336945715-Electrochemistry-Chloralkali.pptx

chlor alkali industry

1. Electrochemistry- Chloralkali By: Gishan Navaratne

2. What Is the Chloralkali industry The Chloralkali industry is a essential part of todays chemical industry's. In this industry electrolysis is used to produce several products such as, sodium hydroxide( caustic soda), chlorine and hydrogen, from the reactant brine. ¾ of the chlorine produces comes from the Chloralkali industry Uses for sodium hydroxide

3. History and facts 1888 - Hermann Nernst developed the theory of the electromotive force of the voltaic cell Although the first formation of chlorine by the electrolysis of brine was attributed to Cruikshank [10] in 1800, it was 90 years later that the electrolytic method was used successfully on a commercial scale  There are three primary electrolytic processes for producing chlorine and caustic soda: the diaphragm cell process, the mercury cell process, and the membrane cell process. The first two have been used for over 100 years; the latter was developed in the past 60.   In 2016, European chlorine production was nearly 9.7 million tonnes Approximately 85% of all pharmaceuticals contain chlorinated compound 86% of crop protection chemicals are made with chlorine chemistry Chlorine kills pathogens --> breaks the chemical bonds in the pathogens 

4. Chloralkali process There are three electrolytic chloralkali process Mercury cell, Diaphragm cell and Membrane cell. Mercury cell and Diaphragm cell, have been proven to be the most environmentally unfriendly, due to asbestos and mercury. Membrane cell was a process later discovered and was proven to be more energy efficient and more environmentally friendly In this process brine is transformed to make chlorine and sodium hydroxide

5. Membrane cell process 1) Chlorine gas is formed through brine being oxidized, 2Cl−( aq ) → Cl2(g) + 2e− 2) Hydrogen gas is formed at the negatively charged cathode where H+ ions in the water is reduced, 2H2O(l) + 2e− → H2(g) + 2OH− 3) Sodium ions flow from the membrane to the cathode and reacts with OH- ions to produce caustic soda, Na+( aq ) + OH−( aq ) → NaOH ( aq ) 4) The membrane prevents CL- from passing though, and finally NaOh is removed from the cell The redox reaction is redox reaction is: 2NaCl(aq) + 2H2O(l) → Cl2(g) + H2(g) + 2NaOH(g)

6. Uses for chlorine and Sodium hydroxide

7. Disadvantages of Chloralkali industry Chlorine bleaching of wood pulp as well as dioxin emissions to the environment Asbestos is used in the diaphragm cell as a separator material. Asbestos is an extremely poisonous material, causing lung cancer and diseases, asbestosis and mesothelioma Most of the world still use Mercury cell and Diaphragm cell Polyvinyl chloride plastic, two huge environmental issues regarding PVC, which include their inability to biodegrade and their generation of dioxins when they are burned for controlled waste recycling.  Mercury leaching into the environment can cause However now due to the new method of membrane cells Chlorine gas can be in the form of posinous gas, which can kill, also it has an irritating odour which can be dangerous to some people exposed to it. If not handled carefully, it can react explosively or form explosive compounds with chemicals like ammonia.

8. Pictures

9. Advantages of Chloralkali industry

10. Work cited