问题 问答题 简答题

叙述一级复床除盐的原理。

答案

参考答案:

一级复床除盐,即水先后通过阳床、脱CO<sub>2</sub>器和阴床来完成。(1)当水通过内部装有H型阳树脂的阳床时发生反应,反应结果是树脂逐层转成金属型,而交换出来的H<sup>+</sup>与水中HCO<sup>3-</sup>、Cl<sup>-</sup>、SO4<sup>2-</sup>等形成稀的酸溶液。(2)当经脱CO<sub>2</sub>后的中间水与阴床中的OH型树脂接触时,会发生反应,从阴树脂中交换下来的OH<sup>-</sup>与从阳树脂中交换下来的H<sup>+</sup>反应生成水,这样水中的盐将基本全部除去,从而获得纯净的一级除盐水。

 

填空题
阅读理解

阅读理解。

     A simple piece of clothesline hangs between some environmentally friendly Americans and their neighbors.

     On one side stand those who see clothes dryers (干衣机) as a waste of energy and a major polluter of the

environment. As a result, they are turning to clotheslines as part of the "what-I-can do environmentalism (环境

保护主义)."

     On the other side are people who are against drying clothes outside, arguing that clotheslines are unpleasant

to look at. They have persuaded Homeowners Associations (HOAs) access the U.S. to ban outdoor clotheslines,

because clothesline drying also tends to lower home value in the neighborhood. This had led to a Right-to-Dry

Movement that is calling for laws to be passed to protect people's right to use clotheslines.

     So far, only three states have laws to protect clothesline. Right-to-Dry supporters argue that there should

be move.

     Matt Reck, 37, is the kind of eco-conscious (有生态意识的) person who feeds his trees with bathwater

and reuses water drops from his air conditioners to water plants. His family also uses a clothesline. But on July

9, 2007, the HOA in Wake Forest, North Carolina, told him that a dissatisfied neighlzir had telephoned them

about him clothesline. The Recks paid no attention to the warming and still dried their clothes on a line in the

yard. "Many people e say they are environmentally friendly but they don't take matters in their own hands,"

says Reck. The local HOA has decided not to take any action, unless more neighbors come to them.

     North Carolina lawmakers are saying that banning clotheslines is not the right thing to do. But HOAs and

housing businesses believe that clothesline drying reminds people of poor neighborhoods. They worry that if

buyers think their future neighbors can't even afford dryers, housing prices will fall.

     Environmentalists say such worries are not necessary, and in view of global warming, that idea needs to

change. As they say, "The clothesline is beautiful. Hanging clothes outside should be encouraged. We all have

to do at least something to slow down the process of global warming."

1. One of the reasons why supporters of clothes dryers are trying to ham clothesline drying is that _____.

A. clothes dryers are more efficient

B. clothesline drying reduces home value

C. clothes dryers are energy-saving

D. clothesline drying is not allowed in most U.S. states

2. Which of the following best describes Matt Reck?

A. He is a kind-hearted man.

B. He is an impolite man.

C. He is and experienced gardener.

D. He is a man of social responsibility.

3. Which of the following best describes Matt Reck?

A. He is a kind-hearted man.

B. He is an impolite man.

C. He is and experienced gardener.

D. He is a man of social responsibility.

4. What is mainly discussed in the text?

A. Clothesline drying: a way to save energy and money.

B. Clothesline drying: a lost art rediscovered.

C. Opposite opinions on clothesline drying.

D. Different varieties of clotheslines.