Question

At one test site for remediation, the water contained 229 ppm TCE and 70.1 ppm perchloroethene. Calculate the mass of iron in mg required to remediate 1L of this ground water.

Answer 1

Groundwater remediation is the process that is used to treat polluted groundwater by removing the pollutants or converting them into harmless products.

Zero valent iron (ZVI) has been intensively studied as a reductant for organic and inorganic pollutants such as nitrate (, Cr(VI) , U and chlorinated organics .

Fe⁰  + RX + H^{+ _----------} Fe^{2+ ₊}  RH + X^-

Considering the above reaction

We can see that TCE has 3 Cl atm and will react with iron in same ratio,so it will require 229*3 =687 ppm of iron

similarly Perchloroethelyen conatins 4 Cl atm and will react with iron in same ratio,so it will require 70.1*4 =280.4 ppm of iron

Total Requirement of Iron = 967.4 ppm

it means 1 g of water require 967.4/1000000 parts of Iron

1000g of water i.e 1Litre =0.9674 parts of Fe

Fe required for treat ment = 0.9674*56 g =54.17 mg