Study On Synthesis And Ion Sieving Performance Of Anti-swelling Titanium Carbide-alginate Composite Membrane

Membrane separation technology has become one of the most important technologies in modern separation science due to its characteristics of environmental protection,high efficiency and low energy consumption.Among them,the separation function film with nano-and sub-nano-sized membrane pores,because of its special transmission and screening behavior for molecules and ions in solution,has shown huge applications in seawater desalination,proton conduction,and energy storage.In recent years,the preparation of separation membranes using two-dimensional nanomaterials has become a cutting-edge topic in the field of membrane separation technology.Among them,the emergence of two-dimensional layered membranes is the preparation of next-generation functional thin films that accurately design membrane structures and accurately control membrane separation performance.Provided the possibility.In this paper,a new two-dimensional material Ti₃C₂T_x is selected to construct a two-dimensional layered film,and the sodium alginate modified Ti₃C₂T_x layered film is used to successfully prepare a two-dimensional layered film with controllable interlayer spacing and unique ion screening performance.Breaking through the two-dimensional layered membrane during ion selective screening,generally facing the problem of interlayer separation due to the entry of solvents,solutes,etc.,affecting the screening efficiency,changing the ion screening ability of the Ti₃C₂T_x layered membrane itself weak defects.The main results obtained are as follows:（1）A single layer Ti₃C₂T_x nanosheet with a size of 2-5μm was prepared,and a Ti₃C₂T_x layered film was prepared by a simple vacuum suction filtration method.SEM,AFM,TEM and other characterization methods prove that the membrane has a good layered structure and regular nanochannels;the experimental results show that the membrane has a certain screening ability for cations of different valence states.（2）Based on the preparation of the Ti₃C₂T_x layered film,sodium alginate was introduced into the interlayers,and a pillar structure was formed between the layers by means of calcium ion crosslinking,and the interlayer spacing was controlled at 7.4±0.2（?）,and calcium crosslinking was successfully prepared sodium alginate modified Ti₃C₂T_x layered film.On the basis of not destroying the original layered structure,the membrane simply and effectively controls the layer spacing,and greatly improves the efficiency of ion screening.The experimental results show that the calcium cross-linked sodium alginate-modified Ti₃C₂T_x layered membrane has a penetration rate ratio of 0.5M Na⁺and Al³⁺of 21:1.In a 0.5 M sodium aluminum mixed salt,the ratio of Na⁺and Al³⁺penetration rate the high reaches 52.5:1.The separation of ions with different valences is applied to the separation of ferric acid in acid wastewater.The ratio of H⁺and Fe²⁺penetration rate is 763,which can effectively separate H⁺and Fe²⁺.（3）Using the unique cross-linking properties of sodium alginate,after introducing sodium alginate into the interlayers,manganese ions are used for cross-linking,and the pillar structure is still formed between the layers.Ti₃C₂T_x layered film modified with sodium alginate.The membrane exhibits different characteristics from calcium cross-linked sodium alginate modified Ti₃C₂T_x layered membrane in ion screening.Due to the cross-linking characteristics of manganese ions and sodium alginate,a large number of hydroxyl groups are introduced between the surface and the layer with the carboxyl group,the electronegativity is increased and the characteristics of the negative electron nanofiltration membrane are exhibited.The ratio of the penetration rate of 5 g/L magnesium chloride to sodium sulfate can be up to 12.05:1.Compared with commercial nanofiltration membranes,its performance was tested.The results showed that its water flux and rejection rate of Na₂SO₄ were higher than that of commercial nanofiltration membranes,which provided a new research direction for two-dimensional layered membranes in the field of nanofiltration.