Good news! Like desalination, better water filters are salvation too!
Can you believe it, it can filter microplastics! (Caution: Irony)
"... the hydrogel is hydrophilic (water-attracting) at cool temperatures, but becomes hydrophobic (water-repelling) when heated. Pollutants such as organic dyes (which were used in lab tests) do get pulled in along with the water at cool temperatures, but because their molecules stick to the gel, they don't get expelled when the water is released at warmer temps. Droplets of oil pollution don't get drawn in in the first place, as the (then) hydrophilic gel rejects them. ... loofah hydrogel can be reused simply by rinsing it with diluted acid or ethanol. ..."
From the abstract:
"Hydrogels are promising soft materials for energy and environmental applications, including sustainable and off-grid water purification and harvesting. A current impediment to technology translation is the low water production rate well below daily human demand. To overcome this challenge, we designed a rapid-response, antifouling, loofah-inspired solar absorber gel (LSAG) capable of producing potable water from various contaminated sources at a rate of ∼26 kg m–2 h–1, which is sufficient to meet daily water demand. The LSAG─produced at room temperature via aqueous processing using an ethylene glycol (EG)–water mixture─uniquely integrates the attributes of poly(N-isopropylacrylamide) (PNIPAm), polydopamine (PDA), and poly(sulfobetaine methacrylate) (PSBMA) to enable off-grid water purification with enhanced photothermal response and the capacity to prevent oil fouling and biofouling. The use of the EG–water mixture was critical to forming the loofah-like structure with enhanced water transport. Remarkably, under sunlight irradiations of 1 and 0.5 sun, the LSAG required only 10 and 20 min to release ∼70% of its stored liquid water, respectively. Equally important, we demonstrate the ability of LSAG to purify water from various harmful sources, including those containing small molecules, oils, metals, and microplastics."
Figure 1. Fabrication and hierarchical porous structures of the hydrogel. (a) Schematic of the fabrication method for L-PNIPAm and LSAG. (b) Schematic of the thermally driven water release process for LSAG. (c) Photograph and microstructure of natural loofah sponge and LSAG.
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