【作者】 王敏；

【导师】 王祥学； 王磊；

【作者基本信息】 华北电力大学 ， 工程硕士（专业学位）， 2024， 硕士

【摘要】 碘污染物的存在被认为是现代社会面临的一个问题,其对人类健康、土壤、大气和生态系统都产生着多方面的影响。到目前为止,无机吸附剂和其他无机-有机杂化MOF等先进材料已经取得了优异的碘捕获能力,尽管这些材料在碘污染物去除方面取得了显著成就,但考虑到它们的制备成本和能力,需要进一步探索和开发更全面的吸附剂。本项研究利用多种农业废料作为原料,并通过不同浓度碱溶液的处理改性,制备出一种新型吸附剂,有效捕获碘污染物。在研究过程中,对吸附剂的结构因素和外部因素进行了全面的控制和研究,以评估其对碘捕获效率的影响。通过元素分析揭示了材料的组成特征;拉曼光谱(Raman)与傅里叶变换红外光谱(FTIR)、X射线光电子能谱(XPS)与X射线衍射(XRD)分别解析了化学与晶体结构;扫描电子显微镜-能量色散X射线能谱(SEM-EDX)提供了表面形态与元素分布的明确信息;热重分析(TG)评定材料的热稳定性,并对改性后的材料测试了抗菌性能。本研究致力于提升碘污染物的捕获效率,旨在为环境可持续发展和公众健康保障作出贡献。通过不断优化吸附剂的性能和制备工艺,期望能够有效地降低环境中碘污染物的浓度,减少对生态系统的不利影响,并为解决当今碘污染问题提供可行的解决方案。为了研究以农业废弃物生物炭(BC)为原料制备的改性生物炭(M-X)对碘污染物的去除研究,设计论文内容工作包括:(1)通过热解法制备生物碳质材料(X-BC),并利用单因素实验探究了不同农业废弃物、不同热解温度在气态碘的氛围中吸附性能,选取具有优良吸附性能的生物炭吸附剂。当反应达到平衡后,柚皮生物炭(SP-BC300)和椰皮生物炭(CS-BC300)在热解温度为300℃时显示出对气态碘优异的吸附效果;同时本研究也选取在农业废弃物中占比较大的水稻秸秆和小麦秸秆作为生物炭的原始原料,同样在300℃的热解条件下,水稻秸秆生物炭(RS-BC300)和小麦秸秆生物炭(WS-BC300)表现出良好的吸附性能;通过吸附动力学模型分析,吸附过程符合伪二阶和Elovich吸附动力学模型,表明吸附过程的高度有序性。(2)在合成X-BC300的基础上,探讨了不同比例碱活化剂改性对吸附性能的影响。结果显示,在改性比例为1:1时,柚皮生物炭(M-SP)和1:5条件下的椰皮生物炭(M-CS)展现出了最优的气态碘吸附效果,吸附量高达2190.8mg/g和2025.3mg/g;改性比例为1:2水稻秸秆生物炭(M-RS)和改性比例为1:4小麦秸秆生物炭(M-WS)也表现出优越的气态碘捕获能力。(3)进一步评估了改性生物炭(M-RS,M-WS,M-SP,M-CS)对液态碘的吸附性能,所有样品均表现出良好的吸附性能。特别是改性椰皮生物炭(M-CS)对液态碘的去除效果最佳,吸附容量达到1226.8mg/L;(4)研究结果表明,农业废弃物来源的改性生物炭对碘污染显示出卓越的去除效果,这主要得益于静电吸附、氢键、π-π相互作用及络合反应等机制的协同作用。这些发现为环境污染处理提供了新的视角和有效材料,展示了生物炭这类材料在实际应用中的巨大潜力。更多还原

【Abstract】 The presence of iodine pollutants is considered to be a problem in modern society,with multifaceted effects on human health,soil,atmosphere and ecosystems.So far,advanced materials such as inorganic adsorbents and other inorganical-organic hybrid MOFs have achieved excellent iodine capture capabilities,and although these materials have made remarkable achievements in iodine contaminant removal,further exploration and development of more comprehensive adsorbents are needed given their preparation costs and capabilities.In this paper,a new type of adsorbent was prepared by using a variety of agricultural wastes as raw materials and impregnated with alkali solution of different concentrations for the removal of iodine pollutants.In the course of the study,the structural factors and external factors of the adsorbent were comprehensively controlled and studied to evaluate their influence on the efficiency of iodine capture.The composition characteristics of the materials were revealed by elemental analysis.The chemical and crystal structures were determined by Raman spectroscopy,Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron spectroscopy(XPS)and X-ray diffraction(XRD).Scanning electron microscopy-Energy dispersive X-ray spectroscopy(SEM-EDX)provides clear information on surface morphology and element distribution.Thermogravimetric analysis(TG)was performed to evaluate the thermal stability of the modified material,and the antibacterial properties of the modified material were tested.Based on these works,this study aims to further improve the capture capacity of iodine pollutants,and make more far-reaching contributions to the realization of environmental sustainable development and public health protection.By optimizing the performance and preparation process of adsorbents,it is expected that the concentration of iodine pollutants in the environment can be effectively reduced,the adverse impact on the ecosystem can be reduced,and a feasible solution can be provided to solve the problem of iodine pollution today.In order to study the removal of iodine pollutants by modified biochar(M-X)prepared from agricultural waste biochar(BC),the contents of this paper include:(1)Biochar material(X-BC)was prepared by pyrolysis method,and the adsorption properties of different agricultural wastes and pyrolysis temperatures in gaseous iodine atmosphere were investigated by single factor experiment,and biochar adsorbents with excellent adsorption properties were selected.When the reaction reached equilibrium,pomelo peel biochar(SP-BC300)and coconut peel biochar(CS-BC300)showed excellent adsorption effect on gaseous iodine at 300℃.At the same time,rice straw biochar(RS-BC)and wheat straw biochar(WS-BC),which accounted for a relatively large proportion of agricultural waste,were selected as raw materials of biochar in this study.Similarly,under the pyrolysis condition of300℃,rice straw biochar(RS-BC300)and wheat straw biochar(WS-BC300)showed good adsorption properties.Through the analysis of adsorption kinetics model,the adsorption process conforms to the pseudo-second-order and Elovich adsorption kinetics model,indicating that the adsorption process is highly ordered.(2)Based on the synthesis of X-BC300,the effects of different proportion of alkali activator modification on the adsorption properties were discussed.The results showed that when the modified ratio was 1:1,pomelo peel biochar(M-SP)and coconut peel biochar(M-CS)showed the best gaseous iodine adsorption effects,with adsorption capacities up to 2190.8mg/g and 2025.3mg/g at 1:5 conditions.Rice straw biochar with modified ratio of 1:2(M-RS)and wheat straw biochar with modified ratio of 1:4(M-WS)also showed superior gaseous iodine capture capacity.(3)The adsorption properties of modified biochar(M-RS,M-WS,M-SP,M-CS)for liquid iodine were further evaluated,and all samples showed good adsorption properties.In particular,the modified coconut peel biochar(M-CS)had the best removal effect on liquid iodine,and the adsorption capacity reached 1226.8mg/L.(4)The results showed that the modified biochar from agricultural waste showed excellent removal effect on iodine pollution,which was mainly due to the synergistic effect of electrostatic adsorption,hydrogen bonding,π-πinteraction and complexation reaction.These findings provide new perspectives and effective materials for environmental pollution treatment,and demonstrate the great potential of such materials in practical applications.更多还原