复掺轻骨料纤维喷射混凝土力学及导热性能试验研究*

为有效隔绝高地温公路隧道、深部高温巷道施工过程中的围岩散热,利用正交试验方法,以不同复合陶粒、陶砂掺量、聚丙烯纤维为影响因素,设计出1种隔热效应的轻骨料纤维喷射混凝土（Lightweight Aggregate Fiber Shotcrete,LAFS）,进行含水率、抗压、劈裂抗拉及导热性能试验,并借助X射线衍射、扫描电镜对LAFS进行机理分析。结果表明:3种因素对LAFS力学及导热性能的影响程度均为陶粒掺量>陶砂掺量>聚丙烯纤维掺量,本试验条件下,复合双掺陶粒、陶砂分别取代石子、砂子的最佳体积率为12%,6%,聚丙烯纤维的最佳掺量范围为0.2%~0.3%。建立的LAFS各性能预测模型可为工程应用LAFS确定其配比时提供试验依据。     

ACF负载金属氧化物及尿素低温去除NO

以活性炭纤维(ACF)负载NiO以及NiO-CeO2制备了一系列催化剂,并在催化剂上负载尿素作为还原剂,研究其在30～120℃范围内的催化还原NO的活性.通过SEM、BET、XRD等表征实验选择性地对催化剂进行了理化特征研究.结果表明,3种不同质量分数的NiO催化剂中,5%NiO/ACF效率较低,10%NiO的催化剂活性以及活性稳定性较好,在90℃即可达到50%左右的NO净化效率,15%NiO/ACF的催化活性稳定性较差.在3种不同质量分数的NiO-CeO2/ACF催化剂中,5%NiO-5%CeO2/ACF的活性以及活性稳定性最好,在110℃可达到55%以上的NO净化效率.10%CeO2-5%NiO/ACF活性高于5%CeO2-10%NiO/ACF;活性金属的最佳负载量为10%,过多的负载量会引起催化剂比表面积的减少从而导致催化剂活性下降;金属氧化物是催化反应的活性中心.对10%CeO2/ACF、10%NiO/ACF和5%CeO2-5%NiO/ACF的研究显示,5%CeO2-5%NiO/ACF的催化活性最好,CeO2和NiO的协同作用使催化剂的活性优于2种单独负载的催化剂.本研究还对催化剂的低温催化机制进行了分析和讨论.     

热纤维梭菌不同菌株的纤维素降解和酒精生产能力

以高温厌氧细菌热纤维梭菌(Clostridium thermocellum LQRI和VPI菌株)和嗜热厌氧乙醇菌(Thermoanaerobacterethanolicus X514和39E菌株)为对象,以不同浓度纤维素为底物,分析了热纤维梭菌不同菌株的纤维素降解和酒精生产能力.结果表明,在热纤维梭菌纯培养体系中,LQRI对纤维素的降解能力明显高于VPI,前者约为后者的1.2倍,但两者的酒精生产能力没有显著差异,LQRI在1%纤维素条件下酒精终浓度约为12 mmol/L,VPI约为10 mmol/L.随着底物纤维素浓度的增加(1%、2%、5%),两者对纤维素降解和酒精生产能力均呈明显下降趋势.在热纤维梭菌和嗜热厌氧乙醇菌混合培养体系中,LQRI对纤维素的降解能力明显高于VPI,前者约为后者的1.28～1.58倍.随着底物浓度的增加,两者的纤维素降解率均逐渐下降,但热纤维梭菌对纤维素降解的绝对数值还受到其它混合培养菌种的影响.此外,LQRI+Thermoanaerobacter混合培养体系的酒精生产能力明显高于VPI+Thermoanaerobacter,前者约为后者的1.27～1.77倍.随着底物浓度的增加,混合培养体系酒精生产能力没有明显下降趋势.     

低环多环芳烃(萘、苊)在活性炭上的热脱附行为

利用SETSYS Evolution 16型热重分析仪,在氮气气氛下分别研究了萘和苊在活性炭(AC)上的热脱附行为,并采用多升温速率法和单升温速率法相结合的方法,得到萘和苊在AC上的热脱附反应动力学方程及其动力学参数,结果表明:萘在AC上的热脱附反应动力学模型为Avrami-Erofeev方程,反应级数为1.5,脱附活化能(E)均值为63.38kJ/mol, lnA均值为11.75;苊在AC上的热脱附反应动力学模型亦为Avrami-Erofeev方程,反应级数为2, E均值为95.49kJ/mol, lnA均值为16.80.     

Removal of airborne microorganisms emitted from a wastewater treatment oxidation ditch by adsorption on activated carbon

Bioaerosol emissions from wastewater and wastewater treatment processes are a significant subgroup of atmospheric aerosols. Most previous work has focused on the evaluation of their biological risks. In this study, however, the adsorption method was applied to reduce airborne microorganisms generated from a pilot scale wastewater treatment facility with oxidation ditch. Results showed adsorption on granule activated carbon (GAC) was an e cient method for the purification of airborne microorganisms. The GAC itself had a maximum adsorption capacity of 2217 CFU/g for airborne bacteria and 225 CFU/g for fungi with a flow rate of 1.50 m3/hr. Over 85% of airborne bacteria and fungi emitted from the oxidation ditch were adsorbed within 80 hr of continuous operation mode. Most of them had a particle size of 0.65–4.7 m. Those airborne microorganisms with small particle size were apt to be adsorbed. The SEM/EDAX, BET and Boehm’s titration methods were applied to analyse the physicochemical characteristics of the GAC. Relationships between GAC surface characteristics and its adsorption performance demonstrated that porous structure, large surface area, and hydrophobicity rendered GAC an e ective absorber of airborne microorganisms. Two regenerate methods, ultraviolet irradiation and high pressure vapor, were compared for the regeneration of used activated carbon. High pressure vapor was an e ective technique as it totally destroyed the microorganisms adhered to the activated carbon. Microscopic observation was also carried out to investigate original and used adsorbents.     

Changes in different organic matter fractions during conventional treatment and advanced treatment

XAD-8 resin isolation of organic matter in water was used to divide organic matter into the hydrophobic and hydrophilic fractions. A pilot plant was used to investigate the change in both fractions during conventional and advanced treatment processes. The treatment of hydrophobic organics (HPO), rather than hydrophilic organicas (HPI), should carry greater emphasis due to HPO’s higher trihalomethane formation potential (THMFP) and haloacetic acid formation potential (HAAFP). The removal of hydrophobic matter and its transmission into hydrophilic matter reduced ultimate DBP yield during the disinfection process. The results showed that sand filtration, ozonation, and biological activated carbon (BAC) filtration had distinct influences on the removal of both organic fractions. Additionally, the combination of processes changed the organic fraction proportions present during treatment. The use of ozonation and BAC maximized organic matter removal e ciency, especially for the hydrophobic fraction. In sum, the combination of pre-ozonation, conventional treatment, and O3-BAC removed 48% of dissolved organic carbon (DOC), 60% of HPO, 30% of HPI, 63% of THMFP, and 85% of HAAFP. The use of conventional treatment and O3-BAC without pre-ozonation had a comparable performance, removing 51% of DOC, 56% of HPO, 45% of HPI, 61% of THMFP, and 72% of HAAFP. The e ectiveness of this analysis method indicated that resin isolation and fractionation should be standardized as an applicable test to help assess water treatment process e ciency.     

活性炭纤维-固相微萃取技术快速检测烤肉中多环芳烃

文章采用新型活性炭纤维(ACF)做为固相微萃取(SPME)的萃取纤维与气相色谱-质谱(GC/MS)联用,建立了一种快速检测烤肉中持久性污染物多环芳烃(PAHs)的方法.烤肉由于其独特的风味深受人们喜爱.但是,在烤肉中含有致癌的PAHs,影响着人们的身体健康.烤肉中PAHs最佳提取条件为:2g匀浆样品,丙酮+甲醇(1∶0...     

活性炭的电解氧化再生研究

通过比较饱和吸附苯酚的活性炭的交换再生和电解再生,揭示了电解再生比交换再生有更高的再生效率。无论是单独的阳极再生还是阴极再生,其再生效率均可超过80%,但由于阳极区的氧化性,可以时苯酚在活性炭的表面聚合,从而降低了再生效率和活性炭的吸附性能。同时,在研究的体系内,200 mA认为是电解过程中最佳的电流强度,这一电流强度不但可以有效地再生活性炭,还可以有效地去除再生出来的苯酚。较小粒径的活性炭不仅有较高的吸附效率,而且也有较高的电解再生效率。     

利用废茶制备活性炭及其吸附性能的研究

实验利用提取茶多酚后的废茶以微波磷酸活化法制备活性炭,研究磷酸活化剂浓度、微波功率、微波辐照时间、浸渍比等因素对制备的活性炭亚甲基蓝吸附值的影响。分别通过单一因素分析及正交实验,找到制备活性炭的最佳条件：微波功率700W、辐照时间8min、磷酸浓度20％、磷酸／样品浸渍（质量）比3：1。利用该最佳条件制备的活性炭,验证实验表明：亚甲基蓝吸附值均〉75．12mg/g,活性炭平均回收率达到65．28％。     

三维电极处理含酚废水的研究

介绍了三维电极法处理技术的一些特点、机制及其在水处理中的应用。在实验中以活性炭投加量、电极电压、反应时间、电解质NaCl投加量、溶液pH值和苯酚初始浓度为研究对象,分析这些因素对苯酚去除率的影响。