New method turns ocean water into drinking water, without waste
Researchers develop solar-thermal desalination that produces fresh water and solid salt without brine waste or chemical pretreatment.
University of Rochester researchers led by Chunlei Guo created a solar desalination system using laser-etched black metal panels that absorb nearly all solar radiation and repel water (superwicking). The grooved surface channels salts and minerals to a passive region, preventing clogging that occurs in conventional solar desalination when minerals like magnesium and calcium crystallize. Testing with real ocean water from Pacific, Atlantic, and Indian Oceans showed the method produces fresh water while collecting salts in solid form rather than liquid brine. A related method extracts lithium from the collected salts using hydrogen titanate nanoparticles, recovering about 50% from Great Salt Lake samples. The approach avoids pre- and post-treatment chemicals and produces recoverable minerals instead of problematic brine discharge.
What HN community is saying
Top comments challenge the article's claims rather than celebrate them. One notes this is a repost from four days prior. Several commenters question whether the brine problem is overstated, noting the ocean is large and concentrated discharge can be managed with long pipes or dilution strategies. A major technical critique argues the paper lacks comparison to conventional reverse osmosis at similar energy input levels and that RO already approaches theoretical efficiency. Commenters debate whether solid salt byproduct is truly advantageous over brine (some call solid salt "a hassle" to dispose of), and note that if salt were economically valuable, existing desalination already extracts it. One clarifies that brine exhibits poor diffusion and tends to sink rather than dilute quickly, making disposal harder than suggested.