María José Luján Facundo

24 Aug 2012

Academic training

2003-2010: Chemical engineering in the discipline of environment, at the polytechnique university of Valencia (UPV), with an average marks of 6,7 and having obtained the prize to the best Final degree Project 09/10 at the high school of industrial engineers.

2010/2011: Official master at the UPV, entitled “Industrial Safety and Environment”.

Professional experience

2009-2011: Grant holder at the chemical and nuclear engineering department, at the polytechnique university of Valencia, working on research about membranes and waste water treatment.

2009: Riba-roja de Túria city council: worked with a practice contract to benefit from the awarding of the grants programme “La Dipu te beca”, helping the environment manager of the city council.

2008: Compo Iberia S.L: fertilizer company situated in La Vall d’Uixó. Worked with a practice contract and held the position of supporting the maintenance and quality manager.


Abstract


Ultrasonic cleaning of ultrafiltration membranes fouled with BSA solution

Introduction

Although membrane processes are widely employed in the dairy industry, the major disadvantage of their application is permeate flux decline due to membrane fouling. In food industries, membrane fouling is mainly due to protein adsorption onto the membrane surface and the internal pore blockage [1].

This work is focused on comparing the membrane cleaning with and without ultrasounds (US) application. In recent years, the US technique has been tentatively introduced in membrane filtration process [2].

Methods

A UF Minipilot plant (Orelis, France) was used for the experiments. It was equipped with a Rayflow flat sheet module from ORELIS (France) with capacity for two membranes of 100 cm2 each one, working in series. The tank for the cleaning solution was a TSD-D 18 ultrasonic bath (TSD, Spain) wich was connected to US generator TSD RF 300 (TSD, Spain).

Two polymeric membranes (UP005 and UH030) supplied by Microdyn Nadir were tested. Their MWCOs were 5 and 30 kDa, respectively.

The feed solution was a bovine serum albumin (BSA, purity>98%, Sigma-Aldrich, Germany) solution with a concentration of 1% w/w.

The membrane fouling tests were carried out at 25 ºC and transmembrane pressure of 2 bar. After the fouling test, the cleaning procedure included a rinsing step (30 min), a chemical cleaning with NaOH solution at 1 bar and a final rinsing step. Temperature and pH of the cleaning solution were varied according to an experimental design carried out by STATGRAPHICS. Membrane cleaning was performed by means of US at a 20.5 kHz frequency and 300 W of nominal power.  

Permeability recovery higher than 95% after each test was required before beginning the following experiment.

Results

Results clearly show that the use of US has a positive effect because higher permeability recovery values than those obtained without US application at the same conditions of temperature and pH of the cleaning solution.

In addition, it is important to note the effect of the pH and temperature of NaOH solution during the cleaning process. The best result is achieved when temperature and pH are 45º C and 9, respectively. Regarding with membrane permeability recovery, the highest value (for the test with US) was 100% and 76.20% for UH030 and UP005 membranes, respectively.

Conclusion

Experimental results from this study showed significant improvements of the permeability recovery using ultrasounds in the cleaning process. The enhancement factor using US is between 1.2 and 1.8 across the full range of our experiments.

Acknowledgements

This research was supported by the Spanish Ministry of Science and Innovation (CTM 2010-20.186).

References

[1] Argüello M. A., Álvarez S., Riera F. A., Álvarez R. (2003) Enzymatic cleaning of inorganic ultrafiltration membranes used for whey protein fractionation. Journal of Membrane Science 216, 121-134.

[2] Ming C., Shuna Z., Hanhua L. (2010) Mechanisms for the enhancement of ultrafiltration and membrane cleaning by different ultrasonic frequencies. Desalination 263, 133-138.