ENVIRONMENTAL CHEMISTRY-2.pptxnnjjhvvfvhhjj

SULPHATE CONCENTRATION IN TAP WATER, BOREHOLE AND PROTECTED WELL WATER FROM LAROO-PECE DIVISION-GULU CITY

1. ENVIRONMENTAL CHEMISTRY Presented by GROUP B

2. QUESTIONS Briefly describe the methods of estimation of Carbon monoxide, Nitrogen dioxide, Nitrogen monoxide, Sulphur dioxide and Sulphur trioxide gases in the atmosphere and control procedure. Briefly describe Greenhouse effects and Global warming Describe briefly, ozone depletion by oxides of nitrogen, chlorofluorocarbons and halogens. Describe briefly the sustainable development goals related to managing global warming

3. Part (a) Methods for estimating and controlling atmospheric gases Carbon Monoxide (CO) Estimation: The most common method for estimating carbon monoxide is Non- Dispersive Infrared (NDIR) Spectroscopy. This technique is based on the principle that CO gas absorbs infrared (IR) radiation at a specific wavelength (4.67 µm). A sample of air is passed through a chamber. An IR beam is directed through the chamber, and the amount of IR light that reaches a detector on the other side is measured. The less light that reaches the detector, the higher the concentration of CO in the air sample. The method is highly selective and provides a continuous measurement

4. Part (a) ;Methods and control continue………

5. Part (a) ;Methods and control continue……. The primary source of CO is the incomplete combustion of fossil fuels, mainly from vehicle engines. The most effective control method is the use of three-way catalytic converters in vehicles. The converter contains a platinum, palladium, and rhodium catalyst that promotes the oxidation of CO to carbon dioxide. Chemical Equation: 2CO(g) + (g ) → 2 (g ) Industrial sources can be controlled by improving combustion efficiency and using filters.  

6. Part (a) ; Methods and control continue……….. Nitrogen Oxides (NOx) Estimation: The most widely used method for measuring nitrogen oxides (NO and ) is Chemiluminescence. This method is based on the chemical reaction between nitric oxide (NO) and ozone ( ). When NO reacts with , it produces an excited nitrogen dioxide molecule ( ). Chemical Equation: NO(g) + (g ) → (g ) + (g ) This excited molecule then releases a photon of light as it returns to a stable state. Chemical Equation: (g ) → (g ) +h ν ( light) The intensity of the light produced is directly proportional to the concentration of NO. To measure total NOx ( NO+ ), the sample is first passed through a converter that reduces to NO, allowing the total to be measured by the same process.  

7. Part (a) ;Methods and control continue….

8. Part (a) ;Methods and control continue…… Control: NOx gases are formed during high-temperature combustion processes (e.g., in engines and power plants) when nitrogen and oxygen in the air react. Control methods focus on either preventing their formation or removing them from exhaust gases. Catalytic Converters: In vehicles, catalytic converters also reduce NOx back to nitrogen gas. Chemical Equation: 2NOx(g) → x (g ) + (g ) Selective Catalytic Reduction (SCR): This is a key method for large industrial sources. Ammonia ( ) or urea is injected into the exhaust stream. In the presence of a catalyst, NOx reacts with the ammonia to form harmless nitrogen gas and water. Chemical Equation: 4NO(g) + 4 (g ) + (g ) → 4 (g ) + 6 (l )  

9. Part (a) : Methods and control continue….. Sulphur Oxides (SOx) Estimation: A common method for estimating sulfur dioxide ( ) is Ultraviolet (UV) Fluorescence Spectrometry. The method involves exposing a sample of air to UV light. The molecules absorb the energy from the UV light and get excited. As they return to their ground state, they emit light at a lower wavelength (fluorescence). The intensity of this fluorescent light is directly proportional to the concentration of .  

10. Part (a) : Methods and control continue……….

11. Part (a) : Methods and control continue……. Control: The primary source of SOx is the combustion of sulfur-containing fossil fuels like coal and crude oil. The most effective control method is Flue Gas Desulfurization (FGD) , also known as "scrubbing." This involves passing the hot flue gases through a slurry of an absorbent, typically limestone (CaCO3) or lime (Ca(OH)2). The SO2 gas reacts with the absorbent to form a solid sulfate or sulfite, which can be safely disposed of. Using Limestone: CaCO3(s) +SO2(g) → CaSO3(s) +CO2(g) Using Lime : Ca(OH)2(s) +SO2(g) → CaSO3(s) +H2O(l) Another method is to simply use low-sulfur fuels .

12. Part (b) Green House effect and global warming Greenhouse Effect: This is a natural process that warms the Earth's surface and atmosphere. Certain gases in the atmosphere, known as greenhouse gases (GHGs), such as water vapor ( ), carbon dioxide ( ), methane ( ), and nitrous oxide ( ), act like a blanket. They are transparent to incoming solar radiation, allowing it to reach the Earth's surface. However, they are very good at absorbing and re-radiating the outgoing infrared (IR) radiation (heat) from the Earth's surface. This trapped heat warms the lower atmosphere and the Earth's surface, making life possible.  

13. Causes of Green House effect Burning of fossils. Industries that use coal, oil and natural gas as fuel, together with power plants are the largest sources of Carbon dioxide generation which is the main gas that contributes to the greenhouse effect. Fossil fuel modes of transport such as bcars, trucks also generate large amounts of Carbon dioxide. Agriculture and livestock. Agricultural and livestock activities generate two of the main greenhouse gases: methane and nitrous oxide is generated in the anaerobic decomposition of agricultural and organic waste in land fills .Deforestation. Natural vegetation masses such as forests have a remarkable ability to absorb carbon dioxide. As the deforestation of the forest surface continues, the atmosphere will retain large proportions of such harmful greenhouse gases. Use of industrial chemicals . Fluorinated gases, chlorofluorocarbons, hydroflourocarbonand perfluorocarbons are used in chemicals like aerosols and foams..

14. GLOBAL WARMING

15. Part (b) Continuing……….. Global Warming: This refers to the long-term rise in the average temperature of the Earth's climate system. It is primarily caused by an increase in the concentration of GHGs in the atmosphere, resulting from human activities such as the burning of fossil fuels (coal, oil, and gas), deforestation, and certain agricultural practices. This human-induced increase in GHGs enhances the natural greenhouse effect, causing more heat to be trapped and leading to an abnormal and rapid increase in global temperatures, which has severe consequences for ecosystems and human societies

16. Effects of Global warming and Agriculture

17. Impact of global warming

18. Part (c) . Ozone depletion The ozone layer, located in the stratosphere, plays a crucial role by absorbing most of the sun's harmful ultraviolet (UV) radiation. The depletion of this layer is caused by human-made chemicals, primarily chlorofluorocarbons (CFCs), halogens, and oxides of nitrogen (NOx). These compounds are very stable in the lower atmosphere but are broken down by intense UV radiation in the stratosphere, releasing highly reactive atoms that act as catalysts in a chain reaction to destroy ozone molecules ( ).  

19. OZONE DEPLETION

20. Part (c) continuing…………… Chlorofluorocarbons (CFCs): A chlorine atom is released from a CFC molecule by UV radiation. This atom then begins a catalytic cycle. Photolysis : A CFC molecule breaks down due to UV light, releasing a chlorine atom. Chemical Equation: ( g) → (g ) + Cl(g) Ozone Destruction: The chlorine atom reacts with an ozone molecule, destroying it and forming chlorine monoxide (ClO) and an oxygen molecule(O2). Chemical Equation: Cl(g) + (g ) →ClO(g) + (g) Chlorine Regeneration: The chlorine monoxide then reacts with a free oxygen atom (also present in the stratosphere), which breaks it apart and regenerates the chlorine atom, allowing it to destroy more ozone molecules. Chemical Equation: ClO(g) +O(g) →Cl(g) + (g) A single chlorine atom can destroy thousands of ozone molecules before being removed from the stratosphere.  

21. Part (c) continuing……….. Oxides of Nitrogen (NOx): Nitrous oxide ( ), released from agricultural activities and industrial processes, travels to the stratosphere where it reacts with an excited oxygen atom to form nitric oxide (NO). Chemical Equation: (g ) +O(g) →2NO(g) This NO then acts as a catalyst in a similar cycle to chlorine, destroying ozone molecules and being regenerated in the process. Chemical Equation: NO(g) + (g ) → (g ) + (g ) Chemical Equation: (g ) +O(g) →NO(g) + (g )  

22. SUSTAINABLE DEVELOPMENT GOALS RELATED TO MANAGING GLOBAL WARMING SDG 13: Climate action SDG 7: Affordable and Clean energy SDG 11: Sustainable cities and communities SDG 12: Responsible consumption and production SDG 15: Life on land

23. SDG 13: CLIMATE ACTION It deals with taking urgent action to combat climate change and its impacts. It is the most direct rule and aims at strengthening resilience and adaptive capacity to climate related hazards, integrate climate change awareness on climate change. It calls for mobilizing financial resources to help developing countries implement climate change mitigation and adaptation strategies. It also calls for integration of climate change measures into policies and planning and building knowledge and capacity to meet climate change.

24. SDG 13 CONTINUED It also calls for promotion of mechanisms to raise capacity for climate planning and management and implementation of UNFCCC (United Nations Framework Convention on Climate Change ) which was adopted in 1992 whose goal was to stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system.

25. SDG 7: AFFORDABLE AND CLEAN ENERGY It ensures access to affordable, reliable, sustainable and modern energy for all. By promoting renewable energy sources like solar, wind and hydro electric. It also directly addresses the largest source of green house gas emissions like burning of fossil fuels. The goal targets by 2030; Increase substantially the share of renewable energy in the global energy mix and double the global rate of improvement in energy efficiency.

26. SDG 7 CONTINUED Enhance international cooperation to facilitate access to clean energy research and technology, including renewable energy, energy efficiency and advanced and cleaner fossil-fuel technology, and promote investment in energy infrastructure and clean energy technology. Expand infrastructure and upgrade technology for supplying modern and sustainable energy services for all in developing countries, in particular least developed countries, small island developing States, and land-locked developing countries.

27. SDG 11: SUSTAINABLE CITIES AND COMMUNITIES It aims at making cities and human settlements inclusive, safe, resilient and sustainable. This includes reducing the adverse per capita to environmental impact of cities which is a major contributor to global warming due to high energy consumption and waste production.

28. SDG 12: RESPONSIBLE CONSUMPTION AND PRODUCTION It ensures sustainable consumption and production patterns. It promotes resource efficiency and sustainable use of resources reducing waste, promoting recycling and encouraging sustainable consumption patterns to help reduce emissions related to manufacturing, transportation and waste management.

29. SDG 15: LIFE ON LAND It deals with protecting, restore and promote sustainable use of terrestrial ecosystems, sustainably manage forests, combat desertification and halt and reverse land degradation and halt biodiversity.

30. References United Nations Uganda. ( n.d. ). Sustainable Development Goals in Uganda . https://uganda.un.org/en/sdgs United Nations Development Programme (UNDP). (2021). Roadmap for the implementation of the SDGs in Uganda 2020/21 – 2024/25 [PDF]. UNDP Uganda. Office of the Prime Minister, Uganda. (2022). SDGs Road Map 2021-2025 [PDF]. https://sdgs.opm.go.ug/wp-content/uploads/2022/05/SDGs-Road-Map-2021-2025. UN Sustainable Development Goals. ( n.d. ). National commitments: Uganda . https://sdgs.un.org/national-commitments-sdg-transformation/23506 West, P. W., & Gaeke, G. C. (1956). Analytical Chemistry, 28(12), 1816–1819.

31. Reference NASA Global Climate Change. (2023, March 15). The greenhouse effect . https://climate.nasa.gov/causes/ . NASA Climate change and global warming