REMOVAL OF HEAVY METALS FROM WASTE WATER BY LIQUID – LIQUID EXTRACTION By Asmaa Saeed Mohamed Amal Mohamed hussien Esraa Zakria Kamel Alexandria University Faculty of Engineering

Introduction.Experimental Part.Variables Studied.Results. Outline

Liquid-liquid Extraction is a mass transfer operation (Diffusion Controlled Operations) in which the feed is contacted with an immiscible or partially immiscible solvent that exhibits preferential affinity towards one or more of the components in the feed (called the solute). Liquid-Liquid Extraction

the feed is called the raffinate stream after it begins to lose the solute. the solvent is called the extract stream when it leaves the contactor. LLE Process Feed Solvent Extract Raffinate A sketch of the basic process

Solvent selection Good selectivity towards soluteNo miscibility with feed solutionEasley recoverable for recycleNon toxic, inflammable and non corrosive

Reasons of using Liquid-Liquid Extraction separation by distillation is ineffective or difficult When the components to be separated are heat sensitive, like antibiotics When more than two components are desired Energy requirements of distillation are very high When the material is non volatile,like mineral salts

Experimental Part

Set up.Procedure.

Setup 1.Agitated column. 2.Rotating shaft. 3.Rotating disc. 4.Stator ring. 5.Liquid distributor. 6.Variable speed motor. 7.Light phase storage tank. 8.Heavy phase storage tank. 9.Centrifugal pump. 10.Control valve.

Procedure The system used was (water, copper sulphate and naphthenic acid). Sampling and analysis. In all experiments, extraction took place from water to naphthenic acid; naphthenic acid was the dispersed phase.

Variables Studied

Concentration of copper sulphate Concentration of naphthenic acid Rotation speed Surface roughness

RESULTS

Mass Transfer at Rotating Disk: The volumetric mass transfer coefficient (K` = KA) of the extraction of copper sulphate from water with naphthenic acid in a recirculating batch rotating disc contactor was obtained using the equation: which upon integration yields: K` is determined by plotting vs. t. K` (cm 3 /sec) is used instead of K (cm/sec) as the interfacial mass transfer area between the two phases could not be calculated.

1.rotation speed

2.concentration of copper sulphate

3.Concentration of naphthenic acid

4.Discs roughness

conclusion the volumetric mass transfer coefficient for rotation disc contactor decreasing with decreasing with increasing concentration of copper sulphate. the volumetric mass transfer coefficient of rotation disc extractor increasing with increase of : 1- the disc rotational speed. 2- degree of disc roughness. 3- the concentration of naphthenic acid.