Abstract
The purpose of this work is to determine parameters for the design of a Moringa seed sand filter for water purification. Moringa oleifera seeds containing cationic antimicrobial proteins have been used as natural coagulants for the removal of turbidity; however, a low removal efficiency and high residual organic levels limit their applications. In this work, Moringa seed extracts were used to reverse the charge of sand (f-sand) to 10 mV at a seed dosage of 5.6 g of seeds/m2 of sand. This f-sand filter demonstrated ∼4 log removal of 1 μm polystyrene particles and >8 log removal of Escherichia coli compared to <0.1 log removal for bare sand. Enhanced removal for particles and E. coli was dominated by attractive electrostatic interactions. Clean bed filtration modeling predicts a sticking coefficient (α) of 0.8 for f-sand compared to a value of 0.01 for bare sand. This α was further validated under a wide range of filtration conditions. Preliminary scale-up analyses suggest a point-of-use f-sand filter that requires a very small amount of seeds annually. The outcome of this work presents the scientific basis for the design of a water purification solution for developing regions, requiring only locally available resources and no use of synthetic chemicals or electricity.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 38-42 |
| Number of pages | 5 |
| Journal | Environmental Science and Technology Letters |
| Volume | 5 |
| Issue number | 1 |
| DOIs | |
| State | Published - Jan 9 2018 |
| Externally published | Yes |
Bibliographical note
Funding Information:This research was funded by a Humanitarian Materials Initiative award sponsored by Covestro. Additional funding was provided by Department of Chemical Engineering of The Pennsylvania State University, a National Science Foundation REU program (EEC-1659497), and Pennsylvania State Global Programs. The authors thank Andrew (Mike) Erdman for providing Moringa seeds. The authors also thank Dr. Tammy Wood for providing the fluorescent E. coli strain. The authors acknowledge Brian Dawson from The Pennsylvania State University Huck Institute of the Life Sciences for supporting the flow cytometry instrumentation and for technical assistance. The authors also thank Prof. Darrell Velegol for helpful comments on the manuscript. The authors also thank Rajarshi Guha, Julie Anderson, Missy Hazen, Phuson Hulamm (Nikon), and Frank Herbert (Nikon) for technical assistance during confocal laser fluorescence microscopy imaging experiments.
Publisher Copyright:
© 2017 American Chemical Society.