Introduction

The invention relates to a device composed of a mixed matrix membrane used for the decontamination of water from heavy metals, such as mercury and cadmium, mainly via chemical and / or electrostatic adsorption. It can be applied both to non-moving volumes of water and to moving water flows.

Technical features

The researchers propose a device composed of a polymeric membrane based on porous metal-organic materials (MOF) which, thanks to the chemical functionalization of the porous material dispersed on the polymeric support, increases the adsorbing properties. In the adsorption of membranes the contaminant is chemically recognized and rapidly captured by the porous hybrid material incorporated as an absorbent in the support membrane. This device conformation significantly increases the selectivity and strength of the adsorbent-contaminant interactions, in particular the adsorbent-mercury. The device is robust (min-max pressure supported 1.5-3 bar), versatile and low cost. Removal is also efficient from waters in which the contaminant is dispersed in small quantities. The removal rate after a number of cycles reaches 99.6%. In a specific application, the invention allows the removal, in a very efficient way, of toxic Hg (II) from aqueous media, reducing the concentration [Hg2+] from the dangerous 3.7 ppm (mg/L) to acceptable limits for drinking water, i.e. below 2 ppb (μg/L).

Possible Applications

• In recycling plants of waterways close to possible polluting sources of industry;
• Purification of waterways next to farms;
• Decontamination of wastewater from artisanal gold mining;
• Upstream of the pipes carrying drinking water.

Advantages

• Robust, versatile and low-cost device for efficient contaminant removal;
• Removal of the contaminant also from water in which it is dispersed in small quantities to make water drinkable;
• Large-scale preparation;
• High stability;
• Reuse of the adsorbent;
• Biocompatibility of the materials used;
• Metal recovery for safe storage respecting the environment and human health.