基于羟基氧化铁的超导磁吸附分离技术除磷研究

发布时间：2018-02-02 18:51

本文关键词： 羟基氧化铁磷吸附解吸超导磁分离回收　出处：《东华理工大学》2017年硕士论文　论文类型：学位论文

【摘要】：磷是造成水体富营养化问题的主要原因,但同时,磷也是重要的矿产资源,研究如何回收废水中的磷元素具有重要的实际意义。目前污水除磷过程强调污染处理,而忽视了磷的资源化,进而产生大量含磷污泥。本课题结合超导磁分离技术,提出利用羟基氧化铁磁性吸附剂进行废水除磷和磷资源化回收的工艺。本课题采用共沉淀法制备出羟基氧化铁,筛分得到平均粒径D50为36.47μm、40.74μm、58.68μm(T1、T2、T3)的三种吸附剂,并进行表征分析。结果表明吸附剂为无定形羟基氧化铁,表面疏松多孔,且符合弱磁性物质特征。Langmuir和Freundlich等温吸附模型均能较好地描述羟基氧化铁对磷的吸附行为,T1-T3样品理论饱和吸附量分别为18.74mg/g、19.19mg/g和19.56mg/g。出水磷浓度随羟基氧化铁投加量升高而减少,初始磷浓度为2.0mg/L和5.0mg/L时,投加量分别为2g/L和4g/L可达到一级A标准。T1样品超导磁分离效果最佳,穿透柱体积为1087个柱体积。磁分离出水磷浓度均低于0.5mg/L,磷去除率最大为92.5%。磷的解吸率随NaOH解吸液浓度增加而增加,当NaOH浓度为1.5mol/L时,磷解吸率为98.57%。以CaCl2为沉淀剂,当n(Ca:P)=6.68时,磷回收率达到91.23%,回收产物磷含量达到40.03%(以P2O5计)。在上述基础上,本课题通过共沉淀法制备Fe_3O_4磁核,分别包覆不同比例的羟基氧化铁,得到H1-H4 Fe_3O_4@FeOOH吸附剂,并进行表征分析。XRD图谱Fe_3O_4的峰强度随Fe_3O_4比例下降而逐渐减弱。红外光谱显示吸附剂表面-OH基团随Fe_3O_4比例增加而减小。XPS能谱显示吸附剂表面铁氧比例和不同价态铁比例接近理论值。带磁核的吸附剂具有强磁性。随着吸附剂中Fe_3O_4比例的增加,吸附剂的饱和吸附量由11.67mg/g逐渐减小到4.55mg/g,且污水对磷的吸附具有抑制作用。为使生活污水达到一级A标准,应投加2g/L H1、3g/L H2、3.5g/L H3或4g/L H4吸附剂。在投加量均为4g/L时,在保证污水达到一级A标准的前提下,H1-H4吸附剂分别可以重复吸附4、3、2、1次。超导磁分离实验结果表明:增大吸附剂磁性和降低流速有助于增大穿透体积。四种吸附剂解吸率相近,均大于98%。XRD分析显示回收产物主要成分为HAP。产物磷含量为38.25%(以P2O5计),回收率达90%以上。利用600mm口径超导磁分离设备估算污水处理量和处理成本:污水处理能力约为6.86×106t/年,处理成本约为2.44元/t。
[Abstract]:Phosphorus is the main cause of eutrophication, but at the same time, phosphorus is also an important mineral resource. It is of great practical significance to study how to recover phosphorus from wastewater. At present, the process of phosphorus removal from wastewater emphasizes the treatment of pollution, but neglects the utilization of phosphorus. Thus, a large amount of phosphorous sludge was produced. This project combined with superconducting magnetic separation technology. The technology of removing phosphorus from wastewater and recycling phosphorus by magnetic adsorbent of ferric hydroxide was put forward. In this paper, ferric hydroxide was prepared by co-precipitation method, and the average particle size D50 was 36.47 渭 m. The three adsorbents of 40.74 渭 m 58.68 渭 m T1T1T2T2T3) were characterized and analyzed. The results showed that the adsorbent was amorphous iron hydroxide with porous surface. The adsorption behavior of ferric hydroxide on phosphorus can be well described by the isothermal adsorption model of Freundlich and Langmuir. The theoretical saturated adsorption capacities of T1-T3 samples were 18.74 mg / g 19.19 mg / g and 19.56 mg / g, respectively. When the initial phosphorus concentration is 2.0 mg / L and 5.0 mg / L respectively, the superconducting magnetic separation of samples with the dosage of 2 g / L and 4 g / L can reach the first A standard. T1. Through the column volume of 1087 column volume. The magnetic separation of water phosphorus concentration is less than 0.5 mg / L, the maximum phosphorus removal rate is 92.5. The phosphorus desorption rate increases with the increase of NaOH desorption concentration. When the concentration of NaOH was 1.5mol / L, the phosphorus desorption rate was 98.57.The recovery of phosphorus reached 91.23% when CaCl2 was used as precipitant and the concentration of CaCl2 was 6.68. The phosphorus content of the recovered product reached 40.03 (calculated as P _ 2O _ 5). On the basis of above mentioned, Fe_3O_4 magnetic nuclei were prepared by co-precipitation method and coated with different proportions of ferric hydroxide respectively. H1-H4 Fe_3O_4@FeOOH adsorbent was obtained. The peak intensity of Fe_3O_4 decreased with the decrease of Fe_3O_4 ratio. The IR spectra showed that the -OH group on the adsorbent surface increased with the increase of Fe_3O_4 ratio. The decrease of. XPS energy spectrum shows that the ratio of iron and oxygen on the surface of adsorbent and the ratio of iron in different valence states are close to the theoretical value. The adsorbent with magnetic nucleus has strong magnetic properties, and the ratio of Fe_3O_4 in the adsorbent increases with the increase of the ratio. The saturated adsorption capacity of adsorbent decreased from 11.67 mg / g to 4.55 mg / g, and the adsorption of phosphorus was inhibited by sewage. 2 g / L H 1 + 3 g / L H 2 + 3.5 g / L H 3 or 4 g / L L H 4 adsorbents should be added. When the dosage is 4 g / L, the wastewater can meet the first A standard. The results of superconducting magnetic separation experiments show that increasing the magnetic properties of the adsorbent and decreasing the velocity of flow can increase the penetrating volume, and the desorption rates of the four adsorbents are similar. XRD analysis showed that the main component of the recovered product was HAP.The phosphorus content of the product was 38.25 (P _ 2O _ 5). The recovery rate is over 90%. The sewage treatment capacity and cost are estimated by using 600mm superconducting magnetic separation equipment. The sewage treatment capacity is about 6.86 脳 10 ~ 6 t / year. The processing cost is about 2.44 yuan / t.
【学位授予单位】：东华理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：X703

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