KINETIC STUDY KINETIC STUDY Simona Gabriela Muntean 1 , Sergiu - - PowerPoint PPT Presentation

Simona Gabriela Muntean Simona Gabriela Muntean1

1, Sergiu Coseri

, Sergiu Coseri2

2, Georgeta

, Georgeta Simu Simu3

3, Oana Paska

, Oana Paska1

1

1 1Institute of Chemistry Timisoara of Romanian Academy, 24 B-dul Mihai Viteazul,

Institute of Chemistry Timisoara of Romanian Academy, 24 B-dul Mihai Viteazul, 300223 Timisoara, Romania; 300223 Timisoara, Romania;

2 2"Petru Poni" Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley,

"Petru Poni" Institute of Macromolecular Chemistry, 41A Grigore Ghica Voda Alley, Iasi, 700487, Romania Iasi, 700487, Romania

3 3University of Medicine and Pharmacy “V. Babeş” Timi

University of Medicine and Pharmacy “V. Babeş” Timiş şoara, Faculty of Pharmacy,

• ara, Faculty of Pharmacy,

Eftimie Murgu 2, 300041 Timişoara, Romania Eftimie Murgu 2, 300041 Timişoara, Romania e-mail: sgmuntean@acad-icht.tm.edu.ro e-mail: sgmuntean@acad-icht.tm.edu.ro

SORPTION OF DIRECT DYES SORPTION OF DIRECT DYES FROM AQUEOUS SOLUTION ONTO FROM AQUEOUS SOLUTION ONTO A SYNTHETIC ADSORBENT. A SYNTHETIC ADSORBENT. KINETIC STUDY KINETIC STUDY

Introduction Introduction

• Industries such as textile, paper, plastics, etc., use great

quantities of water, and chemical substances, for coloring the manufactured articles, and discharge large amounts of wastewater during industrial processing.

• The discharge of coloured wastewater is a major

environmental concern (can produce serious pollution problems) due to their poor biodegradability, carcinogenicity and toxicity.

• The adsorption process provides an attractive alternative

for the treatment of dye contaminated waters because of its simplicity, selectivity and efficiency.

Aim Aim

• To determine the efficiency of copolymer microbeads,

as adsorbent for removal of direct dyes from aqueous solutions

• To study the influences of process variables: contact

time, and initial concentration on the adsorption.

• The kinetics study of the adsorption of direct dyes
• nto adsorbent.

Experimental Experimental

Molecular structure of the studied direct dyes The chemical structure of investigated copolymer (StDVBNMe)

N H N N CO NH N N N NH N CH3 C H3 O O C6H4SO3H C6H4SO3H

HOOC O H N N CONH N N OH HO3S SO3H NH2 N N NO2

OD OD

GD

R: styrene-divinylbenzene copolymer

CH2N+(CH3)3 R Cl-

Method Method

Experimental study

• Dye concentration: 10-5 ÷ 10-4 M;
• Adsorbent dose 100mg/100mL;
• Temperature: 25oC;
• Solution pH: 7.11.

The amount of dye adsorbed

qt: amount of dye adsorbed onto the copolymer unit at time t (mg/g), C0 and Ct: dye concentration in solution at initial time, and at time t (mg/L), V: solution volume (L), W: amount of copolymer (g)

The percentage of dye removal (η)

100

× =

−

C C C

e

η

Ce: dye concentration at equilibrium (mg/L).

W V C C q

t t

⋅ − = ) (

Results and Discussions Results and Discussions

• Fig. 1. Samples of: (a) StDVBNMe ; (b) OD-StDVBNMe; (c) GD-StDVBNMe.

Characterization of copolymer microbeads Characterization of copolymer microbeads

• Fig. 2. SEM images for: (a) StDVBNMe; (b) OD -StDVBNMe; (c) GD –StDVBNMe.

(a) (c) (a) (b) (c) (b)

• Fig. 3. Effect of contact time and dye concentration on the percentage removal of dyes (a. OD, b. GD).

Conditions: pH 7.11; T= 25±1oC, agitating speed 250rpm.

Effect of initial dye concentration and agitation time Effect of initial dye concentration and agitation time

Dye Dye concentration (mg/L) qe (mg/g) te (min) η (%)

OD 8 7.66 35 99.05 40 39.11 75 98.13 80 77.32 90 97.99 GD 10 9.07 65 98.53 45 42.02 130 89.47 90 81.48 205 88.47

(a) (b)

Table 1. Amount and percentage of dyes adsorbed

50 100 10 20 30 40 50 60 70 80

OD

q

t (mg/g)

Time (min)

8 mg/L 40 mg/L 80 mg/L

50 100 150 200 250 10 20 30 40 50 60 70 80

GD

q

t (mg/g)

Time (min)

10 mg/L 45 mg/L 90 mg/L

Adsorption kinetics

The first-order Lagergren model The pseudo-second-order kinetic model

qe , q = amount of dye adsorbed on adsorbent at equilibrium, and any time t, respectively (mg g-1). k1 = the Lagergren rate constant of first order adsorption (min-1) k2 = the equilibrium rate constant of second-order adsorption (g mg-1 min-1)

( )

t q q q

k e e 303 . 2

1

log log − = −

t

e e

q q k q t 1 1

2 2

+ =

• Fig. 4. First-order-kinetics plots of the experimental data for the adsorption of OD and GD onto

StDVBNMe

• Fig. 5. Second order plots for the adsorption of OD and GD onto StDVBNMe

50 100 150 200 250

• 4
• 3
• 2
• 1

1 2

OD

log(q

e-q t)

Time (min)

8 mg/L; R

2=0.9132

40 mg/L; R

2=0.9102

80 mg/L; R

2=0.9441

50 100 150 200 250 300 5 10 15 20

OD

t/q

t

Time (min)

8 mg/L; R

2 =0.9999

40 mg/L; R

2 =0.9978

80 mg/L; R

2 =0.9993

50 100 150 200 250 300 350 400 5 10 15 20 25

GD

t/q

t

Time (min)

10 mg/L; R

2 =0.9956

45 mg/L; R

2 =0.9971

90 mg/L; R

2 =0.9939

50 100 150 200 250 300

• 1.5
• 1.0
• 0.5

0.0 0.5 1.0 1.5 2.0

GD

log(q

e-q t)

Time (min)

10 mg/L; R

2 =0.9627

45 mg/L; R

2 =0.9658

90 mg/L; R

2 =0.9895

Table 4. Comparison of experimental and calculated qe values; first order and second order adsorption rate constant for the adsorption of OD and GD dyes

Dye Initial dye concentration (mg/L) qe (exp) (mg/g)

First order kinetic model Second order kinetic model qe (calc) (mg/g) k1 x 102 (min-1) qe (calc) (mg/g) k2 x 102 (g mg-1 min-1) OD

8 7.66 2.09 5.645 7.72 11.47 40 39.11 20.65 2.303 41.27 0.244 80 77.32 35.6 2.309 80.26 0.134

GD

10 9.07 6.31 3.418 9.84 0.773 45 42.02 28.95 1.985 45.81 0.096 90 81.48 79.47 1.808 83.81 0.026

Conclusions



The removal of two dyes namely OD, and GD from aqueous solution by StDVBNMe was found to be effective.



The StDVBNMe microbeads can by used as a adsorbent in adsorption process in low costs working conditions (room temperature, pH ~ 7).



The adsorption process for OD, and GD dyes removal, can be described by the pseudo-second order kinetic model.

Thank you Thank you for your for your attention! attention!