生理水平的检测。     

Reaction mechanism of platinum dimer cation with ammonia based on the relativistic density functional study

The gas‐phase reactions between Pt and NH₃ have been investigated using the relativistic density functional approach (ZORA‐PW91/TZ2P). The quartet and doublet potential energy surfaces of Pt + NH₃ have been explored. The minimum energy reaction path proceeds through the following steps: Pt(⁴Σ_u) + NH₃ → q‐1 → d‐2 → d‐3 → d‐4 → d‐Pt₂NH⁺ + H₂. In the whole reaction pathway, the step of d‐2 → d‐3 is the rate‐determining step with a energy barrier of 36.1 kcal/mol, and exoergicity of the whole reaction is 12.0 kcal/mol. When Pt₂NH⁺ reacts with NH₃ again, there are two rival reaction paths in the doublet state. One is degradation of NH and another is loss of H₂. In the case of degradation of NH, the activation energy is only 3.4 kcal/mol, and the overall reaction is exothermic by 8.9 kcal/mol. Thus, this reaction is favored both thermodynamically and kinetically. However, in the case of loss of H₂, the rate‐determining step's energy barrier is 64.3 kcal/mol and the overall reaction is endothermic by 8.5 kcal/mol, so it is difficult to take place. Predicted relative energies and barriers along the suggested reaction paths are in reasonable agreement with experimental observations. © 2007 Wiley Periodicals, Inc. Int J Quantum Chem, 2007