<8> M ASTERBONDCASE STUDY UV15TK for 3-D Printing of Reverse Osmosis Feed Spacers with Reduced Scaling Effects Master Bond Inc. 154 Hobart Street, Hackensack, NJ 07601 USA Phone +1.201.343.8983 | Fax +1.201.343.2132 | [email protected]

CASE STUDY UV15TK: for 3-D Printing of Reverse Osmosis Feed Spacers with Reduced Scaling Effects Application In the coming decades, global freshwater shortages will pose a significant hazard for humanity. Not only is clean, fresh water critical for essential human life, but our ever expanding industrial and agricultural footprint further increases the demand for freshwater. A combination of factors including population growth, the destruction of natural reservoirs, industrial pollution and the impacts of climate change will see water as one of the most important commodities of the 21st century....

The goal of these studies sought to design a feed spacer with reduced fouling and enhanced de-scaling properties during membrane cleaning.2 Master Bond UV15TK, a UV-curable epoxy with a relatively high modulus, was chosen for use as a 3-D printing material to directly print micromixer elements of an optimal design onto the semipermeable membrane itself. Fluid dynamic modeling was performed to determine the optimal geometry of the chevron pattern. Optimal flow velocity and turbulent mixing decreases the tendency for scale formation, crystallization of solute species, and decreases the effects...

membrane. Velocities below 0.1 m/s and velocities greater than 0.3 m/s are known to encourage scaling and deterioration in the water flux through the membrane. Figure 3 presents a visual summary of channel feed velocities determined from modelling the offset configured chevrons with interior angles: 60°, 90° and 120° with fixed parameters of 3 mm chevron length, 5.75 mm gap, and an inlet velocity of 0.104 m/s. A chevron interior angle of 90°was found to be optimal. Figure 3. Design optimization modelling the fluid flow channel using COMSOL Multiphysics. Full velocity profile from 0-0.3 m/s varying...

Figure 4. Scaling study comparing 3-D printed micromixer with Master Bond UV15TK (blue) and the standard industrial mesh feed spacer (red) monitoring normalized specific water flux through the RO system.2 In addition to the positive outcome of the scaling study, an interesting phenomenon was observed for the modified system. The process of printing the chevron-shaped elements on the semipermeable membrane has the effect of reducing the active membrane area—the unmodified membrane had an active membrane area of 140 cm2; subtracting the area of the printed chevrons from the total area resulted...

this study could prove useful in the design of next generation RO systems. As scaling and fouling problems are the Achille’s heal of reverse osmosis treatment, the ability to quickly descale an RO system and without the use of hazardous and expensive chemical solutions would be a key advancement in the technology. This work positively contributed to the field of engineering and to the development and advancement of reverse osmosis technology. It was demonstrated that 3-D printed micromixer elements can be optimized to reduce fouling and may also possess novel ability to readily clean and descale...