用于浓缩钛白废酸的新型PVDF/PVDF-HFP共混中空纤维膜制备
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- 英文论文题名：Preparation of novel PVDF/PVDF-HFP blend hollow fiber membrane for water treatment
- 论文作者：吴鹏 ; 蒋兰英
- 英文论文作者：WU Peng ; JIANG Lanying ; School of Metallurgy and Environment ; Central South University ; Chinese National Engineering Research Center for Control & Treatment of Heavy Metal Pollution
- 年：2016
- 作者机构：中南大学冶金与环境学院;国家重金属污染控制与处理工程研究中心;
- 论文关键词：膜蒸馏 ; 共混 ; PVDF-HFP ; 钛白废酸
- 英文论文关键词：membrane distillation ; blend ; PVDF-HFP ; titanium white waste acid
- 会议召开时间：2016-11-25
- 会议录名称：第五届全国膜分离技术在冶金工业中应用研讨会论文集
- 语种：中文
- 分类号：X788;TQ051.893
- 学会代码：LXJT
- 会议名称：第五届全国膜分离技术在冶金工业中应用研讨会
- 会议地点：中国湖南长沙
- 主办单位：中国膜工业协会、中南大学
- 学会名称：中国蓝星(集团)总公司膜科学与技术编辑部
- 页数：2
- 文件大小：90k
- 原文格式：O
- 会议级别：全国
摘要
膜蒸馏是一种新型的膜分离技术,可用于海水淡化、纯净水制备、热敏物料浓缩等方面.疏水膜作为膜蒸馏过程汽-液相平衡的界面及热、质传递的界面,对分离过程起着至关重要的作用.而含氟聚合物由于其低表面能的C—F结构,具有突出的疏水性能.硫酸法是目前我国生产钛白粉的主要方法之一,硫酸法生产钛白粉水解过程会产生大量的废酸(含H_2SO_4约20%,Fe~2+约3%),即每生产1t钛白粉,会产生7-8 t 20%的废硫酸.治理并回收利用这些废酸,是解决环保及硫酸法钛白工业发展的重要课题.膜蒸馏作为一种以物理过程为主的分离技术,既能满足对废酸的回收利用,又能降低环境污染,具有广泛的应用前景.本文以超疏水材料聚偏氟乙烯-六氟丙烯(PVDF-HFP)为第二组分聚合物与PVDF共混,以N-甲基吡咯烷酮(NMP)为溶剂,丙三醇为添加剂,通过湿法纺丝工艺制备成中空纤维膜,采用直接接触式膜蒸馏(DCMD)浓缩钛白废酸.通过相图制作探究不同共混比例条件下的成膜条件以及铸膜液稳定性.讨论了在高聚物的不同配比条件下对于膜的形貌结构、性能的影响.通过扫描电镜(SEM)、差热分析法(DSC)、接触角、孔径测试、孔隙率测试,拉伸性能测试等检测对于中空纤维膜进行一系列表征.在DCMD测试中,通过测定纯水通量来选择性能最优的PVDF/PVDF-HFP共混膜进行浓缩5%NaCl溶液以及20%的模拟钛白废酸溶液.探究在不同进料侧温度、不同流速等条件下对于膜蒸馏测试结果的影响,包括通量、截留率等.
Membrane distillation is a new type of membrane separation technology,which can be used for the preparation of seawater desalination,the preparation of purified water,and the concentration of heat sensitive materials.As the interface between vapor liquid phase equilibrium and heat and mass transfer in the membrane distillation process,hydrophobic membrane plays an important role in the separation process.Because of its low surface energy C—F structure,the fluorine containing polymer has outstanding hydrophobic property.Sulfuric acid is one of the main methods of titanium dioxide production in China at present,the production of titanium dioxide sulfuric acid hydrolysis process will produce a large number of waste acid(containing H_2SO_4 about 20%,Fe~(2+) about 3%).1 tons of titanium dioxide production will produce 7 ~ 8 tons of waste sulfuric acid concentration of 20%.As a separation technology based on physical process,membrane distillation not only can meet the recovery and utilization of waste acid,but also can reduce the environmental pollution.In this paper,using the super hydrophobic material polyvinylidene fluoride hexafluoropropylene(PVDF- HFP) as the second component polymer blend with PVDF,with N- methyl pyrrolidone(NMP) as solvent and glycerol as additive,hollow fiber membrane prepared by wet spinning process,concentratetitanium white waste acid through direct contact membrane distillation(DCMD).The film forming conditions and the stability of casting solution were also studiedby made the phase diagrams.The influence of the structure and properties of the film on the different ratio of polymer was discussed.By means of scanning electron microscope(SEM),differential thermal analysis(DSC),contact angle,pore size test,porosity test,tensile test and so on,a series of characterization of hollow fiber membrane was carried out.In the DCMD test,selected the optimal performance of the PVDF/PVDF-HFP blend membraneby test of pure water flux and then,used for concentrating sodium chloride solution(5wt%) and simulated titanium white waste acid(20wt%).The effects of different inlet temperature and flow rate on the test results of membrane distillation were tested,include flux,rejection rate and so on.
Membrane distillation is a new type of membrane separation technology,which can be used for the preparation of seawater desalination,the preparation of purified water,and the concentration of heat sensitive materials.As the interface between vapor liquid phase equilibrium and heat and mass transfer in the membrane distillation process,hydrophobic membrane plays an important role in the separation process.Because of its low surface energy C—F structure,the fluorine containing polymer has outstanding hydrophobic property.Sulfuric acid is one of the main methods of titanium dioxide production in China at present,the production of titanium dioxide sulfuric acid hydrolysis process will produce a large number of waste acid(containing H_2SO_4 about 20%,Fe~(2+) about 3%).1 tons of titanium dioxide production will produce 7 ~ 8 tons of waste sulfuric acid concentration of 20%.As a separation technology based on physical process,membrane distillation not only can meet the recovery and utilization of waste acid,but also can reduce the environmental pollution.In this paper,using the super hydrophobic material polyvinylidene fluoride hexafluoropropylene(PVDF- HFP) as the second component polymer blend with PVDF,with N- methyl pyrrolidone(NMP) as solvent and glycerol as additive,hollow fiber membrane prepared by wet spinning process,concentratetitanium white waste acid through direct contact membrane distillation(DCMD).The film forming conditions and the stability of casting solution were also studiedby made the phase diagrams.The influence of the structure and properties of the film on the different ratio of polymer was discussed.By means of scanning electron microscope(SEM),differential thermal analysis(DSC),contact angle,pore size test,porosity test,tensile test and so on,a series of characterization of hollow fiber membrane was carried out.In the DCMD test,selected the optimal performance of the PVDF/PVDF-HFP blend membraneby test of pure water flux and then,used for concentrating sodium chloride solution(5wt%) and simulated titanium white waste acid(20wt%).The effects of different inlet temperature and flow rate on the test results of membrane distillation were tested,include flux,rejection rate and so on.
引文
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