Comparative study of flocculation and adsorption behaviour of water treatment proteins from Moringa peregrina and Moringa oleifera seeds

Shirin Nouhi,Philipp Gutfreund,Habauka M Kwaambwa,Adrian R Rennie

doi:10.1038/s41598-019-54069-2

Abstract

Trees of Moringa oleifera are the most widely exploited species of Moringa and proteins extracted from its seeds have been identified as the most efficient natural coagulant for water purification. Largely for climatic reasons, other Moringa species are more accessible in some regions and this paper presents a comparative study of the adsorption to different materials of the proteins extracted from seeds of Moringa peregrina and Moringa oleifera to explore their use as flocculating agents in regions where each is more readily accessible. Results showed that Moringa peregrina seed proteins had higher adsorption to alumina compared to silica, in contrast to opposite behavior for Moringa oleifera. Both species provide cationic proteins that can act as effective coagulants for the various impurities with different surface potential. Despite the considerable similarity of the amino acid composition, the seed proteins have significantly different adsorption and this presents the opportunity to improve processes by choosing the optimal species or combination of species depending on the type of impurity or possible development of separation processes.

Highlights

The most widely exploited natural material for water treatment has been crushed seeds from Moringa oleifera trees[13]
The present study provides a comparison between the interactions of proteins extracted from seeds of Moringa peregrina and Moringa oleifera tree, with model mineral surfaces and colloidal particles
Moringa oleifera seed proteins have been suggested as the most effective natural coagulant/flocculant for water purification purposes, they only grow in specific regions

Summary

Introduction

The most widely exploited natural material for water treatment has been crushed seeds from Moringa oleifera trees[13] This use was first observed as a traditional process in the valley of the Nile river but work by Broin et al.[14], for instance, identified that the protein from the seeds is the effective coagulant. Other seed proteins could be exploited to some extent in a similar manner, systematic comparison of over a hundred natural coagulants has shown that those of Moringa oleifera trees are the most effective[8,9,25,26,27,28]. Moringa seed proteins have been proposed for wider use as a biodegradable, low-toxicity, low-cost and sustainable replacements to the usual synthetic materials and they can be used in a simple way without trained technical supervision[30]

Methods

Results

Conclusion