BIOFOULING CONTROL DR. ELISABETE R. SILVA OLGA FERREIRA ( PhD - - PowerPoint PPT Presentation

NON-TOXIC COATED STRUCTURED FILTERS: A NON-BIOCIDE RELEASE STRATEGY FOR BIOFOULING CONTROL

2ND INTERNATIONAL ELECTRONIC CONFERENCE ON WATER SCIENCES (ECWS-2) 16-30 NOVEMBER, 2017

• DR. ELISABETE R. SILVA

OLGA FERREIRA (PhD STUDENT)

Biofouling

Biological fouling: an spontaneous colonization by a diversity

• f micro/macroorganisms on submerged surfaces.

Adapted from Nurioglu et al., 2015 and Almeida et al., 2007

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Biofouling Burden!

Water contamination (freshwater/seawater) by biofouling attach on industrial surfaces causes serious penalties on several applications: such as water circuits, desalination systems, marine transport. Environmental penalties Economic impacts Health problems

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• Fuel consumption increases for
• peration conditions maintainance
• Gas emissions increases
• Maintainance costs

(Biocorrosion can affect up to 20%)

• Invasive species
• Harmful pathogens

into water in fluid transport systems

• Drag increase on ships hulls (40%)
• Pressure drop increases in water flow industrial circuits

Biofouling Burden!

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Conventional antifouling strategies for biofouling mitigation are mostly based on the releasing of toxic agents! Top Coat Antifouling Layer

BPR EU Regulation Nº528/2012

Is limiting the available antifouling agents

SEVERE RESTRICTIONS! NEW SOLUTIONS ARE SOUGHT!

Anti-Biofouling Strategies

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ECONEA

Activity against hard-shelled and soft- bodied invertebrate animal fouling

• rganisms

Unknown future ecotoxicity/accumulation effects

Booster Agents – Less Toxic?

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Top Coat Layer Top Coat Layer

“A goal properly set is halfway reached” Zig Ziglar lar 1926 26-20 2012

Chemical immobilisation of bioactive agents

Eco-friendly Solution

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Biocides Functionalisation (1st step)

NH OCN-R-NCO

NCO Function

N

OCN-R-NHC=O

• E. R. Silva, O. Ferreira, J. C. M. Bordado Patent Application,

WO 2016/093719 A1 Econea biocide

Eco-friendly solution

 Conversions higher than 95% were achieved.

 FTIR spectra confirmed the functionalisation reaction effectiveness

After functionalisation

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0.00 0.05 0.10 0.15 0.20 0.25 0.30 0.35 0.40

550 1.050 1.550 2.050 2.550 3.050 3.550

Absorbance (a.u.)

Wavenumber (cm-1) Econea-R-N=C=O Econea R-N=C=O

• C=O

R-N=C=O

O=C=N-R-NHC=O N-R (Econea)

No biocidal agent release from the coating - preventing the contamination of the surrounded environment!

A backbone based resin with OH functionality OH OCNH O

• R-NHC=O

N OCNH

• R-NHC=O

Eco-friendly Solution

Immobilisation via Urethane linkage (as example) (2nd step)

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Well Diffusion Method for Staphylococcus aureus

Econea (Positive control) Coating Econea Coating Econea-NCO Reference Coating Other coatings without bioactivity

 Functionalization

• f

the biocidal agent did not affect its bioactivity.  Coatings with immobilized biocide are bioactive. Promising result!

BIOACTIVITY ASSESSMENT

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Econea Econea-NCO Vancomycin

Other tested biocides

DMSO

PROOF-OF-CONCEPT

• 1. Simulated tests in an artificial seawater aquarium

7A 8A 8B 7B Silicone based formulations (A)

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Coated prototypes exposed for 12 months! Coatings with immobilised Econea show an improved antifouling behaviour.

Polyurethane based formulations (B).

7- With immobilised Econea-NCO 8- Reference coating without biocide

• 2. Real field tests- At relative Stationary conditions

Photos gently provided by ENP, SA Pontoon for field tests in Estaleiros Navais de Peniche (ENP), SA

45 Weeks (11 months submerged)

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A B

PROOF-OF-CONCEPT

Coated prototypes, with silicone based formulations, exposed for about 11 months in Atlantic sea: (A) Econea-NCO and (B) Reference coating.

Ceramic Monoliths (200 cpsi)

B A

Silicone based coating with immobilized Econea (A) and Reference coating without biocide (B)

 Coated monolithic filters evidenced uniform polymeric layers and minimal increases of surface roughness.  Adhesion tests are on-going: Cross cut and pull-off tests/others.

Coated Filters with Non-toxic Bioactive Coatings

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Microbial attack cause serious human health infections (E.coli, S. aureus) Transmission from fluid transport systems (e.g. water purification) Non-Toxic preventive actions are urgent!

 An expected high inhibition growth effect for MRSA strain  And a bacteriostatic behaviour was also observed!!!

Antimicrobial Activity of Coated Filters

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• S. aureus MRSA

CIP 106760 strain Uncoated Monolith Coated Monolith

1 2 3 4 5 6 1 2 3 4 5 6 7 8

Absorbance, OD (620 nm) Time (h)

MRSA (CIP 106760) Strain Monolithic support Coated Monolith (SilM) Coated Monolith (SilE-NCO-M)

Auspicious inhibition effects!

Antimicrobial Activity of Coated Filters

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 A complete growth inhibition with the coated monolithic with a silicone based coating containing tethered Econea (SilE-NCO-M).

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CONCLUSIONS

Econea biocide was successfully tethered in polymeric coatings. Promising antifouling behaviors, at simulated and real conditions, were

• btained for silicone based coatings containing the tethered Econea.

Auspicious antimicrobial and bacteriostatic behaviour was found for coated monolithic filters with the Econea/silicone based coating. The developed non-release biocidal coatings acting by contact, are able to avoid toxic agents releasing into the aqueous environment. This approach is presented as a promising environmental friendly and long-lasting antifouling/antimicrobial alternative strategy for the bio- decontamination of waterborne systems.

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"It is the worst of times but it is the best of times because we still have a chance." Sylvia Earle, Oceanographer

Elisabete R. Silva (ersilva@fc.ul.pt)

http://intheochem.fc.ul.pt/newsite/envrem.html