Preparation Of Antibacterial Filter Membrane By Atomizing Dispersion And In Situ Grafting Process

Due to the shortage of fresh water resources,the problem of water pollution is becoming more and more serious.The demand for clean drinking water has prompted people to improve the purification materials and techniques,so as to improve the water treatment effect.At present,the technologies applied in the field of drinking water treatment mainly include membrane purification technology,biological flocculation technology,ozone-activated carbon purification technology,among which membrane separation technology is widely used in the field of drinking water treatment due to its high efficiency and good stability.However,they are easy to be polluted by microorganisms in water in practical application,resulting in reduced purification effect,water flux and mechanical properties.Thus,endowing the filtration membrane material with long-term and stable antibacterial properties can better solve such problems.At present,the preparation methods of antibacterial materials mainly include chemical grafting,nano loading and physical addition,among which chemical grafting has the advantages and characteristics of good stability,no residue,no pollution and even dispersion.However,the common chemical grafting technology has many technical problems,such as complicated process,high water consumption and equipment maintenance cost,which restrict or hinder the development and application of the product.On the basis of the original research work,the research group in this paper has abandoned the complicated chemical processes such as soaking and dosing--drying reaction--repeated washing--drying,and explored the atomization dispersion combined with in-situ grafting technology.Through the design and development of process equipment,atomization and dispersion process and optimization of grafting reaction conditions,the antibacterial methods of in-situ atomization and dispersion grafting were studied,and the application of antibacterial products in drinking water treatment was tested.The specific work and main research results of this paper include:1.The antibacterial modification scheme of fiber membrane materials based on atomization dispersion and in-situ polymerization grafting technology was designed.By controlling the oil-free compressor in the whole process experimental device,the precursor solution was compressed into fog particles less than 3.9 m and atomized to the top of the sample table through the atomization channel.The atomization rate can be adjusted by adjusting the air flow dial at the air outlet of the atomizer,and the atomization rate can be up to 0.2 m L/min.One end of the sample table is connected with a reciprocating rod,which is controlled by a reciprocating motor that can adjust the speed,making uniform reciprocating motion and ensuring uniform and controllable atomization amount.2.In-situ grafting technology and related control technology of silicone quaternary ammonium salt on the surface of fiber filtration membrane were studied.The effects of hydrolysis time and p H value of precursor solution on antibacterial precursor solution were investigated,and the regulation mechanism was analyzed.It was found that the p H value of the precursor solution and the hydrolysis time of the precursor solution were adjusted by glacial acetic acid.The addition of glacial acetic acid can accelerate the hydrolysis of siloxane and produce a large amount of siloxane,thus accelerating the graft reaction between quaternary ammonium salt of organosilicone and the substrate of filter membrane fiber.The filtration membrane fiber for drinking water with the best graft rate and antibacterial effect was optimized,and the best modification preparation technology was as follows: the ratio of coupling agent and silicone quaternary ammonium salt antibacterial agent was 1:2,the p H of antibacterial precursor solution was 7,the hydrolysis time was 4 h,the atomization amount was 0.050 g,the heat treatment temperature was 120 ℃,and the heat treatment time was 60 min.3.Developed long-acting antibacterial composite membranes,the antibacterial properties of filtration membrane materials,intercept performance and TOC content,etc.The results showed that the antibacterial rate is more than 99% of E.coli,intercept performance is more than 94% and TOC organic matter to release a quantity to meet the "GB/T 17219-1998 Standard for Safety Evaluation of Equipment and Protective Materials for Drinking Water Transmission and Distribution" requirements.4.The germicidal performance of antibacterial composite filter film in the long-time water treatment system and its stability in the long time immersion in sodium hypochlorite solution were discussed.The results showed that the water contact Angle of the long-acting antibacterial material prepared by the technique was significantly changed after being treated with sodium hypochlorite solution for 50 h,indicating that the graft modified structure had not been significantly damaged and showed good long-term stability.After treated with circulating bacterial water for 50 times,the antibacterial property and retention property were still higher than 95%,which proved that it had good long-term antibacterial property.