基于磁性Fe–MOF掺杂纳米银环保复合防污剂的制备及其性能

Preparation and Properties of an Environmental Friendly Composite Antifouling Agent Based on Magnetic Fe-MOF Doped Nano-silver

目的研发新型环保防污涂料,在保证海洋防污效果的基础上,尽量减少海洋防污剂的使用量和避免因表面涂层脱落而带来的重金属污染等问题。方法成功制备了2种基于金属有机框架材料(MOF)掺杂纳米银的复合防污剂〔Ag/PDA–Fe–MOF(700℃)、Fe_(3)O_(4)@Fe–MOF@Ag〕。采用水热法制备的Fe–MOF呈正八面体形态,尺寸均匀,约为2~3μm。经过700℃真空退火处理后整体尺寸缩小,达到纳米级别,约为100~200 nm,通过分析X射线衍射图谱证明无磁MOF经过退火后转变为强磁性的Fe_(3)O_(4)。另外,采用共沉淀法和水热法合成的Fe_(3)O_(4)@Fe–MOF也呈正八面体结构,尺寸差别较大,较大的颗粒长度为5~6μm,较小的颗粒粒径仅为400 nm左右。后续通过聚多巴胺和还原法成功在2种颗粒表面组装纳米Ag颗粒,质量分数约为0.66%。结果抑菌圈结果显示,Ag/PDA–Fe–MOF(700℃)对Bacillus subtilis的生长仅有轻微抑制作用;而Fe_(3)O_(4)@Fe–MOF@Ag表现出显著的杀菌效果,抑菌区直径约为1.5 cm。进一步使用荧光染色法考察5%、20%(质量分数)的Fe_(3)O_(4)@Fe–MOF@Ag与聚二甲基硅氧烷(PDMS)杂化制得的涂料的防污性能,发现磁处理后样品的细菌附着情况明显优于未处理样品的细菌附着情况,尤其是20%的Fe_(3)O_(4)@Fe–MOF@Ag复合涂料磁处理后浸泡7 d表面未有活菌附着。结论利用磁性填料的特性使防污剂富集在涂层上表面,降低防污剂的使用量,并减轻防污涂料产生的微塑料污染问题。

The basis of ensuring the marine antifouling effect,minimizing the use of marine antifouling agents,and avoiding the problem of heavy metal pollution caused by the peeling of the surface coating are the key issues to be solved by the research and development of new environmentally friendly antifouling coatings in this paper.In this paper,a new concept of the marine antifouling agent was proposed.A composite antifouling coating was formed by using a magnetic marine antifouling agent and resin-based coating material.The magnetic treatment method was adopted to make sure that most of the magnetic antifouling agent gathered on the surface of the coating,which effectively avoided the problem that the antifouling agent cannot play a bactericidal role inside the coating.Two antifouling agents based on magnetic metal-organic framework(MOF)material doped nanosilver composites(Ag/PDA-Fe-MOF(700℃)and Fe_(3)O_(4)@Fe-MOF@Ag)were successfully prepared in this work.The Fe-MOF particles prepared by the hydrothermal method were octahedrons with uniform size and a side length of 2-3μm.However,after the 700℃vacuum annealing treatment,the particles shrank to nano scale,and the side length was about 100-200 nm.The results of the X-ray diffraction pattern showed that the non-magnetic MOF was transformed into strong magnetic Fe_(3)O_(4) after annealing which caused the changes in particle size.In addition,Fe_(3)O_(4)@Fe-MOF was synthesized by co-precipitation and hydrothermal methods.The particles of Fe_(3)O_(4)@Fe-MOF were also octahedrons,with some smaller impurities on the particle surface because of uneven heating.The larger particles length was 5-6μm,and the smaller particles were only about 400 nm.Then nano-Ag particles were successfully assembled on the surface of the two particles through polydopamine and reduction method,with a mass ratio of about 0.66%.The inhibitory zone method and the fluorescence staining method were both adopted to invest the bacteriostatic ability of the composite materials.The inhibitory zone method results showed that the Ag/PDA-Fe-MOF(700℃)composite possessed little inhibitory effect on the growth of Bacillus subtilis,while the Fe_(3)O_(4)@Fe-MOF@Ag composites exhibited excellent bacteriostatic performance,the bacteriostatic circle diameter was about 1.5 cm.The fluorescence staining method was further used to investigate the content of 5wt.%and 20wt.%Fe_(3)O_(4)@Fe-MOF@Ag in PDMS.It was found that the anti-bacterial adhesion properties of magnetically treated samples were significantly better than that of untreated samples,especially 20wt.%Fe_(3)O_(4)@Fe-MOF@Ag composite coatings.There was no living bacteria attached to the surface of the composite coatings which were soaked in Bacillus subtilis culture medium for 7 days after magnetic treatment.From above mentioned results,it can come to a conclusion that the magnetic antifouling agent can be enriched on the upper surface of the coating,which can reduce the demand quantity of antifouling agent,and so that reduces the micro plastic pollution caused by antifouling coating,which may bring a bright application prospect in marine antifouling aspects in polar sea areas.