作者：Susannah Scott? 翻譯：小婧
? ? 小婧前言：? ??
? ? 在如今經(jīng)濟(jì)發(fā)展迅猛的時代，塑料已成為生活中不可缺少的一部分，塑料給我們帶來了不少便利的同時也對環(huán)境造成了巨大的污染。
? ? 眾所周知，我們要回收利用塑料制品，但是回收利用后真的就完事了嗎？回收利用的效率真的如我們想象中的高嗎？我們能否以另一種富有創(chuàng)造性的方式解決塑料垃圾帶來的污染問題呢？下文將會給你對塑料的回收利用帶來新的見解！
?正文：???
? ?如果你認(rèn)為那些輕薄脆弱的一次性食品塑料袋在塑料垃圾問題中占了絕大多數(shù)，那么請您再仔細(xì)思考下。全世界每年扔掉的塑料垃圾的量可以重建3700km的中國明朝長城。
? ??If you thought those flimsy disposable plastic grocery bags represented most of our plastic waste problem, think again. The volume of plastic the world throws away every year could rebuild the?Ming Dynasty’s Great Wall of China – about 3,700 miles long.
? ? 在這60年以來，用于商業(yè)用途的塑料就已經(jīng)生產(chǎn)了超過83億噸。塑料用途廣泛，重量輕，價格低廉，只要不對它進(jìn)行高溫加熱，它就幾乎堅(jiān)不可摧。正是這些獨(dú)特的性能使它們在無菌食品包裝，節(jié)能運(yùn)輸，紡織品和醫(yī)療防護(hù)設(shè)備的廣泛應(yīng)用中極為有用。但它們堅(jiān)不可摧的性質(zhì)是有代價的。大部分塑料在數(shù)百年內(nèi)的時間內(nèi)在環(huán)境中降解的非常緩慢，正因如此造成了如今塑料垃圾在全球泛濫。其對人類和生態(tài)系統(tǒng)健康帶來的后果尚不完全清楚，但具有潛在的重大意義。
? ??In the six decades that plastic has been manufactured for commercial uses,?more than 8.3 billion metric tons have been produced.?Plastics are light, versatile, cheap and nearly indestructible (as long as they don’t get too hot). These properties make them incredibly useful in an enormous range of applications that includes sterile food packaging, energy-efficient transportation, textiles and medical protective gear. But their indestructible nature comes at a cost. Most of them decompose extremely?slowly in the environment?– on the order of?several hundred years?– where they are creating a global epidemic of plastic trash. Its consequences for human and ecosystem health are still incompletely known, but are potentially momentous.
? ? ?我（Susannah Scott）是一名在塑料設(shè)計制造工藝方面經(jīng)驗(yàn)豐富的化學(xué)家。我開始對將塑料用作大規(guī)模的未開發(fā)資源感興趣。我想知道我們是否可以通過將塑料垃圾轉(zhuǎn)變成更有價值的東西以達(dá)到其遠(yuǎn)離垃圾填埋場和自然環(huán)境的目的。
I am a chemist?with experience in designing processes for making plastics, and I became interested in using plastic as a large, untapped resource for energy and materials. I wondered if we could turn plastic waste into something more valuable to keep it out of landfills and the natural environment.
一種重新使用塑料垃圾的新方法
（A new way to use plastic waste）
? ?塑料是通過以幾乎無限多種方式把大量的碳基小分子串在一起形成聚合物鏈而制成的。
???Plastics are made by stringing together a large number of small, carbon-based molecules in an almost infinite variety of ways to create polymer chains.
??
從單體到聚合物的化學(xué)分子示意圖
?? 要重新利用這些聚合物，回收措施在原則上可以融化并重塑它們，但塑料的性能往往會有所下降。盡管它們可以被用于制造價值更低的材料像塑料木材等等，但（所重新加工）獲得的的塑料材料幾乎都不適合其原始用途。（而最終帶來的）結(jié)果是有效回收的效率非常低。
?To reuse these polymers, recycling facilities could, in principle, melt and reshape them, but plastics’ properties tend to deteriorate. The resulting materials are almost never suitable for their original use,?although they can be used to make lower-value stuff like plastic lumber. The result is a very?low effective rate of recycling.
?? 一種新的方法涉及到把長鏈（其實(shí)就是碳鏈）再次剪斷變成小分子，其挑戰(zhàn)之處在于如何以更精確的方式做到這一點(diǎn)（就是把大分子物質(zhì)轉(zhuǎn)變?yōu)樾》肿游镔|(zhì)）。
?? A new approach involves breaking the long chains down into small molecules again. The challenge is how to do this in a precise way.
?? 由于在最初合成聚合物鏈時會釋放大量的能量。一般地，這意味著將塑料加熱到最高溫但加熱后的塑料材料往往會陷入一團(tuán)糟。同時這樣還浪費(fèi)大量的能源，意味著會有更多的溫室氣體排放到大氣中。
?Since the process of making the chains in the first place?releases a lot of energy,?reversing it requires adding a large amount of energy back in. Generally this means heating up the material to a high temperature – but heating up plastic causes the stuff to turn into a nasty mess. It also wastes a lot of energy, meaning more greenhouse gas emissions
?我在加州大學(xué)圣塔芭芭拉分校的團(tuán)隊(duì)與來自伊利諾伊大學(xué)厄本那-香檳分校和康奈爾分校的同事合作，發(fā)現(xiàn)了一種可以將聚乙烯轉(zhuǎn)變成有用的較小分子的干凈利落的方法。
?My team at UC Santa Barbara, working with colleagues at the University of Illinois Urbana-Champaign and Cornell,?discovered a clean way to turn polyethylene?into useful smaller molecules.
?? 聚乙烯是世界上最有用且最常用的塑料材料之一，它同時也是塑料垃圾的促成因素之一。全球每年生產(chǎn)將近4億噸的塑料，它占據(jù)了三分之一。其用途從無菌食品包裝、防水膜涂料，電纜、電線絕緣外殼，建筑材料、水管到耐磨髖關(guān)節(jié)和膝蓋的替換物，甚至是防彈背心。（可見其用途之廣泛）。
?? Polyethylene is one of the world’s most useful and most used plastic types. It is also one of the largest contributors to plastic waste. It represents a third of the nearly 400 million metric tons of plastic the world makes every year, for purposes ranging from sterile food and medical packaging, waterproof films and coatings, cable and wire insulation, construction materials and water pipes, to wear-resistant hip and knee replacements and even bulletproof vests.
?那這項(xiàng)新工程是如何運(yùn)作的呢？
How the new process works
A simple one-pot process turns polyethylene plastic waste into valuable liquids when it is exposed to a solid chemical catalyst and a little heat.
?? 我們所研發(fā)出來的工程（過程）不需要將塑料（聚合物）進(jìn)行高溫處理，而是運(yùn)用到少量的催化劑——這種催化劑中含有可以從聚合物鏈中除去氫原子的金屬。然后催化劑用除去的氫對與碳鏈固定在一起的碳鍵進(jìn)行切割，從而將一整條長碳鏈分成一塊塊小碎片。
?? The process we have developed does not require high temperatures, but instead depends on tiny amounts of a catalyst containing a metal that removes a little hydrogen from the polymer chain. The catalyst then uses this hydrogen to cut the bonds that hold the carbon chain together, making smaller pieces.
?關(guān)鍵點(diǎn)在于氫分子一旦形成就要立即使用，以使鏈切割為制造更多的氫提供能量。每條鏈重復(fù)多次此過程從而將固體聚合物變成液體。
?The key is using the hydrogen as soon as it forms so that the chain-cutting provides the energy for making more hydrogen. This process is repeated many times for each chain, turning the solid polymer into a liquid.
?? 當(dāng)分子達(dá)到一定大小時，切割速度便會自然減慢，因此防止分子變的太小是很容易的。我們能夠在將有價值的液體轉(zhuǎn)變?yōu)橛杏玫臍怏w之前對其進(jìn)行回收利用。
The chopping slows down naturally when the molecules reach a certain size, so it’s easy to prevent the molecules from becoming too small. We’re able to recover the valuable liquid before it turns into less useful gases.
?? 這些回收的液體中大多數(shù)分子是烷基苯，它們可用作溶劑且很容易就可轉(zhuǎn)變成清潔劑。這類分子（烷基苯）在全球市場上每年約9億元。
A majority of the molecules in the recovered liquid are alkylbenzenes, which are useful as solvents and can easily be turned into detergents. The global market for this type of molecule is about?US$9 billion annually.
? 將廢棄的塑料轉(zhuǎn)變成有價值的分子稱為“升級循環(huán)（up cycling）”。盡管我們的研究只是一個小規(guī)模的示范，但通過初步的經(jīng)濟(jì)分析表明，這項(xiàng)工程很容易在接下來的幾年中得以適應(yīng)并進(jìn)行更大規(guī)模的推廣。通過以具有良好經(jīng)濟(jì)意義的方式重復(fù)使用這些塑料，將這些塑料與環(huán)境相隔離，是雙贏的表現(xiàn)。
Turning waste plastic into valuable molecules is called upcycling. Although our study represented a small-scale demonstration, a preliminary economic analysis suggests that it could easily be adapted to become a much larger-scale process in the next few years.?Keeping plastic out of the environment by reusing it in a way that makes good economic sense is a win-win.
個人觀點(diǎn)：塑料的使用有利有弊，正所謂“Everything has tow sides.”。如今塑料已離不開我們都生活，而將廢棄的塑料轉(zhuǎn)化為高價值的新能源正是對塑料回收利用的創(chuàng)新型轉(zhuǎn)化，創(chuàng)造性發(fā)展。
? 當(dāng)然，我們不能只依賴于回收利用，在生活中我們也應(yīng)當(dāng)減少對塑料制品的使用，減少對塑料制品的依賴性。我們不能在短時間內(nèi)使得生態(tài)環(huán)境得以改善，但我們可以阻止其繼續(xù)惡化。所以，減塑行動，人人有責(zé)！
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參考文獻(xiàn)網(wǎng)址：https://theconversation.com/most-plastic-recycling-produces-low-value-materials-but-weve-found-a-way-to-turn-a-common-plastic-into-high-value-molecules-148506
