# Removal of Microplastics from Drinking Water by Moringa oleifera Seed: Comparative Performance with Alum in Direct and in-Line Filtration Systems

## TL;DR

This study compares the effectiveness of Moringa oleifera seed extract and alum in removing microplastics from drinking water using different filtration systems.

## Contribution

The study demonstrates that Moringa oleifera seed extract performs as well as alum in microplastic removal and works across a broader pH range.

## Key findings

- Moringa oleifera seed extract achieved 98.5% microplastic removal at pH 6.0.
- In-line filtration performed as effectively as direct filtration for microplastic removal.
- Moringa oleifera seed extract reduced specific ultraviolet absorbance by 88%.

## Abstract

In this study, the
removal efficiency of aged polyvinyl chloride
microplastics (Aged-PVC MPs) from low-turbidity drinking water using Moringa oleifera seed saline extract (MOS-SE) and
aluminum sulfate (alum) in direct filtration (coagulation–flocculation–filtration)
and in-line filtration (coagulation–filtration) systems is
investigated. Aged-PVC MPs (15 mg/L, D50 = 15.0 μm) and humic
acid (10 mg/L) were spiked into synthetic water to evaluate removal
performance across pH 5.0–8.0. The optimal conditions achieved
>98% turbidity removal with 30 mg/L MOS-SE and 9 mg/L alum at a
pH
of 6.0, corresponding to 98.5% and 98.7% of Aged-PVC MP removal, respectively,
as confirmed by scanning electron microscopy particle counting. Although
nonintrusive floc imaging revealed differences between coagulated
(43–46 μm) and flocculated aggregates (61–66 μm),
in-line filtration performs equivalently to direct filtration in terms
of MP removal, demonstrating that direct filtration’s flocculation
step was unnecessary. MOS-SE exhibited superior performance across
broader pH ranges (5.0–8.0) compared with alum (5.0–7.0).
While MOS-SE increased dissolved organic carbon because of residual
organic matter, it effectively reduced specific ultraviolet absorbance
(SUVA) by 88%, indicating efficient removal of aromatic natural organic
matter. These findings demonstrate the viability of Moringa oleifera as a sustainable alternative for
MP removal in drinking water treatment via in-line filtration.