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Graphene Could Solve the World's Water Crisis

石墨烯 用途看起来极为广泛 作为全新的物质 让人感觉既有趣又神奇
Graphene is the sexy new wonder material that seems to have a million and one uses.
从超薄的柔性屏幕 到雨天发电太阳能电池
From thin flexible screens to solar cells that work when it’s raining, people are
finding all sorts of potential applications for this one-atom thick sheet of carbon.
在石墨烯所有应用中 科学家现在增加了另一种应用方式:
Now scientists have added another trick to graphene’s repertoire:
making seawater drinkable.
淡化海水的想法 不是才提出来的
Desalination is not a new concept
Israel gets over a quarter of its fresh water
from the mediterranean sea.
不过 对于淡化海水 石墨烯能够让其整个过程效率更高
But graphene could make the whole process much more efficient.
大规模淡化海水主要使用的技术 人们称之为“逆向渗透”
The main technique used for large scale desalination is called reverse osmosis.
Normal osmosis is
穿过半透膜 水会向盐度更高的区域流动
where water flows across a semipermeable membrane to areas of higher saltiness,
你若在小时候 曾向蜗牛倒盐 致其脱水干瘪
if you were one of those kids that poured salt on snails, causing the snail to shrivel up,
对我正在说的 就能够理解了
you know what I am talking about.
而且 男生(大概都这样干过)
而 淡化海水使用的逆向渗透 是指
The reverse osmosis used for desalination, however,
利用压力 迫使海水 改变流向
is when pressure is applied to saltwater to force it in the directions it doesn’t normally flow,
透过专用薄膜 向盐度更低的区域流动
through special membranes to areas of lower salinity,
以便 把淡水分离出来
separating the H2O and
向盐份 呐呐呐 嘿嘿嘿 说再见
telling the salt Na Na Na Na, hey hey hey, goodbye
Get it because sodium is… NA.
好吧 这一切 尽管听上去不错 但是 也有缺点
Anyway, this all sounds great but it’s not perfect,
海水淡化而来的水 十分昂贵
water from desalination is very expensive
其每一英亩尺 都高达1000至2500美元不等
costing anywhere from $1,000 to $2,500 per acre foot,
这样的水量 也就够10个人一年使用
which is about the amount of water 10 people use in a year.
淡化时 将海水用量减少 并循环利用 通常能把费用降低一些
Generally it’s cheaper to just use less water and recycle the water you do use,
不过 特别缺水的地方 也别无他法
but for some particularly dry places there’s no other option.
这些费用有部分 在海水处理之前 就会产生
Part of the expense comes from pre-treating the water,
迫使海水穿过果冻卷似的塑料薄膜 使用的能量会很多
but pumping the water through the jelly-roll-like plastic membranes uses a lot of energy.
Computer models have predicted that
如果 我们 把更厚的薄膜 用超薄的石墨烯层来代替
if we could use super-thin graphene sheets instead of these thicker membranes,
逆向渗透需要的能量 会有15-46%不等的降低
the amount of energy needed for reverse osmosis could be reduced anywhere from 15-46%.
渗透输送使用的能量更低 意味着 淡化海水的费用会更低
Less energy used for pumping means less expensive water, and
这在全球更穷更缺水的地区 会对人们的生活改变极大
that make a huge different to people in the world’s poorer and drier places.
非常不幸 现实与计算机模型 总有差异
Unfortunately reality doesn’t always cooperate with computer models,
要制造能让水和盐分离的石墨烯 不像看起来那样容易
and making graphene that can separate water from salt isn’t as straightforward as it appears.
Researchers found that
when the graphene oxide were submerged in water
they’re swollen a little bit.
尽管 他们仍能过滤纳米粒子 有机分子 甚至 较大颗粒的盐
They would still filter nanoparticles, organic molecules, and even larger salts
但是 对海水普通的盐粒子 却不能过滤
but not the common salts found in seawater,
这样过滤出来的水 能导致身体脱水更严重 饮用起来会十分危险
which are dangerous to drink because they just lead to more dehydration.
这种身体的脱水 也是正常渗透作用在起作用
That’s normal osmosis at work again.
不过 该科研团队 对防止滤网膨胀 控制滤孔的大小 已经研究出了最新的成果
But now new findings from the same group of researchers have figured out how to prevent the swelling and control the pore size.
现在 与盐结合的水分子 无法从滤孔通过
Now the dissolved salts and the water molecules they bind to can’t get through the pores,
然而 自由的水分子却可以 而且通过速度十分快
but free water molecules can, and do so surprisingly fast,
这对尽可能快地制造淡水 是个好消息
which is a good thing when you’re trying to make fresh water as quickly as possible.
研究人员们 希望他们的发现 能让淡化海水的花费更低 以便人们可以负担得起
The researchers hope that their discovery can make desalination more affordable,
这一切 对那些饱受旱灾的贫穷国家 帮助十分巨大
which would be a huge boon to poorer drought stricken countries
毕竟 面对海水淡化工厂数十亿美元的修建费用 这些国家是无法负担的
who can’t afford to build billion-dollar desalination plants.
With climate change threatening to make droughts even worse,
石墨烯 不仅可以用来制作柔性屏幕 还可以用来做其他更有意义的事情
graphene could do more than just make flexible screens.
石墨烯 对拯救生命 可是一大助力
it could help saves lives.
喔 石墨烯 你就是我的英雄
Oh graphene you’re my hero.
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你们认为 淡化海水 是带来了解决干旱的办法
Do you think desalination is the answer to solving drought
还是 带来了资金大量消耗的问题
or is the problem to huge to make a dent in?
Let us know in the comments and
don’t forget to subscribe while you’re down there
如果 你们担心 制造石墨烯 太贵太难而无法成功
If you’re worried that making graphene is still too expensive and hard to make to fulfill
这种担心就是成功在望的迹象 好消息!
it’s promises, good news!
科学家们 对降低石墨烯制造费用 无意间获得一些信息
Scientists accidentally found out how to make it cheaper,
这个内容 会在Trace这里告诉你
and Trace tells you about that right here.
Thank you guys for watching Seeker.