PBC/PLA/凹凸棒土纳米复合材料的制备与性能研究

将聚碳酸丁二醇酯(PBC)/聚乳酸(PLA)全生物降解材料与凹凸棒土制备成PBC/PLA/凹凸棒土纳米复合材料,研究了凹凸棒土对共混材料性能的影响。采用热失重(TG)、差热扫描量热法(DSC)等测试分析方法,分别对全生物降解材料的热性能及结晶性能进行分析和研究。结果表明,加入凹凸棒土制备的全生物降解材料的热稳定性及结晶度都有所提高,改善了材料的性能,扩大了其应用领域。     

FGC（有机硅）外墙内保温施工工艺

FGC(有机硅)外墙内保温墙体材料是，把无机材料(陶瓷纤维、硅藻土)和有机材料(硅胶、淀粉)，辅以化学助剂、有机硅添加剂，采用新工艺复合而成的灰白色粉状物体。     

十水硫酸钠/硅藻土复合相变材料的研究

以硅藻土为载体,十水硫酸钠为相变材料制备复合相变材料。采用X射线衍射(XRD)、扫描电子显微镜(SEM)、差示扫描量热法(DSC)、红外光谱仪(IR)对其微观形貌、物相、化学相容性、形态稳定性、储热性进行了研究。研究结果表明:复合相变材料中十水硫酸钠的最佳吸附量占比60%,对应的相变温度为29.27℃,相变潜热为151.6 J/g。该复合相变材料具有良好的化学相容性、形态稳定性和储热性。     

有机改性蒙脱土对聚氨酯发泡材料阻燃性能的影响

以膨胀石墨(EG)/氢氧化铝(ATH)为阻燃体系,添加改性蒙脱土(O-MMT)制备了聚氨酯复合发泡材料。采用XRD对改性蒙脱土进行结构分析,并采用极限氧指数(LOI)、燃烧速率增长指数(FIGRA)等表征手段对制备的聚氨酯泡沫的燃烧行为进行对比和研究。结果表明,利用十六烷基三甲基溴化铵(CTAB)成功地对蒙脱土(MMT)进行插层改性,改性后的蒙脱土对聚氨酯泡沫材料的LOI影响不显著,但是在添加量为7份时,可以明显地降低材料的燃烧速率增长指数,延缓燃烧的时间,从而整体上提高聚氨酯发泡材料的阻燃性能。     

卸料平台的安全使用方法

卸料平台是为施工吊运周转材料而设置的,在多层或高层建筑施工中,通常采用悬挑式,即悬挑于建筑物之外,以便于吊运材料。其搭设材料通常采用型钢(槽钢、工字钢)、钢管(直径48mm、51mm)和木杆等。怎样确保卸料平台的安全使用呢?建设部颁发的《建筑施工安全检查标准》(JGJ59-99)中规定:卸料平台必须     

抗水分散聚氨酯泡沫注浆材料的制备及性能研究

针对传统聚氨酯(PU)泡沫注浆材料强度低、耐久性和抗水分散性差、无法用于动水环境堵水加固的缺陷,采用聚醚多元醇和聚酯多元醇复配作为多元醇体系、聚醋酸乙烯酯(PVAc)的碳酸丙烯酯溶液作为增黏树脂,制备了抗水分散型PU泡沫注浆材料。研究了各原材料用量对PU泡沫注浆材料抗压强度、耐水解和抗水分散等性能的影响。结果表明,当m(异氰酸酯)∶m(聚醚多元醇)∶m(聚酯多元醇)∶m(扩链剂)∶m(增塑剂)∶m(发泡剂)∶m(增黏树脂)∶m(表面活性剂)∶m(催化剂)=125∶55∶45∶8∶30∶10∶15∶2.0∶1.5时,制备的PU泡沫注浆材料具有良好的抗压强度、耐久性能和抗水分散性能,可用于动水环境的堵水加固处理。     

预应力混凝土吊车梁型式的分析与比较

本文从设计、施工、受力性能、材料用量等方面,对梁的型式(等截面和变截面)和截面尺寸(梁高、腹板厚度、混凝土标号及钢种变化等)加以分析讨论,从而对预应力混凝土吊车梁的设计原则、型式选择和材料采用等提出了具体建议。     

环氧树脂灌浆材料的制备及其性能研究

为确定影响环氧树脂灌浆材料性能的关键因素,采用正交设计方法研究了柔性固化剂(651)与刚性固化剂(T31)的复配比例、促进剂和活性增韧剂掺量等因素对环氧树脂灌浆材料性能的影响,并利用功效系数法对影响因素进行了分析.结果表明,增大柔性固化剂的比例,可降低灌浆材料的压缩模量、提高柔韧性和抗冲击能力;增大促进剂掺量和活性稀释剂比例,有利于提高灌浆材料的压缩强度和抗拉强度;掺加增韧剂能在一定程度上降低灌浆材料的初始黏度.采用功效系数法优选出了2组综合性能最佳的环氧树脂灌浆材料,可以应用于灌浆施工.     

碳包覆对LiMn_(0.5)Fe_(0.5)PO_4/C复合材料形貌的影响

本文采用流变相法合成了碳包覆改性的LiMn_(0.5)Fe_(0.5)PO_4/C锂离子电池正极材料。通过X射线衍射(XRD)、扫描电镜(SEM)等手段,比较和分析了柠檬酸、酒石酸、月桂酸三种碳源对材料结构、形貌的影响。结果表明,以柠檬酸为碳源合成的LiMn_(0.5)Fe_(0.5)PO_4/C是由一次颗粒极小的纳米粒子组成的微纳结构聚集体,具有极高达48.32m2g-1的比表面积。     

混凝土路面的灌缝

法国采用三种材料给混凝土路面灌缝:高温下(120～100℃)溶化后的热态灌注材料;冷态溉注材料(单组分或双组分的弹性材料和非弹性材料);橡胶为基础的材料成品。使用热态灌注材料时,压缩缝的槽深30～35mm、宽12～15mm。使用冷态灌注的弹性材料时,压缩缝的槽深30mm、宽10～12mm。在一条道路上使用不同的方法灌入了20种密封填料。现已确定,采用粘附     

H2O2/TiO2 photocatalytic oxidation of metol. Identification of intermediates and reaction pathways

The applicability of H2O2 to increase the efficiency of TiO2 photocatalytic degradations was investigated. The photographic developer metol [N-methyl-p-aminophenol] that does not adsorb on the surface of TiO2 particulates was used as a model for this purpose. It was proved that metol was mineralised under oxidation with H2O2/TiO2/UV through different thermal and photochemical reactions. Identification of intermediates by both HPLC-electron impact-MS and HPLC-electrospray ionisation-MS helped to elucidate the role of H2O2 and TiO2 in the degradation process and to establish degradation pathways. Intermediates yielded were partially oxygenated aromatic species and dimers, which were amenable to oxidation. The optimal degradation conditions found for mineralisation were 0.4 M H2O2, 5 mg/ml TiO2, pH 9 and irradiation centred at 360 nm (4.9 mW/cm2). The use of oxidants opens an interesting medium to the treatment of effluents containing a diversity of organics since they increase substantially the efficiency of TiO2 photocatalytic degradations.     

The influence of pH and cadmium sulfide on the photocatalytic degradation of 2-chlorophenol in titanium dioxide suspensions

The influence of pH and cadmium sulfide on the photocatalytic degradation of 2-chlorophenol (2-CP) in titanium dioxide suspensions was investigated to evaluate the feasibility of mixed semiconductors on the photodegradation of chlorinated organics in aqueous solution. Apparent first-order rate constants (k(obs)) and initial rate constants were used to evaluate the degradation efficiency of 2-CP. Higher degradation efficiency of 2-CP was observed at higher pH values. The apparent pseudo-first-order rate constant was 0.036 min(-1) at pH 12.5 in TiO2/UV system, while a 2- to 9-fold decrease in k(obs) was observed over the pH range of 2.5-9.5. The addition of phosphate buffer solutions at different pH values have different effects on the degradation of 2-CP. H2PO4- has little effect on the photodegradation of 2-CP, while HPO4(2-) could inhibit the photodegradation efficiency of 2-CP. Chlorocatechol, hydroquinone, benzoquinone and phenol were identified as the predominant aromatic intermediates for the photocatalytic degradation of 2-CP. Moreover, less aromatic intermediates at higher pH were observed. Direct oxidation contributed significantly to the photodegradation of 2-CP. An addition of a semiconductor decreased the initial and apparent first-order rate constants of 2-CP. The cutoff of wavelength of 320nm could diminish the contribution of direct photolysis of 2-CP. The combination of cadmium sulfide and titanium dioxide can lead to an enhanced rate of disappearance of 2-CP compared to those in single semiconductor system. A 1.2 to 2.5-fold increase in rate constant in coupled semiconductor system relative to the single semiconductor system was obtained.     

Photocatalytic degradation of trichloroethylene in water using TiO2 pellets

A recirculating system of aqueous trichloroethylene (TCE) solutions through the packed bed reactor with TiO2 pellets has been developed in order to mineralize TCE without difficulties for filtration and recovery of catalyst. The TiO2 pellets prepared by sol gel method have photocatalytic activity similar to commercially available PC-101 and PC-102 in the powder form and to ST-B11 pellets. In batch experiments with TiO2 powders, Degussa P-25 is the most active photocatalyst, which indicates that specific surface area is not an important factor controlling the photocatalytic activity in aqueous solutions. The degradation rates of TCE in the recirculating system with TiO2 pellets decreased in the presence of H2O2, while were remarkably accelerated by adding S2O8(2-). The presence of S2O8(2-) ions more than 0.01 mol dm(-3) completely suppressed hole-electron recombination and mineralized 50 ppm TCE with the 2 h irradiation. In a reactor without TiO2 photocatalysts, TCE was photodegraded by SO4- radicals which produced by photodissociation of S2O8(2-). The degradation rates increased with increase of the initial S2O8(2-) concentration. However, TCE was not mineralized but converted to intermediates which were slowly degraded to Cl- by continuing the irradiation.     

接枝交联改性壳聚糖吸附性能研究

研究了改性交联壳聚糖羧基成盐和络合吸附Cu2+、Ni2+的特性.结果表明:改性交联壳聚糖对Cu2+、Ni2+的吸附具有Langmuir吸附特征,吸附量与离子核电荷数和络合物的配位相关.该吸附剂对两种相同浓度混合离子的吸附中具有选择性,即优先选择吸附Cu2+,2 h时,吸附选择系数为19.5.     

OUR和INT-ETS表征污泥活性的比较

为探寻能快速评价重金属对污泥活性影响的方法,开展了抑制污泥OUR和INT-ETS活性的试验研究.结果表明,OUR反映重金属毒性作用的灵敏性高于INT-ETS;当活性污泥受到重金属污染后,其OUR降低情况与COD的相似,而INT-ETS活性受到的抑制作用相对较小;各重金属离子表现出了不同的毒性作用,以OUR为评价参数时毒性顺序为:Hg2 ＞Cu2 ＞Ag ＞Cd2 ＞Zn2 ＞Ni2 ＞Pb2 ,以INT-ETS活性为评价参数时则为:Hg2 ＞Ag ＞Cu2 ＞Cd2 ＞Zn2 ＞Ni2 ＞Pb2 .OUR是表征污泥活性受重金属影响的较佳参数.     

Photodegradation of estrone and 17beta-estradiol in water

The TiO(2)-assisted photodegradation of two natural female hormones, estrone (E1) and 17beta-estradiol (E2), was investigated in two UV-photo-reactors, followed by solid-phase extraction and analysis by gas chromatography-mass spectrometry (GC-MS). The degradation of E1 and E2 in both reactors followed the pseudo-first-order kinetics. In reactor 1 (150W), 97% of compounds were degraded within 4h of irradiation. Even more rapid degradation was observed in reactor 2 (15W) where 98% of both compounds disappeared within 1h, due to the shorter wavelength of UV-light in reactor 2 (fixed at 253nm) than reactor 1 (238-579nm). The influences of different initial chemical concentrations, pH value, the presence of dissolved organic matter and hydrogen dioxide, and the catalyst concentration on the degradation rate of E1 and E2 in aqueous solutions were investigated. The results show that the extent of photo-induced degradation of E1 and E2 strongly depends on the water constituents in solution. The degradation rate was increased when pH value was increased from 2 to 7.6, beyond which the degradation rate started to decrease. The presence of humic acid enhanced the degradation of E1 and E2 in both reactors as a result of photosensitisation effect of humic acid chromophore. The degradation rate increased with an increase in H(2)O(2) concentration. The degradation rate was also enhanced by increasing catalyst concentration up to 2g/l. The findings therefore suggest that photocatalysis can be a very effective method of rapidly removing certain EDCs from water.     

Measurements of N2O and CH4 from the aerated composting of food waste

Emissions of N2O and CH4 from an aerated composting system were investigated using small-scale simulated reactors. The results show relatively high emissions of N2O at the beginning of composting, in proportion to the application amount of food waste. After 2 days, the N2O emission decreased to 0.53 ppmv on average, near to the background level in the atmosphere (0.45 ppmv). The addition of composted cattle manure increased N2O emissions not only at the beginning of composting, but also during the later period and resulted in two peak emission curves. Good correlation was observed between the N2O concentration at the air outlet and NO2- concentration in waste, suggesting a generation pathway for N2O from NO2- to N2O. Methane was only detected in treatments containing composted cattle manure. The high emission of methane illustrates the involvement of anoxic/anaerobic microorganisms with the addition of composted manure. The result suggests the existence of anoxic or anaerobic microsite inside the waste particles even though ventilation was employed during the composting process.     

Removal of chlorine dioxide disinfection by-products by ferrous salts

Chlorine dioxide when used as an effective disinfectant forms undesirable disinfection by-products, i.e. chlorite and chlorate ions. The aim of this research was to study the removal of these ions by ferrous ions in the presence or absence of oxygen. The efficiency of Fe+2 for ClO2- and ClO3- removal was followed by a determination of their initial and final concentrations, pH and delta Fe+2 consumed/delta ClO2- removed ratios. The optimal weight ratio of delta Fe+2 consumed/delta ClO2- removed for complete ClO2 removal was found to be close to the theoretical calculated value of 3.31. It was proved that ferrous salts can reduce chlorite ions to harmless Cl- ions. This method can be recommended as a part of ClO2 disinfection to ensure safe drinking water, with no harm to water consumers and to the environment.     

The photocatalytic degradation of dicamba in TiO2 suspensions with the help of hydrogen peroxide by different near UV irradiations

The direct photolysis and the photocatalytic degradations of dicamba in TiO2 suspensions with and without the use of hydrogen peroxide were studied using two different monochromatic UV irradiations (300 and 350 nm). Both the direct photolysis and photocatalytic degradations of dicamba follow pseudo-first-order decay kinetics. Photolysis reactions were slow but the corresponding photocatalysis rates were increased by about 3 and 5 times in the presence of TiO2 at 300 and 350 nm of UV, respectively. Photocatalytic rates were increased with the pH at acidic to neutral ranges because of the increase of hydroxide ions, but the reaction was gradually retarded at the alkaline medium due to the effect of charges repulsion. The different proton sources causing various degrees of rate retardation were due to the presence of the corresponding counter anions. The results of H2O2-assisted photocatalysis experiments showed that a low H2O2 dosage in photocatalysis using UV 300 nm would enhance the decay rate of dicamba by 2.4 times, but an overdose of H2O2 will retard the rate because of the expenditure of hydroxyl radicals. However, this process was found impracticable at UV 350 nm due to the absorption characteristic of H2O2. A neutral initial pH level was found to favour the H2O2-assisted photocatalysis at UV 300 nm. The reactions were highly retarded at the alkaline medium due to the unstable properties of H2O2.     

膨润土对重金属离子Pb~(2+),Zn~(2+),Cr(VI),Cd~(2+)的吸附性能

试验研究了pH值、吸附时间和吸附剂用量对膨润土吸附重金属离子Pb2 ,Zn2 ,Cr(VI)和Cd2 的影响.结果表明,在本试验的pH值、吸附时间及吸附剂用量条件下,膨润土对Pb2 ,Zn2 ,Cd2 的吸附效果均优于其对Cr(VI)的吸附效果;pH值是影响上述吸附的重要因素,离子交换和表面络合是上述吸附的主要形式.