水稻秸秆吸附剂的制备及吸附性能研究

【作者】 刘畅；

【导师】 谢娟；

【作者基本信息】 西南石油大学 ， 材料工程（专业学位）， 2018， 硕士

【摘要】 由于天然的多孔结构和独特的物质基础,水稻秸秆有被制备成为天然物吸附剂的潜质,因而开始在吸附剂领域被很多学者研究。在本课题中,利用水稻秸秆作为原料,制备得到两种吸附剂,并通过改性对吸附剂的性能进行了提升,并对于材料的吸附性能和其他理化性质能进行了表征。在染料吸附部分,先对原始未改性吸附剂进行了测试和动力学评价,发现未改性秸秆吸附剂对于不同种类染料存在一定的吸附选择性,并且发现利用伪二级动力学模型可以对于阳离子染料吸附过程进行描述。之后采用L16(44)正交实验研究了碳化改性对吸附性能的影响,找出了最佳碳化秸秆吸附剂,相对于未改性吸附剂,吸附量提升26%,达到32.975 mg/g,对碱性品红染料去除率达到了 95.45%,在甲基橙亚甲基蓝体系中,对亚甲基蓝的选择去除率更是达到99.82%,而对碱性品红的去除率仅有8.27%,表现出极强的选择性。笔者通过分析得出,对于阳离子型染料的选择性吸附主要原因是表面的电负性基团使得吸附剂表面相对于溶液体系带负电,对于带有正电荷的阳离子染料分子具有化学作用同时对带有负电荷的阴离子染料分子产生一定的排斥从而表现出了选择性。在油性物吸附部分,同样先对原始未改性吸附剂进行了性能测试,发现未改性吸附剂的对于油性物的吸附性能有一定的局限性,所以利用酰化改性通过将酒石酸的羟基与原始吸附剂中的羟基,氨基进行酰化,得到酰化改性后的吸附剂,经过红外光谱分析发现该吸附剂表面有明显的酰化迹象,使得吸附剂在吸油性能上有了一定的提升,对于邻苯二甲酸二丁酯吸附量为10.45 g/g,煤油吸附量为10.78 g/g,液体石蜡吸附量为12.78 g/g,食用油的吸附量分别达到11.28 g/g,且该吸附过程符合伪二级动力学规律。此后为了增加吸附剂的可回收性,通过以乙二醇作为溶剂同时作为还原剂的溶剂热反应,将三氯化铁还原为四氧化三铁负载在吸附剂表面,得到了磁化改性吸附剂,利用XRD表征可以证明四氧化三铁的有效负载并且说明磁性的来源即四氧化三铁。该吸附剂在油水吸附体系中表现出了较好的吸附性能,对不同油性物吸附量相对于纯油体系中的吸附量略有下降,分析其原因是由于磁化改性导致吸附剂亲水性变差,使得在油水体系中对于水的吸附量很少,使得对油性物的吸附量并没有明显下降,且表现出易回收的性能。更多还原

【Abstract】 Due to the natural porous structure and unique material foundation,rice straw has been prepared to be the potential of natural adsorbent.In this thesis,rice straw were used as the raw material to the preparation for two kinds of adsorbent,and using different modification methods to develop the properties of adsorbents,then the adsorption properties of adsorbent and the physical and chemical properties have been characterized.In the part of dye-adsorption,the original unmodified adsorbent was first tested and kinetically evaluated.It was found that the unmodified straw adsorbent had a certain adsorption selectivity for different types of dyes,and it was found that the pseudo-secondary kinetic model could be used for The cationic dye adsorption process is described.the effect of carbonization modification on adsorption performance were studied by orthogonal experiments of L16(44),then,the best carbonized straw adsorbent were found out,compared to unmodified adsorbent,adsorption capacity increased by 26%,reached 32.975 mg/g.the removal of BF reached 95.45%.High select adsorption performance showed in the binary MB and MO solution,the removal rate of MB is 99.82%and the removal rate of MO is only 8.27%.According to the analysis,the main reason for the selective adsorption of cationic dyes is that the electron-negative groups on the surface make the surface of the adsorbent negatively charged with respect to the solution system and have a chemical effect on cationic dye molecules with positive charges while carrying negatively charged anionic dye molecules produce a certain degree of repulsion and thus exhibit selectivity.In the oil-adsorbed part,the performance of the original unmodified adsorbent was tested first,and it was found that the unmodified adsorbent had certain limitations on the adsorption properties of oily substances,so the acylation was used to modify the hydroxyl group of tartaric acid.Acylation with hydroxyl and amino groups in the original adsorbent resulted in an acylated modified adsorbent.After infrared spectrum analysis,the adsorbent showed obvious signs of acylation,which made the adsorbent have a certain degree of oil absorption performance increased to some extent.Dibutyl phthalate absorption capacity is 10.45 g/g,the adsorption capacity of kerosene is 10.78 g/g,the adsorption capacity of liquid paraffin was 12.78 g/g,and that of edible oil reached 11.28 g/g,respectively.And the adsorption process accords with pseudo-second-order kinetics.Thereafter,in order to increase the recoverability of the adsorbent,iron trichloride is reduced to iron tetroxide on the surface of the adsorbent by solvothermal reaction using ethylene glycol as a solvent and a reducing agent simultaneously to obtain a magnetized adsorbent,using XRD characterization can prove the effective load of triiron tetraoxide and explain the source of magnetic iron oxide.The adsorbent showed good adsorption performance in the oil-xwater adsorption system.The adsorption capacity of different oily substances was slightly decreased compared with that in the pure oil system.The reason for the analysis was that the adsorbent was pro-The deterioration of the water makes the amount of water adsorbed in the oil-water system small,so that the amount of adsorption of the oily substance does not decrease significantly,and exhibits an easily recoverable property.更多还原