胶原纤维基多孔碳纤维用于电化学产双氧水——酸处理对产双氧水性能的影响

为获得通过电化学的氧还原反应（ORR）高效原位生成双氧水（H₂O₂）的新型碳材料,基于一类天然生物质-皮胶原纤维为基础材料制备出多孔碳纤维材料（PCFs-x）.利用皮胶原纤维分子中的-COOH、-NH₂等官能团与铁盐之间的较强的络合作用来吸附铁离子,碳化后经酸浸获得PCFs-x材料.XRD、SEM、BET等手段对不同浓度硝酸浸取后所获得的PCFs-x进行系统的结构表征,测试其电子转移数,考察了其氧还原反应活性及电化学还原氧气产H₂O₂的性能.结果表明,胶原纤维经过上述制备流程后可获得有序结构的PCFs-x,其中浓度为1mol/L时获得的材料具有最好的产H₂O₂效果和电流效率,氧还原反应2.5h后H₂O₂累积浓度达到148.81mg/L,电流效率72.33%.实验结果为基于胶原纤维制备新型高效的原位电化学产双氧水的碳材料提供了理论基础与可借鉴的思路.     

Thermal decomposition kinetic of liquid organic peroxides

This study demonstrates the application of isothermal calorimeter for investigating the thermal decomposition of several liquid organic peroxides, such as t-Butyl peroxy acetate (TBPA), Di-tert butyl peroxide (DTBP), and Cumene hydroperoxide (CHP). The decomposition mechanism and kinetic can be identified from case to case. TBPA and DTBP undergo first order reaction, whereas CHP occurs autocatalysis. Accurate kinetic can be assessed on the basis of discerning these various schemes of given samples. Consequently, the thermal runaway or reactive hazards potential of organic peroxides can be determined, for instance as a self accelerating decomposition temperature (SADT).     

The roles of organic degradation products andselenium in the pathogenesis ofKaschin-Beck disease

An investigation on the organic degradation products and selenium in the pathogenesis of Kaschin-Beck disease was carried out. The results demonstrated that the organic degradation products existed in food and drinking water were the pathogens of the KBD; their leading pathological process of cells would be "membrane injury" due to peroxide. As GSH-Px is a selenium contained enzyme, therefore insufficient selenium would be one of the most important conditions to cause KBD.     

UV/H_2O_2对土壤中As(Ⅲ)氧化效果的初步研究

为了减弱As迁移能力,降低其毒性,将土壤中As(Ⅲ)氧化为As(Ⅴ),使其更容易被固定。通过人工模拟的受砷污染土壤研究了自然光、紫外线、H2O2、自然光+H2O2和紫外线+H2O2对As(Ⅲ)的氧化效果。结果表明:5个组合均能氧化As(Ⅲ),紫外线+H2O2组合氧化效果最好,在此基础上通过正交试验确定该组合对As(Ⅲ)氧化的最优操作条件。UVC波段的紫外线氧化效果最好;光照强度12 W、光照时间为6 h时,氧化效果较好,继续增加光照强度和光照时间氧化效果没有明显提高;H2O2投加量为20 m L/kg时氧化效果最好,且继续增加投加量,氧化效果仍能改善。     

Effects of hydrogen addition on the confined and vented explosion behavior of methane in air

Multi-component gas mixture explosion accidents occur and recur frequently, while the safety issues of multi-component gas mixture explosion for hydrogen–methane mixtures have rarely been addressed.Numerical simulation study on the confined and vented explosion characteristics of methane-hydrogen mixture in stoichiometric air was conducted both in the 5 L vessel and the 64 m³ chamber, involving different mixture compositions and initial pressures. Based on the results and analysis, it is shown that the addition of hydrogen has a negative effect on the explosion pressure of methane-hydrogen mixture at adiabatic condition. While in the vented explosion, the addition of the hydrogen has a significant positive effect on the explosion hazard degree. Additionally, the addition of hydrogen can induce a faster reactivity and enhance the sensitivity of the mixture by reducing the explosion time and increasing the rate of pressure rise both in confined and vented explosion. Both the maximum pressure and the maximum rate of pressure rise increase with initial pressure as a linear function, and also rise with the increase of hydrogen content in fuel. The increase in the maximum rate of pressure rise is slight when hydrogen ratio is lower than 0.5, however, it become significant when hydrogen ratio is higher than 0.5. The maximum rate of pressure rise for stoichiometric hydrogen-air is about 10 times the one of stoichiometric methane-air.Furthermore, the vent plays an important role to relief pressure, causing the decrease in explosion pressure and rate of pressure rise, while it can greatly enhance the flame speed, which will extend the hazard range and induce secondary fire damages. Additionally it appears that the addition of hydrogen has a significant increasing effect on the flame speed. The propagation of flame speed in confined explosion can be divided into two stages, increase stage and decrease stage, higher hydrogen content, higher slope. But in the vented explosion, the flame speed keeps increasing with the distance from the ignition point.     

过氧化甲乙酮的热危险性研究

为研究过氧化甲乙酮(MEKPO)在运输与储存中的热危险性,利用差示扫描量热仪(DSC)对质量分数为52%的MEKPO溶液(以2,2,4-三甲基-1,3-戊二醇二异丁酸酯为溶剂)进行测试,得到其起始分解温度T0约为40℃,比放热量ΔH约为1.24 kJ/g。运用加速量热仪(ARC)对3种MEKPO溶液(40%,45%和52%)及MEKPO纯品(化学纯)在绝热条件下进行了热分解测试,并在此基础上,借助Semenov热爆炸模型,计算得到上述样品在50 kg包件下的自加速分解温度(TSADT)分别为65.64,63.72,55.88和51.17℃。研究结果表明,加入稀释稳定剂是降低MEKPO热危险性的有效途径,且MEKPO混合物中其质量分数越大,其危险性越高。     

Catalytic hydrolysis of gaseous HCN over Cu–Ni/γ-Al2O3 catalyst: parameters and conditions

? The Cu–Ni/γ-Al₂O₃ catalyst was prepared to study HCN hydrolysis ? On catalyst calcined at 400°C, the HCN removal efficiency reaches a maximum. ? HCN removal is the highest at 480 min at a H ₂ O/HCN volume ratio of 150 ? The presence of CO facilitates HCN hydrolysis and increases NH ₃ production. ? O ₂ increases the HCN removal and NO_x production but decreases NH ₃ production GRAPHIC ABSTRACT To decompose efficiently hydrogen cyanide (HCN) in exhaust gas, g-Al₂O₃-supported bimetallic-based Cu–Ni catalyst was prepared by incipient-wetness impregnation method. The effects of the calcination temperature, H₂O/HCN volume ratio, reaction temperature, and the presence of CO or O₂ on the HCN removal efficiency on the Cu–Ni/g-Al₂O₃ catalyst were investigated. To examine further the efficiency of HCN hydrolysis, degradation products were analyzed. The results indicate that the HCN removal efficiency increases and then decreases with increasing calcination temperature and H₂O/HCN volume ratio. On catalyst calcined at 400°C, the efficiency reaches a maximum close to 99% at 480 min at a H₂O/HCN volume ratio of 150. The HCN removal efficiency increases with increasing reaction temperature within the range of 100°C–500°C and reaches a maximum at 500°C. This trend may be attributed to the endothermicity of HCN hydrolysis; increasing the temperature favors HCN hydrolysis. However, the removal efficiencies increases very few at 500°C compared with that at 400°C. To conserve energy in industrial operations, 400°C is deemed as the optimal reaction temperature. The presence of CO facilitates HCN hydrolysis andincreases NH₃ production. O₂ substantially increases the HCN removal efficiency and NO_x production but decreases NH₃ production.     

Formation of polychlorinated biphenyls and chlorinated benzenes by heating of bis(2,4‐dichlorobenzoyl) peroxide

The formation of di‐, tri‐, and tetrachlorobenzenes, and di‐ to hexachlorobiphenyls was demonstrated after thermal degradation of bis(2,4‐dichlorobenzoyl) peroxide alone or in various solvents at 250 °C with yields of up to several percent. Possible radical reactions between solvents and the solute are suggested. PCB congeners are also present in silicone rubber crosslinked by this peroxide.     

Kinetics of microwave-enhanced oxidation of phenol by hydrogen peroxide

Aqueous solutions of phenol were oxidized by hydrogen peroxide assisted by microwave (MW) irradiation. A simple kinetic model for the overall degradation of phenol in the presence of excess H₂O₂ is proposed in which the degradation rate of phenol is expressed as a linear function of the concentrations of phenol and H₂O₂. A detailed parametric study showed that the degradation rate of phenol increased with increasing [H₂O₂] until saturation was observed. Phenol degradation followed apparent zero-order kinetics under MW radiation or H₂O₂ oxidation. However, after 90 min of irradiation, the observed kinetics shifted to pseudo first order. The overall reaction rates were significantly enhanced in the combined MW/H₂O₂ system, mainly because microwave could accelerate H₂O₂ to generate hydroxyl radical (^·OH) and other reactive oxygen intermediates. The observed synergetic effects of the MW/H₂O₂ process resulted in an increased in the net reaction rate by a factor of 5.75. When hydrogen peroxide is present in a large stoichiometric excess, the time required to achieve complete mineralization is reduced significantly.     

O3/H2O2法灭活水中剑水蚤类浮游动物

为解决水源水中孳生的水蚤类浮游动物难以被常规的水处理工艺有效地去除,困扰水厂正常生产运行的问题,进行了O2氧化、H2O2氧化和O3／H2O2高级氧化对水体中剑水蚤类浮游动物灭活效果的试验研究．发现3种方法中,O3／H2O2联合时除蚤效果最佳,在蒸馏水中投量为031．0mg／L、H2O24mg／L时,接触30min达到100％的灭蚤率;单独O3氧化效果也较好,投加1．0mg／L的灭蚤率为80％;H2O2氧化效果不理想,投加4mg／L几乎无灭蚤效果。进而考察确定了03／H2O2灭活剑水蚤的最佳工艺条件为：先加O3后加H2O2,投加间隔时间30～60s为宜;并探讨了H2O2投量、水体pH值以及有机物含量对O3／H2O2系统灭活剑水蚤效果的影响。试验中发现H2O2投量在4～10mg／L之间效果无较大变化,有机物含量对灭蚤影响较大,pH值的影响则较小。最后对O3／H2O2预氧化与水处理混凝沉淀工艺的协同除蚤效能进行了考察。结果表明,O3／H2O2预氧化与水处理混凝沉淀工艺的协同作用将会进一步提高除蚤的效果。