26
1.5
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
-3.5
-4.0
-4.5
-5.0
-5.5
-6.0
-6.5
-7.0
-7.5
-8.0
-8.5
-9.0
-9.5
-10.0
-10.5
-11.0
-11.5
-12.0
-12.5
-13.0
pH Variation
∏!!!≡!
Exposure to HCl
• HCl Present (n=3)
a HCl Absent (n=3)
10 20 30 40 50 60 70
Time (minute)
Figure7: pH variations under laser treatment in the presence and absence of
concentrated HCl with the setup in Figure 2. The pH value at the starting point
is set to zero. The difference in pH value from control in which HCl was absence
is about 0.07 after 50 minute of exposure to HCl. Various experiments done
with direct additions of HCl to the remote water also repeated showed
decreases in pH value in the water being measured. Statistical analysis
performed on data collected after exposure to HCl for 30 minutes show that the
results are significant different from control.