氯氟烃和臭氧消耗
科学创新正在快速推进。污染也因此而上升。污染正在引起地球大气的变化。大多数污染物是由人类活动产生的,例如燃料燃烧、工业运营、机动车辆等。二氧化碳、一氧化碳、氮氧化物、二氧化硫、燃料的小固体颗粒、CFC、HFC 和其他有害化学化合物被排放到环境中。森林大火和火山爆发的增加正在加剧这个问题。 CFC 是最严重的污染物之一。让我们深入了解氯氟烃。
氯氟烃
Chlorofluorocarbon is a man-made chemical substance that does not exist in nature. They are synthetic gases. It is a volatile derivative of methane, ethane, and propane that includes carbon, chlorine, and fluorine.
此外,我们可能会在大气中检测到它,因为它会持续很长时间。氯氟烃简称为 CFC,具有以下特性:
- CFC 的生产通常称为氟利昂。
- 在过去的 50 年中,CFC 的排放量急剧增加。
- 它是一种无色、无味、化学惰性的气体。
- CFC 也是造成温室效应的气体之一。
- 由于它与臭氧粒子的破坏性相互作用,它特别危险,臭氧粒子保护地球免受紫外线辐射。
氯氟烃的来源
氟氯化碳主要存在于一些特殊商品中,例如:
- 飞机哈龙:一些国家的航空部门继续使用基于哈龙的灭火系统。它也是一种含 CFC 的冷却剂。要处理这种有害化学物质或回收材料,必须采取决定性的步骤。
- 气溶胶喷雾:含 CFC 的气体用于气溶胶罐和推进剂液体中。该行业正在逐渐过渡到危害较小的碳氢化合物。另一方面,CFC 的使用寿命为 50 至 100 年,并继续对前几十年造成的危害产生影响。
- 空调和冰箱: CFC 最常通过制冷剂排放。冰箱、空调和汽车中使用的冷却剂如果处理不当,会将 CFC 泄漏到大气中。冷却剂要么蒸发,要么进入土壤,同时被 CFC 污染。
- 流氓 CFC:由于没有合适的处置技术或回收工艺,旧的和过期的制冷剂和气雾罐被扔在开放环境中。氟氯化碳从其中渗出,进一步污染环境。
Examples of Chlorofluorocarbons
- Dichlorodifluoromethane, CF2Cl2 (commonly known as CFC-12), is an example of a refrigerant CFC.
- Another formerly common CFC is trichlorofluoromethane, CFCl3 (CFC-11), which boils at 24°C and was originally employed as the propellant in over half of all aerosol cans used worldwide.
什么是臭氧层?
The ozone layer is an area of the earth’s stratosphere that contains high concentrations of ozone and shields the planet from the sun’s damaging UV radiation.
臭氧层位于地球的低层大气中。它能够吸收大约 97-99% 的太阳发出的破坏性紫外线辐射,这会影响地球上的生命。如果臭氧层不存在,数以百万计的人将患上皮肤病并损害免疫系统。
然而,科学家们在南极洲上空发现了一个臭氧洞。这将他们的注意力集中在不同的环境问题以及可能采取的解决这些问题的行动上。氯氟烃、四氯化碳、甲基溴和氢氯氟烃是臭氧空洞的主要原因。
臭氧层消耗
The progressive thinning of the earth’s ozone layer in the upper atmosphere caused by the discharge of chemical compounds containing gaseous bromine or chlorine from factories or other human activities is known as Ozone layer depletion.
臭氧层消耗是高层大气臭氧层的削弱。当大气中的氯和溴原子与臭氧发生反应,破坏臭氧分子时,就会发生这种情况。一个氯原子可以破坏 100,000 个臭氧分子。它被摧毁的速度比它产生的速度要快。
当一些化学物质暴露在高水平的紫外线辐射下时,它们会释放出氯和溴,从而导致臭氧层的消耗。这些物质被称为消耗臭氧层物质 (ODS) 。氯氟烃、四氯化碳、氢氯氟烃和甲基氯仿都是含有氯的臭氧消耗化合物。
哈龙、甲基溴和氢溴氟烃是消耗臭氧的含溴化合物。最常见的消耗臭氧层的化学物质是氯氟烃。只有当氯原子与另一个分子相互作用时,它才会与臭氧发生反应。
臭氧层消耗的影响
臭氧层的消耗会对环境产生负面影响。让我们看看臭氧层消耗对人类和环境造成的主要后果。
- 健康后果:由于臭氧层的消耗,人们将直接暴露在太阳有害的紫外线辐射下。这可能会导致人们出现严重的健康问题,例如皮肤病、癌症、晒伤、白内障、过早衰老和免疫系统减弱。
- 对动物的影响:动物因直接暴露于紫外线辐射而患上皮肤癌和眼癌。
- 对海洋生物的影响:暴露于破坏性的紫外线辐射对浮游生物有重大影响。它们位于水生食物链的顶端。如果浮游生物被杀死,食物链中的生物也会受到影响。
- 环境后果:由于强烈的紫外线辐射,植物的生长、开花和光合作用可能会减少。
示例问题
问题 1:我们如何减少环境中的氯氟烃?
解决方案:
Purchase air conditioning and refrigeration equipment that does not include CFCs as a refrigerant. Purchase aerosol goods that do not include CFCs as propellants. To avoid and limit refrigerant leakage, examine and maintain air-conditioning and refrigeration units on a regular basis.
问题 2:列出一些常用的 CFC。
解决方案:
Following are the two commonly used and well known CFCs:
- Dichlorodifluoromethane, CF2Cl2 (commonly known as CFC-12), is an example of a refrigerant CFC.
- Another formerly common CFC is trichlorofluoromethane, CFCl3 (CFC-11), which boils at 24°C and was originally employed as the propellant in over half of all aerosol cans used worldwide.
问题 3:为什么禁用 CFC?
解决方案:
Chlorofluorocarbons (CFCs) are a class of odorless synthetic compounds. CFCs have been prohibited since 1996 because they deplete the earth’s ozone layer. The depletion of the Ozone Layer will have a negative influence on the earth’s biodiversity. Excessive radiation striking the Earth’s surface will ruin agricultural production and even plant life. It will even result in skin cancer.
问题 4:必须使用哪些预防方法来减少臭氧层消耗?
解决方案:
Following are some preventive methods that must be used to reduce Ozone Layer Depletion:
- Reduce your usage of ozone-depleting chemicals.
- Vehicle usage should be minimized to the greatest extent feasible.
- Use Eco-Friendly Cleaning Supplies
- Nitrous Oxide use should be prohibited.
问题5:臭氧层枯竭的原因是什么?
解决方案:
It has been discovered that the ozone layer is influenced by natural factors such as sunspots and stratospheric winds. However, these have a negligible impact on ozone layer depletion, amounting to less than 1% to 2%, and hence their effects are transient. Some significant volcanic eruptions have also contributed to the ozone layer’s depletion.
Human activities, on the other hand, are the primary cause of ozone layer depletion. It arises as a result of the excessive usage of man-made chemicals such as bromine and chlorine, which are released from man-made compounds such as: chlorofluorocarbon, carbon tetrachloride, hydrochlorofluorocarbons, and methyl chloroform, all of which include chlorine.