Environmental Research:Activated Charcoal

and Water Filtration

River Dell HS (RDHSB) Event #2 Presented by: HyoungBin LeeOradell, NJ Team B Kaitlyn DantoniCoach: Mrs. C. Jacobus Michelle Hao

Chemistry of Activated CarbonPhysisorption• Intermolecular forces (IMF))• Van Der Waals (London dispersion force,

LDF)

Chemisorption• Formation of chemical bond• Complex ion (ligands)

Adsorption equilibrium• Rate of adsorption = rate of desorption

Hypothesis &Experimental MethodHypothesisActivated charcoal will decrease acidity more efficiently than pure charcoal.Experimental Methods Overview- Filtration

- column, regular- Titration to determine pH

- higher pH = better adsorption

Development of Procedure• Two systems of activated charcoal in 0.40M

HAc against wet and dry charcoal, pH then measured• No significant difference between types

• Granular charcoal was more effective than ground

• Stirring method more efficient than column filtration

• Granular vs Ground; experiment performed via column filtration (see Fig. 1)

National Institute of Environmental Health Sciences. Cleaner Air on the Fly: EHP Student Edition, [Online] August 2006, p. A277 http://www.niehs.nih.gov/health/assets/docs_a_e/ehp_student_edition_lesson_cleaner_air_and_water_on_the_fly.pdf (accessed April 21, 2013)

  Wet Charcoal Dried CharcoalInitial pH 2.16 2.16pH after 30 min 2.55 2.61pH after 1 hr 2.60 2.62pH after 1hr and 30min 2.62 2.63

Fig. 1

Development of Procedure Cont .• Minimum time for adsorption process to

reach equilibrium determined with 2.00 g AC in 50 mL ~0.4 M HAc• Reaction ran under 6 different time

intervals in increments of 30 minutes• pH then measured

Time(minutes)

0 30 60 90 120 150

pH value 2.23 2.58 2.60 2.63 2.65 2.66

Set Up

200mL solutions of various concentrations (0.05M-5M) of HAc, one labeled each for pure carbon and activated

carbon.

ProcedureStir Method vs Column Filtration to Reach Equilibrium

Set the stir value of the magnetic stirrer to 360 RPM, let the process run

for 2 hours

50 mL HAc column filtrated through ground carbon

Procedure Cont.Filtration

Filtered pure and activated carbon from acid after two hours of being stirred.

Procedure Cont.

Left:pH test after filtering acetic acid from charcoal

Right:Titrations to

determine change in #

moles

pH and Titrations

Molarity Calculations

0.05M HAc

0.2M HAc

0.3M HAc

0.4M HAc

0.5M HAc

Starting NaOH (mL) 44.5 40.0 36.0 31.0 41.0

Ending NaOH (mL) 44.0 42.65 39.55 36.0 47.2

Used NaOH (mL) 0.50 2.65 3.55 5.00 6.20

Molarity (mol/L) 0.0407 0.215 0.289 0.407 0.5041

ORIGINAL SOLUTION

Molarity Calculations Cont.

0.05M HAc

0.2M HAc

0.3M HAc

0.4M HAc

0.5M HAc

Starting NaOH (mL) 0.1 0.2 2.0 4.7 9.0

Ending NaOH (mL) 0.2 1.95 4.65 8.6 13.85

Used NaOH (mL) 0.10 1.75 2.65 3.90 4.85Molarity (mol/L) 0.0081 0.142 0.215 0.317 0.3943

FILTERED WITH ACTIVATED CARBON

0.05M HAc

0.2M HAc

0.3M HAc

0.4M HAc

0.5M HAc

Starting NaOH (mL) 14.0 14.5 17.0 20.5 25.0

Ending NaOH (mL) 14.5 16.9 20.25 25.0 30.6

Used NaOH (mL) 0.50 2.40 3.25 4.50 5.60Molarity (mol/L) 0.0407 0.195 0.264 0.366 0.4553

FILTERED WITH PURE CARBON

0 0.5 1 1.5 2 2.50

0.02

0.04

0.06

0.08

0.1

0.12

0.14

0.16

f(x) = 0.0136132320665448 ln(x) + 0.0465382601179672

f(x) = 0.0294823165874894 ln(x) + 0.124112265370178

[H+] adsorbedActivated Charcoal (AC) vs. Pure Carbon (C)

Activated CharcoalLogarithmic (Ac-tivated Char-coal)Pure CarbonLogarithmic (Pure Carbon)

Initial concentration of H+ in the solution (M)

conc

entr

atio

n of

H+

ads

orbe

d ()

M

0 0.5 1 1.5 2 2.50

10

20

30

40

50

60

70

80

90f(x) = 12.7315883313048 x^-0.621832257405741R² = 0.968599706805737

% [H+] adsorbedActivated Charcoal (AC) vs. Pure Carbon (C)

Activated CharcoalPower (Activated Charcoal)Pure Carbon

Concentration of initial solution of HAc

%[H

+]

adso

rbed

pH and Le Chatelier’s Principle

• Activated Charcoal: uses LDF• >molecular size = >polarizability = >LDF• C2H3O2

- is greater in size than H+

∴ more C2H3O2- adsorbed than H+

• Le Chatelier’s principle C2H3O2- is adsorbed,

equilibrium shifts to products, increasing [H+]∴ pH decrease

0.05M

HAc

0.2M HAc

0.3M HAc

0.4M HAc

0.5M HAc

Activated

charcoal

3.87

2.71 2.60 2.25 2.19

Pure Charco

al3.44

2.80 2.70 2.63 2.71HC2H3O2 ⇌ H+ + C2H3O2-

0 0.1 0.2 0.3 0.4 0.5 0.600.5

11.5

22.5

33.5

44.5

f(x) = 2.42057751698073 x^-0.106062324875398R² = 0.942764045370073

f(x) = 1.89155119761874 x^-0.2265446598324R² = 0.987642695417233

pH of the solutionSeries1

PH of Acti-vated charcoal

Series3

pH of Charcoal

Series5

initial pH

concentration of initial solution (M)

pH o

f re

mai

ng s

olut

ion

ConclusionBinding Capacity• AC = 0.00336 • C = 0.00115

• Hypothesis supported

• As [H+] inc, chance of adsorption increases