ZrSi_2/硼酚醛泡沫的制备及其裂解产物的增强机制

以ZrSi_2颗粒填充硼酚醛树脂制备了一种耐高温且裂解后结构较为完整的泡沫复合材料。研究了ZrSi_2颗粒质量分数对泡沫复合材料固化机制、高温裂解行为及裂解前后压缩性能的影响,并分析了ZrSi_2颗粒对泡沫复合材料裂解产物的增强机制。结果表明:添加的ZrSi_2颗粒虽未参与硼酚醛树脂的固化交联,但会和硼酚醛树脂裂解放出的气体挥发物发生化学反应,提高了裂解产物的残炭率和压缩比强度。当添加的ZrSi_2颗粒质量为硼酚醛树脂质量的10%时,裂解产物的残炭率和压缩比强度提高最为显著。ZrSi_2/硼酚醛泡沫经过裂解后,ZrSi_2颗粒作为第二相粒子钉扎在裂解产物的孔壁上,化学反应使得部分裂解气体挥发物被吸收并转化为固相产物,明显减少的缺陷提高了裂解产物的力学性能。     

玻璃纤维/环氧树脂泡沫夹层板的热解动力学

使用DTG-60(AH)热重分析仪分析了玻璃纤维/环氧树脂泡沫夹层板在不同升温速率和不同氧含量条件下的热分解特性。结果表明,在空气中玻璃纤维/环氧树脂泡沫夹层板的热分解反应可分为三个阶段。随着升温速率的提高,热分解反应的初始反应温度、终止反应温度以及最大质量损失速率温度均向高温方向移动。氧含量的降低对热分解的第三阶段有较大的影响。采用Flynn-Wall-Ozawa法和Starink法进行热解动力学分析,得到玻璃纤维/环氧树脂泡沫夹层板的表观活化能。     

Non-thermal plasma for oxidation of gaseous products originating from thermal treatment of wastes

A plasma reactor generating non-equilibrium plasma in a gliding discharge was applied as one of the modules of a new laboratory device for hazardous waste destruction. The degradation process of wastes containing an organic part was carried out in two stages. The first one consisted of thermal decomposition of wastes in an inert atmosphere (pyrolysis process in argon flow—the gaseous products are formed from the organic part of wastes). In the second stage products of pyrolysis were oxidized in a gliding discharge. This work was focused on study of the parameters influencing the oxidation process of gases originating from pyrolysis and flowing into the plasma reactor. Oxygen was introduced into the plasma reactor simultaneously with the gases. We investigated two factors significantly affecting the oxidation process: (a) the oxygen concentration in the initial mixture of argon and oxygen and (b) the total flow of argon and oxygen gases. The best oxidation efficiency of the processing gases in the plasma was reached when the oxygen content did not exceed 20% and when the total flow of argon and oxygen was low enough not to cause disturbances of functioning of the plasma reactor.     

Change of monochloroacetic acid to biodegradable organic acids by hydrothermal reaction

The feasibility of biodegradability improvement induced from the structural conversion of refractory pollutants by hydrothermal reaction was investigated. Monochloroacetic acid (MCAA) was selected as a preliminary material represented for linear hydrocarbon structured refractory pollutants. Under the tested conditions, MCAA was partially destructed and then converted to biodegradable reaction products by hydrolysis, dehydration and thermal decomposition. The identified products were glycolic acid, citric acid and formic acid. Total organic carbon (TOC) reduction during the structural conversion did not exceed 24%, except the results at the reaction conditions of 350 degrees C and 17 MPa. However, Produced biodegradable organic acids were reduced by thermal decomposition with increasing reaction temperature and time. At the reaction temperature of 250 and 300 degrees C, biodegradability (BOD/COD(Cr)) was reached at 0.51 in 6.9 min and 0.52 in 7.4 min despite the presence of dissociated chlorine ions. The detachment of recalcitrant chlorine ion from MCAA and the production of biodegradable organic acids by hydrothermal reaction were directly related to the biodegradability improvement of reaction products.     

Polymer-filler derived Mo2C ceramics

Manufacturing, microstructure and properties of novel reaction bonded Mo₂C materials derived from polymer/reactive filler mixtures were investigated. Mo powder was used as a filler to react with carbon bearing decomposition products of poly(methyl- and phenysiloxanes) during pyrolysis in nitrogen atmosphere. Microcrystalline composites with the filler reaction products Mo₃C, Mo₃Si, Mo₅Si₃ embedded in a silicon oxycarbide glass matrix could be formed with complex geometry owing to near net shape polymer/ceramic conversion. Depending on the precursor composition and pyrolysis conditions, ceramic hard materials with a density up to 97% theoretical density, a hardness of 10 GPa, a Young’s Modulus of 250 GPa, a fracture toughness of 5 MPam^1/2 and a flexural strength of 330 MPa were obtained.     

阻燃共聚酯／蒙脱土纳米复合材料的裂解和阻燃机理研究

通过裂解色谱质谱分析，热重分析，XRD和SEM等方法，对实验室合成的一种阻燃共聚酯，蒙脱土纳米复合材料的裂解和阻燃机理进行研究．分析结果表明蒙脱土和阻燃共聚酯DDP的加入都能减少PET裂解过程中可燃小分子化合物的产生，抑制PET的深度裂解反应，同时降低PET起始分解温度．此外，DDP能够有效改善材料燃烧过程中的失重率，抑制PET裂解过程中的自由基反应，而蒙脱土在燃烧过程中随着温度升高，会在炭层表面产生堆积，改变炭层形貌，提高其热稳定性．研究还表明，两者在改善炭层质量，增强其隔热隔氧性能方面存在着协同作用。     

Kinetics of the oxidative degradation of ceramic injection-moulding vehicle

The effective reaction depth during the pyrolysis of ceramic injection-moulded bodies in oxidizing atmospheres was deduced from isothermal thermogravimetry. The kinetic data were analysed (i) for the case of chemical reaction control, (ii) for mass transport control and (iii) for combined chemical and mass transport control. The shrinking core reaction modulus indicates that reaction rate was mainly controlled by the diffusion of oxygen into the surface region and degradation products out. The results are used to discuss the relative merits of oxidative and thermal degradation of organic vehicle for ceramic processing.     

废弃物基活性炭吸附性能的影响因素

研究了以三种固体有机废弃物-锯木屑、纸张、塑料的热解产物（分别简称木炭、纸炭、塑料热解物）为原料，水蒸气为活化剂制备废弃物基活性炭时吸附性能（以碘值表征）的影响因素。结果表明，在一定的塑料热解物含量条件下，活性炭的吸附性能随木炭、纸炭间组成比的增加而增加，而在一定的木炭、纸炭间组成比下，吸附性能随塑料热解物含量的增加而减少；此外废弃物基活性炭的吸附性能随废弃物热解温度的升高呈现为先增加再减少的变化趋势。     

异氰酸酯三聚体对聚异氰脲酸酯泡沫塑料的阻燃作用

利用红外光谱、扫描电镜、热分析、锥形量热仪和高温裂解气相色谱质谱联用等表征方法从凝聚相热分解阶段的机理,凝聚相表面成炭层的阻隔机理和气相机理3方面对异氰酸酯三聚体对聚异氰脲酸酯泡沫塑料(PIR)的阻燃机理进行了研究。结果表明,三聚体能提高PIR泡沫的热稳定性,在燃烧中不易分解;三聚体能使PIR泡沫的成炭量较聚氨酯(PU)泡沫的成炭量提高到29.9%,形成的炭层更为致密,炭层能够阻隔热和氧气,提高阻燃性能;三聚体能减少可燃性多元醇气体的释放量,分解出更多的二氧化碳惰性气体,在气相起到一定的阻燃作用。     

Conversion of bromine during thermal decomposition of printed circuit boards at high temperature

The conversion of bromine during the thermal decomposition of printed circuit boards (PCBs) was investigated at isothermal temperatures ranging from 800°C to 1100°C by using a quartz tube furnace. The influence of temperature, oxygen concentrations (0%, 10% and 21% in the nitrogen-oxygen atmosphere) and content of steam on conversion of bromine was studied. With the increment of temperature, the conversion from organic bromine in the PCBs to inorganic bromine in the gaseous fraction increased from 69.0% to 96.4%. The bromine was mainly evolved as HBr and Br(2) in oxidizing condition and the Br(2)/HBr mass ratio increased at stronger oxidizing atmosphere. The experimental results also indicated that the existence of steam can reduce the formation of Br(2). Furthermore, co-combustion of PCBs with S and CaO, both as addition agents, was investigated, respectively. In the presence of SO(2), Br(2)/HBr mass ratio obviously decreased. Moreover, the utilization of calcium oxide can efficiently promote the conversion of organic bromine to inorganic bromine. According to the experimental results, incinerating PCBs at high temperature can efficiently destroy the organobrominated compounds that are considered to be possible precursors of polybrominated dibenzeo-p-dioxins and dibenzofurans (PBDD/Fs), but the Br(2) and HBr in flue gas should be efficiently controlled.     

Analyzing the pyrolysis kinetics of rice straw,bagasse, and mixtures thereof and product energy yield

In Taiwan, rice straw and bagasse are major agricultural wastes that are produced in extremely large quantities and volumes and contain high moisture content. Current processing methods remain inadequate; therefore, this study focused on the pyrolysis and relevant analyses of rice straw, bagasse, and mixtures thereof to investigate the feasibility of copyrolyzing rice straw and bagasse for renewable energy generation. Mixtures containing various ratios of bagasse and rice straw were examined through physical, chemical, thermogravimetric, and reaction kinetics analyses. Pyrolysis experiments were conducted to investigate the energy yield of the reaction products. Both bagasse and rice straw contained low ash content, and thermal processing effectively reduced the waste volume and cost of final disposal. A mixture content containing approximately 30 wt% rice straw (potassium content reaching 8.50 g/kg) substantially reduced the activation energies required for copyrolysis reactions, subsequently reducing energies required for thermal processing. The solid char generated from pyrolyzing the bagasse and rice straw mixtures did not decay easily and exhibited high storability and transportability. Moreover, volumetric energy densities substantially increased after pyrolysis. Therefore, copyrolysis is arguably a feasible and effective alternative biofuel conversion method for countries that process large quantities of bagasse and rice straw.     

Steam thermolysis of tire shreds: modernization in afterburning of accompanying gas with waste steam

On the basis of experience in the commercial operation of tire-shred steam thermolysis in EnresTec Inc. (Taiwan) producing high-grade commercial carbon, liquid pyrolysis fuel, and accompanying fuel gas by this method, we have proposed a number of engineering solutions and calculated-analytical substantiations for modernization and intensification of the process by afterburning the accompanying gas with waste steam condensable in the scrubber of water gas cleaning of afterburning products. The condensate is completely freed of the organic pyrolysis impurities and the necessity of separating it from the liquid fuel, as is the case with the active process, is excluded.     

Dechlorination of auto shredder residues

Dechlorination of ASR (auto shredder residual) wastes has been studied in the present work. ASR was predechlorinated with Ca(OH)(2) extraction as well as dechlorinated with Ca(OH)(2) during incineration or pyrolysis. Experimentally, pre-dechlorination of ASR via extraction of Cl with a Ca(OH)(2) solution (pH 12.5) may reduce Cl contain in the ASR by 15%. Extraction of Cl at elevated temperatures (such as 373 K), interestingly, led to a further reduction of Cl in the ASR to 33.5%. A small amount of HCl and light hydrocarbons (C(1)-C(5)) were yielded during pyrolysis of the ASR in the presence of Ca(OH)(2) at 773 K. On the contrary, 75-85% of Cl may be mineralized (CaCl(2)) with Ca(OH)(2) (or CaO) during incineration at 1100 K.     

Pyrolysis of municipal solid waste in a fluidized bed for producing valuable pyrolytic oils

In order to recover valuable pyrolytic oils, mixed municipal solid waste was pyrolyzed in a fluidized bed reactor. Results showed that liquid products yielded among 38.4–56.5 wt% and separated into water-soluble phases and organic phases. Moisture was concentrated in the water-soluble phases (39.4–57.3 wt%), making them low in carbon content and heating value. On the other hand, the higher carbon content and lower oxygen content of organic phases make their heating value (27.5–32.1 MJ/kg) and quality higher than bio-oils. Water-soluble phases mainly included acids, carboxylics, phenols, and sugars, which could be used as chemical feedstocks and substantial fuel. Organic phases mostly contained aromatics and phenols and could be used as fossil fuels directly or as chemical materials. Heavy metals of Cd and Pb were proved to be poor in both water-soluble phases and organic phases. As for Zn, it was found to be higher in the water-soluble phases at 450 and 550 °C with quartz sand as bed material than that in crude oils. However, Zn content in organic phases was comparable to crude oils. High-aluminum bauxite and attapulgite as bed materials increased heating value of water-soluble phases and organic phases respectively, and both performed well in reducing the Zn content of water-soluble phases. This work proved that it was an operative way to produce valuable pyrolytic oils by pyrolysis of mixed municipal solid waste.     

The photocatalytic degradation of trichloroethane by chemical vapor deposition method prepared titanium dioxide catalyst

The purpose of the investigation was to study the photocatalytic reaction of trichloroethane using a TiO(2) catalyst deposited in an annular reactor by the chemical vapor deposition (CVD) method. The experimental results indicated the highest decomposition rate of the trichloroethane was 2.71 micro mol/(sm(2)) and the conversion ratio reached a maximum of 99.9%. When the humidity was below 154 micro M, the reaction rate slightly increased with increasing humidity. However, the reaction rate decreased as the humidity increased >154 micro M. Oxygen played a role as an electron acceptor in the reaction, and reduced the recombination of the photogenerated electron-hole pairs. Therefore, the reaction rate rose as the oxygen concentration increased. Nevertheless, after the oxygen concentration reached 12%, the reaction rate reached it maximum and was constant in spite of increasing oxygen concentration. As the initial reactant concentration increased, the reaction rate increased, but the conversion ratio dropped. An increase of light intensity resulted in an increase in the number of photons and thus increased the reaction rate. Accordingly the decomposition of trichloroethane could be fitted by the semi-empirical bimolecular Langmuir-Hinshelwood model. Moreover, the reaction rate was proportional to the 0.48-order of the light intensity.     

The effect of microwave-assisted for photo-catalytic degradation of rhodamine B in aqueous nano TiO2 particles dispersions

The photo-catalytic decomposition of rhodamine B was examined in aqueous nano TiO2 particles dispersions to assess effects of the microwave radiation assisted photo-catalytic process driven by UV radiation. The results of photo-catalytic degradation of rhodamine B showed that the decomposition rate increased with the microwave intensity, UV intensity, TiO2 particle dosages and the circulating fluid velocity. Addition of oxygen gas in the photo-catalytic degradation of rhodamine B increased the reaction rate. The effect of addition of H2O2 was not significant when photo-catalysis was used without additional microwave radiation or when microwave was irradiated without the use of photo-catalysts. When H2O2 was added under simultaneous use of photo-catalysis and microwave irradiation, however, considerably higher degradation reaction rates were observed. This study demonstrates that the microwave irradiation can play a very important role in photo-catalytic degradation.     

有机铜催化剂催化合成三乙氧基硅烷

传统的直接法合成三乙氧基硅烷多以卤化铜为催化剂,存在产品卤素含量高,反应过程中产物易水解的问题.本文以乙酸铜和自制双二乙基磷酸铜为催化剂,对硅粉与催化剂的混合体(触体)进行微波活化处理,研究了活性触体和乙醇进行反应合成三乙氧基硅烷的工艺影响因素,主要考察了微波功率、微波处理时间、反应温度、促进剂及搅拌速度等因素对三乙氧基硅烷的选择性和硅粉转化率的影响.通过对两种有机铜催化剂的对比研究发现,双二乙基磷酸铜的催化效果较好.微波处理触体[m(Si):m(双二乙基磷酸铜)=10∶1],以氟化铵和噻吩为双重促进剂,得到三乙氧基硅烷的选择性达到99.3%,硅粉转化率为41%.     

Microwave enhanced stabilization of heavy metal sludge

A microwave process can be utilized to stabilize the copper ions in heavy metal sludge. The effects of microwave processing on stabilization of heavy metal sludge were studied as a function of additive, power, process time, reaction atmosphere, cooling gas, organic substance, and temperature. Copper leach resistance increased with addition of aluminum metal powder, with increased microwave power, increased processing time, and using a gaseous environment of nitrogen for processing and air for cooling [N2/air]. The organic in the sludge affected stabilization, whether or not the organic smoldered. During heating in conventional ovens, exothermic oxidation of the organic resulted in sludge temperatures of about 500 degrees C for oven control temperatures of 200-500 degrees C. After microwave heating dried the sludge, the sludge temperature rose to 500 degrees C. The reaction between copper ions and metal aluminum in the dried sludge should be regarded as a solid phase reaction. Adding aluminum metal powder and reaction temperature were the key parameters in stabilizing copper in the heavy metal sludge, whether heated by microwave radiation or conventional oven. The mass balance indicates insignificant volatization of the copper during heating.     

Hollow Functional Materials Derived from Metal–Organic Frameworks: Synthetic Strategies,Conversion Mechanisms,and Electrochemical Applications

Hollow materials derived from metal–organic frameworks (MOFs), by virtue of their controllable configuration, composition, porosity, and specific surface area, have shown fascinating physicochemical properties and widespread applications, especially in electrochemical energy storage and conversion. Here, the recent advances in the controllable synthesis are discussed, mainly focusing on the conversion mechanisms from MOFs to hollow‐structured materials. The synthetic strategies of MOF‐derived hollow‐structured materials are broadly sorted into two categories: the controllable synthesis of hollow MOFs and subsequent pyrolysis into functional materials, and the controllable conversion of solid MOFs with predesigned composition and morphology into hollow structures. Based on the formation processes of hollow MOFs and the conversion processes of solid MOFs, the synthetic strategies are further conceptually grouped into six categories: template‐mediated assembly, stepped dissolution–regrowth, selective chemical etching, interfacial ion exchange, heterogeneous contraction, and self‐catalytic pyrolysis. By analyzing and discussing 14 types of reaction processes in detail, a systematic mechanism of conversion from MOFs to hollow‐structured materials is exhibited. Afterward, the applications of these hollow structures as electrode materials for lithium‐ion batteries, hybrid supercapacitors, and electrocatalysis are presented. Finally, an outlook on the emergent challenges and future developments in terms of their controllable fabrications and electrochemical applications is further discussed.     

Pyrolysis treatment of oil sludge and model-free kinetics analysis

Pyrolysis of tank bottom oil sludge was investigated to summarize the pyrolysis characteristics through analyzing the change of mass loss, pyrolysis gas compositions in heating process. For this propose, various approaches including thermogravimetric analysis (TGA), CNHS/O elemental analysis, electrically heated fixed bed quartz reactor coupled with Vario Plus emission monitoring system, and oil-gas evaluation workstation (OGE-II) equipped with a flame ionization detector (FID) were used. The pyrolysis reaction is significant in the range of 473-773 K where multi-peak DTG curves can be gained. Higher heating rate increases the carbon (C) and sulfur (S) contents but decreases hydrogen (H) content in solid residues. The major gaseous products excluding N(2) are CHs (Hydrocarbons), CO(2), H(2), CO. The yield of CHs is significant in the range of 600-723 K. Higher heating rate causes the peak intensity of CHs evolution to increase and the CHs evolution to move towards a high-temperature region. Around 80% of total organic carbon content (TOC) in oil sludge can be converted into CHs in pyrolysis process. The CHs data were used for kinetic analysis by Vyazovkin model-free iso-conversion approach. Dependences of the activation energy on the degree of conversion obtained from different methods were compared.