title: Evaluation of Humic Acid and Tannic Acid Fouling in Graphene Oxide-Coated Ultrafiltration Membranes.
abstract: Three commercially available ultrafiltration (UF) membranes (poly(ether sulfone), PES) that have nominal molecular weight cut-offs (5, 10, and 30 kDa) were coated with graphene oxide (GO) nanosheets. Field-emission scanning electron microscopy, Fourier-transform infrared spectroscopy, confocal laser scanning microscopy, water contact angle measurements, and X-ray photoelectron spectroscopy were employed to determine the changed physicochemical properties of the membranes after GO coating. The water permeability and single-solute rejection of GO-coated (GOC) membranes for humic acid (HA) molecules were significantly higher by approximately 15% and 55%, respectively, compared to those of pristine UF membranes. However, the GOc membranes for single-solute tannic acid (TA) rejection showed similar trends of higher flux decline versus pristine PES membranes, because the relatively smaller TA molecules were readily adsorbed onto the membrane pores. When the mixed-solute of HA and TA rejection tests were performed, in particular, the adsorbed small TA molecules resulted in irreversible membrane fouling due to cake formation and membrane pore blocking on the membrane surface for the HA molecules. Although both membranes showed significantly higher flux declines for small molecules rejection, the GOc membranes showed better performance than the pristine UF membranes in terms of the rejection of various mixed-solute molecules, due to higher membrane recovery and antifouling capabilities.
authors: Department of Civil and Environmental Engineering, University of South Carolina , Columbia, South Carolina 29208, United States.
authors: Kyoung Hoon
authors: KH
authors: Chu
authors: Department of Chemical Engineering, University of South Carolina , 300 Main Street, Columbia, South Carolina 29208, United States.
authors: Yi
authors: Y
authors: Huang
authors: Department of Chemical Engineering, University of South Carolina , 300 Main Street, Columbia, South Carolina 29208, United States.
authors: Miao
authors: M
authors: Yu
authors: Department of Civil and Environmental Engineering, Korea Army Academy at Young-Cheon , 495 Hogook-ro, Kokyungmeon, Young-Cheon, Gyeongbuk 38900, South Korea.
authors: Namguk
authors: N
authors: Her
authors: Department of Civil and Environmental Engineering, University of South Carolina , Columbia, South Carolina 29208, United States.
authors: Joseph R V
authors: JR
authors: Flora
authors: Department of Civil and Environmental Engineering, University of South Carolina , Columbia, South Carolina 29208, United States.
authors: Chang Min
authors: CM
authors: Park
authors: Department of Civil Engineering, Pukyong National University , 45 Yongso-ro, Nam-gu, Busan 608-737, Republic of Korea.
authors: Suhan
authors: S
authors: Kim
authors: School of Urban and Environmental Engineering, Ulsan National Institute of Science and Technology , UNIST-gil 50, Ulju-gun, Ulsan 689-798, South Korea.
authors: Jaeweon
authors: J
authors: Cho
authors: Department of Civil and Environmental Engineering, University of South Carolina , Columbia, South Carolina 29208, United States.
authors: Yeomin
authors: Y
authors: Yoon
keywords: antifouling; graphene oxide coating; humic acid and tannic acid; membrane surface modification; surface water treatment