高强度生物质活性炭纤维制备研究

发布时间：2018-01-16 03:07

本文关键词：高强度生物质活性炭纤维制备研究　出处：《武汉理工大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文以丝瓜络纤维为原材料,水溶性酚醛树脂作为浸渍剂来制备活性炭纤维,研究了高强度生物质活性炭纤维的制备、其表面物理化学性质的表征及其应用于吸附DCB废水。根据升温速率,预氧化温度,预氧化时间,活化温度,活化时间来进行正交试验,得出了最佳的制备条件。最佳制备条件为升温速率为8℃/min,预氧化温度为200℃,预氧化时间为2 h,活化温度为850℃,活化时间为90 min。制备出最佳制备条件下的高强度生物质活性炭纤维(HP-ACF)。利用热重分析研究了丝瓜络纤维,水溶性酚醛树脂,浸渍水溶性酚醛树脂丝瓜络纤维的热解机理,分析了水溶性酚醛树脂与丝瓜络纤维可能存在的反应。选取正交试验的部分样品与HP-ACF,对其进行表面物理化学性质表征。应用扫描电镜(SEM)、N2吸附-脱附等温曲线、X射线衍射(XRD)对其表面物理性质进行表征;应用傅里叶红外光谱(FTIR)对其表面化学性质进行表征。结果表明,通过扫描电镜观察,制备出的ACF表面已经发育生成类石墨片层结构;ACFs的N2吸附-脱附等温曲线形状大致相同,都属于IUPAC分类法中的Ⅰ型吸附等温线,以微孔为主,同时存在着少量的中孔,最终制得的最优条件下产品HP-ACF,比表面积为422.47 m2/g,平均孔径为1.820 nm,孔容为0.192 cm3/g;FTIR证明了高强度生物质ACF表面含有羧基、羟基,并且证明丝瓜络纤维在炭化活化过程形成了芳环化结构。XRD分析表明丝瓜络中纤维素,木质素等的结构被破坏,内部分子发生重排,最终得到无定形碳材料;通过万能试验机对高强度生物质ACF进行抗压强度的测试,抗压强度可达0.246 MPa,可见高强度生物质ACF具有一定抗压能力。选用最佳制备条件下制备的产品HP-ACF应用于吸附DCB废水。研究了温度,pH,投加量对高强度生物质ACF吸附DCB废水的影响,结果表明:高强度生物质ACF的吸附反应为放热反应,最佳吸附温度为25℃;当pH≤5时,HP-ACF对DCB的去除率比较理想,当pH5时,HP-ACF对DCB的去除率急速下降;在吸附20 mg/L的DCB溶液时,当ACF投加量为1 g/L时,高强度生物质活性炭纤维对DCB的去除率趋向于最大值,去除率达到98.29%;分别用Langmuir吸附等温模型与Freundlich吸附等温模型来拟合ACF吸附DCB废水的吸附等温线,相关度R2都大于0.95,采用Langmuir吸附等温模型拟合结果更加吻合;采用伪一级吸附动力学模型和伪二级吸附动力学模型来拟合实验数据,伪二级吸附模型拟合的相关系数为0.9821,伪一级吸附模型拟合的相关系数为0.9534;伪二级吸附模型对高强度生物质ACF吸附DCB废水能更好的描述;吸附后高强度生物质活性炭纤维采用NaOH溶液加热再生法进行再生,再生次数越多,ACF的平衡时的吸附容量与其再生效率都是略降的,再生四次过后,ACF的吸附容量仍然在70%以上,可见高强度生物质ACF具有较好的再生效果。
[Abstract]:In this paper, loofah fiber as raw material, water soluble phenolic resin as impregnating agent to prepare activated carbon fiber, high strength of biomass activated carbon fiber preparation, characterization of the surface physical and chemical properties and its application in adsorption of DCB wastewater. According to the heating rate, pre oxidation temperature, oxidation time, activation temperature the activation time for, orthogonal test, the optimum preparation conditions. The optimum preparation conditions for the heating rate is 8 DEG /min, pre oxidation temperature of 200 DEG C, pre oxidation time was 2 h, activation temperature is 850 DEG C, the activation time of 90 min. was prepared by the best preparation of high strength biomass activated carbon under the condition of the fiber (HP-ACF). The study of Luffa fibers by thermogravimetric analysis, water soluble phenolic resin impregnation, pyrolysis mechanism of water soluble phenolic resin fiber loofah, analysis of water soluble phenolic resin with Loofah fiber possible reaction Some samples with HP-ACF. Select the orthogonal test of surface physical and chemical properties. Its properties by scanning electron microscopy (SEM), N2 adsorption desorption isotherms, X ray diffraction (XRD) were used to characterize the surface physical properties; application of Fourier transform infrared spectroscopy (FTIR) to characterize the surface chemical properties. Show that by scanning electron microscopy, ACF surface preparation has developed to generate layer structure of graphite sheet; N2 adsorption - desorption isothermal ACFs curves are roughly the same, all belong to the type of adsorption isotherms of IUPAC classification, the micropores exist in a small hole, the final optimal conditions the products of HP-ACF, specific surface area is 422.47 m2/g, the average pore size is 1.820 nm, Kong Rong 0.192 cm3/g; FTIR proved that high strength ACF biomass with carboxyl, hydroxyl, and loofah fiber in carbonization and activation process to form a Fang Ring structure.XRD analysis showed that the cellulose loofah, and wooden structure was destroyed, the internal molecular rearrangement, resulting in amorphous carbon materials; through the universal testing machine on the compressive strength of high strength ACF biomass test, the compressive strength can reach 0.246 MPa, can see the high strength ACF biomass has certain compressive capacity selection the best preparation conditions for preparation of HP-ACF products applied to the adsorption of DCB wastewater. The effects of temperature, pH, dosage of high strength ACF biomass adsorption of DCB wastewater the results showed that the adsorption of high strength ACF biomass reaction is an exothermic reaction, the optimum adsorption temperature is 25 DEG C; when pH is less than or equal to 5. HP-ACF on the removal rate of DCB is relatively ideal, when pH5 HP-ACF, the removal rate of DCB decreased rapidly; in the solution of DCB adsorption at 20 mg/L, when the ACF dosage is 1 g/L, the high strength biomass activated carbon fiber on the removal rate of DCB tends to The maximum removal rate reached 98.29%; respectively by Langmuir adsorption isothermal adsorption isotherm model and Freundlich isotherm model to fit the ACF adsorption of DCB wastewater, the related degree of R2 is greater than 0.95, the fitting results of Langmuir adsorption isotherm model is more consistent; using pseudo first-order adsorption kinetics model and pseudo two adsorption kinetic model to fit the experiment the data, correlation coefficient of the pseudo two adsorption model was 0.9821 and the correlation coefficient of the pseudo first-order adsorption model fitting is 0.9534; the pseudo two adsorption model is better for high strength ACF adsorption of DCB wastewater of biomass; biomass activated carbon after adsorption of high strength fiber with NaOH solution and heating regeneration method for regeneration, regeneration times more the equilibrium adsorption capacity of ACF, and the regeneration efficiency is decreased slightly, after four times of regeneration, the adsorption capacity of ACF is still visible in more than 70%, high intensity of biomass ACF has good regeneration effect.

【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TQ424.1;X703

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