光/电/化学催化降解水中二甲基甲酰胺的反应特性

设计了以负载型TiO₂薄膜电极为阳极,以高纯多孔石墨为阴极,以饱和甘汞电极为参比电极的光/电/化学催化反应器,对二甲基甲酰胺(DMF)溶液进行降解. TiO₂/Ti薄膜电极能对阳极槽中的DMF进行降解;同时,阴极槽中产生的过氧化氢(H₂O₂)可与亚铁离子形成Fenton催化体系,对DMF溶液也具有良好的降解作用. 结果表明,在以0.02 mol/L的Na₂SO₄和0.01 mol/L的FeSO₄混合溶液作为支持电解质,初始pH为3.5,阴极电位(-E_c)为0.66 V,曝气强度为1.5 L/min和反应时间为60 min等的条件下,阳极槽和阴极槽中DMF的去除率分别达到85.10%和82.95%.      

双向微槽道多孔复合结构沸腾传热研究

目的研究出新型的表面结构,以提高沸腾传热强化。方法在紫铜板上烧结铜粉多孔层,然后利用线切割对多孔层进行开槽。研究槽道参数包括槽数、槽宽、槽间距和槽向等对沸腾传热效果的影响。结果开槽增大了传热的表面积,有利于气体逸出,减少气体的逸出阻力,从而多孔表面开槽强化了沸腾传热效果,传热系数与光滑表面相比可提高2~3倍。与单向微槽道相比,双向交叉槽道有着更好的传热效果,能够形成一个稳定的液体补充和气体逸出网络。结论在多孔表面加工微型复合结构,能够大幅度提高沸腾传热强化。     

微波等离子体技术及研究进展

从微波等离子体发生及应用研究两个方面综述微波等离子体技术及研究进展,先从微波激励气体放电工作原理及能量传递方式两方面介绍微波等离子体技术,在此基础上,结合实验结果及现有研究成果对微波等离子体的发射光谱特性及温度特性进行论述。在微波等离子体应用研究方面,归纳总结了电子回旋共振微波等离子体、表面波等离子体、谐振腔微波等离子体等几种典型的微波等离子体技术及其特点,结合在薄膜沉积、废气处理、微量元素检测等方面的应用研究现状,对微波等离子体技术存在的问题及发展趋势进行了分析和展望。     

Al3+离子掺杂对负载TiO2薄膜光催化活性的影响

以钛酸丁酯和Al2(SO4)3·18H2O为原料,采用溶胶凝胶法在钛片、玻璃、釉面瓷砖、陶瓷、不锈钢和铝片六种载体上制备了Al3+掺杂TiO2薄膜,讨论了不同Al3+掺杂浓度下,不同载体表面上制备的TiO2薄膜对甲基橙脱色率的影响。试验结果表明Al3+对TiO2薄膜的掺杂效果与载体的类型密切相关,并且不同载体其Al3+掺杂的最佳浓度也不同。Al3+掺杂后,TiO2薄膜光催化活性提高最大的是玻璃,其次是釉面瓷砖、铝片、钛片、陶瓷,最差的是负载不锈钢。     

Production of ammonia from plasma-catalytic decomposition of urea: Effects of carrier gas composition

Effects of carrier gas composition(N_2/air) on NH_3 production, energy efficiency regarding NH_3 production and byproducts formation from plasma-catalytic decomposition of urea were systematically investigated using an Al_2 O_3-packed dielectric barrier discharge(DBD) reactor at room temperature. Results show that the presence of O_2 in the carrier gas accelerates the conversion of urea but leads to less generation of NH_3. The final yield of NH_3 in the gas phase decreased from 70.5%, 78.7%, 66.6% and 67.2% to 54.1%, 51.7%, 49.6% and 53.4% for applied voltages of 17, 19, 21 and 23 kV, respectively when air was used as the carrier gas instead of N_2.From the viewpoint of energy savings, however, air carrier gas is better than N_2 due to reduced energy consumption and increased energy efficiency for decomposition of a fixed amount of urea. Carrier gas composition has little influence on the major decomposition pathways of urea under the synergetic effects of plasma and Al_2 O_3 catalyst to give NH_3 and CO_2 as the main products. Compared to a small amount of N_2 O formed with N_2 as the carrier gas, however,more byproducts including N_2O and NO_2 in the gas phase and NH_4 NO_3 in solid deposits were produced with air as the carrier gas, probably due to the unproductive consumption of NH_3, the possible intermediate HNCO and even urea by the abundant active oxygen species and nitrogen oxides generated in air-DBD plasma.     

微波辐照下碳化硅与沸石负载氧化铜催化剂协同去除甲苯的实验研究

实验采用浸渍法制备沸石负载氧化铜催化剂,对催化剂的表面形貌进行了表征分析,考察了催化剂在微波场中的升温曲线和对甲苯的吸附能力.催化剂与吸波材料碳化硅混合后装入石英管内组成固定床反应器,考察了微波辐照下碳化硅与催化剂协同氧化甲苯废气的降解效果.研究表明,氧化铜在沸石表面分布比较均匀;催化剂对甲苯的吸附为单层吸附,吸附量为...     

金属丝网负载TiO_2光催化降解染料废水

通过溶胶-凝胶法制备纳米二氧化钛,采用浸渍提拉的方法将TiO2固定在金属丝网上,通过掺杂碳黑获得高比表面的催化薄膜,用比表面仪、X-ray衍射仪进行表征。设计了光催化降解染料废水的反应装置,探讨了制备工艺和光催化反应条件对催化性能的影响。结果表明:在pH值为4.0、加入2.5mL/LH2O2的反应条件下,用400℃热处理温度、镀膜4次的催化薄膜对染料脱色率达92.4%,COD去除率达75.6%。     

村镇生活垃圾与秸秆混合焚烧过程中多环芳烃(PAHs)释放特征

为了解我国农村地区生活垃圾与玉米秸秆焚烧处置过程烟气中多环芳烃(PAHs)释放特征,对我国农村地区生活垃圾可燃组分以及生活垃圾与玉米秸秆混合焚烧组分在焚烧过程烟气中PAHs化合物释放特征进行分析,利用气相色谱-质谱仪(GC-MS)对样品中的16种PAHs进行分析,研究气态以及颗粒态PAHs的释放因子、环数比例、气固态分配以及排放特征值.结果表明气态PAHs排放因子为当垃圾与秸秆混合比例为1∶2时PAHs的总量最多,而颗粒态为当垃圾与秸秆混合比例为1∶3时PAHs的总量最多;气态PAHs主要集中于2～3环低环数化合物,颗粒态PAHs则主要以中低环数(3～4环)化合物为主,本研究为促进我国村镇生活垃圾处理与资源化运用提供理论依据.     

等离子体分解SO2实验

介绍了在低温常压条件下,应用等离子体分解有害气体ＳＯ２的实验结果,通过实验总结出ＳＯ２浓度,气体流量以及烟气温度ＳＯ２分解率的影响规律,比较了脉冲叠加正、负直流电压产生的等离子体分解ＳＯ２的能耗和分解量。实验结果表明,该项技术耗能低,ＳＯ２分解率高。每消耗１ｋＷ·ｈ电能可分解１．６１－１．９７ｋｇＳＯ２气体,分解率达８０％以上。     

Photoelectrocatalytic degradation of high COD dipterex pesticide by using TiO2/Ni photo electrode

A TiO₂ thin film electrode deposited on porous nickel net (TiO₂/Ni) was prepared by the sol-gel method, and the surface morphology, crystal structure features and the grain size were characterized by Field emission scan electron microscopy (FESEM) and X-ray diffraction (XRD). The photoelectrocatalytic system was set up using a UV high-pressure mercury lamp as the light source, TiO₂ coated on foamed nickel as photo anode, Pt sheet as counter electrode and the pesticide dipterex in synthetic wastewater. Various factors that influence the photoelectrocatalytic decomposition of dipterex pesticide have been studied, such as degradation time, the type of electrolyte, current density, original pH value and different degradation methods. The prepared catalysts were employed to photoelectrocatalytically degrade the pesticide dipterex under UV irradiation, comparing the results with photocatalytic degradation and electrochemical oxidation. The results indicated that under the optimal conditions of 0.02 mol/L NaCl as the supporting electrolyte, current density = 2.5 mA/cm², pH 6.0 and dipterex pesticide 40 mg/L, and reaction time 2 hr, dipterex chemical oxygen demand (COD) removal rate and organophosphorous conversion of up to 82.6% and 83.5% were achieved, respectively. The method of photoelectrocatalytic degradation is more efficient than photocatalysis and electrochemical oxidation. The possible roles of the electrolytes on the reactions and probable mechanisms were also discussed.     

Decomposition characteristics of toluene by a corona radical shower system

Non-thermal plasma technologies offer an innovative approach to decomposing various volatile organic compounds(VOCs). The decomposition of toluene from simulated flue gas was investigated using a pipe electrode with nozzles for the generation of free radicals. Corona characteristics and decomposition of toluene were investigated experimentally. In addition, the decomposition mechanism of toluene was explored in view of reaction rate. The experimental results showed that the humidity of additional gas has an important effect on corona characteristics and modes and stable streamer corona can be generated through optimizing flow rate and humidity of additional gas. Applied voltage, concentration of toluene, humidity of toluene and resident time are some important factors affecting decomposition efficiency. Under optimizing conditions, the decomposition efficiency of toluene can reach 80%. These results can give a conclusion that the corona radical shower technology is feasible and effective on the removal of toluene in the flue gas.     

响应面法优化固相微萃取饮用水中的DBP

文章建立了直接浸入固相微萃取-气质联用测定饮用水中邻苯二甲酸二正丁酯(DBP)含量的方法。通过响应面法优化100-μm PDMS纤维萃取自来水中DBP的条件,以DBP的峰面积为指标,考察了萃取温度、萃取时间和解析时间三个主要因素对萃取效果的影响。经响应面优化的最佳SPME萃取条件如下:萃取温度53.17℃,萃取时间50.49 min,解析时间4.62 min。在优化条件下,DBP的理论最大峰面积为7.16×108,验证值为6.68×108,与理论值相差6.70%。结果表明,响应面法适用于饮用水中邻苯二甲酸二正丁酯固相微萃取条件的优化,经优化得到的参数准确可靠。     

Cu-Mg-Al催化剂上NOx储存及分解性能研究

采用共沉淀方法制备了Cu-Mg-Al水滑石混合氧化物催化剂,并对该催化剂及其前驱物进行了XRD表征.使用等温吸附、程序升温脱附以及C₃H₆程序升温表面反应分别考察了催化剂上NO_x储存及分解反应性能.结果表明,由于Cu-Mg-Al催化剂中CuO组分发挥了NO氧化作用,促进了进气中NO_x以硝酸盐方式吸附在催化剂上,因此该催化剂具有很好的NO_x储存性能;在富燃条件下,C₃H₆能够显著降低催化剂上硝酸盐的热稳定性,在160～360 ℃温度范围内,这些硝酸盐会迅速分解成气态NO_x,同时随着C₃H₆加入量的提高,C₃H₆也可以将少量气态NO_x进行还原.     

Mercury release behaviors of Guizhou bituminous coal during co-pyrolysis: Influence of chlorella

Co-pyrolysis of coal and seaweed can not only effectively decrease the carbon footprint but also improve the quality and output of coal pyrolysis products, however, the influence of seaweed on thermal releasing behaviors of mercury during co-pyrolysis process are still unclear. In this work, the chlorella and Guizhou bituminous coal were mixed and used to reveal the mercury release behavior during co-pyrolysis by the temperature programmed pyrolysis experiments, thermogravimetric and differential thermogravimetric analysis (TG-DTG) and thermogravimetry-mass spectrometry (TG-MS) methods, offering a sufficient explanation on the control technology of mercury pollutants in co-pyrolysis. The results exhibited that a large amount of reducing gases such as CO, H₂ and H₂O were generated in chlorella at the temperature range of 100-500°C, which was favorable for the transformation from oxidized mercury to elemental mercury, thus remarkably increased the release of elemental mercury in the raw coal sample. The mixed chlorella also significantly lowered the decomposition temperature range (from 400-600 to 300-400°C) of pyrite-bound mercury and decreased the decomposition temperatures of the pyrite-bound mercury species. Additionally, in the co-pyrolysis about 91.82% of mercury was released into the gas phase below 400°C and was 13.77% higher than that of in individual pyrolysis of coal.     

Inhibitory effects of nisin-coated multi-walled carbon nanotube sheet on biofilm formation from Bacillus anthracis spores

Multi-walled carbon nanotube（MWCNT） sheet was fabricated from a drawable MWCNT forest and then deposited on poly（methyl methacrylate） film. The film was further coated with a natural antimicrobial peptide nisin. We studied the effects of nisin coating on the attachment of Bacillus anthracis spores, the germination of attached spores, and the subsequent biofilm formation from attached spores. It was found that the strong adsorptivity and the super hydrophobicity of MWCNTs provided an ideal platform for nisin coating. Nisin coating on MWCNT sheets decreased surface hydrophobicity, reduced spore attachment, and reduced the germination of attached spores by 3.5 fold, and further inhibited the subsequent biofilm formation by 94.6% compared to that on uncoated MWCNT sheet. Nisin also changed the morphology of vegetative cells in the formed biofilm.The results of this study demonstrated that the anti-adhesion and antimicrobial effect of nisin in combination with the physical properties of carbon nanotubes had the potential in producing effective anti-biofilm formation surfaces.     

改性石墨电极对DNP废水的降解过程研究

使用自制改性石墨/PTFE气体扩散电极作为阴极,铁电极作为阳极,构成电-Fenton反应体系对2,4-二硝基苯酚废水进行处理。一定电解条件下,研究了D(N/P)、D(N/P/Cu)自制气体扩散阴极电极对2,4-二硝基苯酚废水的处理效果及处理过程废水中金属离子、电导率的变化情况。结果表明,电解60 min时D(N/P/Cu)电极对DNP的去除率达到80.9%,最大去除率比D(N/P)高22.43%。阴极电极中铜离子的掺入不仅提高了电解效率,而且也大大降低了铁阳极的消耗及铁泥的产生量。对D(N/P/Cu)电极电解后的沉淀底物进行了红外光谱分析,发现沉淀物中除了未被降解的DNP外还含有分解产生的小分子烷烃类、胺类等中间产物。通过SEM对改性石墨电极表面进行了观察,发现电极材料粘合牢固紧凑,表面分布许多微小气孔,其中在改性石墨中掺入铜离子的D(N/P/Cu)电极表面更加致密光滑。     

外置式联合等离子体光解技术去除苯乙烯气体

开发了用一个高压电源同时产生等离子体和KrI* 准分子紫外辐射的外置式联合等离子体光解(Outer Combined Plasma Photolysis, OCPP)技术,并用于降解模拟流动态苯乙烯气体. 结果表明:在Kr和I₂充入量分别为26.60 kPa和6 mg, 气体流速为3.26 m3/h, 初始ρ(苯乙烯)为1 265 mg/m3,外施电压为9.0 kV的条件下,苯乙烯的去除率达84.4%;与介质阻挡放电技术相比,苯乙烯的去除率提高了20.6%,能率提高了5.7 g/(kW·h). 同时,研究了OCPP技术降解苯乙烯的影响因素,包括Kr和I₂的充入量、石英材质、气体流速、初始ρ(苯乙烯)及反应器结构. 采用红外光谱仪和气质联用仪分析了结焦产物,探讨了OCPP技术降解苯乙烯的机理.      

DBD降解氮中甲苯气体产生的二次有机副产物检测

为了研究低温等离子体降解有机废气过程中产生的二次有机副产物的形成机理及其影响因素,以介质阻挡放电(DBD)产生的低温等离子体降解氮中甲苯气体为研究对象,利用质子转移反应飞行时间质谱仪(PTR-TOF-MS)实时在线检测降解尾气中有机副产物的成分及其浓度,分析了二次有机副产物形成的机理,探讨了影响二次有机副产物生成的关键因素.研究发现,氮中甲苯低温等离子体降解尾气中主要的有机副产物为HCN和CH3CN,其浓度与待降解甲苯的平均可资用能有关.由平均可资用能的测试分析可知,在DBD有机物降解装置、电源输入功率、降解气体流量等参数确定的情况下,待降解有机物存在一个浓度极值,大于该浓度极值将使得降解尾气中有机副产物的浓度明显增加.在低温等离子体降解装置参数确定的情况下,控制待降解有机物的浓度是减少有副产物产生的有效手段和方法.     

Study on the mechanism of copper–ammonia complex decomposition in struvite formation process and enhanced ammonia and copper removal

Heavy metals and ammonia are difficult to remove from wastewater, as they easily combine into refractory complexes. The struvite formation method (SFM) was applied for the complex decomposition and simultaneous removal of heavy metal and ammonia. The results indicated that ammonia deprivation by SFM was the key factor leading to the decomposition of the copper–ammonia complex ion. Ammonia was separated from solution as crystalline struvite, and the copper mainly co-precipitated as copper hydroxide together with struvite. Hydrogen bonding and electrostatic attraction were considered to be the main surface interactions between struvite and copper hydroxide. Hydrogen bonding was concluded to be the key factor leading to the co-precipitation. In addition, incorporation of copper ions into the struvite crystal also occurred during the treatment process.     

典型进口废铜废铝初级加工原料模拟熔炼烟气中重金属产生特性研究

随着我国全面禁止固体废物入境,如何从传统的进口废铜废铝中甄别高品质再生铜再生铝原料,是精准打击固体废物入境、确保行业急需高品质原料进口的关键.选取典型进口废铜废铝初级加工原料样品,采用高温管式炉模拟不同原料类型、熔炼温度、夹杂物和熔炼剂等因素对于熔炼过程烟气中重金属产生特性的影响.结果表明:①当进口铜加工材原料熔炼温度从900℃升至1 300℃时,烟气中Cr、Ni、Zn、Pb浓度随温度升高而增加,且进口铜加工材原料熔炼过程烟气中整体上重金属的产生量比铜米、漆包线多,当夹杂物含量从0增至1.0%时烟气中重金属浓度呈增长趋势,熔炼入炉的进口铜加工材原料的夹杂物含量控制在0.5%以内,可有效减少烟气中Pb和Zn等重金属的产生.②当进口汽车铝切片原料熔炼温度从500℃升至900℃时,烟气中Cr、Ni、Zn、Pb、Cu浓度均随温度升高而增加,熔炼剂中添加C₂Cl₆比添加NaCl、KCl和NH₄Cl等更利于重金属的产生,夹杂物含量从0增至1.0%时,烟气中Cr、Ni、Pb浓度均不断增加,Zn和Cu浓度则逐渐减少.研究结果为我国制定高品质再生铜再生铝原料标准、精准打击固体废物入境提供了数据支持.