The effects of activated Al2O3 on the recycling of light oil from the catalytic pyrolysis of waste printed circuit boards

The effects of employing activated Al₂O₃ during the catalytic pyrolysis of waste printed circuit boards (WPCBs) are investigated, focusing on the recycling of light oil. Variations in the pyrolysis process are studied through analysis of the phase distribution, water content and boiling point fractions of the resulting products. Product composition and carbon number distribution are analyzed using gas chromatography techniques. The use of activated Al₂O₃ increases the light oil fraction and also reduces the quantity of brominated products formed. It was determined that the best yield of light oil and most efficient debromination resulted from catalytic pyrolysis at 600 °C. Applying catalyst-to-feed ratios in the range of 1.0–1.5 also maximizes the yield of light oil. The major oil fraction resulting from catalytic pyrolysis has a boiling point range of 0–250 °C and carbon number range of C6–C9, showing for use as a potential fuel after suitable treatment such as hydrogenation. At a higher catalyst-to-feed ratio of 2.0, activated Al₂O₃ generates a high proportion of light oil fractions containing a significant quantity of chemicals such as phenol (52.67% at 600 °C), although an overall lower yield of oil is obtained. The oil produced in this manner may also be used as a raw material feedstock for the production of various other useful chemicals.     

Cu–Mn–Ce ternary mixed-oxide catalysts for catalytic combustion of toluene

Cu–Mn, Cu–Mn–Ce, and Cu–Ce mixed-oxide catalysts were prepared by a citric acid sol–gel method and then characterized by XRD, BET, H₂-TPR and XPS analyses. Their catalytic properties were investigated in the toluene combustion reaction. Results showed that the Cu–Mn–Ce ternary mixed-oxide catalyst with 1:2:4 mole ratios had the highest catalytic activity, and 99% toluene conversion was achieved at temperatures below 220°C. In the Cu–Mn–Ce catalyst, a portion of Cu and Mn species entered into the CeO₂ fluorite lattice, which led to the formation of a ceria-based solid solution. Excess Cu and Mn oxides existed on the surface of the ceria-based solid solution. The coexistence of Cu–Mn mixed oxides and the ceria-based solid solution resulted in a better synergetic interaction than the Cu–Mn and Cu–Ce catalysts, which promoted catalyst reducibility, increased oxygen mobility, and enhanced the formation of abundant active oxygen species.     

Remarkable promotion effect of trace sulfation on OMS-2 nanorod catalysts for the catalytic combustion of ethanol

OMS-2 nanorod catalysts were synthesized by a hydrothermal redox reaction method using MnSO₄ (OMS-2-SO₄) and Mn(CH₃COO)₂ (OMS-2-AC) as precursors. SO₄^2 −-doped OMS-2-AC catalysts with different SO₄^2 − concentrations were prepared next by adding (NH₄)₂SO₄ solution into OMS-2-AC samples to investigate the effect of the anion SO₄^2 − on the OMS-2-AC catalyst. All catalysts were then tested for the catalytic oxidation of ethanol. The OMS-2-SO₄ catalyst synthesized demonstrated much better activity than OMS-2-AC. The SO₄^2 − doping greatly influenced the activity of the OMS-2-AC catalyst, with a dramatic promotion of activity for suitable concentration of SO₄^2 − (SO₄/catalyst = 0.5% W/W). The samples were characterized by X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), inductively coupled plasma optical emission spectroscopy (ICP-OES), NH₃-TPD and H₂-TPR techniques. The results showed that the presence of a suitable amount of SO₄^2 − species in the OMS-2-AC catalyst could decrease the Mn–O bond strength and also enhance the lattice oxygen and acid site concentrations, which then effectively promoted the catalytic activity of OMS-2-AC toward ethanol oxidation. Thus it was confirmed that the better catalytic performance of OMS-2-SO₄ compared to OMS-2-AC is due to the presence of some residual SO₄^2 − species in OMS-2-SO₄ samples.     

不同方法测定水体总氮存在的问题探讨及条件优化研究

利用碱性过硫酸钾消解紫外分光光度法,探讨了消解时间和消解温度对空白吸光值的影响,认为增加消解时间可以降低空白吸光值,而提高消解温度对空白吸光值的影响不大;对于某些样品中总氮含量低于氨氮含量的现象,将碱性过硫酸钾装入小试管,再放入装有水样的比色管中,虽然能够减少氨气形式逸出的氮含量,但回收率较低;连续流动和流动注射-盐酸萘乙二胺分光光度法,在以后的修订中应增加过硫酸钾含氮量以及镉柱还原能力大小的界定.     

Hydrothermal-treated Pt/Al2O3 as an excellent catalyst for toluene total oxidation

The preparation of highly active supported noble metal catalysts with a low noble metal loading has always been the ultimate goal of researchers working on catalysis. Hydrothermally treated Pt/Al₂O₃ (Pt/Al₂O₃-H) exhibits better catalytic activity than that (Pt/Al₂O₃-C) treated via the conventional calcination approach. At the high space velocity of 100,000 mL/(g∙hr), the temperature that correspond to 50% toluene conversion (T₅₀) of Pt/Al₂O₃-H is 115°C lower than that of Pt/Al₂O₃-C, and the turnover frequency (TOF) value can reach 0.0756 sec⁻¹. The mechanism by which the hydrothermal approach enhances Pt/Al₂O₃ activity has been investigated. The structure associated with the high catalytic activity of Pt nanoparticles (NPs) can be retained via hydrothermal treatment. Furthermore, the support is transformed to AlO(OH) with numerous surface hydroxyl groups, which in turn can facilitate the adsorption of toluene. And the synergistic effects of Pt NPs and AlO(OH) increases the contents of Pt in oxidation state and active oxygen, which are beneficial for toluene oxidation.     

染料探针技术对二级出水中优势污染物的定量检测

分别以刚果红和中性红为染料探针,建立了牛血清蛋白质(BSA)和海藻酸多糖(SA)含量与共振光散射(RLS)发射光谱强度间的线性关系;以甲苯胺蓝为染料探针,建立了腐殖酸(HA)含量与紫外吸光度间的线性关系;优化了3种标准物质的检测浓度范围及溶液p H值条件;考察了染料探针分析方法对标准物的二元和三元混合样品中的回收率.结果表明在适宜的浓度范围内,BSA、HA、SA浓度与染料探针光谱强度间的线性相关系数R0.98,3种标准物在混合样品中的回收率不小于95%,标准误差低于0.11%.以紫外光谱和3D-EEM光谱特征作为城市污水二级出水样品中蛋白质、多糖和腐殖酸的定性依据,确认了4种二级出水样品中的优势污染物.通过染料-探针技术与国标法测得的多糖和蛋白质质量浓度的相对偏差在1.2%~0.04%之间.     

分光光度法测定染料废水中的对氨基酚

以由地洛试剂为氧化剂，用分光光度法测定染料废水中对氨基酚的含量，进行了波长，贝特洛试剂用量及显色时间等分析条件的选择。精密度和准确度实验结果表明，该准确，快速，可用于染料废水中对氨基酚的测定。     

不同物质对铬价态测定结果的影响

采用单波长法和双波长法,分别考察了KH2PO4、H3PO4、H2SO4、KNO3、牛肉膏和蛋白胨对Cr(III)和Cr(VI)质量浓度测定的影响。结果显示,Cr(III)和Cr(VI)在测量中是相互影响的,并且Cr(III)对Cr(VI)影响较显著。在单波长法测定中,牛肉膏、蛋白胨及2种酸对Cr(III)和Cr(VI)的影响较钾盐对其影响更为显著,H3PO4和H2SO4对Cr(III)和Cr(VI)的特征吸收峰值影响最大,降低幅度在20%～50%。这些物质对双波长法测定Cr(VI)几乎没有影响;但对Cr(III)测定中,H2SO4和H3PO4的影响较大,其相对误差分别为14.57%和8.87%,其余物质产生的相对误差均小于1.6%。因此,双波长法可用于生物样品中Cr(III)和Cr(VI)的测定,线性范围分别为0～160 mg/L和0～80mg/L。     

铜（Ⅱ）－二乙基二硫代氨基甲酸钠－乳化剂OP光度法测定土壤有效铜

本文研究了二乙基二硫代氨基甲酸钠（铜试剂）水相光度法测定微量铜（Ⅱ）的条件．在乳化剂ＯＰ（聚乙二醇辛基本基醚）存在的情况下．在ｐＨ８．５的缓冲介质中，铜（Ⅱ）与铜试剂形成棕黄色的配合物，显色体系在４５４ｎｍ处有最大吸收，其表观摩尔吸光系数为１．４３×１０４Ｌ／ｍｏｌ·ｃｍ，铜（Ⅱ）含量在０－６０μｇ／２５ｍｌ范围内服从比耳定律．该方法简便、快速，应用于土壤有效铜的测定，结果与原子吸收法基本一致．