印染污泥的活性炭负载过渡金属化合物非均相催化臭氧化

采用湿式浸渍法,将6种含过渡金属(Cu,Fe,Zn,Ni,Mn,Ce)元素的化合物负载在活性炭（AC）上,制得6种催化剂AC/M(M=Cu,Fe,Zn,Ni,Mn,Ce),在室温条件下,催化臭氧化处理苯酚溶液和印染污泥。 催化剂AC/M通过Boehm滴定、XRD和BET分析进行表征。 苯酚的3种降解方法中,AC/M催化剂的臭氧催化最好,AC/M吸附处理次之,单独臭氧处理的效果最差。 在苯酚的降解处理过程中,AC/M催化臭氧化处理苯酚溶液的效率依次为：AC/Fe＞AC/Zn＞AC/Ni＞AC/Ce＞AC/Cu＞AC/Mn。 AC/M催化剂催化臭氧化效果随溶液pH值的增大而增强。 AC/M催化剂处理印染污泥的效率依次为：AC/Fe＞AC/Zn＞AC/Ce=AC/Ni＞AC/Cu＞AC/Mn,AC/Fe催化臭氧化处理印染污泥可使污泥中有机质含量降低8.17%。     

TiO2/活性炭负载型光催化剂的溶胶-凝胶法合成及表征

以钛酸四丁酯为钛源,采用溶胶-凝胶法在多孔活性炭(AC)表面合成TiO2前驱体,在氮气保护下程序升温处理制得TiO2/AC负载型光催化剂.采用X射线衍射、漫反射光谱、傅里叶变换红外光谱、扫描电镜、能量色散谱和低温液氮吸附等对光催化剂晶相结构、光谱特征及表面结构进行了表征.结果表明,AC可提高TiO2分散性能,降低TiO2团聚体的尺寸,并抑制其由锐钛矿相向金红石相的转变.TiO2与AC接触界面处有Ti-O-C键生成.另外,AC的含量对TiO2的能阈结构和晶粒大小影响不大.苯酚溶液的光催化降解测试结果表明,AC负载可为TiO2提供高浓度反应环境,适宜量的负载可显著提高TiO2对有机稀溶液的光催化降解活性.对于50mg/L苯酚的光催化降解,AC的质量分数分别为5%,9%和11%时催化剂协同系数分别为1.1,1.5和1.3.循环使用7次后,AC含量为9%的催化剂对苯酚的降解率仍达95.84%.     

Elucidating the Underlying Reactivities of Alternating Current Electrosynthesis by Time-Resolved Mapping of Short-Lived Reactive Intermediates

Alternating current (AC) electrolysis is an emerging field in synthetic chemistry, however its mechanistic studies are challenged by the effective characterization of the elusive intermediate processes. Herein, we develop an operando electrochemical mass spectrometry platform that allows time-resolved mapping of stepwise electrosynthetic reactive intermediates in both direct current and alternating current modes. By dissecting the key intermediate processes of electrochemical functionalization of arylamines, the unique reactivities of AC electrosynthesis, including minimizing the over-oxidation/reduction through the inverse process, and enabling effective reaction of short-lived intermediates generated by oxidation and reduction in paired electrolysis, were evidenced and verified. Notably, the controlled kinetics of reactive N-centered radical intermediates in multistep sequential AC electrosynthesis to minimize the competing reactions was discovered. Overall, this work provides direct evidence for the mechanism of AC electrolysis, and clarifies the underlying reasons for its high efficiency, which will benefit the rational design of AC electrosynthetic reactions.     

Bifunctional activated carbon with dual photocatalysis and adsorption capabilities for efficient phenol removal

Bifunctional activated carbons (AC) with the abilities of both photocatalysis and adsorption were fabricated via the sol?Cgel route combined with hydrothermal treatment and N₂ reactivation method. TiO₂ was located mainly at the entrance of the surface macropores of AC. Under UV light irradiation, efficient removal of phenol was realized by combination of adsorption and photocatalytic degradation for the obtained bifunctional materials. In insufficient light or dark, phenol removal occurred mainly through adsorption. The prepared bifunctional carbon with a mass ratio of 50 TiO₂ per AC ratio exhibited high efficiency for phenol removal. The total phenol removal capacity of 50TiO₂/AC was almost 5 times of that of pure AC and 6 times of that pure TiO₂ after 10 cycles. The prepared bifunctional carbons possess the advantages of high pollutant removal capability and good recyclability, making them promising for the efficient treatment of lightly polluted aqueous solutions.     

苯酚在热氧化法制备的SnO2/Ti 电极上的电氧化研究

A SnO₂/Ti electrode prepared by thermal oxidation was used as the anode for galvanostatic electrolysis in acidic solution containing phenol, the time-dependances of phenol concentration,chemical oxygen demand in solution(COD)and instantaneous current efficiency were determined during electrolysis.The results show that with the SnO₂/Ti anode instead of Pt,the COD significantly decreases at the same charge passage, and average current efficiency of oxidation increases by three times The mechanism for phenol oxidation at two electrodes was discussed.     

苯酚在热氧化法制备的SnO2/Ti电极上的电氧化研究

以热氧化法制备的ＳｎＯ２／Ｔｉ电极作为阳极用于含苯酚酸性溶液的恒电流电解,测定了苯酚浓度、溶液中化学需氧量（ＣＯＤ）以及瞬时电流效率等随电解时间的变化。结果表明,用ＳｎＯ２／Ｔｉ电极代替铂作为阳极可使相同氧化电量下的ＣＯＤ明显下降,而平均电流效率提高了３倍,讨论了两种电极上苯酚氧化的反应机理。     

吸附有苯酚氧化残留物的Cu-Ce/AC吸附 催化剂的氢处理研究

对经苯酚吸附和干态催化氧化过程后吸附有苯酚残留物的活性炭载氧化铜和氧化铈(Cu Ce/AC)进行了氢处理研究。结果表明,氢处理可明显促进残留物的分解,恢复Cu Ce/AC对苯酚的吸附性能,减少在后续苯酚氧化过程中苯酚脱附量。氢处理温度越高,苯酚吸附容量恢复得越好。但氢处理不能恢复Cu Ce/AC对苯酚的催化氧化活性,是由于活性组分晶粒长大所致。     

Cu-Ce/AC吸附-催化剂对所吸附苯酚的催化氧化行为的研究

对活性炭载氧化铜和氧化铈（Cu-Ce/AC）吸附 催化剂在连续吸附-催化氧化苯酚循环过程中的催化氧化活性和失活原因进行了研究。结果表明,Cu-Ce/AC的苯酚吸附性能和催化氧化活性随着吸附 催化氧化循环次数的增加而逐渐降低,经5次循环后,苯酚的初始氧化温度提高约25℃。通过对使用过的Cu Ce/ACs进行XPS、ICP分析, 发现Ce和Cu的流失较小,苯酚残留物覆盖表面Ce和Cu是苯酚催化氧化活性降低的主要原因,残留物主要含有C-O-C和C-OH等官能团。     

苯直接一步氧化合成苯酚

苯直接一步氧化合成苯酚是开辟苯酚合成路线具有挑战性的热点课题之一.近年来研究和开发了以N2O、H2O2和O23种不同氧化剂体系为核心和主流的苯氧化合成苯酚路线.本文详细综述了目前3种不同氧化体系的研究进展和趋势,分析了各种合成路线的特点和工业应用前景.以N2O为氧化剂合成苯酚路线,技术趋于成熟,但N2O来源受限而影响其经济性和推广应用;以H2O2为氧化剂合成苯酚路线,是环境友好过程,有开发潜力,但技术还很不成熟,而且也因H2O2价格昂贵带来了经济成本问题;以O2为氧化剂、氢气为还原剂体系合成苯酚路线,是环境清洁可持续发展制备路线,具有很好的开发潜力,此外无机膜催化合成苯酚路线也更具吸引力.     

Enhanced Production of Laccase from Coriolus versicolor NCIM 996 by Nutrient Optimization Using Response Surface Methodology

Plackett and Burman design criterion and central composite design were applied successfully for enhanced production of laccase by Coriolus versicolor NCIM 996 for the first time. Plackett and Burman design criterion was applied to screen the significance of ten nutrients on laccase production by C. versicolor NCIM 996. Out of the ten nutrients tested, starch, yeast extract, MnSO(4), MgSO(4) x 7H(2)O, and phenol were found to have significant effect on laccase production. A central composite design was applied to determine the optimum concentrations of the significant variables obtained from Plackett-Burman design. The optimized medium composition for production of laccase was (g/l): starch, 30.0; yeast extract, 4.53; MnSO(4), 0.002; MgSO(4) x 7H(2)O, 0.755; and phenol, 0.026, and the optimum laccase production was 6,590.26 (U/l), which was 7.6 times greater than the control.     

增强型电场协助光催化降解有机污染物的初步研究

众所周知 ,Ti O2 的光催化量子效率低是限制该光催化技术走向应用的重要因素 .近年来 ,研究通过电场协助来提高其光催化反应效率的文献报导逐渐增多 [1～ 3 ] .这类技术中通常把 Ti O2 做成膜电极 ,并对该膜电极施加数十到数百毫伏的阳极偏压 ,致使光生电子更易离开催化剂表面 ,从而提高光催化效率 .例如 ,Butterfield等[2 ] 把 Ti O2 做成膜电极 ,发现光催化效率得到明显提高 .但目前该类工作多关注于具有二维特性的膜电极体系 .由于受膜电极单位活性面积的限制 ,在技术上很难大幅度提高时空降解率 ,使得这种方法在实际应用中可能受到限…     

Electrowetting without electrolysis on self-healing dielectrics

An electrowetting system with protection against dielectric breakdown is presented. It comprises an electrolyte and a Parylene-C film deposited on an aluminum electrode. The system demonstrates virtually instantaneous self-healing (within 100 ms) after dielectric breakdown under both DC and certain AC electrowetting conditions. DC current response during electrowetting on intentionally damaged Parylene-C is presented. Also presented is a characterization of DC offset voltages and duty cycle percentages required for electrolysis free AC electrowetting between 10 Hz and 4 kHz.     

金属担载量对CuO/AC干法催化氧化苯酚的影响

采用程序升温氧化（TPO）技术和吸附 催化氧化循环实验,研究了金属担载量对CuO/AC催化-吸附剂干法催化氧化苯酚的影响。结果表明，随着金属担载量的增加，CuO/AC催化-吸附剂的苯酚催化氧化活性升高，并且苯酚与催化-吸附剂之间的相互作用增强，使吸附的苯酚不易脱附/降解脱附。同时，CuO/AC催化 吸附剂自身的烧蚀活性也随金属担载量的增加而升高。对于吸附-干法催化氧化法而言，CuO/AC存在一个较佳的金属担载量范围，该范围以Cu的质量分数计为3%～5%。     

离子液体/季铵盐辅助氯过氧化物酶促氧化合成聚酚

基于氯过氧化物酶(CPO)催化氧化苯酚衍生物单体,建立了一个聚酚的绿色合成体系.以对苯基苯酚、对甲基苯酚、4-乙基苯酚、对羟基肉桂酸、对异丙基苯酚和邻甲基苯酚等6种底物为考察对象,以聚合物的产率、聚合度及热稳定性为评价指标,研究了体系中引入离子液体(ILs)或季铵盐(QAS)以及底物结构和反应微环境等对聚合反应和聚合物性质的影响.结果表明,引入少量咪唑类ILs或QAS可有效提高产物收率,其中ILs/QAS的阳离子基团越大和疏水链越短,越有利于酶催化聚合反应的进行;而ILs/QAS添加量的影响则呈现"钟罩"型规律.同时,苯酚对位取代远比邻位取代有利于聚合反应进行;而对位取代基中烷基类给电子基团比芳香基取代更有优势,所得聚合物的聚合度和热稳定性相对增大,但随着取代基团的增大,其空间位阻不利于聚合物产率的提高;反应体系的p H应控制在弱酸性至近中性,以避免竞争性的副反应的发生;而氧化剂H_2O_2则需要采用间歇式加入以抑制瞬时过浓导致CPO活性中心卟啉环的氧化损伤.基于CPO的活性中心结构分析了聚合机理.     

Electrochemical oxidation of phenol at boron-doped diamond electrode. Application to electro-organic synthesis and wastewater treatment

The electrochemical behaviour of a synthetic boron-doped diamond thin film electrode (BDD) has been studied in acid media containing phenol using cyclic voltammetry and bulk electrolysis. The results have shown that in the potential region of water stability direct electron transfers can occur on BDD surface resulting in electrode fouling due to the formation of a polymeric film on its surface. During electrolysis in the potential region of oxygen evolution, complex oxidation reactions can take place due to electrogenerated hydroxyl radicals. Electrode fouling is inhibited under these conditions. Depending on the experimental conditions, the electrogenerated hydroxyl radicals can lead to the combustion of phenol or to the selective oxidation of phenol to benzoquinone. The experimental results have also been compared to a theoretical model that permits the prediction of the evolution with time of phenol concentration, during its combustion, or during its selective oxidation to benzoquinone.     

Synthesis and Temperature-dependent Electrochemical Properties of Boron-doped Diamond Electrodes on Titanium

On the sand-blasting-treated titanium(Ti) substrate, the boron-doped diamond(BDD) electrodes with a wide potential window were prepared by microwave plasma chemical vapor deposition(MPCVD). The electrochemical oxidation ratios of phenol at BDD/Ti electrodes at elevated temperatures(from 20 ℃ to 80 ℃) were examined by the chemical oxygen demand(COD) of phenol electrolyte during electrolysis. The results show that the COD removal was increased at high temperatures and the optimized temperature for enhancing the electrochemical oxidation ratio of phenol is 60 ℃. The mechanism for the temperature-dependent electrochemical oxidation ratios of phenol at the electrodes was investigated. The study would be favorable for further improving the performance of BDD/Ti electrodes, especially working at high temperatures.     

表面改性活性炭活化过硫酸盐降解苯酚

采用硝酸氧化联合高温处理法对活性炭(AC)进行表面改性(样品记为ACNH),并将其用于活化过硫酸盐(PS)降解苯酚.通过氮气等温吸附、元素分析、X射线光电子能谱和扫描电子显微镜等手段对改性前后活性炭的表面性质进行了表征分析.考察了活性炭投加量、PS/苯酚摩尔比、苯酚初始浓度和初始p H等条件对苯酚降解率的影响.结果表明,改性后活性炭活化PS能力显著提高,在ACNH/PS体系中苯酚的降解速率是AC0/PS体系中的5倍;ACNH的pH值适用范围宽;活性炭表面醌基、吡喃酮结构和碳原子平面层上的离域π电子(Cπ)在活化PS过程中起主要作用,而羧基起抑制作用.     

含水的凝胶电解质电化学特性及其在锂水电池中的初试

应用交流阻抗谱研究以聚甲基丙烯酸＿聚甲基丙烯酸锂＿甘油(GPE)作为锂水电池正极的体系,根据等效电路计算,发现升高温度和增加水含量均可提高体系的电导率.该体系导电过程类似于聚合物浓溶液,水分能降低聚合物的玻璃化温度,电解过程相当于电解水,分解电压1.50V.使用GPE组装室温全固态锂水电池,测定了该电池在恒负载(5.2kΩ)下放电曲线,发现当以石墨正极作集电极时,该电池能持续放电2h.使放电电压和放电电流下降的因素是:锂与GPE内水分反应生成的膜逐渐增厚,正极反应生成氢气,GPE内水份的扩散速率.     

Liquid-phase adsorption: Characterization and use of activated carbon prepared from diosgenin production residue

The adsorption behavior of activated carbon (AC) prepared from the residue of diosgenin by-product was characterized. The adsorption capacities of AC such as iodine, phenol and methylene blue (MB) are 933.28, 145.38 and 165 mg/g, respectively. The results of MP analysis and BJH method show AC has developed micropore and mesopore volumes, which are 0.1621 and 0.2623 cm³/g respectively, with the mean pore diameter of 1.49 nm. Comparison of the liquid phase adsorption capacities of AC to the standard activated carbon (SAC) and the commercial activated carbon (CAC) for wastewater treatment showed AC was superior to SAC and CAC. Experiments on phenol and MB adsorption and COD and chroma removal from diosgenin wastewater were carried out under different conditions of contact time, temperature, concentration, adsorbent dose and pH. The removal of COD and chroma of 10-multiple wastewater is 92.46 mg/g and 88 %, respectively. Adsorption parameters for the Langmuir and Freundlich isotherm models were determined. At lower temperatures, the data for phenol and COD fitted Freundlich model better than Langmuir model and vise versa for MB and chroma. Adsorption followed second-order kinetics. The study proves that AC prepared from the residue of diosgenin by-product can be used as adsorbent for the treatment of diosogenin wastewater as a cost-effective approach of resource recycle of Discorea zingiberensis C.H. Wright.