Reporter ： Weikang Zhang

Date ： 2012-12-11

Adsorption removal of phosphate from water by model-La/Al zeolite adsorbents

Tianjin University

Contents

Background

Current situation

The treatment technologies presently available for phosphorus removal include:

a)biological treatment

b)chemical precipitation

c)ion exchange

d)Adsorption Most of these approaches are generally more suitable for

the removal of phosphate of higher concentration.

• Adsorption is recommended as one of the most effective removal processes for the low concentrations of phosphorus.

• Many types of adsorbents for phosphate removal have been investigated.

AdsorbentActive

component SupportPreparation

methods Source

LaAl-PILC La2O3/Al2O3Montmorillonite

100 meshSolid-liquid mixed

Stirred for 5hStanded for 24h

Kunming university of science and technology

La-Ves La2O3Vesuvianite

Solid-liquid mixedStanded for 40h

Calclined at 673K for 3h

Yunnan Normal

University

La-Zeo La2O3

Naturalzeolite

Diameter of 90μmSolid-liquid mixed

calcined

Southeast University

Main work

• Materical characterization

• Phosphate adsorption experiment

• Adsorption isotherm

• Phosphate adsorption kinetics

• Influence on adsorption of phosphate

• Stability

• Regeneration studies

Adsorption isotherm and kinetics

1mol/L NH4Cl 100ml

Natrual zeolite 50g

Washing with deionized water

25 ℃

12h

3.44gLaCl3·7H2O

2.61gAl(NO3)3·6H2O20ml deionized water

Dry 100 ℃

Calcined 550 8h℃

25℃

impregnated24h

Dry 80 ℃

Calcined 500 2h℃La/Al-zeo Catalyst

Figure 1. Process of impregnation method to prepare La/Al-zeo catalyst

Experiment

Figure 2.1ppm 100ml, contact time is 12h,0.1g

2 3 4 5 6 7 8 9 100.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Adso

rptio

n c

apaci

ty (m

g/g

)

Initial PH

Adsorption kinetics

0 2 4 6 8 100.0

0.2

0.4

0.6

0.8

1.0

1.2

Adso

rptio

n c

apaci

ty (m

g/g

)

contact time (h)

Figure 3. initial concentration is 5ppm, 200ml, 0.2g

Adsorption isotherm

Figure 4. various initial concentrations 100ml,50mg, contact time is 48h

0 5 10 15 20 250

2

4

6

8

10

12

14

16

Ads

orpt

ion

capa

city

(m

g/g)

Equilibrium concentration (mg/L)

Next work• Regeneration studies

10mg/L solution

Fresh absorbent

0.8mol/L NaCl

PH=10.5

25 ℃

Washing with deionized water

25 ℃

Impregnated3.5h

Dry25℃

500℃

Calcined 1h

regeneratedabsorbent