Complexation kinetics
This presentation is the property of its rightful owner.
Sponsored Links
1 / 19

Humic Science & Technology VIII March 16-18, 2005 Northeastern University Boston, MA, USA PowerPoint PPT Presentation


  • 57 Views
  • Uploaded on
  • Presentation posted in: General

complexation kinetics. in humic colloidal systems. martina klučáková pavla žbánková miloslav pekař. Brno University of Technology Faculty of Chemistry Institute of Physical and Applied Chemistry. Humic Science & Technology VIII March 16-18, 2005 Northeastern University Boston, MA, USA.

Download Presentation

Humic Science & Technology VIII March 16-18, 2005 Northeastern University Boston, MA, USA

An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -

Presentation Transcript


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

complexation kinetics

in humic colloidal systems

martina klučáková

pavla žbánková

miloslav pekař

Brno University of Technology

Faculty of Chemistry

Institute of Physical and Applied Chemistry

Humic Science & Technology VIIIMarch 16-18, 2005Northeastern University

Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

why...?

  • interaction of metal ions with humic acids

  • toxicity of natural systems

  • carry on previous study (Cu2+)

  • etc.

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

lignite mine

location...?

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

material...?

  • lignitic humic acid

  • raw material: South-Moravian lignite

  • isolation: alkalic extraction (NaOH)

normalized on dry ash-free HA

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

experimental...?

0.1-1.0 g/L

humic sols

humic gels

17 % HA

Co2+

Ni2+

0.01 - 0.20 M

physical & chemical interactions

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

Cu2+ + HR CuR+ + H+

2CuR+ CuR2 + Cu2+

humic sols

previous results:

0.2 M (Cu2+)

1 g/dm3 (HA)

I = 0.1 M (sol)

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

humic sols

0.2 M (Co2+)

0.2 M (Ni2+)

1 g/dm3 (HA); I = 0.1 M (sol)

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

differences...

Co2+&Ni2+

Cu2+

conductivity and pH increases stop in the same moment

conductivity increases while pH-value is constant

D[H+]

1×10-6 mol/L

8×10-7 mol/L

D[H+]

3×10-5 mol/L

pH increasing is slower than in the case of

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

MeCl2 Me2+ + 2Cl-

Me2+ + 4H2O Me(OH)2 + 2H3O+

HR + H2O H3O+ + R-

2H2O H3O+ + OH-

Me2+ + R- MeR+

Me2+ + HR + H2O MeR+ + H3O+

2MeR+ MeR2 + Me2+

MeR+ + HR + H2O MeR2 + H3O+

MeR+ + R- MeR2

humic sols

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

humic sols

Ni2+ (0.01M)

sol (1 g/L)

sol (0.1 g/L)

0.01M Me2+– conductivity decreases (sol 0.1 – 1 g/L); I = 0.1 M

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

humic sols

sol (1 g/L)

Ni2+(0.01 M)

Ni2+(0.20 M)

I = 0.5 M (sol 0.1 – 1 g/L)  no minimum on pH-curve

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

humic gels

gel

Co2+(0.01 M)

Co2+(0.20 M)

gel  no minimum on pH-curve

conductivity only increases (Me2+: 0.01 – 0.20 M)

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

humic sols & gels

summary reaction:

H2R + Me2+ MeR + 2H+

t = 0a b 0 h

t>0 a – x b – x x h + 2x

t ∞ 0 b – a a h + 2a

2nd order kinetic rate equation:

dx / dt = k (a-x) (b-x)

kt = 1 / (b-a) ln [a(b-x) / (b(a-x))]

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

humic sols & gels

apparent rate constants: sols (0.1 g/L; I = 0.1 M)

b>> a

[m3/mol.s]

apparent rate constants: gels

[m3/mol.s]

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

humic gels

diffusion from constant source

  • one-dimensional diffusion

  • T, p = const.; D D (c)

example: Ni2+

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

humic gels

diffusion from constant source (24 h)

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

humic gels

diffusion from time-variable source

example: Co2+

24 h

0.20 M

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

conclusions...

  • complex interaction mechanism HA-metal ions

  • non-ideal kinetics

  • diffusion-affected interaction with humic gel

  • …….

Humic Science & Technology VIII, March 16-18, 2005, Northeastern University, Boston, MA, USA


Humic science technology viii march 16 18 2005 northeastern university boston ma usa

thanks


  • Login