【作者】 张艳素；

【导师】 伦小秀； 豆小敏；

【作者基本信息】 北京林业大学 ， 环境科学， 2012， 硕士

【摘要】 我国高砷和高氟地下水分布广泛,同时工业活动导致的地下水砷、氟污染事故频发,经济高效的饮用水除砷、除氟技术受到广泛关注。本文对制备的铁锆复合氧化物进行了去除水中As(V)、F-的吸附性能研究及机制探讨。采用批式静态实验(如：吸附时间、pH、初始浓度、共存离子等因素的影响实验)和长期动态处理含砷含氟水效果的方法研究铁锆复合氧化物颗粒去除砷氟的性能。同时,采用EDX-Mapping、红外(FTIR)、X射线光电子能谱(XPS)、SO42-释放量等分析检测技术探讨了铁锆复合氧化物去除砷氟的机制。制备的粉末铁锆复合氧化物吸附剂为无定形结构,颗粒吸附剂的孔径分布为3.6～218μm、比表面积为95.5m2·g-1、破碎强度为22.1±2.0N、机械强度为9.1%±1.7%。铁锆复合氧化物对As(V)的去除研究结果表明,铁锆复合氧化物颗粒去除As(V)过程符合准二级动力学方程,吸附速率主要由颗粒内扩散控制；在较宽的pH范围(pH3.0～9.0)对吸附剂去除As(V)的效果影响不大；吸附As(V)的等温线很好的符合Langmuir I吸附等温线方程；实际应用中需考虑HCO3和腐殖酸对As(V)的去除影响；3.0%浓度的NaOH为最佳脱附As(V)浓度；进水As(V)浓度为500μg·L-1、SV (Space Velocity)2.0h-1,出水As(V)浓度达到10μg·L-1的穿透浓度前,总计处理2433BV (Bed Volume)的含As(V)水样。使用后的吸附剂颗粒浸出性毒性测试证实其为惰性的、可安全填埋的；As(V)主要被吸附在铁锆复合氧化物颗粒的表面,吸附过程中As(V)主要与吸附剂表面Fe-OH置换作用。铁锆复合氧化物对F-的去除研究结果表明,铁锆复合氧化物颗粒去除F-的动力学过程符合准二级动力学模型,吸附开始的0.56h内主要由膜扩散控制,0.56h后主要由颗粒内扩散控制；在pH3.5～9.0；吸附F-等温线符合Freundlich等温线模型；考虑实际水中共存离子浓度,HCO3-对吸附剂吸附F-影响；0.01mol·L-1的NaOH对吸附F-后的吸附剂脱附再生效果最佳；处理实际含氟水样时,SV分别为0.5、1.0、3.0h-1出水氟浓度超过1.0mg·L-1时,其过水床体积分别为370、239、128BV。吸附后的耗竭材料的浸出性毒性研究认为吸附剂是安全的；吸附剂的表面和内部均能吸附F-,其去除水中F-的机理主要是吸附剂表面Zr-OH与水中F-的置换作用。更多还原

【Abstract】 Arsenic and fluoride contamination in ground water are occurring in many provinces of China and the frequent industrial activities also added excessive arsenic and fluoride into groundwater. Therefore, cost-effective technology for arsenic and fluoride removal received extensive attention. Iron-Zirconium oxide adsorbent was used for arsenic and fluoride removal in this study. The batch experiments (the adsorption effects were examined under varying conditions of adsorption time, pH, initial concentration, co-existing anions, et al.) and long-term dynamic effects were used to describe the performance of arsenic and fluoride on granular of iron-zirconium oxide. The EDX-Mapping, infrared (FTIR), X-ray photoelectron spectroscopy (XPS), release of sulfate, and other analytical techniques were explored to characterization the mechanism of arsenic and fluoride on iron-zirconium oxide.The powder of Iron-Zirconium oxide adsorbent had an amorphous strcture. The pore size distribution, surface area, crushing strength and mechanical strength of granular adsorbent were3.6-218μm,95.5m2·g-1,22.1±2.0N,9.1%±1.7%, respectively.The results of arsenic removal with Iron-Zirconium oxide adsorbent revealed that:the adsorption process was well fitted by pseudo-second-order kinetic model and was controlled by intrapartical diffusion; arsenic removal would not be effected by pH at a broad range (from3.0-9.0); the adsorption isotherms were well described by Langmuir isotherm equation; considering the normal concentration of co-existing anions and HA in natural groundwater, HCO3-and HA would take into account; the best desorption concentration of NaOH for granular adsorbent was3%; with an influent concentration of500μg·L-1and SV2h-1,2433bed volumes of water was obtained before effluent water of arsenic reaching10μg·L-1; the used granular adsorbent was inert and could be safely land filled:the adsorption sites on adsorbent for arsenic occurred at the particle surface; the mechnism of arsenic(V) removal was surface hydroxyl replacement during the adsorprion process and Fe-OH sites played key roles in arsenic removal.The results of fluoride removal with Iron-Zirconium oxide adsorbent revealed that:the adsorption process was well described by pseudo-second-order kinetic model; the adsorption process was mainly controlled by film diffusion in0.56h and then controlled by intrapatical diffusion; The adsorbent performed well over a wide pH range of3.5-9.0; the adsorption isotherms were fitted by Freundlich isotherm equation; considering the normal concentration of co-existing anions and HA in groundwater, HA and HCO3-would take into account; the best desorption concentration of NaOH for granular adsorbent was0.01mol·L-1; using actual groundwater as influent, about370,239and128BV of groundwater were treated before1.0mg·L-1was reached under SV of0.5,1and3h-1, respectively; the spent granular was inert and could be safely disposed of in landfill; fluoride could get into the whole granular adsorbent; the mechanism of fluoride removal was hydroxyl replacement and Zr-OH sites played key roles in F-adsorption.更多还原