Question

A solution contains 300 mg/L of glycine: CH2(NH2)COOH. Glycine is oxidized by O2 to carbon dioxide, water, and ammonia (NH3). a. Find the theoretical BOD of this solution. b. The glycine in a 1.0 liter solution is fully oxidized. How much carbon dioxide and ammonia are produced?

Answer 1

Given Data

Glycine (CH₂(NH₂)COOH) = 300 mg/l = 0.3 g/l

To determine

1. Theoretical BOD of Solution
2. Amount of CO₂ and NH₃ Produced

Solution (1)

Balanced equation of oxidization of Glycine

NH₃ can be further oxidized as

1.5 Mole O₂ is required for oxidization of Glycine and convert it into CO₂ and Ammoia (NH₃). 2 Mole of O₂ is more required for oxidization of Ammonia (NH₃). Hence Amount of Oxygen required for fully oxidization of Glycine i.e Theoritical Oxygen Demand for 1 Mole of Glycine will be

= 1.5 + 2 = 3.5 Mole O₂ per Moleof Glycine

Molecular Weight of Glycine = 75 g

Molecular Weight of Oxygen = 32 g

No of Mole in Glycine Sol = 0.004 Mole

Amount of O₂ required = 3.5 x 0.004 x 32

= 0.448 g

Hence Theoretical Oxygen Demand of Glycine is 0.448 g .

Solution (2)

1 Mole of Glycine will produce 1 Mole of Ammonia (NH₃) and 2 Mole of CO_2.

Molecular Weight of Ammonia (NH₃) = 17 g

Molecular Weight of CO₂ = 44 g

Moecular Weight of Glycine = 75 g

Amount of Ammonia Produced will be

Ammonia produced = 0.068 g

Amount of CO₂ Produced will be

CO₂ produced = 0.352 g

Hence Amount of Ammonia produced will be 0.068 g and CO₂ produced will be 0.352 g.