填充床生物膜反应器动力学模型

提出两种填充床生物膜反应器动力学模型。模型１假设生物膜的厚度受膜内底物浓度所限制；模型Ⅱ假设生物膜厚度为常数，膜中的扩散忽略不计。两种模型正合微分方程的解析解与数值解表示出十分的吻合。     

炭纤维和活性炭甲醇气相吸附动力学和等温线

采用不同原料、不同活化过程的两种活性炭和两种炭纤维(PAN、Rayon基)进行了甲醇气相静态吸附,结合其吸附动力学和等温线的数据研究了有关扩散问题,发现温度与所用样品表面化学性质、中孔率、孔隙(形态与大小)微织构对其吸附动力学有影响。     

腐植酸保水剂吸附氮磷特性研究

以硫酸铵代替氮、以磷酸氢二钾代替磷,采用静态吸附法测定自制腐植酸保水剂吸附对氮／磷的吸附量;改变铵根离子和磷酸根离子浓度绘制吸附等温线,并采用几种模型对等温吸附数据进行拟合,确立了其等温吸附模型。结果表明：自制腐植酸保水剂对铵根离子或磷酸根离子具有很大的吸附容量,磷酸氢二钾浓度小于18g/L、硫酸铵浓度小于10g／L的范围内,吸附量随浓度的升高快速增加。该保水剂对硫酸铵的等温吸附在0-10g／L范围内较好的符合平方曲线模型,而磷酸氢二钾浓度在0-18g／L范围内对磷酸根的吸附更好的符合直线模型。     

改性甘蔗渣吸附水中Th(Ⅳ)的研究

以NaOH改性前后的甘蔗渣为吸附剂,采用静态吸附法,研究了pH、离子强度、吸附时间、溶液浓度和温度等因素对改性前后甘蔗渣吸附水中Th(Ⅳ)的影响。结果表明:pH对吸附的影响较大,离子强度对吸附的影响较弱,表明Th(Ⅳ)在改性前后甘蔗渣上的吸附受表面络合控制;升高温度有利于吸附反应;改性前的甘蔗渣达到吸附平衡的时间为120min,改性后的甘蔗渣达到吸附平衡的时间为180min;改性前后甘蔗渣吸附Th(Ⅳ)的过程符合准二级动力学模型和Langmuir吸附等温模型,这表明Th(Ⅳ)在改性前后甘蔗渣上的吸附是受化学作用控制的单分子层的吸附。     

改性麦糠对刚果红模拟废水吸附性能的研究

将天然麦糠分别用氢氧化钠、乙二胺四乙酸(EDTA)、盐酸进行改性,制得一系列改性麦糠。经筛选,用经氢氧化钠改性后的麦糠作为吸附剂,分别探讨了氢氧化钠浓度、改性时间以及液固比对改性麦糠吸附刚果红(CR)染料的影响。确定氢氧化钠改性麦糠的最优条件为:氢氧化钠质量浓度为80g/L,改性时间为90min,液固比为20∶1,此时脱色率为94.81%,吸附量为11.85mg/g。吸附动力学研究表明,该吸附过程符合准二级吸附动力学模型,属于化学吸附。其等温吸附过程可以用Langmuir方程描述,表现为单分子吸附。     

香蕉皮粉对结晶紫废水的吸附动力学与吸附热力学研究

以香蕉皮粉为吸附剂,探究了pH值、结晶紫初始浓度、吸附剂用量、振荡速度、温度、吸附时间对结晶紫吸附效果的影响。结果表明:香蕉皮粉对结晶紫废水的最佳吸附条件是:pH 7.0、结晶紫废水初始质量浓度100mg/L、香蕉皮粉用量8g/L、振荡速度120r/min、吸附时间150min、温度30℃,其吸附率达94.29%。Freundlich型方程比Langmuir型方程对等温吸附试验数据拟合更好,说明吸附是以多层吸附为主。分别用准一级、准二级动力学模型,Elovich方程、双常数方程,对吸附动力学过程进行拟合,结果表明:准二级模型对实验数据拟合效果较好,说明该吸附过程以化学吸附为主。     

活性炭对正丁烷的吸附动力学研究

以木屑为原料、磷酸为活化剂,经过碳化、活化两步法制备的丁烷吸附炭,并考察了活性炭的吸附时间、正丁烷流量和吸附温度的变化对正丁烷吸附性能的影响;研究了活性炭在不同温度下的吸附动力学行为。实验证明,活性炭吸附正丁烷是一个吸附与解吸并存的快速物理吸附过程。正丁烷流量显著影响活性炭的吸附速率和吸附时间,但不影响活性炭的饱和吸附量(qe)。活性炭对正丁烷的饱和吸附量随着温度的升高而降低,表明正丁烷在活性炭上的吸附为放热反应。活性炭对正丁烷的吸附动力学行为遵循班厄姆动力学方程,其相关系数R2均>0.99,通过班厄姆方程计算得到的qe与实验得到的qe非常接近,通过拟合可以得到理想的吸附速率方程。     

水滑石除磷的吸附动力学研究

采用共沉淀法制备了Mg/Al水滑石,研究了不同Mg/Al物质的量比、材料用量、不同pH条件下Mg/Al水滑石吸附除磷的动力学特征,从而对吸附速率的控制过程进行分析。结果表明水滑石对磷的吸附能较好地符合准二级动力学方程、Elovich动力学方程和内扩散模型。n(Mg)/n(Al)=3是水滑石最理想配比,水滑石投加量越大,外扩散过程越慢;一定范围内pH的升高能促进水滑石对磷吸附速率和吸附容量的提升。     

高温聚酯化反应动力学的研究(Ⅰ) 聚酯化反应动力学模型

通过系统分析和评价前人的研究结果，论证了对苯二甲酸（PTA）与乙二醇的酯化反应符合符合二级反应的假设；通过对该体系中可能存在的各种反应进行分析，提出对聚酯化反应动力学的研究需要重点研究其中的几个主要反应，即：可逆的酯化反应，酯化缩合反应，缩聚反应和副反应二甘醇的生成。在进行反应体系的物料衡算时，考虑到了PTA与反应液的非均相的影响，在此基础上建立了动力学模型。     

复配壳聚糖树脂对Cu2+的等温吸附及吸附动力学研究

以活性炭和壳聚糖为复配原料合成复配壳聚糖树脂,对树脂的结构进行扫描电镜和红外表征,并研究了复配壳聚糖树脂对Cu2+的等温吸附动力学特性。结果表明复配改性后的壳聚糖具有多孔结构,比表面积增大;交联反应发生在壳聚糖分子中的氨基和羟基上;复配壳聚糖树脂对Cu2+的吸附符合Langmuir和Freundlich等温吸附模型;其吸附动力学过程符合Lagergren二级动力学方程,吸附过程容易进行。     

双酚AP基苯并噁嗪树脂等温固化动力学研究

以4,4'-(1-苯乙基)双酚(双酚AP)、正辛胺和甲醛为原料,采用溶剂法合成了一种新型双酚AP基苯并噁嗪单体,利用FT-IR和1H NMR对产物结构进行了表征,采用差式扫描量热仪(DSC)研究了苯并噁嗪单体的等温固化反应动力学.结果表明,该树脂体系的固化反应在反应前期为化学动力学控制,后期变为扩散控制占主导地位的反应,苯并噁嗪的固化过程为自催化和扩散控制.在反应后期实验数据和理论数据出现了偏差,通过将扩散因子引入到自催化模型中,改进后的自催化模型与实验数据相符.     

Mass transfer, kinetics and equilibrium studies for the biosorption of methylene blue using Paspalum notatum

Batch experiments were carried out for the sorption of methylene blue onto Paspalum notatum. The operating variables studied were initial dye concentration, initial solution pH, adsorbent dosage and contact time. Experimental equilibrium data were fitted to Freundlich, Langmuir and Redlich-Peterson isotherms by non-linear regression method. Six error functions was used to determine the optimum isotherm by non-linear regression method. The present study shows r2 as the best error function to determine the parameters involved in both two- and three-parameter isotherms. Langmuir isotherm was found to be the optimum isotherm for methylene blue onto P. notatum. The monolayer methylene blue sorption capacity of P. notatum was found to be 31 mg/g. The kinetics of methylene blue onto P. notatum was found to follow a pseudo second order kinetics. A Boyd plot confirms the external mass transfer as the rate-limiting step in the dye sorption process. The influence of initial dye concentration on the dye sorption process was represented in the form of dimensionless mass transfer numbers (Sh/Sc0.33) and was found to vary as C(0)-5x10(-6).     

Studies on biosorption equilibrium and kinetics of Cd2+ by Streptomyces sp. K33 and HL-12

The sorption of Cd(2+) by Streptomyces sp. K33 and HL-12 was investigated. The removal efficiency increased with pH, but no obvious differences with different temperatures. Fourier transform infrared (FT-IR) was used to characterize the interaction between Cd(2+) and K33 and HL-12. Results revealed that the presence of amino, carboxyl, hydroxyl and carbonyl groups were responsible for the biosorption of Cd(2+). Strain HL-12 had more changes in the functional groups than K33. Biosorption equilibrium was established earlier by strain K33 than that by HL-12, and K33 had higher adsorption ratio. Langmuir, Freundlich and Dubinin-Radushkevich (D-R) isotherms were used to describe the adsorption experiment, Langmuir model fitted the experiment data best. Strain K33 showed greater sorption capacities with 38.49 mg Cd(2+)/g dry cells. Pseudo-first-order and second-order kinetic models were used to describe the kinetic data, and second-order kinetic model fitted better. About 70% recovery of Cd(2+) could be obtained at pH 相似文献   

Kinetic and equilibrium studies on the removal of acid dyes from aqueous solutions by adsorption onto activated carbon cloth

Removal of acid dyes Acid Blue 45, Acid Blue 92, Acid Blue 120 and Acid Blue 129 from aqueous solutions by adsorption onto high area activated carbon cloth (ACC) was investigated. Kinetics of adsorption was followed by in situ UV-spectroscopy and the data were treated according to pseudo-first-order, pseudo-second-order and intraparticle diffusion models. It was found that the adsorption process of these dyes onto ACC follows the pseudo-second-order model. Adsorption isotherms were derived at 25 degrees C on the basis of batch analysis. Isotherm data were treated according to Langmuir and Freundlich models. The fits of experimental data to these equations were examined.     

多孔聚丙烯酸钠树脂吸湿动力学与热力学研究

为改善树脂吸湿性能,充分发挥树脂在吸湿领域的实际应用,本文系统分析了多孔聚丙烯酸钠树脂的吸湿过程及吸湿机理.通过测定多孔树脂在不同湿度下的吸湿量,得到其吸湿等温线,并确定其吸附类型;测定树脂在80%相对湿度下的吸湿曲线,采用动力学理论分析树脂吸湿速率,并与无孔聚丙烯酸钠树脂吸湿速率进行比较;测定树脂在不同温度下的吸湿量计算其吸湿热力学参数,研究树脂吸湿所能到达的程度.结果表明:树脂满足Ⅲ型吸附等温线,对吸附等温线进行线性拟合,树脂吸湿过程可用Freundlich吸附等温式进行描述;树脂吸湿符合二级吸附动力学模型,且多孔聚丙烯酸钠树脂的吸湿速率明显高于无孔聚丙烯酸钠树脂;树脂吸湿过程的焓变、熵变、吉布斯自由能变化均小于零,说明树脂吸湿过程是放热自发的.研究发现:树脂吸湿过程同时包含物理吸附和化学吸附,且以化学吸附为主;多孔结构的存在有利于提高树脂吸湿速率;降低温度有利于树脂吸湿.     

玉米须吸附剂去除水溶液中Pb2+的研究

利用废弃物玉米须制备生物质吸附剂,研究其对废水中重金属Pb2+的吸附效果。考察体系pH值、Pb2+初始浓度、吸附剂添加量以及共存离子K+、Na+、Ca2+、Mg2+对吸附率的影响。结果表明:在25℃,玉米须吸附Pb2+的最佳pH值为4.0;吸附剂添加量为0.150g,金属初始浓度为40mg/L时,吸附率高达99%以上。其动力学数据符合准二级动力学模型,Langmuir-Freundlich模型成功拟合了平衡数据,由该模型所得吸附剂的最大吸附容量为68.533mg/g。利用Zeta电位仪、红外光谱仪和扫描电镜进一步探讨玉米须对重金属的吸附机理。结果表明:玉米须外表面遍布墙形褶皱,断面存在孔道,这有利于对Pb2+的吸附;当体系pH>2.0时,玉米须颗粒表面带负电,可以和Pb2+发生静电吸附;-COOH、-OH、-C=O等含氧官能团参与了吸附过程。     

Comparative study of the biosorption of Pb(II), Ni(II) and Cr(VI) ions onto S. cerevisiae: determination of biosorption heats

In this study, the biosorption of Pb(II), Ni(II) and Cr(VI) ions onto inactive Saccharomyces cerevisiae was investigated as a function of initial pH, initial metal ion concentration and temperature. The Langmuir model was applied to experimental equilibrium data of Pb(II), Ni(II) and Cr(VI) biosorption depending on temperature and the maximum metal ions uptake at optimum biosorption temperature of 25 °C, were found to be 270.3, 46.3 and 32.6 mg g⁻¹, respectively. Using the Langmuir constant, b values obtained at different temperatures, the biosorption heats of Pb(II), Ni(II) and Cr(VI) were determined as −1.125, −1.912 and −2.89 kcal mol⁻¹, respectively. The results indicated that the biosorption of Pb(II), Ni(II) and Cr(VI) ions to S. cerevisiae is by the physical adsorption and has an exothermic nature.     

碳纤维表面化学镀镍工艺及机理研究

研究了碱性条件下碳纤维表面化学镀镍工艺及机理。结果表明随着施镀温度的升高,pH值的增大,络合剂含量的减少,金属镍的沉积速率越大,但是镀液稳定性越差;碳纤维表面化学镀镍过程有明显的诱导期、加速期、减速期和稳定期4个阶段,并且当沉积时间过长、温度过高、pH值越大时,镀层出现胞状沉积结构。实验条件下,反应速率方程V=K[OH-]a[Na6H5O7]b[Ni 2＋]c[H2PO2-]dexp（-Ea/RT）中的[OH-]反应级数a=0.26565,[Na6H5O7]的反应级数b=-0.23287,表面活化能Ea=61.034kJ/mol。     

微胶囊萃取钪的动力学研究

用乙基纤维素、海藻酸钙为膜材,分别采用水浴干燥法、锐孔法制备微胶囊,从理论上对微胶囊萃取钪的动力学方程进行了推导,得到一级反应动力学方程．实验表明,乙基纤维素微胶囊的渗透系数大于海藻酸钙微胶囊的渗透系数,从而具有较小传质阻力,适合于钪的萃取．