A method for preparing ion-exchange fibers by ultraviolet light grafting

Abstract

The invention discloses a method for preparing an ion exchange fiber by ultraviolet grafting. The method comprises the steps of cleaning a polypropylene knitmesh, extracting the polypropylene knitmesh with acetone, taking the polypropylene knitmesh out for drying, soaking the extracted polypropylene knitmesh in an acetone or alcohol solution with 10-30wt% of benzophenone, taking the polypropylene knitmesh out after 10-30 min for natural airing in a dark place, putting the aired polypropylene knitmesh in a quartz tube with grafting reaction liquid, removing oxygen in a test tube by supplying nitrogen, carrying out reaction for 30-120 min under ultraviolet irradiation, and finally carrying out water washing, acetone extraction and drying to obtain the ion exchange fiber grafted with a carboxyl functional group on the surface. A preparation route and a method which are low in equipment investment, simple in technology, energy-saving and efficient and have no environmental pollution are established, and the ion exchange fiber with the characteristic of efficiently absorbing heavy metal ions is obtained.

Description

technical field [0001] The invention relates to the technical field of ion exchange materials and surface modification of polymer materials, in particular to a method for preparing ion exchange fibers by ultraviolet light grafting. Background technique [0002] Ion exchange fiber is a new type of fibrous ion exchange material. It not only has the adsorption and separation capabilities of ion exchange resins, but also has the characteristics of fibers. It is a functional material with research and development prospects. Compared with traditional granular ion exchange resins, ion exchange fibers generally have a diameter of 20 to 300 μm, large specific surface area, short mass transfer distance, fast adsorption and desorption, and large adsorption capacity, and can be used in various forms, such as fiber , staple fibers, fabrics, non-woven fabrics, felts, nets, etc., for practical purposes in different ways. Among many water treatment methods, ion exchange is the most economi...

AI Technical Summary

Problems solved by technology

For example, in the patent CN1607213A, UV light is not directly irradiated on the surface of the polymer material but is irradiated on the photosensitizer by one-step method, and the polymer material is placed in the volatile gas of the photosensitizer or immersed in the inert organic solution or aqueous solution of the photosensitizer. Grafting modification by free radical reaction, this method uses baffles to prevent polymer materials from being irradiated by ultraviolet light, and uses the photosensitizer excited by ultraviolet light to diffuse to the surface of the substrate, and then induces grafting of monomers, but because the reaction space is too large Factors such as large factors lead to low grafting efficiency and low monomer utilization; and the two-step method of the patent CN1607214A, the first step is to irradiate the volatile gas of the photosensitizer or the inert organic solution of the photosensitizer by ultraviolet light, and the macromolecule The free radical reaction on the surface of the material introduces dormant radicals, and the second step is to carry out graft polymerization with grafted monomers. This way, the polymer material with dormant free radicals on the surface and the grafted monomers are contacted in a small reaction space. , compared with the one-step method, the grafting rate has been improved, but it is still relatively low, and the operation is complicated, and the dormant base on the surface is easily lost in the air, which is not conducive to practical application; compared with the above two methods, the patent CN102493187A proposes to directly Mix the functional monomer and the initiator, add the crosslinking agent, use ultrasonic vibration to dissolve, then evenly drop on the surface of the polypropylene fiber, and place it under ultraviolet light to obtain the polypropylene ion chelating fiber. The method is simple to operate, and the grafting rate can reach 230%. However, this method cannot overcome the influence of light and dark areas, and the surface of the material is not evenly grafted. Moreover, according to the data of its adsorption capacity, its maximum adsorption capacity is very low, which is far from satisfying Ion Exchanger Requirements

[0006] In summary, the methods for grafting by ultraviolet irradiation have the following problems: light and dark areas, low grafting rate, uneven grafting on the surface

Due to these limitations, it is impossible to obtain graft materials with high grafting efficiency and good adsorption performance, and cannot meet the performance requirements of ion exchange fibers as adsorbent materials, so there is no practical application value.

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