# Efficient removal of noxious methylene blue and crystal violet dyes at neutral conditions by reusable montmorillonite/NiFe2O4@amine-functionalized chitosan composite

## TL;DR

A reusable composite material efficiently removes harmful dyes from water at neutral pH, showing promise for environmental cleanup.

## Contribution

A novel amine-functionalized chitosan composite with magnetic properties is developed for efficient and reusable dye removal under neutral conditions.

## Key findings

- The composite achieved maximum adsorption capacities of 137 mg/g for methylene blue and 118 mg/g for crystal violet.
- The material retained over 87% adsorption efficiency after ten reuse cycles.
- It effectively removed dyes from real water samples like agricultural and river water at neutral pH.

## Abstract

The jeopardy of the synthetic dyes effluents on human health and the environment has swiftly aggravated, threatening human survival. Hence, sustained studies have figured out the most acceptable way to eliminate this poisonous contaminant. Thereby, our investigation aimed to fabricate montmorillonite/magnetic NiFe2O4@amine-functionalized chitosan (MMT-mAmCs) composite as a promising green adsorbent to remove the cationic methylene blue (MB) and crystal violet (CV) dyes from the wastewater in neutral conditions. Interestingly, MMT-mAmCs composite carries high negative charges at a wide pH range from 4 to 11 as clarified from zeta potential measurements, asserting its suitability to adsorb the cationic contaminants. In addition, the experimental study confirmed that the optimum pH to adsorb both MB and CV was pH 7, inferring the ability of MMT-mAmCs to adsorb both cationic dyes in simple process conditions. Furthermore, the ferromagnetic behavior of the MMT-mAmCs composite is additional merit to our adsorbent that provides facile, fast, and flawless separation. Notably, the as-fabricated composite revealed an auspicious adsorbability towards the adsorptive removal of MB and CV, since the maximum adsorption capacity of MB and CV were 137 and 118 mg/g, respectively. Moreover, the isotherm and kinetic investigatins depicted that the adsorption of both cationic dyes fitted Langmuir and Pseudo 2nd order models, respectively. Besides, the advanced adsorbent preserved satisfactory adsorption characteristics with maximal removal efficacy exceeding 87% after reuse for ten consecutive cycles. More importantly, MMT-mAmCs efficiently adsorbed MB and CV from real agricultural water, Nile river water and wastewater samples at the neutral pH medium, reflecting its potentiality to be a superb reusable candidate for adsorptive removal cationic pollutants from their aquatic media.