Polyamine-Based Organo-Clays for Polluted Water Treatment: Effect of Polyamine Structure and Content.

Cinzia Cristiani,Giovanni Dotelli,Paola Gallo Stampino,Elisabetta Finocchio,Maurizio Licchelli,Elena Maria Iannicelli-Zubiani

doi:10.3390/polym11050897

Cinzia Cristiani, Giovanni Dotelli + Show 4 more

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https://doi.org/10.3390/polym11050897

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Abstract

Hybrid materials based on clays and polyamines are supposed to be efficient heavy metals sorbents due to the well-known adsorption behaviour of the clay matrix and to the coordination properties of un-protonated amino groups. For this purpose, a montmorillonite clay was modified with three different aliphatic polyamines: L6 and L10 have a linear structure with six and ten amino groups, respectively, while B14 is a branched polyamine with fourteen amino groups. Initial amine concentration was the main parameter investigated and data were fitted with Langmuir and Freundlich models. Interaction mechanisms between clay and amines were deeply investigated by different experimental techniques such as X-ray powder diffraction (XRD), thermal analysis measurements (DTG), Fourier Transform Infrared Spectroscopy (FT-IR) and diffuse reflectance (NIR) spectroscopy. Experimental results showed that the amount of amines efficiently immobilized in the solid phase can be increased by increasing the initial concentration of polyamines in the clay modification process. These data were best fitted by Freundlich model, indicating a presence of surface sites of different nature. In the resulting hybrid materials, neither the accessibility of the NH/NH2 groups of the amines, nor the accessibility of the structural OH of the clay was hindered. Several preliminary tests in La ions’ uptake and release from aqueous solution were also carried out. In the conditions used for this study, total metal ion removal was achieved at sufficiently low linear amine loadings (i.e., 0.45 mmol/gclay for the small L6 amine), suggesting that these hybrid materials are promising for the proposed application in environmental remediation.

Highlights

In recent years, water issues have progressively gained prominence in view of water relationship with the three pillars of a sustainable development: that is, economic, social and environmental [1].It is an undeniable fact that unsustainable development pathways have generated immense pressures on water resources, affecting its quality and availability and the Earth’s capacity to sustain the growing demands for freshwater is being challenged [2,3]
In the conditions used for this study, total metal ion removal was achieved at sufficiently low linear amine loadings (i.e., 0.45 mmol/gclay for the small L6 amine), suggesting that these hybrid materials are promising for the proposed application in environmental remediation
The value is Themolecular extent of the intercalation reaction is clearlyofirrespective of amine and plateau molecular weight

Summary

Introduction

Water issues have progressively gained prominence in view of water relationship with the three pillars of a sustainable development: that is, economic, social and environmental [1]. It is an undeniable fact that unsustainable development pathways have generated immense pressures on water resources, affecting its quality and availability and the Earth’s capacity to sustain the growing demands for freshwater is being challenged [2,3]. Water is a key resource for industrial and manufacturing processes (e.g., heating, cooling, cleaning, rinsing, etc.) but wastewater that is generated can cause environmental damage when it is discharged without any treatment. Polymers 2019, 11, 897 pollutants in water generally include heavy metals and /or huge amounts of organic pollutants whose removal is mandatory but requires the application of complex and expensive processes [4]. Conventional techniques proposed for this purpose, such as ion exchange, precipitation, electrodialysis, reverse osmosis, ultrafiltration, flocculation, biosorption, adsorption and so forth [5,6]

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