Environmentally Friendly Photothermal Membranes for Halite Recovery from Reverse Osmosis Brine via Solar-Driven...

Area of Science:

• Materials Science
• Environmental Science
• Chemical Engineering

Background:

• Seawater reverse osmosis (SWRO) is crucial for freshwater but generates environmentally concerning hypersaline brine.
• Existing methods like membrane distillation-crystallization (MD-MCr) for brine treatment are energy-intensive.
• Sustainable solutions are needed to manage brine disposal and recover valuable resources.

Purpose of the Study:

• To develop and evaluate a novel photothermal membrane crystallization (PhMCr) process for brine valorization.
• To utilize solar energy for efficient water evaporation and mineral extraction from SWRO brine.
• To investigate the performance of photothermal mixed matrix membranes (MMMs) in this process.

Main Methods:

• Fabrication of photothermal mixed matrix membranes (MMMs) using polyvinylidene fluoride (PVDF) with graphene oxide (GO) or carbon black (CB) via non-solvent-induced phase separation (NIPS).
• Characterization of MMMs' morphology and photothermal properties.
• Application of PhMCr using solar radiation for brine evaporation, supersaturation, and sodium chloride (NaCl) crystallization.

Main Results:

• The developed MMMs exhibited effective light-to-heat conversion under solar radiation.
• PhMCr successfully induced water evaporation and supersaturation in SWRO brine.
• Sodium chloride (NaCl) nucleation and crystallization were achieved, demonstrating mineral extraction capabilities.

Conclusions:

• Photothermal membrane crystallization (PhMCr) presents a promising, energy-efficient approach for sustainable brine valorization.
• The use of solar energy in PhMCr reduces reliance on conventional energy sources for desalination.
• This technology offers a pathway towards a more sustainable desalination industry by recovering water and minerals from brine.