Removal of Pyrethrin from Aqueous Effluents by Adsorptive Micellar Flocculation

Pardon K Kuipa,Olga Kuipa

doi:10.1155/2015/735631

Abstract

The equilibrium adsorption of pyrethrin onto aggregates formed by the flocculation of micelles of the surfactant sodium dodecyl sulphate (SDS) with aluminium sulphate is reported. The experimental results were analysed using different adsorption isotherms (Langmuir, Freundlich, Redlich-Peterson, Sips, Radke-Prausnitz, Temkin, linear equilibrium, and the Dubin-Radushkevich isotherms). The Freundlich and linear equilibrium isotherms best describe the adsorption of pyrethrin onto SDS micellar flocs, with the Freundlich adsorption constant,KF, and the mass distribution coefficient,KD, of 64.266 ((mg/g)(L/mg)1/n) and 119.65 L/g, respectively. Applicability of the Freundlich adsorption model suggests that heterogeneous surface adsorption affects the adsorption. The mean free energy value estimated using the Dubinin-Radushkevich isotherm was 0.136 kJ/mol indicating that physisorption may be predominant in the adsorption process.

Highlights

Pesticides may cause acute and chronic toxicity problems in aquatic environments and sometimes even entire food chains
A promising technology involves the adsorption of small molecules onto micellar aggregates which are formed when Al3+ cations interact with sodium dodecyl sulphate (SDS) micelles to form cylindrical to worm-like aggregates [1, 2]
We have investigated the equilibrium adsorption of pyrethrin onto aggregates formed by the flocculation of micelles of the surfactant sodium dodecyl sulphate (SDS) with aluminium sulphate

Summary

Introduction

Pesticides may cause acute and chronic toxicity problems in aquatic environments and sometimes even entire food chains. There is mounting pressure to minimise, at source, the upstream discharge of pesticides from manufacturing facilities. A promising technology involves the adsorption of small molecules onto micellar aggregates which are formed when Al3+ cations interact with sodium dodecyl sulphate (SDS) micelles to form cylindrical to worm-like aggregates [1, 2]. These aggregates form quickly and usually integrate all the micellar surfactant into one single floc which may float on top of the solution and can be filtered [3]. Micellar flocculation may involve the formation of complexes since large cationic complexes may be expected within the Stern layer due to the high Al3+ concentration [7]

Methods

Results

Conclusion