Lunds universitet / LTH / 2009-02-26

Tillämpad vattenkemi 2010Applied Aquatic Chemistry 2010

Jan-Olle MalmLars Stenberg

Deptartment of Chemistry

Per WarfvingeDepartment of Chemical Engineering

Lunds universitet / LTH / 2009-02-26

After the course, you should:

• understand key chemical processes in surface waters and groundwaters

• be able to apply your knowledge about chemical equilibrium on real-world problems

• have developed your computation skills

• be able to interpret chemical phenomena and express your ideas in writing

Lunds universitet / LTH / 2009-02-26

What we do

• Basic chemistry – lectures by Jan-Olle Malm

• Applied Water Chemistry – lectures by Per Warfvinge

• Exercises and preparation of a workbook

• Labwork– The CO2/water system– Chemical analyses and charge balance– Microbial redox reactions

Lunds universitet / LTH / 2009-02-26

Perspective: Water chemistry as a result of complex interactions

Lunds universitet / LTH / 2009-02-26

• Limited climatic change • Fresh air• Only natural acidification• High quality groundwater• Vital lakes and streams• Vibrant wetlands• Oceans in balance• No eutrophication• Diverse forests• Rich farmland• Great mountains• Good built environment• Safe radiation• Protective ozone layer

Water Atmosphere

National environmental goals:

Lunds universitet / LTH / 2009-02-26

Links to previous courses

• Hydrology and aquatic ecoogy– Links between chemistry and biology– Growth limiting element, carbon sources

• Physics– Balances, thermodynamics, computations

• Geology– Link bedrock/soil to water quality– Open and closed aquifers

• Themodynamics– Equilibrium concept, ”free energy”, kinetics

• Mathematics– Algebraic equations (dependence, rank)

Lunds universitet / LTH / 2009-02-26

…and further on

• Statistics W3– Computational skills

• Masstransport W3– Modeling of dynamic systems– Chemistry in a context– Contaminant transport in groundwater

• Environment and Management W3– Link environmental issues - environmental legislation – Environmental assessment

• Degree project and – work!

Lunds universitet / LTH / 2009-02-26

What does an Environmental engineer need to master?

• Processes dealing with the pH and redox-conditions in water

– Gas-water interactions

– Acid-base equilibria

– Dissolution and precipitation reactions

– Reduction - oxidization reactions

• Less important

– Phase distribution equilibria

– Complexing

Lunds universitet / LTH / 2009-02-26

Key chemical concepts

• Equilibrium

• Equilibrium equations

• Charge neutrality

• Charge balances

Lunds universitet / LTH / 2009-02-26

Water chemistry units• mol/L

– Used for equilibrium/kinetic calculations

• mg/L– Commonly uses for N and P

• eq/L or molc/L– equivalents/L = charge * mol/L– Commonly used for comparisons and trend analysis– Can be used to set up charge balances

Lunds universitet / LTH / 2009-02-26

The Charge Balance - Stream water from the Kålmården area

Lunds universitet / LTH / 2009-02-26

Most important acid-base system in nature: CO2-water

Lunds universitet / LTH / 2009-02-26

Water chemistry: First week

Date Time Room Type Instructor

Mon 15/3 10-12 B Lecture, AWC 1-2 PW

13-14 F Lecture, AWC 1-2 PW

20-21 Read AWC 1-2

Tue 16/3 10-12 G Lecture, Chang 15/16 (pH) JOM

15-17 H, I Exercise JAM, MP, JOM

Thur 18/3 13/19 Lab 1 JAM, MP

Fri 19/3 8-10 H, I Exercise JAM, MP, JOM

13-15 F Lecture, Chang 17 (buffers) JOM

15-19 Lab 1 JAM, MP

Lunds universitet / LTH / 2009-02-26

Sensitivityof aquatic species to pH

pH 4 pH 5 pH 6

ål

gädda

abborre

harr

mört

bäckslända

dagslända

snäcka

kräfta

sötvattensmärla

bäckbräsma

vitmossa

Lunds universitet / LTH / 2009-02-26

Key chemical concepts

• Equilibrium

• Equilibrium equations

• Charge neutrality

• Charge balances

Lunds universitet / LTH / 2009-02-26

Global reservoirs of water

Lunds universitet / LTH / 2009-02-26

Laboration 1:Equilibrium gas/liquid

• CO2 in N2 is bubbled through ”pure” water

• Experimental determination of gas-liquid equilibrium

constant

• When: Wednesday - Thursday

• Where: Level 0, labs close to Ideon

• Staff: Jenny Axén Mårtensson, Malin Rosenberg

Lunds universitet / LTH / 2009-02-26

Globally most common ions in surface waters/ground waters

Anion Reference valuemmole/L Cation Reference value

mmole/LHCO3

- 3 Ca2+ 1

SO42- 0.1 Na+ 1

Cl- 0.1 Mg2+ 0.4

NO3- 0.01 K+ 0.05

Sr2+ 0.001