Graphene oxide based ultrafiltration membranes for photocatalytic degradation of organic pollutants in salty water

• Type: Article in International Scientific Journal
• Date: 2015

Authors

Luisa M. Pastrana-Martínez (Author) FEUP; Sergio Morales Torres (Author) FEUP; José L. Figueiredo (Author) FEUP; Joaquim L. Faria (Author) FEUP; Adrián M. T. Silva (Author) FEUP

Journal

Title: Water Research

Vol. 77

Pages: 179-190

ISSN: 0043-1354

Publisher: Elsevier

Indexing

ISI Web of Knowledge - 41 Citations

ISI Web of Science

Scopus - 74 Citations

Associated Projects

LSRE-LCM - Laboratório de Processos de Separação e Reação - Laboratório de Catálise e Materiais

NEPCAT - Novo equipamento envolvendo processos catalíticos integrados para tratamento de poluentes orgânicos e desinfeção de águas

Other information

Authenticus ID: P-00A-AT5

DOI: 10.1016/j.watres.2015.03.014

Abstract (EN): Flat sheet ultrafiltration (UF) membranes with photocatalytic properties were prepared with lab-made TiO2 and graphene oxide-TiO2 (GOT), and also with a reference TiO2 photocatalyst from Evonik (P25). These membranes were tested in continuous operation mode for the degradation and mineralization of a pharmaceutical compound, diphenhydramine (DP), and an organic dye, methyl orange (MO), under both near-LIVNis and visible light irradiation. The effect of NaCl was investigated considering simulated brackish water (NaCl 0.5 g L-1) and simulated seawater (NaCl 35 g L-1). The results indicated that the membranes prepared with the GOT composite (M-GOT) exhibited the highest photocatalytic activity, outperforming those prepared with bare TiO2 (M-TiO2) and P25 (M-P25), both inactive under visible light illumination. The best performance of M-GOT may be due to the lower band-gap energy (2.9 eV) of GOT. In general, the permeate flux was also higher for M-GOT probably due to a combined effect of its highest photocatalytic activity, highest hydrophilicity (contact angles of 11 degrees, 17 degrees and 18 degrees for M-GOT, M-TiO2 and M-P25, respectively) and higher porosity (71%). The presence of NaCl had a detrimental effect on the efficiency of the membranes, since chloride anions can act as hole and hydroxyl radical scavengers, but it did not affect the catalytic stability of these membranes. A hierarchically ordered membrane was also prepared by intercalating a freestanding GO membrane in the structure of the M-GOT membrane (M-GO/GOT). The results showed considerably higher pollutant removal in darkness and good photocatalytic activity under near-LTVNis and visible light irradiation in continuous mode experiments.

Language: English

Type (Professor's evaluation): Scientific

No. of pages: 12