During the production of oil and gas, a large amount of oily wastewater is generated, which would pollute the environment if discharged without proper treatment. As one of the most promising treatment options, membrane material used for oily wastewater treatment should possess desirable properties of high hydraulic performance combined with high membrane fouling resistance. This project employs the vapor induced phase separation (VIPS) technique to develop a hydrophilic polyvinylidene fluoride (PVDF) membrane with polyethylene glycol (PEG) as an additive for produced water treatment. Results show that thanks to its slow nonsolvent intake, the VIPS method hinders additive leaching during the cast film immersion. The results also reveal that the exposure of the film to the open air before immersion greatly influences the structure of the developed membranes. By extending the exposure time from 0 to 30 min, the membrane morphology change from typical asymmetric with large macrovoids to the macrovoid-free porous symmetric membrane with a granular structure, which corresponds to 35% increment of steady-state permeability to 189 L·m−2h−1bar−1, while maintaining >90% of oil rejection. It was also found that more PEG content resides in the membrane matrix when the exposure time is extended, contributes to the elevation of surface hydrophilicity, which improves the membrane antifouling properties. Overall results demonstrate the potential of VIPS method for the fabrication of hydrophilic PVDF membrane by helping to preserve hydrophilic additive in the membrane matrices.
6Application of ultrafiltration membranes for removal of humic acids is investigated below. 7 Membrane filtration processes were compared using two different set-ups: circular flow and 8 stirred dead end flow. The transmembrane pressure, temperature, feed concentration, pH, ionic 9 strength and shear stresses applied on the membrane surfaces were kept constant whilst the 10 permeate flux and solute rejection were measured during the experiments with both set-ups. It 11 was shown that the rejection (both the observed and the true rejection) in the case of circular 12 flow was higher than in the case of dead end flow. The mass transfer coefficients were 13 determined for both set-ups. In the case of stirred dead end, it ranged in from (2.14-4.72) x 10 -6 14 m/s; however, for circular cross flow system, the mass transfer coefficients were found in the 15 range (2.24-3.22) x 10 -5 m/s. Comparison of the mass transfer coefficients obtained for both 16 systems showed that it was significantly higher for circular flow systems as compared with 17 stirred dead end system at similar operating conditions. Energy consumed per volume of 18 purified water by circular flow system (0.345 kW) was found to be much lower when by stirred 19 dead end system (0.955 kW). This proved that the performance of circular flow system was 20 more efficient in terms of rejection, mass transfer coefficient and energy consumption. 21
Water is a quintessential element for the survival of mankind. Its variety of uses means that it is always in a constant state of demand. The supply of water most primarily comes from large reservoirs of water such as lakes, streams, and the ocean itself. As such, it is good practice to monitor its quality to ensure it is fit for human consumption. Current water quality monitoring is often carried out in traditional labs but is time consuming and prone to inaccuracies. Therefore, this paper aims to investigate the feasibility of implementing an Arduino-based sensor system for water quality monitoring. A simple prototype consisting of a microcontroller and multiple attached sensors was employed to conduct weekly onsite tests at multiple daily intervals. It was found that the system works reliably but is reliant on human assistance and prone to data inaccuracies. The system however, provides a solid foundation for future expansion works of the same category to elevate the system to being Internet of Things (IoT) friendly.
A well-defined comparative study between stirred dead end and circular crossflow for microfiltration of china clay suspensions has been undertaken. The comparisons have been made with respect to convective mass transfer coefficients, permeation and rejection rates, and energy consumption. Similar operating and hydrodynamic conditions were implemented for the comparison. According to our experimental data the circular crossflow module was proven to perform better as compared with the stirred dead end system due to the higher mass transfer coefficients, higher permeation rates and lower energy consumption. The mass transfer coefficients observed are comparable to those previously found in vortex flow filtration and dead end flow filtration. The presence of Dean vortices in the circular crossflow module promotes flow instabilities in the curved channel flow path which reduce the concentration polarization effect during the filtration process. The concentration polarization effect however deteriorated due to solute build up (high solute concentration at the membrane surface) and decrease of the shear stress, i.e., the particle lift forces on the membrane surface. This resulted in deposition of particles on the membrane surface. In terms of energy consumption, for the same energy cost the limiting flux reached in circular crossflow was found to be higher than in the stirred dead end unit.
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