Impact of Moringa Oleifera extraction conditions on zeta potential and coagulation effectiveness

• Published in: Journal of environmental chemical engineering 2021-02, Vol.9 (1), p.104687, Article 104687
• Main Authors: Skaf, Dorothy W., Punzi, Vito L., Rolle, Javaz T., Cullen, Elizabeth
• Format: Article
• Language: English
• Subjects: Coagulation; Extraction; Moringa oleifera; Turbidity reduction; Zeta potential
• ISSN: 2213-3437; 2213-3437
• DOI: 10.1016/j.jece.2020.104687

•Extraction time affected the zeta potential and coagulation performance of aqueous protein extracts from moringa seeds.•Treatment of sample suspensions with the moringa extract yielded nearly 90 % turbidity reduction.•The impact of the extract on zeta potential did not always correlate with coagulation performance.•The removal of oil from the seeds before extraction increased stability of the coagulation agents in the extract. Extraction time affected the zeta potential (ZP) and coagulation performance of aqueous protein extracts obtained from both whole and defatted Moringa oleifera (MO) seeds. The ZP of kaolin and TiO2 suspensions increased with the extract dose and the extract from defatted seeds was more effective in increasing ZP than similar concentration extracts from whole seeds. As the extraction time increased from 1−30 min, the extracted solution had less impact on the ZP of kaolin and TiO2 suspensions. Although the concentration of protein in the aqueous extract reached an equilibrium value within a 15-min extraction time, the impact of the extract on ZP decreased with longer extraction time. For the conditions in this study, nearly 90 % turbidity reduction was achieved. However, while the water quality improved, the lowest residual turbidity of kaolin suspensions with an initial turbidity of approximately 60 NTU did not achieve the WHO guideline of 5 NTU. The extract from defatted seed solids could be used for up to seven days without significant degradation in coagulation performance, while the extract from whole seeds showed signs of degradation after only four days.