pH Neutralization For Pollution Control

Mahesh Parikh                  Daniel Boone
                               6710 N. Washetenaw Ave.
                               Chicago IL 60645
                               (312) 534-2160

Objectives:

1. Acid and Base Recognition
2. Neutralization of Acid and Base Chemicals for Pollution Control
3. Practical Application For Chemical Industries
                                  
Materials needed:

Vinegar (Acetic acid)
Baking Soda
Distilled Water
Hydrogen peroxide
Detergent
All purpose cleaner
Industrial effluent
Caustic lye (NaOH)         
pHydrion paper 
Ammonia 
Lime 
Beakers, test tubes, stirrers

Strategy:

Divide whole class into four groups.  Each person from respective group 
takes vinegar solution in beaker about 10mL.  Each group should also collect
pHydrion paper.  Then each group has to dip pHydrion paper into vinegar
solution and observe the color.  From the color of the pHydrion paper, each
group will decide pH numerical value by referring to the color chart.  Each
group should record the pH value in record data sheet.  From pH value, each
group will be able to decide whether vinegar solution is acidic or alkaline.

      Second chemical solution to be given to each group is washing soda. Repeat 
the same procedure. 

      Third chemical solution to be given to each group is hydrogen peroxide.  
Repeat the same procedure.   

      Then the teacher demonstrates dilute hydrochloric acid to show its pH 
value, that is acidic. 

      Next, pH of mild detergent is to be tested, that is almost neutral.

      Other solutions we tested were all purpose cleaner, ammonia, caustic lye, 
and industrial effluent.

      Thereafter ask each group to make a chart.  Let them prepare three 
columns, one for acid, one for base, and one for neutral.  Discussed results 
with students.  Have students continue filling results in data chart. 

      After testing industrial effluent class discussed consequences of its 
disposal to sewer system. 

      Take 20mL of hydrochloric acid in beaker.  Add same amount of lime (CaCO3)
into beaker.  Stir it and measure its pH value.  If mixed solution is not 
achieving pH value as 7 then keep on adding lime solution until it achieves pH
value as 7.  At this point, titration is said to be completed.  Explain to 
students that quantity of lime material required for neutralization depends on
concentration of acid.  
    
      After this, explain to the students that is why lime is commonly used for 
neutralizing industrial effluent.  The reasons explained were that lime is a
strong base, economical, and most to use.

      Second neutralization process shown to students was caustic lye, and 
strong hydrochloric acid.  

Application:

Use overhead projector to show transparency of standard model of small scale 
industry pollution treatment plant, explain its operation, and design.

Conclusion:

During enrichment sessions, we had discussed the importance of neutralization 
process.  Students explained that if industrial effluent is not neutralized then 
effluent will corrode the sewer pipelines and it will penetrate inside the soil.  
Seepage of effluent remains as ground water so when a tube well is used, the 
water will come out polluted.  This polluted water is toxic and harmful for 
domestic purpose.