A Harvard-led team of researchers have shown that liquid-gated membranes (LGMs) help improve the industrial wastewater purifying process.
According to Harvard’s Wyss Institute and its collaborators – the universities of Northeastern and Waterloo, LGMs filter nanoclay particles out of water with two-fold higher efficiency, nearly threefold longer time-to-foul, and a reduction in the pressure required for filtration over conventional membranes.
This makes it a valuable solution for reducing the cost and electricity consumption of high-impact industrial processes such as oil and gas drilling.
LGMs mimic nature’s use of liquid-filled pores to control the movement of liquids, gases and particles through biological filters using the lowest possible amount of energy.
This is similar to how small stomata openings in plants’ leaves allow gases to pass through.
Each LGM is coated with a liquid that acts as a reversible gate, filling and sealing its pores in the ‘closed’ state.
When pressure is applied to the membrane, the liquid inside the pores is pulled to the sides, creating open, liquid-lined pores.
These pores can be tuned to allow the passage of specific liquids or gases, and resist fouling due to the liquid layer’s slippery surface.
The use of fluid-lined pores also enables the separation of a target compound from a mixture of different substances, which is common in industrial liquid processing.
Unlike untreated membranes, LGMs are able to filter water three times longer than the standard membranes before requiring a ‘backwash’ procedure to remove particles that had accumulated on the membrane.
Less frequent backwashing could translate to a reduction in the use of cleaning chemicals and energy required to pump backwash water, and improve the filtration rate in industrial water treatment settings.
This advantage also gives LGMs a longer lifespan and makes more of the filtrate recoverable for alternate uses.
Additionally, the LGMs required 16% less pressure to initiate the filtration process, reflecting further energy savings.
Wyss Institute/Harvard University