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关键词： Corn straw   Liquid fraction of digestate   Hydrolysis and acidification   Physicochemical characterization   Microbial community structure  

摘要： The effectiveness of hydrolysis and acidification via liquid fraction of digestate (LFD-HA) strategy on enhancing methane production of corn straw (CS) were explored in this study. A post-hydrolysis and acidification (HA) process was applied to treating CS by adding LFD to the acidogenic reactor to improve microbial pre-decomposition and further solubilize recalcitrant organic polymers. Through combining the LFD and HA modification, the process was upgraded with associated improvement in anaerobic digestion (AD) performance. The variations of physico-chemical structure and AD performance of CS after LFD-HA compared with NaOH modification were analyzed. The results evidenced that LFD-HA promoted degradation of lignin monomer compounds from macromolecular polymers to aromatic compounds and acetic acid. The lignocellulosic structures and linkages were destroyed by hydroxy radical and hydrolytic enzyme. Compared with CS without pretreatment, the highest methane yield of LFD-HA CS was 265.1 mL.g(-1)VS(-1), and the digestion time (T-80) was shortened by 27.8%. The populations of Methanobacteriaceae, Methanosarcinaceae and Ruminococcaceae were enriched during LFD-HA process. This research proposed that LFD-HA was an efficient and eco-friendly process in improving lignocellulose degradation and bio-methane generation from CS.

关键词： 物理化学   复合含能材料   球磨法   燃烧热   点火延迟时间  

摘要： 为改进Al基复合含能材料的燃烧性能,采用先氧化后还原热处理方法制备了多层石墨烯,结合高能球磨法制备了Al-C、Al-B和Al-B-C 3种复合材料,并采用SEM-EDS和XRD等方法表征了复合材料的结构;采用氧弹量热仪测定了复合材料的燃烧热;采用CO2激光点火器测定了复合材料的点火延迟时间。结果表明,制备的多层还原氧化石墨烯比表面积为85.5m^(2)/g,孔径介于15~200nm之间;在600℃和700℃热处理的Al-C材料具有最高的燃烧热值,材料的点火延迟时间随热处理温度的升高而有所延长;Al-B复合材料在高温下易生成AlB2合金,这使得未经热处理的材料具有最高的燃烧热值,而750℃处理的材料具有最小的点火延迟时间;经过600℃和700℃热处理的Al-B-C复合材料的燃烧热值最高,过多B的加入会抑制材料的燃烧,但也会缩短材料的点火延迟时间。

关键词： 模拟高放废液   回转煅烧   煅烧产物   物理化学性质  

摘要： 模拟高放废液在回转煅烧过程中容易粘壁,影响其及时输送。为了实现转形工艺和固化工艺的顺利衔接,需要通过改变工艺条件来使煅烧产物顺利出料。同时煅烧条件的变化会导致煅烧产物物理化学性质发生变化。采用动力堆燃耗45 GWd/t(以U计)乏燃料后处理产生的模拟高放废液,研究了不同温度、不同转速条件下煅烧产物的粒径分布、含水量、振实密度、脱硝率等物理化学性质,研究结果显示:升高煅烧温度可以使煅烧产物粒径更加均匀,当煅烧温度在600~700℃、转速在15~20 r/min时,煅烧产物的含水率小于2%,振实密度在1.7 g/cm^(3)左右,脱硝率能达到99%以上,煅烧过程中的粘壁现象较少,能实现煅烧过程中的顺利出料。

关键词： 物理化学   安全工程教育   蒸汽锅炉爆炸   火灾   锈蚀   现代教育技术  

摘要： 如何强化安全工程教育是化学化工类专业高等教育的一个重要课题。通过对蒸汽锅炉爆炸、火灾爆燃事故以及锈蚀危害等3个实例的详细讲述,指出在物理化学的教学中,若适时融入相关的安全工程教育,可以使学生深刻理解安全事故发生及防范所依赖的物理化学原理,从而起到安全意识的内化作用。教学中现代教育技术的引入可以增强这一效果。

关键词： Manganese   Biofiltration   Microbiome   Acclimation   Homogeneous oxidation   Redox Modelling  

摘要： This study investigated treatment strategies which accelerated the acclimation of new Mn-removing biofilters to help utilities respond to changing Mn regulations, such as the recent introduction of a health-based maximum acceptable concentration and a reduction in the aesthetic objective for Mn in drinking water by Health Canada. Bench-scale filters of either GAC or anthracite media were fed with applied water containing Mn (17-61 mu g/L) from a full-scale plant over 294 days. Treatment strategies included the addition of H2O2 (1 mg/L) and/or an increase in pH from 6.8 to 7.5 through the addition of NaOH. The potential physico-chemical and biological mechanisms responsible for accelerated biofilter acclimation under the various redox conditions were investi-gated through thermodynamic modelling, to predict homogeneous Mn oxide formation, and 16S rRNA gene amplicon sequencing, to characterize the microbial community within the filters. GAC filters treated with NaOH, and both H2O2 and NaOH, were the first to acclimate (< 20 mu g/L Mn in filter effluent) after 59 and 63 days respectively, while the ambient GAC filter took almost 3 times as long to acclimate (168 days), and the anthracite filters which received the same chemically adjusted water took almost 4 times as long (226 and 251 days, respectively). The accelerated acclimation in the treated GAC filters was likely due to physico-chemical oxidation via three potential mechanisms: (1) homogeneous oxidation of dissolved Mn(II) to Mn(III)/Mn(IV) oxides and the subsequent removal of oxides from solution through adherence to the GAC surface, (2) adsorption of dissolved Mn(II) to GAC and subsequent homogeneous or biological oxidation, or (3) formation of colloidal Mn(III)/Mn (IV) oxides and subsequent adsorption of dissolved Mn(II) to the Mn colloids. In the untreated GAC filter and all anthracite filters, which did not benefit from improved redox conditions or an active surface, physico-chemical mechanisms alone were i

关键词： 物理化学   Bu-NENA   HTPE   GAP   相结构   介观动力学模拟  

摘要： 采用介观动力学(MesoDyn)模拟方法对比研究了含能增塑剂丁基硝氧乙基硝胺(Bu-NENA)与端羟基聚醚(HTPE)、聚叠氮缩水甘油醚(GAP)共混体系的相结构及其相演变过程和影响因素,用共混实验对Bu-NENA与HTPE、GAP的相容性进行了观察。模拟结果表明:Bu-NENA与HTPE、GAP均具有较好的混溶性,且Bu-NENA与HTPE的混溶性优于Bu-NENA与GAP,与混溶性实验的结果一致。25℃条件下,HTPE/Bu-NENA混合体系中Bu-NENA质量分数在50%以下时,HTPE和Bu-NENA混溶性较好;GAP/Bu-NENA混合体系中Bu-NENA质量分数在50%时,GAP和Bu-NENA的混溶性较其他比例时差。但在GAP/Bu-NENA混合体系中,GAP和Bu-NENA的有序度参数P均较小,接近于0,GAP/Bu-NENA混合体系混溶性良好;Bu-NENA的质量分数对GAP/Bu-NENA混合体系混溶性影响不大。

关键词： 物理化学   tFe_(2)O_(3)/rGO纳米复合材料   石墨烯   CL-20   热行为  

摘要： 采用水热法合成出十四面体氧化铁,然后自组装制备出十四面体氧化铁/石墨烯纳米复合材料(tFe_(2)O_(3)/rGO);采用X-射线粉末衍射仪(XRD)、X-射线光电子能谱仪(XPS)、扫描电子显微镜(SEM)和透射电子显微镜(TEM)等对tFe_(2)O_(3)/rGO纳米复合材料进行了表征;利用差示扫描量热法(DSC)研究了tFe_(2)O_(3)和tFe_(2)O_(3)/rGO对六硝基六氮杂异伍兹烷(CL-20)热分解行为的影响,分析了tFe_(2)O_(3)/rGO复合材料对CL-20的热分解催化效果及其对CL-20的热分解动力学和热安全性的影响。结果表明,引入石墨烯可有效降低tFe_(2)O_(3)颗粒大面积的团聚程度,并且tFe_(2)O_(3)/rGO具有更大的比表面积;石墨烯的引入降低了tFe_(2)O_(3)/CL-20热分解反应的活化能及热分解温度,但未改变其热分解机理;tFe_(2)O_(3)/rGO和tFe_(2)O_(3)使得CL-20的放热分解峰温分别提前了5.35℃和4.79℃,热稳定性降低,表明所制备的tFe_(2)O_(3)/rGO复合材料能有效催化CL-20的热分解。

关键词： 煤气化细渣   碳灰分离   持水能力   化学结构   微观形貌   孔隙结构  

摘要： 煤气化是煤炭清洁高效利用的关键技术,煤气化过程中产生了大量的细渣,细渣中复杂的碳-灰交融状态以及高水分含量限制了其资源化利用,碳灰分离是煤气化细渣资源化利用的必要前提。本研究采用泡沫浮选法对宁东地区3种不同气化工艺产生的细渣(SNB1细渣,XTY细渣和JC细渣)进行碳灰分离,分析了气化细渣及其碳灰分离产物的基本物性和持水能力,并借助傅里叶变换红外光谱仪、扫描电子显微镜和物理吸附仪研究,对比了气化细渣及其碳灰分离产物物理化学结构差异,以期为气化细渣的低成本处置与资源化利用提供参考。结果表明:通过泡沫浮选可以将3种细渣中的碳-灰进行不同程度的分离,泡沫浮选过程可以有效地将“游离”的球形矿物质颗粒与残碳颗粒进行分离,残碳表面和孔内灰颗粒相对更难去除。其中SNB1细渣的碳-灰分离效果最好,SNB1残碳中灰分降低至38.65%,SNB1尾灰中的灰分高达99.16%。经过泡沫浮选后,残碳和尾灰的持水能力相较于对应原气化细渣均有不同程度的降低,其中3种尾灰持水能力的降幅尤为显著(79.34%~96.61%)。此外,气化细渣及其碳灰分离产物中存在大量的圆柱形孔,碳-灰分离过程使得部分阻塞残碳颗粒中孔的微细球形矿物质颗粒脱离,从而使得残碳中微孔和中孔的数目增加,比表面积增大,而尾灰中主要以球形矿物质颗粒相互熔融而形成的缝隙中孔为主。碳灰分离过程使得部分夹带在残碳孔道内部的亲水性较强的微细球形矿物质颗粒被泡沫浮选过程去除,二氧化硅亲水位点相对减少,这使得3种残碳的持水能力相对于原气化细渣都有所降低。3种尾灰由于具有较低的比表面积(29.383~46.875 m^(2)/g),因而具有更低的持水能力。

关键词： 物理化学   Al/PVDF   Al/CuO/PVDF铝热剂   纳米铝粉   静电喷雾沉积   可视化火焰温度  

摘要： 为了研究Al/CuO铝热剂的高能量释放速率对Al/PVDF薄膜燃烧性能的影响,采用静电喷雾沉积法将Al/CuO/5%PVDF或Al/CuO/10%PVDF铝热剂与Al/PVDF薄膜原位层间堆积得到多层复合薄膜,通过调控Al/CuO/PVDF铝热剂的组成结构和厚度来调控该薄膜的燃烧性能,获得了该多层薄膜的线性燃速、可视化火焰温度和归一化热密流随铝热剂组成和厚度的变化规律。结果表明,铝热剂的组成和厚度直接决定薄膜的燃速大小和燃烧传热方式,除了Al/PVDF-Al/CuO/5%PVDF 3层薄膜表现为对流燃烧,燃速(104±10)cm/s,火焰温度2700K,其他多层薄膜的燃速只有5.5~12.0cm/s、火焰温度只有1570~1700K,Al/PVDF层对Al/CuO/5%PVDF或Al/CuO/10%PVDF层的紧密约束将铝热剂燃烧的对流传热方式可能转化为热传导和热辐射传热。Al-PVDF反应和Al-CuO反应之间的相互作用削弱了Al/CuO/PVDF铝热剂的高能量密度和高能量释放速率优势。

关键词： 物理化学实验   教学改革   创新   实践   综合能力  

摘要： 针对当前工科院校《物理化学实验》课程出现的实验内容设置陈旧、教学方式单一、理论脱离实际和学生自主学习意识差等问题。笔者提出物理化学实验教学改革要重视内容和方式,强调科学研究前沿与实际生产需求相结合并增加综合自主创新型实验项目。通过一系列的改革措施,从根本上改变学生的学习观念,培养学生发现、分析和独立解决问题的能力。这将提高学生在面对我国经济发展方式转变,产业结构调整等新形势的综合能力。