A carbon nanotube (CNT) integrated polymer composite membrane with a polyvinyl alcohol barrier layer has been prepared to separate oil from water for treatment of oil-containing waste water. The CNTs were synthesised using chemical vapour deposition, and a phase inversion method was employed for the blending of the CNTs in the polymer composite solution for casting of the membrane. Relative to the baseline polymer, an increase of 119% in the tensile strength, 77% in the Young's modulus and 258% in the toughness is seen for a concentration of 7.5% CNTs in the polymer composite. The permeate through the membrane shows oil concentrations below the acceptable 10 mg/L limit with an excellent throughput and oil rejection of over 95%.
BTEX (benzene, toluene, ethylbenzene, and xylene) compounds are common water resource and potable water pollutants that are often left undetected and untreated by municipal treatment systems in spite of the negative repercussions associated with their ingestion. The US EPA has classified these pollutants as priority pollutant, yet they are persistently present in a variety of water resources. In this review paper, we highlight the sources and reported concentrations of BTEX compounds in water and explore historical remediation techniques that have been applied such as bioremediation and natural attenuation. We also highlight emerging possibilities and future directions for remediation techniques, such as nanotechnology-based materials and novel green materials (tannins) that can be applied to ensure removal of these compounds in water.
This paper focuses on modifying a PES membrane with acid-functionalised carbon nanotubes (CNT) for industrial wastewater treatment. Embedding acid functionalised carbon nanotubes (CNTs) within the membrane matrix would increase the membrane flux by increasing the membrane pore size and surface area, rejection and thermal stability. Pure PES membranes were prepared by phase inversion method and infused with CNTs at 2.5, 5, 7.5 and 10 wt% loading to fabricate PES/2.5 wt% CNT, PES/5 wt% CNT, PES/7.5 wt% CNT and PES/10 wt% CNT membranes respectively. Characterisation was performed using Transmission Electron Microscopy (TEM) to determine CNT morphology, X-ray Diffraction (XRD) to determine the functional groups attached to CNTs, Thermogravimetric Analysis (TGA) to determine the thermal stability of the membranes, Scanning Electron Microscope (SEM) to determine membrane morphology, Bunauer-Emmett-Teller (BET) method to obtain pore size information and Contact Angle (CA) to determine the membrane hydrophilicity. Membrane performance was then evaluated with a dead-end stirred cell using industrial wastewater containing traces of Cu, Fe, Ni, Zn and Cl. Permeate flux results showed a direct proportion relationship with increasing CNT loading and increasing pressure (100 kPa, 300 kPa, 500 kPa, 700 kPa, 900 kPa and 1100 kPa). PES/5 wt% CNT membrane showed the most enhanced performance compared to the other membranes, achieving reasonably high flux of 43.7 L/m2h and rejection of 89.6% Cu, 100% Fe, 90.5% Ni, 68.8% Zn and 99.99% Cl at 300 kPa. The results obtained showed that the PES membrane embedded with functionalised CNTs could be used for the treatment of industrial wastewater.
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