【作者】 刘洋；

【导师】 韩润平；

【作者基本信息】 郑州大学 ， 环境科学， 2024， 硕士

【摘要】 对农业废弃物进行有效综合利用,如通过改性提高其吸附性能,应用于污染物的去除,值得研究。本文以花生壳(PS)为基础材料,采用共沉淀法负载四氧化三铁,生成磁性花生壳Fe3O4-PS。接着利用十六烷基三甲基溴化铵(CTAB)进行进一步改性,成功制备了 CTAB-Fe3O4-PS。同时,通过溶剂热法和原位生长法制备了 MOF改性的花生壳复合材料NH2-MIL-Al(53)-PS。采用热重分析(TG)、扫描电镜(SEM)、比表面积分析(BET)、红外光谱图分析(FTIR)、光电子能谱分析(XPS)等技术对材料进行了表征,并通过表征结果证明材料均改性成功。将以上三种复合材料作为吸附剂,对水体中的盐酸土霉素(OTC-HCl)、六价铬(Cr(Ⅵ))、2,4-二氯苯氧乙酸(2,4-D)、茜素红(AR)和双酚A(BPA)的吸附特征进行了研究,主要结果如下。Fe3O4-PS对OTC-HCl的吸附研究结果表明,pH为3时吸附量最大,共存离子的存在对于吸附有负面的影响。293 K时由实验得到的最大吸附量为85.3 mg·g-1。吸附等温线符合Langmuir模型,吸附动力学更加符合Elovich模型。热力学研究表明,吸附是自发、熵增的吸热过程。0.1 moL·L-1 NaOH可以用于材料的解吸再生。XPS分析和吸附实验结果说明Fe3O4-PS对OTC-HCl的吸附过程存在静电引力、π-π堆积作用、络合作用和氢键作用。CTAB-Fe3O4-PS对AR和BPA的吸附,pH保持为AR原溶液pH(3.35)时和BPA原溶液pH(6.03)时,材料对污染物吸附效果较好,盐的存在对于两种污染物的吸附均产生负影响。293 K时对AR和BPA的最大吸附量分别为79.8 mg·g-1 和 61.0 mg·g-1。CTAB-Fe3O4-PS 对 AR 的吸附等温线符合 Freundlich 模型来描述,吸附动力学更加符合Pseudo-second-order动力学模型;CTAB-Fe3O4-PS对BPA的吸附等温线则更加符合Langmuir和Koble-Corrigan两种模型,吸附动力学方面则符合Elovich和Double Constant模型。热力学研究表明,材料对AR的吸附是自发、熵增的吸热反应,而对于BPA的吸附是自发、熵增的放热反应。对于两种污染物,最佳的解吸再生试剂分别是0.1 moL·L-1 NaOH和75%的无水乙醇。XPS分析和吸附结果说明CTAB-Fe3O4-PS对于AR吸附主要通过络合作用、静电引力、氢键和π-π堆积,对于BPA的吸附主要为氢键作用力、络合作用和π-π堆积作用为主。NH2-MIL-53(Al)-PS 对 Cr(Ⅵ)和 2,4-D 的吸附研究结果表明,NH2-MIL-53(Al)-PS对Cr(Ⅵ)的吸附在pH为2时最好,对2,4-D的吸附在pH为3时最好,盐的存在均不利于吸附。293 K时对Cr(Ⅵ)和2,4-D的最大吸附量分别为258 mg·g-1 和 66.6 mg·g-1。NH2-MIL-53(Al)-PS 对 Cr(Ⅵ)的吸附等温线较为符合Freundlich 模型,吸附动力学符合 Elovich 模型和 Intrapartical diffusion 方程。NH2-MIL-53(Al)-PS对2,4-D的吸附则是符合Langmuir模型,吸附动力学符合Elovich模型和Double Constant模型。热力学研究表明,两种吸附均为自发的、熵增的吸热过程。两种污染物对应的最佳解吸试剂均为0.1 moL·L-1 NaOH。NH2-MIL-53(Al)-PS对Cr(Ⅵ)的吸附主要为氢键、静电引力、络合作用,对于2,4-D的吸附则是以氢键、静电引力和π-π堆积作用为主。三种改性材料对比改性之前的吸附效果均有提升,对目标污染物具有较强的吸附效果,且稳定性好,所得结果为其在去除水体中有机污染物的应用提供基础依据。更多还原

【Abstract】 The effective comprehensive utilization of agricultural wastes,such as improving their adsorption properties through modification and applying them for pollutant removal,is worth studying.In this paper,peanut shells(PS)were used as the base material and loaded with ferric tetraoxide by co-precipitation method to generate magnetic peanut shells Fe3O4-PS.Then,cetyltrimethylammonium bromide(CTAB)was utilized for further modification,and the CTAB-Fe3O4-PS was successfully prepared.At the same time,MOF-modified peanut shells composites were prepared by solvent-thermal and in-situ growth method,NH2-MIL-Al(53)-PS.The materials were characterized by thermogravimetric analysis(TG),scanning electron microscopy(SEM),specific surface area analysis(BET),infrared spectrogram analysis(FTIR),and photoelectron spectroscopy analysis(XPS),and all of them were proved to be successfully modified by the characterization results.The above three composites were used as adsorbents to characterize the adsorption of oxytetracycline hydrochloride(OTC-HCl),hexavalent chromium(Cr(VI)),2,4-dichlorophenoxyacetic acid(2,4-D),alizarin red(AR),and bisphenol A(BPA)in the water body,and the main results are as follows.The adsorption results of Fe3O4-PS toward OTC-HCl show that there is in favor of adsorption at solution pH 3.The presence of coexisting ions without adjusting the pH of the original solution(3.52)has a negative effect on the adsorption.The maximum adsorption quantity is 85.3 mg·g-1 at 293 K from experiments.The adsorption isotherm is well predicted by Langmuir model.The adsorption kinetics is better described using Elovich model.Thermodynamic studies show that adsorption is a spontaneous endothermic reaction with increasing entropy.0.1 moL·L-1 NaOH can be used for desorption regeneration of materials.The results of XPS analysis and adsorption experiments indicate that there are electrostatic attraction,π-π stacking,complexation and hydrogen bonding in the adsorption process of Fe3O4-PS on OTC HCl.The adsorption effect of CTAB-Fe3O4-PS toward AR and BPA is better when the pH of the original solution of AR(3.35)and the original solution of BPA(6.03)are maintained.The presence of salt has a negative effect on the adsorption of both pollutants.The max adsorption quantity from experiments is 79.8 mg·g-1 for AR and 61.0 mg·g-1 for BPA at 293 K,respectively.The adsorption isotherm of CTAB-Fe3O4PS for AR is more conformed with the Freundlich model,and the adsorption kinetics is more consistent with the Pseudo-second-order kinetic model.The adsorption isotherm of BPA on CTAB-Fe3O4-PS is well fitted using Langmuir and KobleCorrigan models,and the adsorption kinetics is well fitted using Elovich and Double Constant models.Thermodynamic studies show that the adsorption of AR is a spontaneous and entropic endothermic reaction.The adsorption of BPA is a spontaneous exothermic reaction with increased entropy.For the two pollutants,the best desorption reagents are 0.1 moL·L-1 NaOH and 75%ethanol.The results of XPS analysis and adsorption indicate that the adsorption of CTAB-Fe3O4-PS to AR is mainly through complexation,electrostatic attraction,hydrogen bond and π-πaccumulation,while the adsorption of BPA is mainly through hydrogen bond force,complexation and π-π accumulation.The results of adsorption studies for Cr(Ⅵ)and 2,4-D onto NH2-MIL-53(Al)-PS show that the adsorption is best at pH 2 for Cr(Ⅵ)and at pH 3 for 2,4-D.The presence of common salts is not conducive to adsorption.The adsorption quantity from experiments is up to 258 mg·g-1 for Cr(Ⅵ)and 66.6 mg·g-1 for 2,4-D at 293 K,respectively.The adsorption isotherm of NH2-MIL-53(Al)-PS toward Cr(Ⅵ)is well described using Freundlich model,and the adsorption kinetics is better predicted using Elovich model and Intrapartical diffusion equation,respectively.The adsorption of NH2-MIL-53(Al)-PS toward 2,4-D is more consistent with the Langmuir model.The adsorption kinetics is in good agreement with Elovich model and Double Constant model.Thermodynamic studies show that both kinds of adsorption are spontaneous endothermic processes with increasing entropy.The best desorption reagent for both pollutants was 0.1 moL·L-1 NaOH.The adsorption of Cr(Ⅵ)by NH2-MIL-53(Al)-PS is mainly hydrogen bonding,electrostatic attraction and complexation,while the adsorption of 2,4-D is mainly hydrogen bonding,electrostatic attraction and π-πaccumulation.Compared with before modification,the adsorption effect of the three modified materials was improved.There was good adsorption capacity of composites toward the target pollutants with good stability of materials.The results provided a basis for their application in the removal of organic pollutants in water bodies.更多还原