【作者】 王静；

【导师】 朱晓丽； 焦文涛；

【作者基本信息】 西北大学 ， 工程硕士（专业学位）， 2020， 硕士

【摘要】 抗生素由于其效果好、广谱抗菌等特点而被广泛使用。未被吸收利用及丢弃的抗生素会通过多种渠道进入到环境中,导致其在环境中有大量检出。近年来磺胺类抗生素在我国的土壤、地表水及地下水中的检出率较高,因其难降解并且处理工艺有限,对生态环境、人类健康等产生了诸多不良影响。如何有效去除或降低抗生素类污染物对环境的危害已经引起了广泛关注。基于废物利用的生物炭技术不仅可以避免环境污染,还可以实现废弃物资源化的目标。目前,关于防控磺胺类抗生素向地下水环境迁移方面的研究,尤其是利用固体废弃物阻控磺胺类抗生素的研究十分有限,难以支撑再生水补充地下水源中污染风险的防控。因此,本文针对固体废弃物经过炭化后的新产品是否可以有效提升对磺胺类抗生素的吸附及相关机理进行了研究。选取3种生活中常见的固体废弃物（牛粪、茄子杆和煤矸石）为原料制成单一固废炭材料对水溶液中的磺胺二甲嘧啶（SMZ）进行吸附,并通过吸附剂添加量、溶液酸碱度及离子强度的单因素影响实验确定最优的吸附条件。将凹凸棒石废脱色土（SDE）在300、400、500℃下高温碳化成复合材料（分别记作A/C-300、A/C-400、A/C-500）,在最佳吸附条件下利用上述6种固废炭材料对SMZ进行吸附。通过动力学、等温吸附和热力学研究6种炭材料对SMZ的吸附性能和吸附特性。并通过元素分析仪、扫描电镜（SEM）、透射电镜（TEM）、Zeta电位分析仪、比表面积和孔体积分析仪、红外光谱（FT-IR）及Boehm滴定等手段对吸附材料进行了表征,探讨了其对SMZ的吸附机理。单一固废炭材料的吸附结果表明,牛粪炭、秸秆炭和煤矸石炭对SMZ的吸附在24h时基本到达平衡。三种炭材料对SMZ的吸附动力学特性可以用准二级动力学模型很好地模拟,R²在0.996～0.999之间,吸附速率随着炭材料上的有效吸附位点的减少而减小。该反应过程主要分为膜扩散、颗粒内扩散和平衡3个阶段。Freundlich模型能更好地拟合该反应数据,R²在0.993～0.999之间,主要为物理吸附,是自发的放热反应。在p H值为4左右,炭材料添加量为0.05 g且不添加无机盐的条件下,吸附效果最好。三种炭材料的最大吸附量从大到小排序为牛粪炭(19.64 mg·g^-1)>煤矸石炭(12.06 mg·g^-1)>秸秆炭(9.16 mg·g^-1)。SMZ在三种炭材料上的吸附机制主要有:氢键作用、多分子层的静电吸附和孔隙填充等。其中,静电吸附为主要吸附机制。牛粪炭吸附性能最好主要是由于其含氧官能团较为丰富、负电荷较多、比表面积和孔容较大。复合材料（A/C）吸附结果表明,其吸附过程与单一固废炭材料的过程相似,准二级动力学方程和Freundlich方程也能很好的模拟SMZ在复合固废炭材料上的吸附。然而,SMZ在复合材料上的吸附属于吸热反应,升高温度有利于该反应进行。A/C-300的吸附性能相对最好,最大吸附量为53.19 mg·g^-1。吸附机理如下:1)静电吸附:在p H=4时,A/C表面带负电荷,可以吸附呈阳离子状态的SMZ;2)氢键:A/C上的羟基与SMZ的苯环反应生成氢键;3)π-πEDA相互作用:磺酰胺基和氨基作为电子受体,A/C表面上的碳原子作为电子供体,形成π-πEDA相互作用;4)疏水作用:A/C表面分布着一定数量的疏水位点,产生疏水效应,吸附疏水性的SMZ。其中,氢键作用和π-πEDA作用可能是此吸附过程的主要机制。相关研究结果可为再生水回灌过程中防控磺胺类抗生素向地下水迁移提供了一种新的阻控材料,为“固体废弃物资源化”提供了一种新的新思路。更多还原

【Abstract】 Antibiotics are widely used due to their good effect and broad-spectrum antibacterial characteristics,which leads to a large number of antibiotics entering the environment through various ways.In recent years,the detection rate of sulfanilamide antibiotics in soil,surface water and groundwater in china is high.Because of its difficult degradation and limited treatment technology,it has a lot of adverse effects on the ecological environment and human health.How to effectively remove or reduce the harm of antibiotic pollutants to the environment has aroused widespread concern.Biochar technology based on waste utilization can not only avoid environmental pollution,but also achieve the goal of waste recycling.At present,the research on the prevention and control of sulfonamide migration to groundwater environment,especially the use of solid waste to prevent and control sulfanilamide antibiotics is very limited,and it is difficult to support the prevention and control of pollution risk in reclaimed water supplement groundwater source.Therefore,in this paper,whether the new products after carbonization of solid waste can effectively enhance the adsorption of sulfonamides and related mechanisms were studied.Three kinds of common solid wastes（cow dung,eggplant stem and coal gangue）were selected as raw materials to make adsorbent to adsorb sulfamethazine（SMZ）in water.The optimal adsorption conditions were determined by the single factor experiment of the amount of adsorbent,p H value of solution and ionic strength.The composite solid waste carbon materials（A/C-300,A/C-400 and A/C-500）were carbonized from attapulgite waste decolorizing soil（SDE）at 300,400 and 500℃at high temperature.The SMZ was adsorbed by the above six solid waste carbon materials under the optimal adsorption conditions.The adsorption properties and adsorption properties of six carbon materials for SMZ were studied by kinetics,isothermal adsorption and thermodynamics.The adsorption materials were characterized by elemental analysis,scanning electron microscopy（SEM）,transmission electron microscopy（TEM）,zeta potential analyzer,specific surface area and pore volume analyzer,FT-IR and Boehm titration.The adsorption results of single solid waste carbon showed that the adsorption of SMZ by cow dung carbon,straw carbon and coal gangue carbon reached equilibrium at 24 h.The adsorption kinetics of SMZ on three kinds of carbon materials can be well simulated by quasi second order kinetic model.R²is between 0.996 and 0.999,and the adsorption rate decreases with the decrease of effective adsorption sites on carbon materials.The reaction process can be divided into three stages:membrane diffusion,intra particle diffusion and equilibrium.Freundlich model can better fit the reaction data.R²is between 0.993 and 0.999,which is mainly physical adsorption and spontaneous exothermic reaction.Under the condition of p H value of 4,carbon material dosage of 0.05 g and no inorganic salt,the adsorption effect is the best.The order of the maximum adsorption capacity of the three carbon materials was cow dung carbon(19.64 mg·g^-1)>coal gangue carbon(12.06 mg·g^-1)>straw carbon(9.16 mg·g^-1).The adsorption mechanisms of SMZ on the three kinds of carbon materials mainly include hydrogen bonding,electrostatic adsorption of multi molecular layer and pore filling.Electrostatic adsorption is the main adsorption mechanism.The best adsorption performance of cow dung carbon is mainly due to its rich oxygen-containing functional groups,more negative charges,larger specific surface area and pore volume.The results show that the adsorption process of composite solid waste carbon（A/C）is similar to that of single solid waste carbon.The quasi second order kinetic equation and Freundlich equation can also well simulate the adsorption of SMZ on the composite solid waste carbon material.However,the adsorption of SMZ on the composites belongs to endothermic reaction,which is beneficial to the reaction with increasing temperature.The adsorption capacity of A/C-300 was the best,and the maximum adsorption capacity was 53.19 mg·g^-1.The adsorption mechanism is as follows:1)electrostatic adsorption:the SMZ presented as cationic state can be adsorbed by A/C with negative surface charges by electrostatic interaction at p H=4;2)H-Bonding:hydroxyl groups on A/C can react with phenyl rings of SMZ to form hydrogen bonds;3)π-πEDA interactions:sulfonamide and amino groups on SMZ acted as electron acceptors and carbon atoms on A/C surface acted as electron donors to formπ-πEDA interactions;4)Hydrophobic interaction:A/C surface distributes a certain number of hydrophobic sites,which can produce hydrophobic effect and adsorb hydrophobic SMZ.Among them,the H-Bonding andπ-πEDA interactions may be the main mechanisms in the adsorption process.The work provides a new adsorption material for the inhibition of sulfonamide antibiotics,and provides a new idea of"treating pollution by waste".更多还原