Construction Of Hydrophilic Coating On Polypropylene Membrane Based On Hydrophobic Interaction And Its Uranium Extraction Performance

With the development of the nuclear industry,an increasing amount of radioactive wastewater containing uranium is being produced.If it is allowed to be discharged into the environment,it will cause serious harm to the ecological environment and human health.Therefore,the treatment of uranium-containing wastewater is a crucial research direction supported by nuclear environmental protection and ecological safety.Currently,numerous technologies have been developed to treat wastewater containing uranium,and adsorption methods have garnered significant attention owing to their advantages such as ease of operation and low energy consumption.Polyolefin-based adsorption materials are often used in the treatment of wastewater containing uranium because of their low cost,good chemical stability,and mechanical strength.However,due to the inert surface of polyolefins and the lack of reactive groups,methods such as plasma grafting and high-energy radiation grafting are commonly used to introduce functional groups,which often destroy the molecular structure of polyolefins and reduce their mechanical strength.Therefore,it is urgent to develop mild modification methods to endow them with adsorption properties.Based on this,the paper proposes a non-chemical surface modification method induced by hydrophobic interaction.This method does not destroy the chemical structure of polyolefins but provides numerous uranium adsorption sites.Additionally,it endows the polyolefins with antibacterial and other functional properties.The primary focus of the research includes the contents and results of this method.（1）Preparation of hydrophobically induced hydrogen bonding self-assembled coatings and their uranium extraction propertiesBy using a gentle and simple layer-by-layer self-assembly approach,polypropylene（PP）porous membranes can offer abundant adsorption sites for selectively extracting uranium from nuclear waste water containing uranium.Lysozyme has been selected as a pre coating due to its strong hydrophobic interaction with PP membranes.Lysozyme and phytic acid are self-assembling components bonded by hydrogen,and both have a strong affinity for binding uranium.Due to the excellent controllability of this method,it is possible to linearly adjust the content and thickness of the lysozyme and phytic acid coating to obtain the optimal uranium affinity membrane.This membrane can have an adsorption capacity of up to 90.07 mg-U/g-membrane（2143.83 mg-U/g-coating）.Additionally,lysozyme provides the PP film with outstanding properties of antifouling,antibacterial,and anti-adhesion.Even in the presence of bacteria and model pollutants,the modified membrane is able to maintain an adsorption capacity of over 85%.In dynamic adsorption experiments,uranyl ions can more easily come into contact with the adsorption sites.Thus,the adsorption capacity increases with the increase in flow rate and the number of layers.This has broad practical applications.（2）Preparation of hydrophobically induced in situ mineralized coatings and their uranium extraction propertiesA hydrophilic coating,based on trivalent iron salicylaldoxime（SA）,was applied to the surface of a PP film through co-deposition.Simultaneously,in-situ mineralization occurred resulting in the formation ofβ-Fe OOH.Salicylaldehyde oxime andβ-Fe OOH contain numerous hydroxyl groups that can chelate with uranium.Additionally,β-Fe OOH exhibits outstanding photocatalytic performance and can reduce uranium under light induction.It combines traditional adsorption methods with photocatalytic technology in order to enhance the uranium extraction performance of modified PP films.Through investigation into the effects of the p H of the deposition solution,the mass ratio of SA to Fe³⁺,and the deposition time on the surface hydrophilicity of the modified PP film,it was determined that the ideal deposition conditions were a p H of 6,a SA to Fe³⁺mass ratio of2:20,and a deposition time of at least 8 hours.The prepared membrane exhibits good chemical stability,antibacterial properties,and recyclability.Under light conditions,the modified PP film can extract uranium from a 50 m L uranium solution（p H=6,50 mg/L）and reach saturation within 1 hour.The equilibrium extraction amount is as high as 170.21mg/g.In addition,uranium was extracted using a dynamic photocatalytic device,achieving an extraction rate of 98.36%.This indicates its potential for valuable applications in real-life scenarios.