Development of a Novel fly ash based Zeolite for

treatment of Waste Water

By

Vinit Sehgal,

B.E. Student,

Department of Civil Engineering,

BIT-Mesra, Ranchi

66%

26%

3% 5%

Thermal

Hydel

Nuclear

RES

Energy status in India

Source:Ministry of power, 2009

www.powermin.nic.in

Current Utilisation of Fly Ash

Fly ash is currently being used majorly in soil back filling,in making bricks of fly ash and hence making green houses and a component in portland cement.

Preparation of a novel fly ash based zeolite for treatment of waste water

Our Utilisation Aspects of Fly Ash:

Utilisation Aspects: Synthesis of novel fly ash based Zeolite for waste water treatment

Synthesis of Zeolites & Process Optimization

Zeolite CharacterizationEfficiency testing for Cation removal by

Ion exchangeAnion removal by Surface ModificationIncorporation of disinfecting agentsEfficiency Testing

More on Zeolites

 Role of Zeolites??Zeolites are microporous aluminosilicates of the general formula Mx/n [(AlO2)x (SiO2)y].z H2O where n is the charge of the metal cation, M n+.

M is usually Na+, K+ or Ca2+ and z is the number of moles of water of hydration, which is highly variable. In this framework, some of the silicon atoms are replaced by aluminium atoms. Zeolites are found in nature and they are also synthesized for catalytic selectivity. Because of the three dimensional cage like structure, zeolites can be used as ion-exchange materials and selective adsorbents.

Zeolite can be regenerated using a salt solution which provides a high concentration of sodium ions to reverse the exchange reaction. In this case hardness is released as a concentrated chloride Ca X or Mg X +2NaCl→Na2X + CaCl2 or MgCl2

CaMg

SO42-

2Cl-

2HCO3-

Na2 Z ZCaMg

Na2SO42NaCl2NaHCO3

2+

Chemistry in ActionAdsorption( Molecu

lar Sieves)Ion Exchange

CaCl2 + Na2Z CaZ+ 2NaCl

MgCl + Na2Z MgZ +2NaCl

CaSO4 +Na2Z CaZ + Na2SO4

Mg2SO4 + Na2Z MgZ + Na2SO4

Ca(HCO3)2Na2Z CaZ + 2NaHCO3

Mg(HCO3) + Na2Z MgZ + 2NaHCO3

The Synthesis

Zeolite Synthesis from Fly Ash

ConventionalHydrothermal Treatment

Fusion Membrane Extraction Microwave

Pre-Treatment

FA+NaOH/KOH

Zeolite

50% Conversion

FA+ NaOHPellets

Sodium Silicate

Dissolve in Alkaline Solution

Hydrothermal Treatment

50% Conversion

Silicone Extraction

Fusion

Hydrothermal Treatment with addition of AlumninateSolution

High Purity

5500cReflux & Stirring

FA+ 2M NaOH

Microwave Heating for 2 hrs

Hydrothermal Treatment

Centrifugation

Drying & Crystallization

Chemical TreatmentAlkali source: NaOH/KOHFA slurry with Solid:liquid ratio=140gm:350ml.

Refluxed for 98hrs under strong agitation and at 383 K temp. till the pH becomes neutral

Microwave Synthesis

Combination of Conventional and microwave synthesis

Increase in Porosity and hence high CEC values

Better Quality of Zeolites

Important Requisites:

High CECpH controlEffect of Time, Temp and BaseProcess Optimization

Our Product

The zeolite prepared in the lab.Observe the porous nature of the zeolite formed.

Our Results

Photograph of SEM at X5500.Observe the smooth surface of the fly ash particle.

SEM report of the zeolite prepared.Observe the difference in the surface of the zeolite compared to that of the fly ash.

"Micropores" formation in action(SEM photograph of a leached sample of fly ash)

EDXS report of the fly ash sample taken.Observe high amount of Al and Si in the sample.

EDXS report of the zeolite prepared.Observe the increased amount of Na in the sample.

The concentration of zeolite v/s turbidity of wastewater curve.Observe at a particular concentration of zeolite,the turbidity is reduced to 50% of initial value.

0.0 0.2 0.4 0.6 0.8 1.0 1.225

30

35

40

45

50

55

Tu

rbity

Concentration(gm/800 ml)

B

Absorbance v/s wavelength curve for wastewater and zeolite treated wastewater.Observe the reduction in absorbance of the samples taken.This effectively proves that zeolite is capable of removing colour from the wastewater.

450 500 550 600 650

0.2

0.4

0.6

0.8

1.0

Wastewater Zeolite treated water( )

Ab

so

rba

nce

(w

.r.t

dis

til w

ate

r)

Wavelength (nm)

Dosage Fe(III) concentration % removal0% 0.8ppm __________

0.025%0.2ppm

75%

0.037%BDL

100%

0.050%BDL

100%

0.062%BDL

100%

Percentage removal of iron from water using fly ash based zeolite through standard jar test procedure:

Conclusion…

the Zeolite so formed is capable of reducing turbidity ,colour and metal content present in the waste water sample .

Thank you……