8.5 Acid Deposition

rainwater ph

5.6

rainwater equations

CO2 + H2O > H2CO3

H2CO3 > H+ + HCO3-

HCO3- > H+ + CO3 2-

major pollutants that cause acid deposition

sulfur dioxide (SO2) and nitrogen oxides (NO, NO2)

how nitrogen II oxide forms

N2 + O2 > 2NO

how nitrogen IV oxide forms

2NO + O2 > 2NO2

how do nitric acid and nitrous acid form

2NO2 + H2O > HNO3 + HNO2

how does nitrous acid make nitric acid

2HNO2 + O2 > 2HNO3

how is sulfur dioxide formed

S + O2 > SO2

how is sulfur trioxide formed

2SO2 + O2 > 2SO3

how is sulfurous acid formed

SO2 + H2O > H2SO3

H2SO3 + H2O > HSO3- + H3O+

how is sulfuric acid formed

SO3 + H2O > H2SO4

what do building materials contain

calcium carbonate CaCO3

how does calcium carbonate react with acid rain

CaCO3 + H2SO4 > CaSO4 + CO2 + H2O

how does iron react with acid rain

Fe+ H2SO4 > FeSO4 + H2

what are pre-combustion methods

used to reduce sulfur emissions, applied to fuels before combustion, can be done through physical cleaning or mineral beneficiation

what is a pre-combustion method

crushing coal, then using flotation to reduce the sulfur, can remove up to 80-90% of inorganic sulfur

what are post-combustion methods

remove sulfur dioxide, nitrogen oxides, heavy metals and dioxins from combustion gases before release into the atmosphere

what is a post-combustion method

calcium oxide or lime reacts with sulfur dioxide to remove it from flue gases

CaO + SO2 > CaSO3