超支化高浓水煤浆分散剂的合成与性能研究

以脱氢枞胺为核心,采用发散合成法,与丙烯酸甲酯和乙二胺交替进行迈克尔加成反应和酰胺化缩合反应,合成了1.5代的超支化分子。在此基础上,以1.5代的超支化分子为起始剂,与牛磺酸反应制备了一种超支化水煤浆分散剂。通过红外光谱和核磁共振氢谱对合成物的结构进行了表征,并将其应用于陕西神府煤制浆,考察了浆体的表观粘度、流变性及静态稳定性。研究表明,在分散剂用量用0.4%(占浆体质量百分比),水煤浆的成浆质量浓度可达到67%,粘度为987mPa.s;流变性实验研究表明,浆体属于假塑性流体;超支化分散剂在煤粒表面的吸附量曲线近似呈L型,吸附量大,并且其制得的浆体具有良好的稳定性。     

乳液浆体蓄冷性能实验研究

本文选用二甲基硅油作为油相,硅烷偶联剂作为添加剂制备了乳液浆体,利用混合量热法测试了二甲基硅油-水乳液浆体的含冰率与二甲基硅油、硅烷偶联剂添加量和温度间的关系。实验表明:在相同的相变结晶时间内,随着二甲基硅油质量分数的增加,乳液的冰点和含冰率降低。虽然硅烷偶联剂的添加降低了含冰率,但可以防止冰浆粘附容器壁面,改善了流动性。当添加的硅烷偶联剂和二甲基硅油质量分数分别为4%和10%,环境温度为-8.5℃,相变结晶时间为90 min时,制备的乳液浆体含冰率达到33.4%,浆体不粘附壁面,浆体颗粒分散均匀,具有良好的流动性。     

超声辐照对高密度聚乙烯热稳定性及结晶性的影响

采用自行设计的超声辐照装置,研究了不同超声辐照功率(0 W,100 W,200 W,300 W,400 W)及不同超声辐照时间(0 min,5 min,10 min,15 min)对高密度聚乙烯(HDPE)的热稳定性、结晶性及流变性能的影响。通过同步热分析仪分析得出超声辐照功率越大,辐照时间越长,HDPE的热稳定性能越好,400 W下辐照15 min的HDPE 5%失重温度比未辐照的HDPE 5%失重温度提高了近26%;通过X射线衍射及差示扫描量热分析得出超声辐照会有细化晶粒的作用,辐照功率和辐照时间对结晶度均有影响且在功率200 W辐照5 min时,结晶度达到最大;通过旋转流变仪表征得出经超声辐照处理的HDPE的剪切黏度都有所降低,在400 W的超声功率下辐照10 min时,剪切黏度达到最低,利于加工成型。     

Al2O3浆料体系中偶联剂的选择含量及作用影响

偶联剂能够增加陶瓷粉体和有机载体的相容性,起到降低浆料体系粘度和增加陶瓷固相体积分数的作用.本文测定了不同的偶联剂在Al2O3粉体表面的单分子层饱和吸附量(硬脂酸为2.22%、十八醇为2.15%和铝酸酯为3.36%),并测定分析了不同的偶联剂在单分子层饱和吸附含量下对Al2O3浆料体系粘度的影响,以及不同的操作条件对粘度的影响.     

聚羧酸减水剂对硫铝酸盐水泥水化及硬化的影响

为研究聚羧酸减水剂(PCE)对硫铝酸盐水泥(SAC)水化及硬化的影响,本工作以PCE对SAC标准稠度用水量、初始流动度、经时损失、粘度、凝结时间以及强度的影响进行了试验,同时测试了PCE对SAC浆体的水化温升以及水化产物的影响。结果表明:PCE在SAC浆体中的最佳掺量为0. 4%,减水率可达33%以上,初始流动度可达375 mm以上,初凝与终凝时间分别由24 min和36 min延至117 min和129 min。PCE对SAC浆体的流动度改善明显,并产生一定的缓凝作用。PCE掺量在0. 2%～0. 4%范围内,早期强度发展缓慢,但不影响其后期强度的增长。PCE掺量为0. 4%时,7 d抗压强度达102 MPa,抗折强度达11. 6 MPa。相比对照组,7 d抗压强度提高41. 8%,抗折强度提高20. 8%。     

羧基/磺酸基含量对聚羧酸盐水煤浆分散剂性能的影响

以甲基丙烯酸(MAA)、烯丙基磺酸钠(SAS)按一定比例合成了5种含有不同—COO~(-1)/—SO_3~(-1)比值的聚羧酸盐水煤浆分散剂PMAS系列。并通过红外光谱(FT-IR)、凝胶渗透色谱(GPC)进行了表征。并将其作用于彬长煤制浆,在用量0.4%(质量分数)时,水煤浆浆浓为65%时,考察了浆体的表观黏度与—COO~(-1)/—SO_3~(-1)比值的关系,在不同浓度下的zeta电位以及pH值对水煤浆应用的影响等。结果表明,当—COO~(-1)/—SO_3~(-1)比值为约3.238时,浆体的表观粘度最低,稳定性理想,此时浆体的zeta电位能达到-38mV,水煤浆粘度随着pH值的增大逐渐降低,当pH值大于10时水煤浆粘度趋于稳定。     

磁性膨胀石墨的制备及对油的吸附分离与再生

以硝酸钴和硝酸铁为主要原料,采用化学共沉淀法制备CoFe2O4纳米磁性微粒,然后将其与膨胀石墨复合制得CoFe2O4载量不同的磁性膨胀石墨。用X射线衍射(XRD)、透射电镜(TEM)、震动样品磁强计(VSM)、扫描电镜(SEM)对CoFe2O4纳米磁性微粒和磁性膨胀石墨进行了表征。并研究了CoFe2O4载量不同的磁性膨胀石墨对不同油类的饱和吸油量、对水和油的竞争吸附比、不同吸附时间和环境温度对饱和吸油量的影响、磁分离回收及离心法再生吸附后的磁性膨胀石墨。结果表明,合成的CoFe2O4结晶度高,晶粒度约为13nm。CoFe2O4载量越低、油品粘度越高,磁性膨胀石墨的饱和吸油量越大;油品粘度越大,油、水竞争吸附时水含量越低;磁性膨胀石墨10s即可达到饱和吸油量的80%,90s后达到饱和吸附;CoFe2O4载量为35%时,磁回收率为99.2%,且再生离心转速为3000r/min时再生吸油量达到较大值。     

可注射磷酸钙骨水泥的流变性能研究

采用高级流变扩展系统研究了添加剂种类及其含量对可注射磷酸钙骨水泥(ICPC)流变特性的影响。采用稳态流动实验表征浆体的静态粘度,用触变环面积、应力降低率和屈服应力表征ICPC浆体的触变性,并进行动态频率扫描和动态时间扫描实验动态监测ICPC的粘、弹、塑性变化规律以及水化反应过程流变参数的依时性。结果表明:添加剂并不改变ICPC的粘弹性。水溶性高分子化合物的加入提高了ICPC的粘度和触变性,利于整个体系的稳定;添加剂不同程度上提高了ICPC剪切后的网络结构恢复能力和稳定性,尤其以黄原胶和几丁糖最为明显。在此基础上,评估了加入黄原胶后ICPC形成凝胶的时间,约为2 563～2 600 s。此外,随着黄原胶含量的增加,ICPC触变环面积增加,但形成的网络结构在高剪切状态下并不稳定。     

炼油厂污油超声破乳脱水

以含水量（体积分数）20%~30%的中石化扬子炼油厂提供的污油为研究对象,在实验室条件下,采用超声波破乳技术进行脱水研究。在超声频率为20 kHz的条件下,考察了超声的其他参数对污油脱水的影响。结果表明：超声辐照时间为5min、超声激励电压为100V、超声辐照后热沉降温度为60℃、沉降时间为2h时,污油破乳脱水效果比较好,作用后,污油含水率可以降低到3.2%。按照小试得到的最佳工艺参数进行中试实验,其污油破乳脱水效果跟预计的结果相当,含水率可以降低到7.2%。     

挥发萘回用对萘系高效减水剂性能的影响

萘系高效减水剂合成过程中回收的挥发萘颜色较深,与工业萘相比纯度降低近3%。使用掺有挥发萘合成的萘系高效减水剂配制水泥净浆,研究表明,随着挥发萘掺入量的增加,净浆初始流动度减小,经时损失增大;混凝土试验表明,随着挥发萘掺入量的增加,萘系高效减水剂的减水率降低,增强作用减弱。因此,在挥发萘回用过程中,掺量不宜过大,最好不要超过5%。     

超声对Ti/SnO2+Sb2O3/PbO2电极材料结构及电极性能的影响

用SEM和XRD技术测定和分析了不同超声波作用时间下Ti／SnO2 Sb2O3／PbO2电极材料的表面形貌和结构，应用循环伏安法研究了超声波作用时间对Ti／SnO2 Sb2O3／PbO2电极在1．0mol／LH2SO4溶液中的伏安特性的影响．实验结果表明：超声波作用于电极材料会对电极表面的形貌和结构产生影响；电极经超声处理20min后，其循环伏安峰电流与未经超声波作用时相比增加了近1倍；电极的电化学活性表面积随超声波作用时间的延长呈先增大后减小的趋势，在本实验中超声波作用时间为20min时，伏安电荷最大，即活性表面积最大.     

三效催化剂涂层制备与性能研究

薄水锅石作为γ-Al₂O₃的前驱体,加入CeO₂-ZrO₂-La₂O₃和扩孔剂等助剂制备蜂窝陶瓷载体涂层,研究了涂层料液的表观粘度、因含量与载体负载量的关系,粘度对料液中粒径分布和涂层性能的影响,利用SEM、BET表面积、超声波震荡和热冲击等方法研究了涂层的性能.结果表明,涂层料液中适宜的固含量为30％～40％;一次浸量>二次浸量>三次浸量,适宜的负载量为8％～15％;低粘度料液以小颗粒为主,颗粒分布均匀,制备的涂层有较好的抗震动和抗热冲击性能;高粘度涂层料液的颗粒较大和粒径分布较宽,有利于提高载体的负载量,但涂层的性能明显下降.堇青石蜂窝陶瓷载体经一步法负载涂层后,可获得约 50 m²/g的表面积.     

Ultrasonication of wastewater sludge--consequences on biodegradability and flowability

The present study deals with pre-treatment of wastewater sludge by ultrasonic waves at frequency of 20 kHz using fully automated lab-scale ultrasonication equipment. Different wastewater sludge solids concentrations, ultrasonication intensities, and exposure times of pre-treatment were investigated for the optimization of ultrasonication treatment process. The parameters of pre-treatment process were optimized by using response surface methodology. A 2(3) central composite design was performed for optimization. The screening experiment step comprised steepest ascent methodology to determine optimal domain. The effect of ultrasonication treatment was assessed in terms of increase in soluble solids and the biodegradability of the wastewater sludge. In addition, rheological parameter of wastewater sludge, namely, viscosity was also measured to ascertain the suitability of wastewater sludge for conventional treatment processes as well as submerged fermentation, a major step for the production of value-added products from sludge. It was observed that the ultrasonication intensity and pre-treatment exposure time significantly affected the efficiency of the ultrasonication process followed by the solids concentration. The optimal conditions of ultrasonic pre-treatment were 0.75 W/cm(2) ultrasonication intensity, 60 min, and 23 g/L total solids concentration. The increases in soluble chemical oxygen demand and biodegradability, by aerobic sludge digestion process, in terms of total solids consumption increased by 45.5% and 56%, respectively. The flowability of ultrasonicated sludge in terms of viscosity showed exponential behaviour at different total solids concentrations, and pseudoplastic and thixotropic behaviour similar to raw sludge. Nevertheless, the magnitude of viscosity values of ultrasonicated sludge was always lower than the raw sludge.     

超声辐照作用下PP/POE共混体系结构与性能的研究

研究了超声辐照对PP/POE共混体系的挤出加工流变行为、力学性能及结晶行为的影响。结果表明:在超声辐照作用下PP/POE共混体系的熔体表观黏度随超声功率的增加而减小,超声辐照能降低口模压力,提高挤出物产量。适宜功率的超声辐照有助于POE粒子的破碎和在PP基体中的均匀分散,改善二者相容性,提高了共混体系的冲击性能。     

磁性Fe3O4纳米复合材料的制备及其对Pb(II)的吸附

为解决磁性纳米Fe₃O₄易被腐蚀、团聚等问题,可对其进行功能化修饰。在超声波辐照下首先制备磁性纳米Fe₃O₄颗粒,然后选用2,5-二氨基苯磺酸(SP)和间苯二胺(mPD)单体为引入剂进行功能化修饰,制备得到富含氨基、磺酸基和亚氨基活性官能团的金属基复合材料Fe3O4-mPD/SP(95∶5),并采用FTIR、TEM、XRD等手段对其进行表征,证实了超声波辐照法制得的磁性纳米复合材料具有稳定性好、反应活性高、粒径小和比表面积更大等特点。同时考察其对Pb(II)的吸附性能,结果表明：mPD和SP摩尔比、溶液pH值、竞争性阳离子种类和反应温度等因素均会影响吸附效果;等温吸附过程符合Freundlich模型,吉布斯自由能?G0<0,吸附是一个自发过程;Pb(II)的吸附行为符合准二级动力学,速率常数k₂=3.61×10^-3 g·mg^-1·min^-1,平衡吸附量q_e=63.297 mg·g     

Surface-charge density and potential of coal-liquid mixtures and control of their stability and fluidity

The preparation conditions of concentrated (>70%) aqueous suspensions of coal were optimized, as were the surface charge density and the surface potential of the coal-water suspensions. The theoretical study showed that (1–3) or (2–3) electrolytes such as Na₂SO₄ or Na₅P₃O₁₀, greatly increase the surface charge density and the surface potential of the coal particles in water. This study has led to the interesting result that thinners and stabilizing agents of concentrated clay suspensions, such as lignosulphonates, tripolyphosphates, polynaphtalene sulphonates, etc., must also be good thinners and stabilizing agents for ground coal-water suspensions. Two parameters were controlled: the stability and the fluidity of the suspensions. A penetrometry technique revealed the importance of the resistance coefficient,C _r that can be used as a criterion for the evaluation of coal-water mixture stability and fluidity. Concentrated coal suspensions (about 75% of solid by weight) were prepared in water by using different additives, for instance sodium tripolyphosphate (NaTPP) and surfactants like lignosulphonates (by coupling of the dispersion and stabilizing effects) with the optimum concentration ratio of these two products equal to 1.9. The stability of the suspensions was then greater than 2 months and the viscosity was 1900 cP.     

热处理对无烟煤/聚苯胺复合材料电容性能的影响

先对无烟煤进行低温真空热处理,除去在无烟煤的孔隙内和外表面吸附的低分子碳氢化合物,再将苯胺引入无烟煤的孔隙和外表面上,原位聚合制备出无烟煤/聚苯胺复合材料。分别用氮气吸附仪、扫描电子显微镜(SEM)、傅立叶红外光谱仪(FTIR)、电化学工作站和电阻率测定仪对其微观结构与电容性能进行了表征,结果发现:低温真空热处理增大了无烟煤的比表面、孔容和孔径,且没有破坏煤的大分子骨架,促进了煤大分子与聚苯胺链间的氢键作用,有效地改善了复合材料的电容特性。无烟煤经140℃真空热处理150min后制得的复合材料,在表面有均匀的微纳米级聚苯胺颗粒附着,比电容达到231.60F/g(3.33A/g),且循环可逆性更好。     

Synthesis of mesoporous ZSM-5 from rice husk ash with ultrasound assisted alkali-treatment method used in catalytic cracking of light naphtha

A series of mesoporous ZSM-5 zeolite was synthesized with ultrasonic assisted alkali-treatment technique and their catalytic activity was investigated in catalytic cracking of light naphtha. ZSM-5 zeolite was synthesized from rice husk ash without using any organic template. Effect of alkali-treatment conditions on physicochemical properties of synthesized zeolite was investigated with XRD, FESEM, TEM, N2 adsorption-desorption isotherm, NH3-TPD and TGA technique. It was found that ultrasound energy facilitates the creation of hierarchical structure of ZSM-5 during alkali-treatment. According to XRD analysis, zeolite structure was preserved after 20 min ultrasonic assisted alkaline treatment. However, prolonged dessilication time led to the destruction of MFI zeolite structure. The synthesized ZSM-5 represented highly ordered hexagonal-shape morphology. With increasing alkali-treatment time, the plough land roughness appeared on the surface of zeolite. Comparison of the textural properties samples revealed that the mesopore surface area of alkali-treated samples increased considerably with the increase of ultrasonic assisted alkali-treatment time. Results from catalytic activity tests showed that ultrasound energy has great influence on the activity of ZSM-5. The sample had the highest activity after alkali-treated for 20 min in presence of ultrasound energy which was due to their appropriate hierarchical structure.     

Investigation of the stability of an alumina suspension in the presence of ionic polyacrylamide

The influence of solution pH on the adsorption mechanism of polyacrylamide (PAM) on the alumina surface and stability of its suspension in the presence of polymer were investigated. The structure of polymer adsorption layer was determined from the spectrophotometric, viscosity, surface charge and zeta potential measurements which enable determination of adsorbed amount of polymer, thickness of the polymer adsorption layer, surface charge density and zeta potential of Al₂O₃ particles in the absence and presence of PAM. The measurements of stability of alumina suspension without and with adsorbed polyacrylamide were also carried out using two methods: spectrophotometry and turbidimetry. The obtained results indicate that solution pH influences the structure of PAM adsorption layer (decrease of adsorbed amounts of polymer and increase of its adsorption layer thickness with the increasing pH). These conformational changes of polyacrylamide molecules with the rising pH have an impact on stability of the alumina suspension. The most pronounced effect of polymer on the stabilization properties of investigated systems is observed for PAM addition at pH 6 resulting in a great destabilization of the alumina particles by bridging flocculation.     

Effect of particle size and adsorption equilibrium time on pore structure characterization in low pressure N2 adsorption of coal: An experimental study

This study examined the influence of particle sizes and adsorption equilibrium time (AET) on pore structure characterization using low pressure N₂ adsorption (LPGA-N₂) method. The results demonstrate that pore structures change with progressive crushing. The increase in pore volume in the minipore and mesopore with decreasing coal particle sizes was caused by creating additional large pores during the crushing. The tendency of decreasing at first and then increasing was observed for both the specific surface area (SSA) and micropore volume, demonstrating that the micropore structure was primarily damaged and then followed by additional micropores being created when the sample was broken down smaller than 80 mesh. It is difficult to choose a suitable coal particle size for LPGA-N₂ measurement to yield pore structure parameters closest to the “real” values due to the difficulty in evaluating the compound effect of crushing on pore structures. To make testing results closer to the coal structure under in situ conditions, we propose 1∼3 mm as the preferred coal particle size. Additionally, many replicate experiments were performed by adjusting the AET to ensure LPGA-N₂ isotherms in equilibrium states. The results indicate that a decrease in particle size did not reduce the time for reaching N₂ adsorption equilibrium. Comparison of pore size distributions under different AETs shows that the AETs' increase has a little influence on the measurement of minipore and mesopore but has a positive correlation with micropore, revealing that N₂ adsorption equilibrium is mainly influenced by the micropore whose volume is underestimated at small AETs. The optimal AET for LPGA-N₂ measurement was 8 min and its yielded data can more accurately characterize the pore structure parameters.