Removal of hazardous elements from WaterBased on theme of utilization of waste materials from Steel Industry

Presented by (Team 2): ShubhamManikantaMitul

Mentor - Mr. Bharadwaz Bhagawati

IIT Roorkee

Cr+6F -

Cl As+3

• 19 out of 35 states & UT affected

• Gujrat , AP & Rajasthan

• Sources:Black rock salt, dental products

• Toxic in form of halogenated solvents like CCl4.

• TCE found in 790 /1300 NPL sites.

• DDT is a major contamination.

• West Bengal – 9 out of 16 districts

• In UP 4% samples > 0.05 ppm

• Found near thermal power plants.

• Lethal above 1ppm

•Combines with blood cells.•Carcinogenic and readily soluble in water.•Leather tanning, coolants are sources of Cr(VI).

F- Cl- As 3+ Cr 6+

Affected Regions

19/ 35 States and UT (Gujarat, AP &

Rajasthan)

790/ 1300 samples (NPL)

throughout India

West Bengal (9/ 16 districts), UP, Bihar, Assam

Regions around Kanpur and Ranipet, TN

Sources Black Rock Salt, Dental Products

DDT, Halogenated Hydrocarbons

Found Near Thermal Power

PlantsLeather Tanning,

Coolants

WHO Standard 1.5 ppm 0.04 ppm 0.01 ppm 0.05 ppm

Harmful Effects Skeletal Fluorosis Throat Infection > 1 ppm : Lethal Carcinogenic &

readily water soluble

Hazardous Elements

Properties of Zero Valent Iron:

• Strong Reducing Agent.• Good Adsorbent.• De-chlorinate Halogenated

Solvents.

Zero Valent Iron

Concept:

Conventional Methods

FeCl3 FeSO4

• Sodium Borohydride

• Hydrazine

Polyphenols are good reducing agents

FeCl3 HSM scale LD Slag

GT Extract

Fe0 not obtainedFe0 Obtained

Disadvantages• NaBH4 was highly expensive• Hydrazine Reduction needed 8

hours and costlier setup.• Toxic

FeSO4

Profound

Green Tea Extract (Polyphenol)

Fe0 Obtained

Innovative

Advantages• Eco-friendly• Inexpensive and takes less time• Easy Setup

Slag HSM

Polyphenols

Fe3O4

Wet Magnetic Separation

NaOH

Sources of Polyphenol

• Tannic Acid• Green Tea Leaves• Karela• Neem• Cloves

Modified method

ZVI (Fe0) Obtained

Fe(OH)3 Fe(OH)3

Ball millingnZVI

Efficiency & optimum parameters

contaminated samples

Dissolved in Aqua Regia

Synthesis of nZVI

Nano Zero Valent Iron

Green tea extract Iron compound(FeCl3,HSM Scale, FeSO4)

ZVI

145 C for 30 min.Ball Milling

NaOH

Results for Obtaining nZVI: Sample

No. Iron compound Initial Concentration of Reducing Agent

Efficiency (%) of formation on nZVI

1 FeCl3 1 % Green Tea 90.92

2 FeCl3 2 % Green Tea 60.96

3 FeCl3 4 % Green Tea 44.62

4 FeCl3 10 % Karela Extract 14.77

5 FeCl3 2.5 % Neem Extract 25.62

6 FeSO4 2 % Green Tea 41.83

7 Fe2O3 2 % Green Tea -

8 HSM mill (Fe3O4) 2 % Green Tea 32.55

9 LD Slag 2 % Green Tea -

Testing Results

• Cr(VI) is reduced by ZVI, followed by formation on Cr-Fe hydroxide alloy, which is precipitated out.

Chromium5ppm of Cr(+6) solution

Cleaned water after filtration

Conclusion:• nZVI is better reducing agent to remediate hazardous contaminants from water.• Filters using nZVI as a adsorbent are more efficient and cheap in compare to

others.• We came to the conclusion that on reducing size, surface area increases which

helps in fast filtration

Present in two oxidation states –

As(III) & As(V)• As(III)• Non-ionic (H3AsO3) at

neutral pH• High solubility

• As(V)• Ionic (H2AsO4

-/HAsO42-) at

neutral pH• Some phases are less

soluble

Adsorption using nZVI

Fluorine Chlorine

NaF + Water

Mixed with nZVI

Response Surface Methodology (RSM)

Box – Behnken experiment

Beta-elimination pathwayC2Cl4 + 4Fe0 + 4H+ C➔ 2H4 + 4Fe2+ + Cl-

Polychlorobiphenyls(PCBs)/ Chlorinated ethylene

Converted directly to hydrocarbons

Mixed with nZVI

“Don’t pray for easy lives, Pray to be stronger Men”- John F. Kennedy

Thank You