多金属氧酸盐为介体的杨木KP浆电化学介体脱木素研究

以多金属氧酸盐Na8[PMo7V5O40]为介体,对杨木硫酸盐浆进行了电化学介体脱木素的研究.结果表明,采用钌钛涂层电极为阳极,不锈钢为阴极,以Na8[PMo7V5O40]为介体对杨木硫酸盐浆进行无隔膜电化学处理,能够有效脱除纸浆中的残余木素,而浆的黏度损失不大.Na8[PMo7V5O40]最优的电化学介体脱木素条件为:Na8[PMo7V5O40]浓度5 mmol/L,电压2.5V,温度80℃,时间7h,pH值2.0～3.0,Na2SO4用量0.1mol/L.该条件下,纸浆卡伯值从17.3降至11.4,黏度从1018 mL/g降至846 mL/g.电化学处理后的废液可进行多次循环使用.     

紫脲酸为介体的杨木硫酸盐浆电化学漂白

对杨木硫酸盐浆进行了电化学介体漂白(EM)的研究。结果表明,采用钌钛涂层电极为阳极,不锈钢为阴极,以紫脲酸为介体对杨木硫酸盐浆进行无隔膜电化学处理,能有效脱除纸浆中的残余木素,而浆的黏度损失较小。最优的电化学介体催化漂白(Em)条件为:VIO浓度1.8mmol/L,电压2.5V,温度50℃,时间5h,pH值4.5,Na2SO4浓度0.05mol/L。在该工艺条件下,纸浆卡伯值从17.4降至11.7,浆的黏度由1144cm3/g降至1059cm3/g。浆料经EME处理后,卡伯值降至7.9,木素脱除率达55.2%,黏度仅降至1032cm3/g,白度由原浆的39.2%ISO提高至51.2%ISO。     

漆酶／介体催化体系中介体的反应性能

对用于漆酶/介体催化体系的介体N-羟基-N-乙酰基苯胺（NHA）的氧化还原势以及在反应体系中的可逆性进行了研究,比较了NHA和1-羟基苯并三唑（HBT）与漆酶氧化藜芦醇的反应动力学,并且比较了几种介体的漆酶/介体体系中的脱木素效果。结果表明NHA与漆酶构成的催化体系具有较强的脱木素性能。     

杨木硫酸盐浆高浓电化学介体脱木素研究

本文对杨木硫酸盐浆在高浓条件下电化学介体脱木素的效果进行了研究。实验过程中根据电化学介体脱木素的工艺特点,设计制备了高浓电化学介体脱木素装置,并就该装置的电化学介体脱木素效果及脱木素后浆料的后续可漂性进行了探讨。结果表明:使用设计的电化学介体脱木素装置,能有效地提高电化学介体脱木素的浓度。在紫脲酸浓度2.0mmol/L,温度50℃,电解槽电压2.5V,pH 3.0的工艺条件下,浆浓在3%～5%之间,循环流量为0.5L/min,处理时间为8h时,具有较好的脱木素效果。木素脱除率可达到30%左右,经过后续碱处理后,木素脱除率可达到41.4%,黏度降低率仅为10%左右。并且电化学介体脱木素后的纸浆具有较好的过氧化氢后续可漂性,当过氧化氢用量在2.5%时,其白度可达80%ISO以上。     

多金属氧酸盐用于纸浆漂白的研究进展

简单介绍了多金属氧酸盐具有的结构和特性,重点概述了其在纸浆漂白中的应用研究情况,主要包括多金属氧酸盐在氧脱木素中的催化作用及催化机理,多金属氧酸盐催化的H2O2漂白以及多金属氧酸盐在漆酶介体体系、电化学介体脱木素中的应用进展。     

复合电化学-生化法处理桉木CTMP制浆废水的研究

采用复合电化学-生化法对桉木CTMP制浆废水进行处理,并与微电解法和混凝法进行比较,考察了电偶腐蚀电流电位,修饰电极表面形貌,Zeta电位,温度和金属离子浓度等对电化学处理效果的影响,并初步探讨了复合电化学法的作用机制.结果表明,金属M3是合适的微电池阳极材料,电沉积法制备的Ti/SnO2 -Sb2 O3 -MnO2/PbO2电极性能良好,过渡金属离子可加速自由基链反应,新生态金属离子络合物能破坏色度胶粒的稳定性从而易于脱除色度.复合电化学法能有效降低色度(去除率＞95％)和CODCr,可生化性明显改善,处理效果显著优于混凝法和微电解法.SBR生化法进一步处理废水,CODCr降低约79.8％～86.6％.     

复合电化学-生化法处理桉木CTMP制浆废水的研究

采用复合电化学一生化法对桉木CTMP制浆废水进行处理,并与微电解法和混凝法进行比较,考察了电偶腐蚀电流电位,修饰电极表面形貌,Zeta电位,温度和金属离子浓度等对电化学处理效果的影响,并初步探讨了复合电化学法的作用机制.结果表明,金属M3是合适的微电池阳极材料,电沉积法制备的Ti/SnO2-Sb2O3-MnO2/PbO2电极性能良好,过渡金属离子可加速自由基链反应,新生态金属离子络合物能破坏色度胶粒的稳定性从而易于脱除色度.复合电化学法能有效降低色度(去除率>95%)和CODCr,可生化性明显改善,处理效果显著优于混凝法和微电解法.SBR生化法进一步处理废水,CODCr降低约79.8%～86.6%.     

电化学氧化法处理阴离子表面活性剂废水的实验研究

采用小型电化学反应器，利用不同的电极材料，对阴离子表面活性剂(DBS)的电化学氧化行为及各种工艺条件对降解效果的影响规律进行了实验。结果表明，在无隔膜复极性固定床电解槽内，以不锈钢为阴极,以钛基RuΩ2电极为阳极,以活性炭颗粒为填充电极。在合适的工艺条件下，阴离子表面活性剂废水具有较好的降解效果，降解率可达到96％以上，CODCr去除率大于84%。     

基于聚吡咯/石墨烯的甘油酶电极的构建及性能研究

本文以循环伏安法在玻碳电极表面制备了聚吡咯(PPy)膜,以水热还原法制备了三维石墨烯(GN),并以此构建了甘油酶电极。所构建的甘油酶电极以甘油激酶(GK)和甘油三磷酸氧化酶(GPO)为催化剂,以三维石墨烯(GN)为载体,以聚吡咯(PPy)为介体,以Nafion溶液作为粘结剂。该甘油酶电极可以在酶、介体及电极表面提供良好的电子转移。论文探究了吡咯的聚合条件,并采用扫描电子显微镜及电化学方法对其进行了表征;对该酶电极的修饰材料、工作条件等进行了优化,采用电化学方法对其性能进行了评价。结果表明,聚吡咯的聚合圈数为8时其导电性能最优,所述的基于聚吡咯/石墨烯的甘油酶电极在pH为7.0,浓度为0.2mmol/L的磷酸缓冲溶液对甘油有着较高的电流响应,其催化电流达46.2μA,电流密度达677.6μA/cm~2。     

麦草浆的生物漂白

采用聚木糖酶和漆酶对麦草浆进行漂前生物预处理。聚木糖酶预处理的最佳条件为:p H值5.5,温度60℃,聚木糖酶用量6 IU/g,预处理时间75 min,搅拌速率80 r/min。漆酶催化脱木素的最佳条件为:p H值3.5,温度60℃,漆酶用量22.5 IU/g,介体用量1.5%,脱木素时间10 h,搅拌速率120r/min。聚木糖酶预处理可破坏木素-碳水化合物复合体的结构,降低纸浆中己烯糖醛酸含量。与无聚木糖酶预处理纸浆相比,聚木糖酶预处理纸浆卡伯值降低幅度较大,如X(聚木糖酶预处理)-L(漆酶催化脱木素)-E(碱性过氧化氢抽提)漂白浆的卡伯值较L-E漂白浆低7.2%,X-LM(漆酶/介体体系催化脱木素)-E漂白浆的卡伯值较LM-E漂白浆低24.8%。依次使用聚木糖酶和漆酶处理可有效提高纸浆生物漂白的效果。     

Essential explanation of the strong mineralization performance of boron-doped diamond electrodes

Electrochemical oxidation of p-nitrophenol was examined using differentanodic materials, including T/boron-doped diamond (BDD), Ti/SnO2-Sb/PbO2, and Ti/SnO2-Sb anodes. The results demonstrated that Ti/BDD anodes had a much stronger mineralization performance than the other two anodes. Furthermore, it was found that hydroxyl radicals could mainly exist as free hydroxyl radicals at BDD anodes, which could react with organic compounds effectively. This implied that the dominant mechanism for a much higher mineralization capacity of BDD anodes would be attributed to the existence of free hydroxyl radicals in the BDD anode cell rather than adsorbed hydroxyl radicals on the BDD anode. To further corroborate this hypothesis, electrochemical oxidation of p-substituted phenols (p-nitrophenol, p-hydroxybenzaldehyde, phenol, p-cresol, and p-methoxyphenol) was examined at the Ti/BDD, Ti/SnO2-Sb/ PbO2, and Ti/SnO2-Sb anodes, respectively. The study revealed that for Ti/BDD electrodes, the degradation rate of p-substituted phenols (k) increased with the increase of Hammett's constant (sigma), which confirmed the dominance of free hydroxyl radicals at BDD anodes and its effective reaction with organics therein. For Ti/SnO2-Sb/PbO2 electrodes, the degradation rate of p-substituted phenols (k) increased with the increase of initial surface concentration gamma (representing the adsorption capacity of phenols to electrode surface), which indicated that organic compounds mainly reacted with adsorbed hydroxyl radicals at PbO2 anodes. For Ti/SnO2-Sb electrodes, however, k increased with the increase of the integrated parameter S (representing the effects of both sigma and gamma), which implied that organic compounds reacted with both adsorbed hydroxyl radicals and free hydroxyl radicals at SnO2 anodes.     

普鲁士蓝/石墨烯修饰电极检测酱油中的亚硝酸盐

利用电化学沉淀普鲁士蓝纳米粒子在石墨烯的表面,采用差分脉冲伏安法对该电极进行表征,并研究亚硝酸根离子在修饰电极上的电化学行为。结果表明:在0.10 mol/L磷酸盐缓冲液(pH 7.0)中,亚硝酸根在1×10-6~1×10-2 mol/L浓度范围内呈线性关系,信噪比为3时检出限为3×10-8 mol/L。所构建的普鲁士蓝/石墨烯修饰电极对亚硝酸根离子具有良好的电催化活性,表现出良好的稳定性、重复性和抗干扰能力,同时将所构建的复合材料修饰电极应用于酱油中亚硝酸盐的检测。     

Hydrogen production with a microbial biocathode

This paper, for the first time, describes the development of a microbial biocathode for hydrogen production that is based on a naturally selected mixed culture of electrochemically active micro-organisms. This is achieved through a three-phase biocathode startup procedure that effectively turned an acetate- and hydrogen-oxidizing bioanode into a hydrogen-producing biocathode by reversing the polarity of the electrode. The microbial biocathode that was obtained in this way had a current density of about -1.2 A/Nm2 at a potential of -0.7 V. This was 3.6 times higher than that of a control electrode (-0.3 A/m2). Furthermore, the microbial biocathode produced about 0.63 m3 H2/m3 cathode liquid volume/day at a cathodic hydrogen efficiency of 49% during hydrogen yield tests, whereas the control electrode produced 0.08 m3 H2/m3 cathode liquid volume/day at a cathodic hydrogen efficiency of 25%. The effluent of the biocathode chamber could be used to inoculate another electrochemical cell that subsequently also developed an identical hydrogen-producing biocathode (-1.1 A/m2 at a potential of -0.7 V). Scanning electron micrographs of both microbial biocathodes showed a well-developed biofilm on the electrode surface.     

Electrochemical oxidation as a final treatment of synthetic tannery wastewater

Vegetable tannery wastewaters contain high concentrations of organics and other chemicals that inhibit the activity of microorganisms during biological oxidations, so biorefractory organics that are not removed by biological treatment must be eliminated by a tertiary or advanced wastewater treatment. In this paper, the applicability of electrochemical oxidation as a tertiary treatment of a vegetable tannery wastewater was investigated by performing galvanostatic electrolysis using lead dioxide (Ti/PbO2) and mixed titanium and ruthenium oxide (Ti/TiRuO2) as anodes under different experimental conditions. The experimental results showed that both the electrodes performed complete mineralization of the wastewater. In particular, the oxidation took place on the PbO2 anode by direct electron transfer and indirect oxidation mediated by active chlorine, while it occurred on the Ti/TiRuO2 anode only by indirect oxidation. Furthermore, the Ti/PbO2 gave a somewhat higher oxidation rate than that observed for the Ti/TiRuO2 anode. Although the Ti/TiRuO2 required almost the same energy consumption for complete COD removal, it was more stable and did not release toxic ions, so it was the best candidate for industrial applications. With the Ti/TiRuO2 anode, the rate of tannery wastewater oxidation increased with the current density, pH, and temperature of the solution. These results strongly indicate that electrochemical methods can be applied effectively as a final treatment of vegetable tannery wastewater allowing the complete removal of COD, tannin, and ammonium and decolorization.     

Efficient electrochemical oxidation of perfluorooctanoate using a Ti/SnO2-Sb-Bi anode

The electrochemical decomposition of persistent perfluorooctanoate (PFOA) with a Ti/SnO2-Sb-Bi electrode was demonstrated in this study. After 2 h electrolysis, over 99% of PFOA (25 mL of 50 mg·L(-1)) was degraded with a first-order kinetic constant of 1.93 h(-1). The intermediate products including short-chain perfluorocarboxyl anions (CF3COO-, C2F5COO-, C3F7COO-, C4F9COO-, C5F11COO-, and C6F13COO-) and F- were detected in the aqueous solution. The electrochemical oxidation mechanism was revealed, that PFOA decomposition first occurred through a direct one electron transfer from the carboxyl group in PFOA to the anode at the potential of 3.37 V (vs saturated calomel electrode, SCE). After that, the PFOA radical was decarboxylated to form perfluoroheptyl radical which allowed a defluorination reaction between perfluoroheptyl radical and hydroxyl radical/O2. Electrospray ionization (ESI) mass spectrum further confirmed that the oxidation of PFOA on the Ti/SnO2-Sb-Bi electrode proceeded from the carboxyl group in PFOA rather than C-C cleavage, and the decomposition processes followed the CF2 unzipping cycle. The electrochemical technique with the Ti/SnO2-Sb-Bi electrode provided a potential method for PFOA degradation in the aqueous solution.     

Ti/SnO_2-Sb_2O_5-CuO电极制备及其降解模拟高盐印染废水中氨氮的研究

本文采用热分解法制备了Ti/SnO_2-Sb_2O_5-CuO电极,通过SEM、极化曲线及强化寿命测试对电极性能进行检测分析。研究发现相较于Ti/Sn O2-Sb2O5电极,Ti/SnO_2-Sb_2O_5-CuO电极表层更加致密,析氧电位更高,析氯电位更低,电极强化寿命更长。以模拟高盐印染废水中铵态氮作为研究对象,考察了Ti/SnO_2-Sb_2O_5-CuO电极的降解性能,结果表明:50 mg/L氨氮,氯离子浓度10 g/L,氨氮的降解速率和去除效率随氯离子浓度的增加而增加;氯离子浓度≥10 g/L,继续增加氯离子浓度,降解速率和去除效率无明显变化;在2~10 m A/cm2范围内,增加电流密度,降解速率加快,但氨氮的去除率变化不大;Ti/SnO_2-Sb_2O_5-CuO电极对氨氮的去除率可达90%以上,废水中氨氮浓度能降低到3 mg/L以下,达到印染废水的国家排放标准。     

二氧化锰/石墨烯/棉织物复合电极的制备及其电化学性能

为研究并增强柔性织物电极的电化学性能,采用改进Hummers法制备得到高浓度氧化石墨烯水溶胶,并通过干涂层法将氧化石墨烯涂覆于棉织物表面,经化学-微波两步还原法还原氧化石墨烯,制备了石墨烯/棉织物。进一步采用电化学沉积法将二氧化锰沉积在石墨烯/棉织物上,得到二氧化锰/石墨烯/棉织物复合电极材料。借助扫描电子显微镜、X射线衍射仪和红外光谱仪对复合电极材料的形貌和结构进行表征。研究结果表明:复合电极材料在0.25 A/g的电流密度下比电容达到490 F/g,1 000次电容放电后电容保持在95.5%,能量密度达到17.01 W·h /kg。     

基于石墨烯构建的电化学传感器测定抗坏血酸

制备石墨烯修饰电极建立电化学方法实现对抗坏血酸的测定。采用电化学还原技术,通过一步电沉积制备石墨烯修饰玻碳电极(ERGO/GCE),并用循环伏安法研究抗坏血酸(ascorbicacid,AA)在该修饰电极上的电化学行为,结果表明,所制备的石墨烯修饰电极较裸玻碳电极对抗坏血酸有显著的电催化效果。在p H=6.5的磷酸盐缓冲溶液中,AA在-0.4 V～0.8 V扫描电位范围内有1个不可逆的氧化峰出现。在优化的实验条件下,AA的浓度在1.7×10-3 mol/L～2×10-5 mol/L范围内与其氧化峰电流值呈良好的线性关系,相关系数为0.991,最低检出限为9×10-6mol/L(S/N=3)。探究了修饰电极的稳定性、抗干扰性,结果表明电极稳定性良好,抗干扰能力较强。用此修饰电极对橙汁中的AA含量进行检测,加标回收率在97.95%～98.68%之间。用本文建立的电化学方法可用于橙汁中AA的测定,结果比较满意。     

纸浆电化学漂白的研究进展

分析了电化学用于纸浆漂白的基本理论依据,概述了各种电化学漂白的研究现状及其进展,包括电化学含氯漂白、电化学连二亚硫酸盐漂白、电化学过氧化氢漂白、电化学催化的氧碱漂白以及电化学介体漂白,重点介绍了电化学介体漂白的研究进展.