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  • Let's do a small experiment

    讓我們做一個小實驗

  • Would you rather drink this water, or this water?

    你願意喝這個水,還是這個水?

  • Well, of course you would choose the water on the left

    那你當然會選擇左邊的水了

  • Unfortunately, some people in other parts of the world have no choice at all

    不幸的是,世界上其他地方的一些人別無選擇。

  • Did you know that small floating particles in drinking water can

    您是否知道飲用水中的小漂浮顆粒可以

  • make you sick? Imagine we have a super powerful microscope and we can

    讓你生病?想象一下,我們有一個超級強大的顯微鏡,我們可以。

  • zoom into the water. ZOOM!

    放大到水中。ZOOM!

  • What will we find? What are these small, floating particles,

    我們會發現什麼?這些漂浮的小顆粒是什麼。

  • and how do they float? These particles are of two types:

    以及它們是如何漂浮的?這些顆粒有兩種類型。

  • inorganic (like clay, silt, and mineral oxides) and

    無機物(如粘土、淤泥和礦物氧化物)和

  • organic (such as algae, protozoa, and bacteria).

    有機物(如藻類、原生動物和細菌);

  • The bacteria, once ingested by humans, can sometimes be fatal.

    這種細菌一旦被人類攝入,有時會致命。

  • All of these small particles are able to float, because they are not heavy enough

    所有這些小顆粒都能漂浮起來,因為它們不夠重。

  • to settle to the bottom by gravity. Suspended particles that are too

    在重力作用下沉入海底。懸浮顆粒如果太大

  • light and small to settle are called colloids.

    輕而小的沉降稱為膠體。

  • When looked at together, these colloids cause a state of cloudiness

    當這些膠體一起看時,會造成一種渾濁的狀態。

  • or haziness, known as turbidity. The more cloudy a fluid looks, the more

    或朦朧感,稱為濁度。液體看起來越渾濁,就越是

  • turbid it is. Here we see four beakers of

    它是渾濁的。在這裡,我們看到四個燒杯的

  • water with increasing levels of turbidity, from left to right.

    水的渾濁程度越來越高,從左到右。

  • There is a relation between turbidity and the risk of getting a disease.

    渾濁度和得病的風險是有關係的。

  • Science shows that the more turbid

    科學表明,越是渾濁的

  • the drinking water is, the higher the risk of getting sick is.

    飲水越多,生病的風險越大。

  • Now why is this? This is because toxic compounds can

    現在為什麼會這樣呢?這是因為有毒化合物可以

  • adsorb, that is, stick to the surface of the suspended colloids.

    吸附,即粘附在懸浮膠體的表面。

  • The more colloids there are, the more toxic the water can become.

    膠體越多,水的毒性就越大。

  • These toxic materials and bacteria can cause cholera,

    這些有毒物質和細菌可以引起霍亂。

  • salmonellosis, hepatitis A, dysentery,

    沙門氏菌病、A肝、痢疾。

  • and e-coli infection. These illnesses effect and kill

    和大腸桿菌感染。這些疾病影響和殺死

  • millions of people a year, and are especially dangerous to children, whose weak

    每年有數以百萬計的人死亡,對兒童尤其危險,因為他們的身體虛弱。

  • immune systems cannot provide an adequate defense.

    免疫系統無法提供足夠的防禦。

  • Fortunately, we can do something about this! One of the very

    幸運的是,我們可以做一些事情!其中一個非常

  • practical ways to clean this turbid water is called flocculation

    清理這種渾濁的水的實用方法叫做絮凝法

  • Flocculation is the process in which colloids aggregate,

    絮凝是膠體聚集的過程。

  • or come together to form larger particles called flocks, by the addition

    或聚集在一起形成更大的顆粒,稱為羊群,通過添加。

  • of a chemical called a flocculant. Typical flocculants

    稱為絮凝劑的化學物質。典型的絮凝劑

  • include Alum and Ferrix, because they work well with high turbidity fluid mixtures

    包括Alum和Ferrix,因為它們能很好地處理高濁度流體混合物。

  • Now, let's demonstrate how flocculation works. First, we'll need

    現在,讓我們來演示一下絮凝的工作原理。首先,我們需要

  • to go out and collect some muddy water from the Charles River

    去收集一些查爾斯河的泥水。

  • Here are two beakers filled with the same amount of muddy Charles River water

    這裡有兩個燒杯,裝滿了同樣數量的查爾斯河泥水。

  • On the left is our control, which will remain untouched,

    左邊是我們的控制權,它將保持不受影響。

  • and on the right, we'll add 3mL of prepared flocculant solution

    在右邊,我們將添加3mL準備好的絮凝劑溶液。

  • Then we'll stir for two minutes, and wait

    然後我們會攪拌兩分鐘,然後等待。

  • Wow! What just happened?

    哇!剛剛發生了什麼?

  • The colloids in the turbid water on the left may never settle

    左邊濁水中的膠體可能永遠不會沉澱下來

  • whereas, with the addition of just a little bit of flocculant

    而只要加一點絮凝劑

  • the water on the right became clear.

    右邊的水變得清澈起來。

  • In order to make this water potable, it will require skimming and filtration

    為了使這些水可以飲用,需要進行脫脂和過濾。

  • and maybe some additional treatment

    也許還需要一些額外的治療

  • If you're wondering what's going on, let's explain how this flocculant business works.

    如果你'想知道是怎麼回事,讓我們'來解釋一下這個絮凝劑業務是如何工作的。

  • Almost all colloids have negatively charged surfaces

    幾乎所有的膠體都有帶負電的表面。

  • This means that positive ions, or charged particles in water

    這意味著,正離子,或水中的帶電粒子。

  • will attract to the colloid surface, forming a first layer.

    將吸引到膠體表面,形成第一層。

  • Recall how like poles of a magnet will repel, while opposite poles will attract.

    回想一下磁鐵的同類極性會排斥,而相反極性會吸引。

  • The same occurs with colloids in water.

    水中的膠體也是如此。

  • A diffuse layer, made up of a mix of positive and negative ions will then surround the first

    然後,由正負離子混合組成的擴散層將包圍第一層。

  • forming what is called a double layer.

    形成所謂的雙層。

  • This double layer provides a repulsive force which prevents two colloids from sticking to each other.

    這種雙層提供了一種排斥力,防止兩個膠體相互粘連。

  • Once the flocculant is added, it adheres to the surfaces of the particles,

    一旦加入絮凝劑,它就會附著在顆粒的表面。

  • compressing the double layer,

    壓縮雙層。

  • and allowing the colloids to stick to each other and form "flocks"

    並讓膠體相互粘連,形成"群&quot。

  • These flocks are now heavy enough to settle to the bottom by gravity.

    這些羊群現在已經很重了,可以靠重力沉澱到底部。

  • Given how effective flocculation is, many countries around the world

    鑑於絮凝的效果,世界上許多國家

  • use this method for cleaning their water supplies.

    使用這種方法來清洗他們的供水。

  • Did you know that Singapore, for instance, produces drinking water from sewer water

    你知道嗎,比如新加坡,用下水道的水生產飲用水。

  • using a number of methods, including flocculation?

    採用多種方法,包括絮凝?

  • As the global population increases

    隨著全球人口的增加

  • and freshwater resources become more and more scarce

    淡水資源越來越稀缺的問題。

  • flocculation is one tool that can supply clean, healthy, and tasty drinking water

    絮凝是一種可以提供清潔、健康和美味飲用水的工具。

  • worldwide.

    在全球範圍內,

Let's do a small experiment

讓我們做一個小實驗

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