📄 chemistry

Sustainable Moringa Derived Acrylic acid Based Nanocomposite Hydrogel for Dual Removal of Ionic and Dye Pollutants

This study presents a sustainable sodium alginate/acrylic acid–iron nanoparticle–Moringa seed powder nanocomposite hydrogel that effectively removes potassium ions and Azure B dye from textile wastewater through synergistic adsorption and alum-assisted coagulation, achieving removal efficiencies of up to 85% and 98% respectively.

Original authors: Rimsha Saleem, Naeem Abbas, Amina Asghar, Muhammad Hammad Khan, Kainat Fatima

Published 2026-09-28

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CC BY 4.0

Original authors: Rimsha Saleem, Naeem Abbas, Amina Asghar, Muhammad Hammad Khan, Kainat Fatima

Original paper licensed under CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). ✨ This is an AI-generated explanation of the paper below. It is not written or endorsed by the authors. For technical accuracy, refer to the original paper. Read full disclaimer

Water pollution from factories is a persistent global challenge, particularly when it comes to the textile industry. The dyeing of fabrics generates vast amounts of wastewater laden with two distinct types of harmful contaminants: colorful synthetic dyes that stain rivers and inorganic salts that alter the water's chemical balance. Traditional methods for cleaning this water often struggle to handle both problems at once, frequently leaving behind toxic residues or requiring expensive, energy-intensive processes. Scientists have long sought materials that can act as a sponge, soaking up these diverse pollutants efficiently and sustainably. The goal is to find a solution that is not only effective but also derived from nature, reducing the environmental footprint of the cleanup process itself.

In a recent study, researchers from Pakistan have developed a new material designed to tackle this dual problem simultaneously. They created a specialized gel, known as a hydrogel, which acts as a highly effective filter for wastewater. This material is built from a combination of natural and synthetic components. The base is formed from sodium alginate, a substance derived from seaweed, and acrylic acid, which provides a sturdy framework. Into this polymer network, the team embedded two key ingredients: iron oxide nanoparticles and a powder made from the seeds of the Moringa tree. Moringa seeds are well-known in local communities for their natural ability to clarify water, while the iron nanoparticles add magnetic properties and extra surface area for trapping pollutants. The result is a hybrid material that looks like small, porous beads, offering a vast internal landscape for contaminants to get stuck.

The researchers tested this new hydrogel by exposing it to water containing two specific pollutants: Azure B, a bright blue cationic dye commonly used in textiles, and potassium ions, which represent the inorganic salts often found in industrial effluent. To ensure the material worked as intended, they first confirmed its structure using various imaging and chemical analysis tools. These tests revealed that the iron nanoparticles and Moringa powder were successfully integrated into the gel matrix, creating a rough, porous surface rich in chemical groups capable of binding to pollutants. The analysis showed that the material possessed the necessary chemical "hands" to reach out and grab both the dye molecules and the dissolved ions.

When the team put the hydrogel to work in a series of experiments, they found it performed exceptionally well. By adjusting factors such as the acidity of the water, the amount of material used, and the duration of the treatment, they optimized the cleaning process. The results were striking: the hydrogel removed nearly all of the Azure B dye from the water, achieving a removal rate of approximately 98 percent. It also successfully extracted potassium ions, removing about 85 percent of them. The process was further enhanced by adding a small amount of alum, a common coagulant, which helped the hydrogel clump together with the pollutants, making them easier to separate from the water. The study demonstrated that the material works through a combination of mechanisms, including electrical attraction between the gel and the pollutants, the swapping of ions, and the formation of chemical bonds on the surface.

The researchers used advanced statistical methods to map out exactly how different conditions affected the cleaning efficiency, ensuring that the results were not just a lucky guess but a reproducible outcome. Their data confirmed that the interaction between the pH of the water, the dosage of the hydrogel, and the time allowed for the reaction were critical factors. The study concludes that this Moringa-derived nanocomposite offers a promising, sustainable path forward for treating complex industrial wastewater. By combining a bio-based seed powder with engineered nanoparticles in a simple gel, the team has created a material that addresses two major water quality issues at once, offering a potential solution that is both effective and environmentally friendly.

Technical Summary: Sustainable Moringa Derived Acrylic Acid Based Nanocomposite Hydrogel for Dual Removal of Ionic and Dye Pollutants

Problem Statement
Industrial wastewater, particularly from the textile sector, presents a complex environmental challenge due to the simultaneous presence of hazardous organic dyes (such as Azure B) and inorganic ionic contaminants (such as potassium ions). Conventional treatment methods, including coagulation, membrane filtration, and traditional adsorption, often suffer from high operational costs, the generation of secondary sludge, and limited selectivity when addressing mixed pollutants. There is a critical need for sustainable, cost-effective, and multifunctional remediation materials capable of removing both organic and inorganic contaminants efficiently.

Methodology
The study focuses on the synthesis and evaluation of a novel nanocomposite hydrogel designated as SA/AA–Fe–MSP. This material integrates three primary components:

Polymeric Matrix: A crosslinked network of Sodium Alginate (SA) and Acrylic Acid (AA).
Nanoparticles: $\alpha$ -Fe $_2$ O $_3$ (iron oxide) nanoparticles synthesized via a citric acid-assisted method involving calcination at 400 °C.
Bio-adsorbent: Moringa oleifera seed powder (MSP), utilized for its natural coagulating and adsorbing properties.

The synthesis involved free radical polymerization of SA and AA in the presence of iron nanoparticles and MSP, followed by crosslinking with CaCl $_2$ to form hydrogel beads. The material was characterized using Fourier Transform Infrared Spectroscopy (FTIR), Scanning Electron Microscopy with Energy Dispersive X-ray analysis (SEM-EDX), and X-ray Diffraction (XRD) to confirm functional groups, morphology, and crystalline phases.

Adsorption experiments were conducted in batch mode to evaluate the removal of Potassium (K $^+$ ) ions and Azure B dye. The study employed Response Surface Methodology (RSM) based on a Central Composite Design (CCD) to optimize four key variables: pH, adsorbent dose, alum concentration (used as a coagulant aid), and shaking time. Comparative tests were performed to assess the synergistic effects of the composite alone versus the composite combined with alum.

Key Contributions and Results

Material Characterization: FTIR analysis confirmed the successful incorporation of all components, identifying O–H, C=O, and Fe–O stretching vibrations. SEM revealed a rough, porous morphology with uniform dispersion of nanoparticles and MSP within the polymer matrix, while XRD confirmed the presence of crystalline $\alpha$ -Fe $_2$ O $_3$ phases within a semi-amorphous polymeric network. EDX verified the elemental composition, including Carbon, Oxygen, Calcium (from crosslinking), and Iron.
Pollutant Removal Efficiency: The optimized SA/AA–Fe–MSP hydrogel demonstrated high efficacy in dual-pollutant removal.
- Azure B Dye: Achieved a maximum removal efficiency of approximately 98%.
- Potassium Ions (K $^+$ ): Achieved a maximum removal efficiency of approximately 85%.
- The inclusion of alum as a coagulant significantly enhanced the removal of potassium ions compared to the composite alone.
Statistical Optimization: The RSM analysis indicated that a quadratic model best described the system. For potassium removal, pH, shaking time, and the interaction between pH and shaking time were significant factors. For Azure B removal, pH was the most dominant factor, followed by alum dose and shaking time. The models showed high correlation coefficients ( $R^2$ = 0.8003 for K $^+$ and $R^2$ = 0.9623 for Azure B), confirming the reliability of the optimization.
Mechanisms: The removal process is attributed to a combination of mechanisms:
- For K $^+$ : Electrostatic attraction, ion exchange between K $^+$ and carboxylate groups, and coagulation facilitated by alum.
- For Azure B: Electrostatic attraction, hydrogen bonding, $\pi$ – $\pi$ interactions, and surface complexation.

Significance and Claims
The authors claim that this study presents a sustainable approach to wastewater treatment by utilizing bio-based materials (Moringa oleifera) and iron nanoparticles within a polymeric hydrogel. The primary significance lies in the material's ability to simultaneously target both ionic and dye pollutants, a capability often lacking in single-function adsorbents. The study highlights that the integration of natural coagulants (Moringa) with synthetic polymers and nanoparticles creates a synergistic effect that enhances adsorption capacity.

The paper positions the SA/AA–Fe–MSP hydrogel as a cost-effective and environmentally friendly alternative to conventional treatment methods. By achieving high removal efficiencies through a facile synthesis route and optimizing process parameters via RSM, the authors suggest the material holds potential for application in advanced wastewater treatment systems, particularly for textile effluents with complex contaminant profiles. The work underscores the viability of bio-derived nanocomposites as a sustainable solution for remediation of contaminated aquatic environments.

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