Hybrid Polymer-functionalized Mesoporous Structures as new Versatile Adsorbents for Micropollutant Removal – HYPOSTAR

The SURHYMI project aims at developing a sustainable and integrated approach for the synthesis of hybrid mesoporous films and membranes densely and homogeneously functionalized by polymers, designed as platform materials for the elaboration of micropollutant removal devices. The control of the textural and chemical properties of the supported films and membranes (pore diameter and topology, and functions (acid, basic, cyclodextrin) in the mesopores), will allow to evaluate their performances in the reversible sorption of anionic, cationic and hydrophobic micropollutants based on electrostatic interactions or host-guest complexes. Novel polyion complex micelles (PIC) as well as host-guest inclusion complex (InC) micelles will be evaluated for the first time for their ability to controllably form a variety of ordered mesostructures by the sol-gel route, first as powders by macroscopic precipitation and then as films and membranes by deposition-evaporation. PIC micelles will be formed by electrostatic complexation between double-hydrophilic block copolymers (DHBC) and oppositely charged polyions, auxiliaries of micellisation. Poly(acrylic acid) and poly(aminoethylacrylamide) based DHBCs will be synthesized by RAFT in acidic media in order to protect the chain-transfer agent. Then, they will be used as platform polymers for the preparation by amidation reactions of a range of new DHBCs with beta-cyclodextrin (CD). Polymers with beta-CD functionalities will enable the formation of inclusion complex micelles (InC) with ditopic/multitopic guest species, which will be studied as silica structuring agents. PIC and InC assemblies will be evaluated for the first time as structuring, functionalizing and porogenic agents of functional mesoporous supported films and membranes. The new methodology developed should allow the preparation of materials whose mesopores will be intrinsically functionalized in a homogeneous and dense way by the targeted and previously prepared functions. The films will be prepared by evaporation induced assembly (EISA process). Depositions will be performed first on dense substrates, then on porous substrates. The disassembly of PIC and InC will allow the elution of the micellisation auxiliaries and will reveal the intrinsic functionalization of the layers with the three types of functions, acid, basic, and CD. The porous textures, thicknesses, density profiles and permeability of the functional films will be characterized. The influence of these properties will be evaluated for the sorption of model micropollutants as a function of physicochemical parameters (pH, concentration, ionic strength). Four organic micropollutants (hydrophilic cationic and anionic, as well as hydrophobic) were selected to demonstrate the specific and reversible character of the sorption mechanism in hybrid mesoporous silica-based platform materials. The kinetics, reversibility and repeatability of the sorption process will be studied as well as the chemical and structural recyclability and aging of the adsorbent materials. These results will be transferred to supported membranes to evaluate their filtration performance, chemical and structural stability and the mechanical properties of the prepared membrane materials.