光助电催化降解偶氮染料酸性橙II的降解过程研究

使用自制的具有电催化活性和光催化活性TiO2改性的β-PbO2电极,研究了光助电催化氧化过程、电催化氧化过程和光催化氧化过程对于偶氮染料酸性橙Ⅱ的降解.用紫外可见光谱和高效液相色谱分析了3种降解过程中不同的降解行为,对降解产物进行了FTIR和GC-MS分析.结果表明,单独电催化过程不同于其它2种过程,出现了醌类物质的大量累积;而在光助电催化氧化过程中,光催化氧化过程大大抑制了电催化氧化过程中累积的高毒性醌类物质.在2 h内,光助电催化氧化过程是其它2种过程TOC去除率的1.56倍,产生了明显的协同作用.3种降解过程遵循相同的降解历程,都经历了产生醌类物质到低分子量有机酸的步骤.     

微波无极灯:一种具有前景的高效光催化光源

微波无极灯具有制造容易、价格低廉、能耗小和光强大等优点。作为光催化氧化的光源时,由于微波的协同作用可有效提高光催化活性,并能简化反应器。从发光机理、微波协同作用、优缺点和影响因素等方面,对微波无极灯在光催化领域的研究进行详细阐述。     

Mechanism of enhanced removal of quinonic intermediates during electrochemical oxidation of Orange Ⅱ under ultraviolet irradiation

The effect of ultraviolet irradiation on generation of radicals and formation of intermediates was investigated in electrochemical oxidation of the azo-dye Orange I1 using a TiO2-modified β- PbO2 electrode. It was found that a characteristic absorbance of quinonic compounds at 255 nm, which is responsible for the rate-determining step during aromatics degradation, was formed only in electrocatalytic oxidation. The dye can be oxidized by either HO radicals or direct electron transfer. Quinonic compounds were produced concurrently. The removal of TOC by photo-assisted electrocatalytic oxidation was 1.56 times that of the sum of the other two processes, indicating a significant synergetic effect. In addition, once the ultraviolet irradiation was introduced into the process of electrocatalytic oxidation, the degradation rate of quinonic compounds was enhanced by as much as a factor of two. The more efficient generation of HO radicals resulted from the introduction of ultraviolet irradiation in electrocatalytic oxidation led to the significant synergetic effect as well as the inhibiting effect on the accumulation of quinonic compounds.     

冻融循环作用下西藏东南冰碛土剪切力学特性试验研究∗

西藏东南地区冰碛土堆积体广泛分布,冻融作用严重影响冰碛土堆积体稳定性。对西藏东南及川滇地区 200 组冰碛土粒径级配进行对比分析,并通过室内直剪试验研究了不同含水量和冻融循环作用下冰碛土剪切力学特性,结合试样体积变化及水分迁移规律分析黏聚力劣化机制。结果表明：(1)冰碛土粒径范围较广,相比川滇地区, 西藏东南冰碛土细粒含量更多;(2)冻融循环后,黏聚力 c 呈负指数型函数降低,内摩擦角 φ 波动幅度-6.47%~+ 5.46%;(3)含水量越高、冻融循环次数越多、垂直应力越大的试样剪胀性越弱,剪缩性越强;冻融循环条件下,含水量越高的试样剪切带厚度变化范围越大;(4)冻融 6 次后,冰碛土体积无显著增长,水分迁移呈规律性,与黏聚力在冻融 6 次后劣化减缓相一致。     

Sustainable catalytic oxidation of glycerol: a review

Environmental Chemistry Letters - Valorization of biomass-derived feedstocks for the supply of high-value chemicals, clean fuel and electricity is gaining importance in the context of the circular...     

利用粉煤灰生产陶粒滤料探讨

本文结合生物滤池技术和陶粒生产工艺,探讨生产用做水处理滤料的粉煤灰陶粒的生产方法,并从原料选择、生产工艺及产品应用方面加以阐述。     

一体式MBR处理高氨氮小区生活污水中试研究

在一体式MBR处理高浓度有机废水研究的基础上 ,针对高氨氮城市小区生活污水进行中试研究。着重研究了不同运行状况下处理效果、影响因素及膜通量的衰减规律。试验表明 :通过增设泥水回流和缺氧区可将氨氮去除率从60 %提高到 95 %以上 ,在进水CODCr为 3 3 0mg L、NH3为 10 0mg L时 ,出水CODCr和NH3分别低于 2 5mg L、5mg L ,且其它指标均达到生活杂用水水质标准 (CJ2 5 1 89)。     

水解+加压MBR处理淀粉废水研究

对水解+加压MBR处理中等难降解淀粉废水进行了探索性研究。试验结果表明增加水解酸化预处理后加压MBR处理效果有明显增加,不同操作压力下,膜过滤出水COD仅为无水解酸化预处理时的1/2。在操作压力为045MPa,进水COD10430mg/L,容积负荷522kgCOD/m3·d时,膜滤出水COD仅为202mg/L,COD去除率高达9981%。     

Production and contribution of hydroxyl radicals between the DSA anode and water interface

Hydroxyl radicals play the key role during electrochemical oxidation and photoelectrochemical oxidation. The production and e ect of hydroxyl radicals on the interface between DSA anode and water was investigated by examining the quenching e ect of iso-propanol on Orange II decolorization. We observed that with an increase in electrode potential from 4 to 12 V across electrodes at pH 7.0, the contribution percentage of hydroxyl radicals increased dramatically. More OH radicals were produced in acidic and alkaline conditions than at neutral conditions. At electrode potential of 4 V, the contribution percentage of hydroxyl radicals was obviously higher at near neutral pH conditions, while removal e ciency of Orange II achieved was the lowest concurrently. Finally, for photocatalytic oxidation, electrochemical oxidation, and photoelectrochemical oxidation using the same DSA electrode, the e ect of hydroxyl radicals proved to be dominant in photocatalytic oxidation but the contribution of hydroxyl radicals was not dominant in electrochemical oxidation, which implies the necessity of UV irradiation for electrochemical oxidation during water treatment.