Carbon nanotube embedded ultrafiltration membranes for the treatment of rapid granular multimedia prefiltered beauty hair salon and municipal wastewater

Abstract

Currently, the world is faced with major challenges of water scarcity and water quality, thus the coupling of wastewater treatment technologies for reuse of reclaimed water is a very attractive option. In this study, polyethersulfone (PES) ultrafiltration (UF) nanocomposite membranes containing carboxylic functionalized multiwalled carbon nanotubes (COOH-MWCNTs) were fabricated via the non-solvent induced phase separation (NIPS) method. The membranes were fabricated using polyethylene (PEG) 400 as an additive. Scanning electron microscopy (SEM) examination of the nanocomposite membranes showed that the membranes had porous cross-sectional morphologies and improved porosity with increased PEG 400 content. These membranes were used as an advanced treatment step for the purification of beauty hair salon wastewater. The membrane containing 8.5 wt% PEG achieved 80.84%, 77.51% and 94.51% turbidity removal of the rapid granular multimedia prefiltered beauty hair salon wastewater, municipal effluent and influent wastewater samples, respectively. Poor rejection of most organics in the wastewater samples by the modified membranes was observed. In addition, significant reduction in organic content by the modified membrane in municipal influent sample was confirmed by quadruple time-of-flight liquid chromatography mass spectrometry (QTOF LC-MS) which indicated reduced peaks intensity. The higher the PEG 400 dosage, the larger the pore sizes and the lower the contact angle values and thus, enhanced pure water flux and lower rejection of organics was observed. Energy dispersive X-ray spectroscopy (EDS) of fouled membrane surfaces indicated that metal ions played a role in cake formation. Pressure had no influence on the fouling mechanism of the membrane containing 8.5 wt% PEG and 100% relative wastewater flux restoration was obtained after chemical cleaning of these membranes. These results suggest that an additional advanced water treatment technology may be required for the effective treatment of beauty hair salon wastewater for reuse purposes.