f locculants for water treatment
DESCRIPTION
F locculants for Water Treatment. Date: May ???,2011 Speaker :Speaker A 、 Speaker B 、 Speaker C. Objectives. Flocculation of ferric hydroxide(Fe(OH) 3 ) colloidal solution is affected by the different pH values. → research the flocculation of Fe(OH) 3(aq) at different pH value - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/1.jpg)
Flocculants Flocculants for for
Water TreatmentWater Treatment
Date: May ???,2011Speaker :Speaker A 、 Speaker B 、
Speaker C
![Page 2: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/2.jpg)
Objectives • Flocculation of ferric hydroxide(Fe(OH)3)
colloidal solution is affected by the different pH values.
→ research the flocculation of Fe(OH)3(aq) at different pH value
• Ferric hydroxide colloidal solution performs excellently on the adsorption of heavy metal ions.
→ research the adsorption of lead ions (Pb2
+ ), zinc ions (Zn2 + ), chromium(VI) ions to decrease the huge volume of waste water containing heavy metal ions in high school chemistry laboratory
![Page 3: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/3.jpg)
ColloidsColloids• Colloid : substance microscopically
dispersed throughout another one.• Colloidal system : consists of two
separate phases - a dispersed phase and a continuous phase .
• Diameter of dispersed-phase particles : approximately 5 and 200 nm.
![Page 4: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/4.jpg)
Properties of Properties of Colloids Colloids
• Tyndall effect : light scattering by particles in a colloid or particles in a fine suspension.
• Absorption : another characteristic of colloids.
![Page 5: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/5.jpg)
Tyndall Tyndall effecteffect
• The Tyndall effect can be used to tell the difference between the true solution, and colloid.
![Page 6: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/6.jpg)
Flocculants for Water Flocculants for Water treatment treatment
• Flocculants : causing colloids and other suspended particles in liquids to improve the sedimentation of small particles.
![Page 7: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/7.jpg)
Al(OH)Al(OH)33
• Al(OH)3 : the basis for application of as coagulant in water purification.
• Alzheimer’s disease : traces of aluminium are found in brain lesions sometimes, so there is concern that consumption of excess aluminium compounds may cause or contribute to the development of this.
![Page 8: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/8.jpg)
Fe(OH)Fe(OH)33
• Preparation of Fe(OH)3 :
Fe(NO3)3 + NaOH → Fe(OH)3 +
NaNO3
Fe(OH)Fe(OH)33
![Page 9: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/9.jpg)
Fe(OH)Fe(OH)33
• Absorbent for suspension in raw water.
• Removal of Pb2 + and other heavy metal ions.
![Page 10: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/10.jpg)
Hydrolysis of ferric ion • Ferric ion hydrolyzes in water : [Fe(H2O)6]3+ + H2O → [Fe(H2O)5(OH)2]2+ + H3O+
[Fe(H2O)5(OH)]2++H2O→[Fe(H2O)4(OH)2]++H3O+
2[Fe(H2O)6]3+→[Fe(H2O)4(OH)2Fe(H2O)4]4+
+2H3O+
• When pH value of the solution decreases, the hydrolysis of ferric ions decreases too.
![Page 11: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/11.jpg)
• With the increasing of pH value, the solution changes from yellow to brown, reddish brown, and finally red-brown, which is the color of Fe(OH)3(s).
pH12pH12pH3pH3
![Page 12: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/12.jpg)
Removal of Pb2 +、 Zn2
+、 Cr(VI)• Large volume of waste water containing Pb2
+、 Zn2 +、 or Cr(VI) ions is produced by the experiments in the high school chemistry course.
• Pb2+ 、 Zn2 + and Cr(VI) ions are poisoned for human body , so we try to use Fe(OH)3 colloid to remove them to decrease the volume of waste water.
• Research the absorption ability of Fe(OH)3 colloid at different pH value.
![Page 13: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/13.jpg)
Experiment :• Adjust the pH value of Fe(OH)3(aq) from 6 to
13.• Prepare the stock solution containing Pb2 +
、 Zn2 +、 or Cr(VI) ions
• Mix Fe(OH)3(aq) and the stock solution for 5ml each at different pH value.
• Mix solutions are stood for a certain time.• Withdraw 5ml clear mix solution.• Analyze the concentration of heavy metal
ions in the clear solution by ICP-MS in the Instrumentation Center at National Tsing Hua University.
![Page 14: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/14.jpg)
Analyze the [Pb2 + ] by ICP-MS
• The [Pb2 + ] in the stock solution is 7174 ppm.
pH 13 12 11 10 9 8 7 6
Experiment 1
0.462
1.17
11.3 14.3
90.2
Experiment 2
0.417
2.39
0.817
2.8 30.7
181
741
979
![Page 15: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/15.jpg)
• The absorption of Zn2 + by Fe(OH)3 is excellent.
• The higher pH value, the less [Pb2+]
absorption of Pb2 by Fe(OH)3+colliod
0
200
400
600
800
1000
6 7 8 9 10 11 12 13
pH
ppm
![Page 16: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/16.jpg)
The [Zn2+] in the stock solution is 4784 ppm
Analyze the [ZnAnalyze the [Zn22 + ] by ] by ICP-MSICP-MS
pH 13 12 11 10 9 8 7
ppm 2.67 1178 1490 1669 1579 1827 1947
‧ The absorption of Zn2+ by Fe(OH)3 is
excellent, and is better at higher pH value .
‧ At pH 13 ,the zinc ions is left only about
0.056%.
![Page 17: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/17.jpg)
• The absorption of zinc ions is better at higher pH value.
absorption of Zn2 by Fe(OH)3+colliod
0
500
1000
1500
2000
7 8 9 10 11 12 13
pH
ppm
![Page 18: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/18.jpg)
Analyze the [Cr(VI)] by ICP-MS
• There are two species of Cr(VI) :
K2CrO4(aq) K2Cr2O7(aq)
• Both the two species are poisoned.
![Page 19: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/19.jpg)
a) 0.01M K2CrO4(aq) :
[Cr(VI)] in stock solution is 563 ppmpH 13.5
413 12 11 10 9 8 7
ppm 265 262 263 278 277 255 246 197
absorption of Cr6 by Fe(OH)3 colliod+
0
50
100
150
200
250
300
7 8 9 10 11 12 13 13.54
pH
ppm
![Page 20: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/20.jpg)
b) 0.001M K2CrO4(aq)
[Cr(VI)] in stock solution is 56.4 ppmpH 13.1
713 12 11 10 9 8 7
ppm 22.1 25.9 25.1 26.4 26.3 23.2 14.6 3.72
absorption of Cr6+ by Fe(OH)3 colliod
0
5
10
15
20
25
30
7 8 9 10 11 12 13 13.17
pH
ppm
![Page 21: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/21.jpg)
• The absorption of Cr(VI) by Fe(OH)3 colloid is far worse than the absorption of Pb2 + and Zn2 + ions.
• The best absorption is at pH 7.• There is a chemical equilibrium
between CrO42- and Cr2O7
2- :2CrO4
2- + 2H+ Cr2O72- + H2O
Cr2O72- will exist more than CrO4
2- in the acidic solution. Fe(OH)3 will have a better capability of absorption for Cr2O7
2-
![Page 22: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/22.jpg)
Conclusion The absorptions of Pb2 + 、 Zn2 + and Cr(VI)
ions by Fe(OH)3 colloid perform excellent.
The higher the pH value is ,the better the absorption of Pb2 + and Zn2 + ions by colloidal ferric hydroxide solution is.
At pH 13 , the lead ions is left only about 0.006%.
At pH 13 ,the zinc ions is left only about 0.056%.
![Page 23: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/23.jpg)
Conclusion
The absorption of chromium(VI) ions by
colloidal Fe(OH)3 solution is far worse
than the absorption of lead ions and zinc
ions. And the better condensation effect
will happen at pH 7.
![Page 24: F locculants for Water Treatment](https://reader036.vdocuments.mx/reader036/viewer/2022062518/568146e8550346895db42166/html5/thumbnails/24.jpg)
Thanks for your Thanks for your attention!!attention!!TT oohh iiaannkkss ff nnoorr yyoouurr aa ttee tttt nn !!!!