改性硅砂及其吸附磷和氟的研究

发布时间：2018-06-24 21:39

  本文选题：改性硅砂 + 磷酸根　； 参考：《济南大学》2017年硕士论文

【摘要】：含磷、氟的废水是当前环境污染的重要组成部分。吸附法是去除废水中磷和氟常用的方法之一。实验通过在硅砂表面构建多孔二氧化硅包覆层,氨基功能化后再负载金属离子以制备改性硅砂,并吸附水溶液中的磷酸根和氟离子。实验还利用了氨基功能化的硅砂处理实际电镀含铜废水后再吸附磷和氟。论文为处理废水中金属离子以及磷、氟提供了新的思路。实验采用模板法与溶胶-凝胶法相结合,以正硅酸四乙酯为硅源、十六烷基三甲基溴化铵为模板剂在碱性条件下,在硅砂表面形成多孔SiO2包覆层,此包覆硅砂经N-(β-氨乙基-γ-氨丙基)甲基二甲氧基硅烷功能化并负载金属离子(Fe、Al、Cu)进行改性,得到三种改性硅砂(Fe(III)-NH2-sand、Al(III)-NH2-sand、Cu(II)-NH2-sand)。采用FTIR、氮气等温吸附和火焰原子吸收光谱等手段对改性硅砂进行了表征。实验研究了三种改性硅砂对磷和氟的吸附,探究pH值、反应温度、时间、初始离子浓度对吸附效果的影响,从而确定了最佳吸附条件。三种硅砂对磷、氟的吸附过程均符合Langmuir模型和准二级动力学方程。通过三种改性硅砂对磷进行吸附,Fe(III)-NH2-sand吸附磷酸根的最佳pH值为4,当磷酸根的离子浓度为200mg/L,吸附时间为180min,吸附温度为65℃时,最大吸附量为7.2mg/g。Al(III)-NH2-sand对磷酸根吸附的最佳pH为2,当磷酸根的离子浓度为100mg/L,吸附时间为90min,吸附温度为65℃时,最大吸附量为2.5mg/g。Cu(II)-NH2-sand对磷酸根的吸附最佳pH值为2,当磷酸根的浓度为100mg/L,吸附时间达到120min,吸附温度为65℃时,最大吸附量为2mg/g。三种改性硅砂吸附氟离子,实验表明Fe(III)-NH2-sand吸附氟离子的最佳pH值为2,当氟离子的浓度为120mg/L,吸附时间达到90min,吸附温度为65℃时,最大吸附量为5.1mg/g。Al(III)-NH2-sand对氟离子吸附的最佳pH为5,当氟离子的浓度为200mg/L,吸附时间为90min,吸附温度为65℃时,最大吸附量为4.3mg/g。Cu(II)-NH2-sand对氟离子的吸附最佳离子pH值为4,当氟离子的浓度为100mg/L,吸附时间达到60min,吸附温度为65℃时,最大吸附量为1.2mg/g。三种改性硅砂对于磷和氟的的吸附效果对比发现:Fe(III)-NH2-sandAl(III)-NH2-sandCu(II)-NH2-sand。实验利用氨基功能化硅砂对实际电镀含铜废水进行吸附,并将吸附后的硅砂分别用于去除磷酸根和氟离子,经过四次连续吸附后,溶液中的磷、氟分别达到了国家排放要求,实现了一种双重净化废水的模式。
[Abstract]:Wastewater containing phosphorus and fluorine is an important part of current environmental pollution. Adsorption is one of the commonly used methods to remove phosphorus and fluorine from wastewater. In this experiment, porous silica coating layer was constructed on the surface of silica sand. After amino functionalization, metal ions were loaded to prepare modified silica sand, and phosphate and fluorine ions were adsorbed in aqueous solution. Amino-functionalized silica sand was used to treat copper-containing wastewater and then to adsorb phosphorus and fluorine. This paper provides a new idea for the treatment of metal ions, phosphorus and fluorine in wastewater. In this experiment, a porous Sio _ 2 coating layer was formed on the surface of silica sand with tetraethyl orthosilicate as silicon source and hexadecyltrimethylammonium bromide as template under alkaline conditions. The coated silica sand was functionalized by N- (尾 -aminoethyl- 纬 -aminopropyl) methyl dimethoxy silane and modified with metal ions (Fe (III) -NH _ 2-NH _ 2-sand Al (III) -NH _ 2-sandU Cu (II) -NH _ 2-sand). The modified silica sand was characterized by FTIR, nitrogen isothermal adsorption and flame atomic absorption spectrometry. The effects of pH, reaction temperature, time and initial ion concentration on the adsorption of phosphorus and fluorine were studied. The adsorption process of phosphorus and fluorine by three kinds of silica sand is in accordance with Langmuir model and quasi second order kinetic equation. The optimum pH value of phosphate adsorbed by three kinds of modified silica sand is 4. When the ion concentration of phosphate is 200 mg / L, the adsorption time is 180 min and the adsorption temperature is 65 鈩，

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