Y. (Yuan) Lei

MSc student

University of Twente

Science and Technology

Meander, ME 316

P.O. Box 217

7500 AE Enschede

The Netherlands

Email y.lei@student.utwente.nl

Research description

“Stability of inorganic coating on an organic membrane structure”

Work is being done on coating an organic membrane structure (e.g. polyethersulfone) totally with inorganic material such silica. The walls of the pores of the organic membrane (pore size: several micrometers) should be covered by e.g. silica, while retaining the ability to flow fluid through the membrane structure. The fluid should “see” only inorganic material since the polymeric skeleton is wholly covered by inorganic material.

The aim of this work is to make use of the favourable surface/volume ratio of a membrane structure for processes such as adsorption, catalysis, etc. and/or to combine this with a membrane separation process.

For safety and economic reasons, it is important that the inorganic coating stays adhered to the membrane structure. This graduation project assignment could focus on the adhesion of e.g. silica onto a polyethersulfone membrane structure. Questions that could be researched are (this list is not limitative):

1.	How much coating material is lost from the membrane structure during normal operation?

2.	How can the lost material be characterised (e.g. particle size) and what are the consequences for (food) safety?

3.	What factors in the coating procedure influence the stability most, and how to tune these for maximum stability?

4.	All the questions can also be posed for cleaning conditions.

Preparing the coated membranes is part of the assignment, as well as characterisation of these coated membranes. Techniques that could be used for characterisation are for example:

·	Dynamic light scattering (DLS) for determination of particles in the membrane permeate.

·	Thermogravimetric analysis (TGA) for determination of silica content of coated (used) membranes.

·	Scanning Electron Microscopy (SEM) to get a feeling for the membrane surface & cross section. SEM-EDX (Energy-dispersive X-ray spectroscopy) could enlighten more about the silica content.

·	Surface area determination of the coated membrane, by e.g. nitrogen adsorption.

This assignment is meant for a master graduation project. The work will be carried out at the laboratories of SFI/MST (Meander, UT) in close corporation with the PhD-student. This assignment is deliberately formulated in a broad manner, so that the master student can choose his/her own path, in corporation with the PhD-student. Therefore, along the way some narrowing down of the assignment should be done.