Abstract    Silver-impregnated membrane was facilely prepared by ex situ silver nanoparticles (NPs) blending method using polyethersulfone (PES) as the base polymer. A total of three membranes [F1(S0), F2(S0.5) and F3(S2.0)] were fabricated at different weight percentages of polymer and silver (Ag) loadings to compare their effects on membrane morphological and performance properties. All membrane types were characterized using scanning electron microscope (SEM), energy-dispersive X-ray, Fourier-transform infrared spectroscopy, zeta potential analyzer and contact angle analysis. Characterization data and background theories from the literature were used to study and relate the effect of silver nanoparticles (AgNPs) on the physicochemical properties of the PES/Ag composite membranes with respect to pure water permeability, structural property, surface charge and surface hydrophilicity. Solute rejection performance and antibacterial property of the PES/Ag composite membranes were performed using humic acid (HA) and Escherichia coli (E. Coli) bacteria. The results showed that the membrane with the highest Ag loading (F3) exhibited the highest pure water permeability among all the composite membranes. This phenomenon could be attributed to the morphological changes of the membrane due to the addition of Ag. In this study, contact angle of the membranes showed decreasing trend with the addition of Ag as well as the increase in Ag loading. On the contrary, pore radius of the membranes was found increased with increasing in Ag loading. Owing to this, the F3 membrane demonstrated relatively lower HA rejection (i.e. 89.55%) compared to the pure PES membrane. In terms of the antibacterial performance evaluation, one can confidently state that the membranes with the addition of Ag showed excellent property in biofouling mitigation based on numerous dead E. coli observed on the membrane surface under SEM analysis.

Keywords    antibacterial, E. coli, hydrophilicity, polyethersulfone, silver nanoparticle

چکیده    ممبران آغشته به نقره با استفاده از ترکیب کردن نانوذرات نقره خارجی (NPs) با پلی اترسولون (PES) به عنوان پلیمر پايه به صورت ساده آماده شد. در مجموع سه ممبران [F1(S0)، F2(S0.5) و F3(S2.0)] با در صدهای وزنی متفاوت پلیمر و بارهای نقره (Ag) فراهم شد تا اثرات آن بر خواص مورفولوژیکی و عملکرد ممبران مقایسه شود. تمامی ممبران ها با استفاده از میکروسکوپ الکترونی روبشی (SEM)، طیف سنجی پراش انرژی پرتو ایکس، تحلیل پتانسیل زتا و تحلیل زاویه تماس طبقه بندی شدند. با استفاده از داده های توصیفی و نظریه های پس زمینه برگرفته از مقالات، اثر نانوذرات نقره (AgNPs) بر روی خواص فیزیکوشیمیایی ممبران های ترکیبی PES/Ag نسبت به ظرفیت تراوایی آب، خواص ساختاری، بار سطحی و قدرت آبدوستی سطحی مورد مطالعه و بررسی قرار گرفت. عملکرد محلول فیلتر شده و ویژگی ضد باکتری ممبران های ترکیبی PES/Ag به وسیله اسید هیومیک (HA) و باکتری اشرشیا کولیفورم( E. coli) انجام شد. نتایج نشان داد که ممبران با بیشترین مقدار بار گذاری Ag (F3) بیشترین ظرفیت تراوایی آب را در میان ممبران های ترکیبی را بدست آورد. این پدیده میتواند به علت تغیرات مورفولوژیکی ممبران در اثر مقدار بیشتر Ag باشد. در این مطالعه زاویه تماس ممبران ها با افزودن Ag و همچنین افزایش بار گذاری Ag روند کاهشی را نشان داد. از طرف دیگر، شعاع منفذی ممبران ها، با افزایش بار گذاری Ag روند افزایشی را نشان داد. از اینرو، ممبران F3 در مقایسه با ممبران خالص PES مقدار نسبتا پایین تری از HA رد شده را( به مقدار 89.55%) نشان داد. با توجه به ارزیابی عملکرد ضد باکتری می توان با اطمینان بیان کرد که ممبران ها با افزودن Ag دارای خصوصیات عالی در کاهش آلودگی زیستی می باشند. این نتیجه گیری بر اساس مشاهده تعداد بی شماره باکتریهای مرده اشرشیا کولیفورم برسطح ممبران به وسیله میکروسکوپ الکترونی روبشی حاصل شد.

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