Knowledge Management System Of Institute of process engineering,CAS
铁碳微电解是利用金属腐蚀原理，形成原电池对废水进行处理的工艺，又称内电解法。铁碳微电解可实现对废水中的磷、COD、重金属等污染物得同步处理，是一项被广泛研究与应用的废水处理技术。目前主要商业填料普遍采用铁基材料（铁屑或铁粉）与固体碳基材料（炭粉、煤炭、活性炭等）通过物理混合堆填或焙烧成型（规整化）的制备方式，这种铁碳固体颗粒或粉体的物理混合物，在废水处理过程中存在反应速率慢、污染物去除效率低等问题而影响废水的处理效果和效率，且长期使用易于钝化和板结，造成实际应用中填料更换频繁增加运行成本，制约了微电解技术的推广应用。本课题针对目前微电解填料制备技术存在的共性问题，提出了一种新型铁碳微电解填料的制备工艺，通过改变铁碳活性组分的结合方式，在铁基材料表面均匀沉积碳微粒，建立微尺度规模的铁碳一体化微电解体系，以增加单位体积内微原电池数量及铁-碳接触面积，实现对污水污染物高效的脱除性能。本论文主要从技术原理、工艺优化、应用评价三个方面对新型铁碳微电解填料制备技术的开发与应用进行研究，主要研究内容和结果如下：（1）新型微电解填料的制备与表征。以焦油为碳源，以海绵铁为铁基材料，通过均质化-碳化-成型新方法制备新型铁碳一体化微电解填料，采用扫描电镜与能谱分析仪（SEM-EDS）、X射线衍射仪（XRD）和元素分析仪等技术手段对各关键处理阶段填料进行表征分析，结果表明碳化处理过程产生大量碳微粒均匀附着于铁基材料表面及内部孔道，利于增加铁碳有效接触面积，通过深度还原提高填料中单质铁的含量以提高微原电池数量，使得新型填料比传统填料表现出较高的除磷性能。（2）新型微电解填料制备工艺优化实验研究。采用单因素法分别开展了新型填料的碳化和成型参数优化实验，通过考察焦油比、碳化/焙烧温度以及恒温时间对碳化/焙烧过程的影响规律，获取了优化的操作参数；在焦油/铁比0.3、室温升至950 ℃恒温0 min的碳化处理条件，以及粘结剂30%、900 ℃恒温焙烧90 min的成型处理条件下制备的填料对磷脱除率达98%，出水磷浓度达到GB18918-2002要求A类城镇污水中磷排放标准。（3）新型微电解填料处理废水应用评价。以污泥厌氧消化后脱水滤液和工业废水为处理对象，选择优化条件下制备的新型铁碳填料进行应用评价实验，采用单因素法考察了操作条件对填料脱除磷及COD性能的影响规律，结果表明新型铁碳填料可实现对磷和COD的同步脱除，提高固液比和曝气量、降低初始pH、延长反应时间可有效提高填料对污染物的处理性能，优化评价条件下出水TP均可达到排放标准。;Iron-carbon micro-electrolysis is a wastewater treatment process basing on the corrosion of iron, which is also called internal electrolysis. Iron-carbon micro-electrolysis technology can simultaneously remove pollutants from water， such as phosphorus, COD and heavy metals, and has been widely studied and applied. The current commercial filler is a physical mixture of solid particles or powders, which is based on iron-based materials (iron scraps or iron powder) and solid carbon-based materials (carbon powder, coal, activated carbon, etc.) and is prepared by physical mixing or by roasting (regularization). When applied in wastewater treatment, commercial filler shows disadvantage of slow reaction rate and low pollutant removal efficiency. And iron carbon filler is easy to passivate and compact after long-term use, which leads to frequent replacement of fillers and increases operating costs. The above problems restrict the promotion and application of micro-electrolysis technology. A novel preparation process of iron-carbon micro-electrolytic filler is proposed to overcome these issues. This paper establishes a micro-scale iron-carbon micro-electrolysis system by depositing carbon particles on the surface of iron substrates. It is the new bonding mode of iron-carbon that increases the number of micro-primary cells per unit volume and the contact between iron and carbon. The efficient removal of sewage pollutants is achieved. This thesis includes three aspects: technical principle, process optimization and application performance. And the preparation and application of novel iron-carbon micro-electrolytic filler have been investigated. The major findings are listed as following:(1) Preparation and characterization of new micro-electrolytic fillers. Using tar as carbon source and sponge iron as iron-based material, a novel process was proposed to prepare iron-carbon filler. Preparation procedures of the novel process include homogenizing, carbonizing and forming. The products are characterized by SEM-EDS and XRD and Elemental analyzer. The results show that, carbon are deposited on the surface and internal pores of sponge iron during carbonizing process, increasing the contact between iron and carbon. The content of elemental iron in the filler increases after deep reduction, contributing to increase of the number of micro-primary batteries. Finally, the new filler exhibited excellent phosphorus removal performance compared to conventional iron-carbon filler (Fe/C). (2) The preparation conditions are optimized. The carbonization and forming parameters optimization experiments of new fillers were carried out by single factor method. Optimal parameters are obtained by investigating the effect of ratio of tar to sponge iron, carbonization/roasting temperature and holding time on the carbonization/roasting process. When mass ratio of tar to sponge iron, carbonizing temperature, holding time, binder mass fraction, roasting temperature and time are set as 0.3, 950 °C, 0 min, 30%, 900 °C and 90 min, respectively, the synthetic Fe-C filler will exhibit an optimized phosphorus removal performance, giving a removal efficiency as high as 98% , which meets with discharge standard of phosphorous– contained sewage.(3) Treatment of wastewater by novel micro-electrolytic filler. Novel iron carbon fillers were prepared under optimized conditions and were used to treat dewatering filtrate from sludge hydrothermal-anaerobic digestion and industrial wastewater. The effect of operating conditions on the removal of phosphorus and COD by fillers was investigated by single factor method. The results show that phosphorus and COD can be removed simultaneously. The removal performance of the filler on the contaminant can be effectively improved by increasing the solid-liquid ratio and aeration rate, reducing the initial pH, and prolonging the reaction time. After treatment under optimal evaluation conditions, the effluent phosphorus meets with discharge standard of phosphorous– contained sewage.
|杜利军. 新型铁碳填料的制备与废水除磷性能研究[D]. 中国科学院大学,2019.|
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