Amino grafted MCM-41 as highly efficient and reversible ecofriendly adsorbent material for the Direct Blue removal from wastewater

2/4/2019 12:00:00 AM

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Authors:Vito Rizzi, Eko Adi Prasetyanto, Pengkun Chen, Jennifer Gubitosa, , Angela Agostiano, Luisa De Cola, Pinalysa Cosma

Publication date: Januari 2019

Journal of Molecular Liquids

Volume:  273

Link : https://www.sciencedirect.com/science/article/pii/S0167732218337048

 

Abstract:

The very high adsorption efficiency of Direct Blue (DB), an anionic toxic azo dye, onto amino grafted mesoporous silica nanoparticles (MCM-41), was studied in this paper, for possible industrial applications. Interesting challenges and advances are proposed in this field, presenting an adsorbent able to efficiently and rapidly remove the anionic dye from water. The important added value of this work regards the system recycle, which allows both the DB and adsorbent material recover, with a global reduction of the environmental impact, in the viewpoint of the green economy. Indeed, this paper is the first example of very fast removal and recycle of great amounts of DB with adsorbent materials characterized by impressive adsorption/desorption capacities, at least of around 300?mg/g for each adsorption cycle, potentially increasable by performing consecutive cycles of DB adsorption/desorption. In detail, the MCM-41 amino functionalization (MCM-41-NH₂) was obtained after (MCM-41-POST) and during (MCM-41-PRE) the synthesis of MCM-41, obtaining materials with different behavior towards the DB adsorption. The MCM-41-NH₂ surface features and porous structure, before and after the dye adsorption, were carefully characterized. Considering the adsorption process, for investigating the nature of the DB/MCM-41-NH₂ interaction, several parameters were studied: the contact time, the DB solutions pH values, adsorbent material and dye amount, with the additional analysis of how the adsorption process was influenced by the presence of electrolytes. The isotherms of adsorption were also considered. Although MCM-41-PRE exhibited a higher affinity towards DB molecules, the MCM-41-POST were able to rapidly desorb it, thus recycling both DB and the adsorbent material.

 

Keywords :

Wastewater, Adsorption, Silica, Mesoporous materials, Direct dyes, MCM-41