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SO2
NOx
파일
• Combustion of S in fossil fuels
• Smelting (metal ore extraction)
• S + O2 → SO2
• Internal combustion engine
• NO and NO2 formation
• N2 + O2 → NO
• NO unstable and forms NO2 in air
◦ 2NO + O2 → 2NO2
2SO2 + 2H2O → 2H2SO3 (sulfurous acid)
In the presence of O2:
2H2SO3 + O2 → 2H2SO4 (sulfuric acid)
NO2 + H2O → HNO2 + HNO3 (nitrous acid + nitric acid)
In the presence of O2:
2HNO2 + O2 → 2HNO3
CaCO3(s) + H2SO4(aq) → CaSO4(aq) + H2O(l) + CO2(g)
(metal carbonate + acid reaction)
CaCO3(s) + 2HNO3(aq) → Ca(NO3)2(aq) + H2O(l) + CO2(g)
(metal carbonate + acid reaction)
Fe(s) + H2SO4(aq) → FeSO4(aq) + H2(g)
(metal + acid reaction)
Al2O3(s) + 6HNO3(aq) → 2Al(NO3)3(aq) + 3H2O(l)
(metal oxide + acid reaction)
Leaching
1. solubilisation of mineral ions in soil, Mg2+, Ca2+, and K+
2. reduced absorption by plants
3. Dysfunctional, e.g. photosynthesis not possible without Mg2+
Toxicity
1. solubilisation of Al(OH)3 (insoluble in water) - plant root damage by Al3+
2. dry deposition block gas exchange pores
Toxicity
1. many fish cannot survive at pH below 5
2. solubilisation of Al(OH)3 (insoluble in water) - reduced O2 absorption by interfering with fish gill
Eutrophication of water bodies
1. Over-fertilisation due to excess nitrates
2. Algal bloom/blockage of sunlight/O2 depletion
Pre-combustion methods
→ hydrodesulfurization: production of HS instead of SO2 which can then be recaptured to form sulfur
Post-combustion methods
→ flue gas treatment : running SO2 gas through CaO to capture CaSO4
CaO(s) + SO2(g) → CaSO3(s)
CaCO3(s) + SO2(g) → CaSO3(s) + CO2(g)
2CaSO3(s) + O2(g) → 2CaSO4(s)
Catalytic converters in vehicles
→ conversion of NO to N2 and O2, conversion of CO and hydrocarbons to CO2 and H2O
Three reactions of the catalytic converter:
1. NO → N2 + O2
1. 2CO + O2 → 2CO2
1. CxH2y + (x+ ½y)O2 → xCO2 + yH2O*
*for a generic hydrocarbon
https://lh7-us.googleusercontent.com/C9a0u_SVPzfErsed_3EYwHMG6cmZxuKbUSoonZZijeZA_xJpTemtmZSwvAeWLcLB01dhnXap4jdI2YqsPNkem_xSa3-UIhbcuVPvgpmXJzNQ0Pw5Q6HP0q1sXeC96_wkGbIBgd7VNCAJQCjGnUtVSjY