LTL type nanozeolites utilized in surface photonics structures for environmental sensors

Abstract

A B S T R A C TEnvironmental monitoring has been continuously increasing due to an emerging global emphasis on the importance of sustainable development. Improving water quality monitoring and control is a challenge that calls for innovative solutions. Current methods of water monitoring are costly and analytical techniques suitable for field use are limited. There is a need for accurate, long-term monitoring of environmental contaminants using sensors that can be operated on site. The aim of our research is to theoretically model, fabricate and characterise holographic sensors for water quality monitoring that are simple to operate, capable of sensing copper present in fresh water and have relatively low cost. The sensors are created by holographic recording of surface relief gratings (SRG) in a self-processing photopolymer material. Interrogation of these structures by light allows indirect measurements of ion concentration in real time. The SRG structures are modified by coating with porous LTL-nanoparticles (nanosized zeolites) which selectively adsorb copper ions. The suitability of the sensors for detection of copper (II) present in water at concentration levels 1-4 mM is reported. The current detection limit of the sensor is 63 ppm.

Supramolecular Organization in Confined Nanospaces

“…For example, high stability combined with the extraordinary luminescence properties of silver clusters in zeolite microcrystals are appealing for applications such as bio imaging and bio sensing . Also, recent promising attempts of realizing greatly effective environmental sensors make use of crystalline zeolite nanoparticles in the fabrication of surface photonic structures …”

“…[788] Also, recent promising attempts of realizing greatly effective environmental sensors make use of crystalline zeolite nanoparticles in the fabrication of surface photonic structures. [789] Zeolite L-based antenna materials guarantee a maximum loading of the donor molecules -which results in an extremely high speed for exciton transport -and a low loading of acceptor molecules, thus minimal self-absorption losses: the acceptors can nearly quantitatively capture the excitation energy. [665] Though the composites are technically suitable for use in solar cells and sensing applications (Section 7), acidity inside the zeolite L channel is still a limiting factor towards attaining maximum concentration of donor molecules inside the host.…”

Modified Surface Relief Layer Created by Holographic Lithography: Application to Selective Sodium and Potassium Sensing

“…The synthesis procedure of acrylamide based photopolymer has been previously presented [ 19 , 20 ]. All the chemicals used in this work were of analytical grade, they were purchased from Sigma Aldrich, and used without further modification.…”

In-Situ Ellipsometric Study of the Optical Properties of LTL-Doped Thin Film Sensors for Copper(II) Ion Detection

“…As in [7], the ellipsometry measurements necessitated prolonged exposure of the zeolite films to water. In order to facilitate increased mechanical stability of the LTL-type zeolite films in solution, the LTL-type zeolites were mixed with a pre-hydrolyzed tetraethyl orthosilicate (TEOS).…”

“…Thus, changes in n, ∆n and d due to analyte exposure can be indirectly measured via the η. Recently, Sabad-e-Gul et al implemented this approach for the development of a surface relief diffraction grating (SRG)-based sensor for the detection of heavy metal ions in water [7]. The SRG-based sensor, fabricated via the holographic lithography of an acrylate photopolymer surface, which is subsequently functionalized with zeolite nanoparticles, successfully detected low concentrations of copper (Cu 2+ ), Pb 2+ and Ca 2+ cations.…”