物理化学学报 >> 2020, Vol. 36 >> Issue (1): 1906044.doi: 10.3866/PKU.WHXB201906044

所属专题: 庆祝唐有祺院士百岁华诞特刊

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具有抗生物污染活性的分子筛膜用于高效油水分离

王百先1,王琪菲1,邸建城1,*(),于吉红1,2,*()   

  1. 1 吉林大学化学学院,无机合成与制备化学国家重点实验室,长春 130012
    2 吉林大学未来科学国际合作联合实验室,长春 130012
  • 收稿日期:2019-06-11 录用日期:2019-07-19 发布日期:2019-07-26
  • 通讯作者: 邸建城,于吉红 E-mail:jcdi@jlu.edu.cn;jihong@jlu.edu.cn
  • 基金资助:
    国家自然科学基金(21621001);国家自然科学基金(21835002);111计划(B17020);吉林省/吉林大学新材料合作建设项目资金(SXGJSF2017-3)

Zeolite-Coated Anti-Biofouling Mesh Film for Efficient Oil-Water Separation

Baixian Wang1,Qifei Wang1,Jiancheng Di1,*(),Jihong Yu1,2,*()   

  1. 1 State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, College of Chemistry, Jilin University, Changchun 130012, P. R. China
    2 International Center of Future Science, Jilin University, Changchun 130012, P. R. China
  • Received:2019-06-11 Accepted:2019-07-19 Published:2019-07-26
  • Contact: Jiancheng Di,Jihong Yu E-mail:jcdi@jlu.edu.cn;jihong@jlu.edu.cn
  • Supported by:
    The project was supported by the National Natural Science Foundation of China(21621001);The project was supported by the National Natural Science Foundation of China(21835002);the 111 Project, China(B17020);the Jilin Province/Jilin University Co-construction Project-Funds for New Materials, China(SXGJSF2017-3)

摘要:

随着经济全球化的发展,频发的石油泄露事故以及工业生产时排放的含油污水已经严重威胁到水体生态环境和人体健康。传统上处理含油废水的方式主要包括离心法,撇沫法,浮选法和油吸附技术等等。然而较低的分离效率以及吸油材料后处理过程中所产生的二次污染等缺点限制了这些方法在实际中的应用。最近,基于过滤膜材料表面特殊浸润性的分离技术已被广泛用于含油废水中油污的富集和回收。其中,具有空气中超亲水/水下超疏油特性的分离膜的制备引起了人们广泛的研究兴趣。在油水分离过程中,这种分离膜可以选择性地允许水通过,同时将油污阻隔在膜的上方。然而,水中的微生物易于附着在此类亲水膜上,降低其分离性能,并最终导致膜的阻塞。在本工作中,我们利用晶种和二次水热生长技术,在不锈钢网基底上包覆了具有MFI拓扑结构的ZSM-5分子筛涂层,并进一步通过离子交换过程将分子筛孔道中70%的Na+离子取代为Ag+离子。所制备的分子筛膜(Ag@ZCMFs)在空气中表现出超双亲性(水和油的接触角均为0°),而当被浸没在水中时,其浸润性转变为水下超疏油性(水下油接触角为151.27°± 4.34°)。基于这种特殊的浸润性,Ag@ZCMF可以实现对众多油水混合物的有效分离,其分离效率均超过99%。在Ag@ZCMF的合成过程中,可通过改变二次水热生长时间来调变膜中所预留的针孔的直径,从而调整分离膜的水通量和油侵入压。例如,二次水热生长时间为14 h的分子筛膜(Ag@ZCMF-14)中针孔的平均直径约为21 μm,在分离过程中,该膜的水通量和油穿透压分别达到54720 L·m-2·h-1和4357 Pa。抗腐蚀试验和摩擦试验证实Ag@ZCMF-14具有良好的化学稳定性和机械稳定性。经过10次分离-再生循环过程,Ag@ZCMF-14的分离能力没有明显的衰减,说明Ag@ZCMF-14具有较高的分离稳定性。此外,负载的Ag+使得该分子筛膜具有优异的抗生物污染性能,可以有效抑制操作环境中藻类和细菌的生长,由此避免油水分离过程中膜的阻塞。其中,Ag@ZCMF-14对大肠杆菌的抑菌率达到99.6%。这些结果表明具有抗生物污染的Ag@ZCMF在处理含油废水方面有着广阔的实际应用前景。

关键词: 分子筛, 浸润性, 油水分离, 离子交换, 抗生物污染

Abstract:

The development of the global economy has been accompanied by frequent oil spills caused by accidental leaks and industrial manufacturing, which have seriously threatened the aquatic environment and human health. Traditional methods for the treatment of oily wastewater include centrifugation, skimming, flotation, oil-absorbing technology, etc., which are limited by low separation efficiency as well as secondary pollution during the post-processing of oil absorption materials. Recently, separation technologies utilizing the special wettabilities of filtration membranes have been developed to enrich and recycle oils from wastewater. Among these, the fabrication of superhydrophilic/underwater superhydrophobic membranes have attracted intensive research interest, which can selectively allow the passage of water through the membrane while blocking the oils. However, microorganisms are more likely to breed on these hydrophilic surfaces, eventually leading to the blockage of the membranes. In this study, ZSM-5 zeolite crystals (MFI topological structure) were coated onto the stainless-steel meshes by means of seeding and secondary hydrothermal growth. Then, 70% of the total Na+ ions in the zeolite channels were substituted by Ag+ ions via an ion exchange process. The resultant membranes (Ag@ZCMFs) were superamphiphilic in air, with both water contact angle and oil contact angle of approximately 0°. However, they became superoleophobic when immersed in water, and the underwater oil contact angle reached 151.27° ± 4.34°. In terms of special wettability, Ag@ZCMF achieved efficient separation for various oil-water mixtures with separation efficiencies above 99%. The water flux and intrusion pressure of Ag@ZCMF depended on the diameter of pinholes in the membrane, which could be modulated by altering the time of secondary hydrothermal growth. For instance, the average diameter of pinholes in Ag@ZCMF with optimum secondary growth time of 14 h (Ag@ZCMF-14) reached approximately 21 μm, giving rise to the water flux and intrusion pressure of 54720 L·m-2·h-1 and 4357 Pa, respectively. The anti-corrosion test and rubbing test confirmed the high chemical and mechanical stability of Ag@ZCMF-14, respectively. The separation efficiency of Ag@ZCMF-14 remained stable during ten purification-regeneration cycles, and no obvious attenuation was observed, proving the high separation stability of Ag@ZCMF-14. Furthermore, the loaded Ag+ ions afforded the membrane excellent anti-biofouling activity, which could effectively inhibit the growth of both alga and bacteria in the operating environment, thus preventing membrane blockage during the oil-water separation process. In particular, the bacteriostatic rate of Ag@ZCMF-14 to Escherichia coli reached to 99.6%. These results demonstrate that Ag@ZCMFs with anti-biofouling activity has promising potential future applications in the removal of oil slicks from oily wastewater.

Key words: Zeolite, Wettability, Oil-water separation, Ion exchange, Anti-biofouling activity

MSC2000: 

  • O647