๐๐๐ข๐๐ง๐ญ๐ข๐ฌ๐ญ๐ฌ ๐๐ฎ๐ซ๐ง ๐๐ข๐ฑ๐๐ ๐๐ฅ๐๐ฌ๐ญ๐ข๐ ๐๐๐ฌ๐ญ๐ ๐ข๐ง๐ญ๐จ ๐๐ฅ๐๐๐ง ๐๐ฒ๐๐ซ๐จ๐ ๐๐ง
Mixed plastic waste is nearly impossible to recycle, with billions of tons choking landfills and incinerators worldwide. Now scientists in California and South Korea have developed a unique, experimental method to manage this problematic stream. It’s designed to deliver another advantage: converting the trash into clean hydrogen while trapping carbon before it’s released to the air.
Study co-author Woo-Jae Kim, a professor at Ewha Womans University, Korea, believes the thermal technology could achieve a $4-per-kilogram (kg) hydrogen cost. This would put it in line with North American subsidized rates for green hydrogen (produced via water electrolysis), which costs $3.50 to $6.00 per kg.
According to Kim, the competitive edge comes down to a few efficiencies. The process uses half the operating temperature of conventional gasification, requiring less energy. And it’s a fairly simple, one-step method. But the true differentiator is the use of sodium hydroxide (NaOH) as a catalyst—this chemical compound rapidly breaks down plastics, requiring almost no sorting, while boosting hydrogen yield.
“Recycling would be the best answer if you could separate all plastic types. Then you could generate new plastic with the same compound. But separating them is difficult. So, we are extracting their hydrogen [to manufacture other products],” Kim says.
“But now the problem is, what do we with the carbon, which makes carbon dioxide (CO2)—it’s a harmful greenhouse gas,” he says.
In answer, the team put the plastic-busting NaOH to work on a second task: capturing the CO2 released during the reaction and turning it into stable, solid sodium carbonate.
source : Waste360
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