Environmental Sensors for Air and Water Pollution Monitoring

Nan Wang, Jin Wu, M Baranski, S Muttikulangara,

L Norford, M Triantafyllou, G Barbastathis and JM Miao

June 29, 2015 1SMART CENSAM

Content

Shark-Inspired MEMS Chemical Sensor for Heavy Metal Detection

3D Graphene Hydrogel based Air Pollutant Sensing

Light Field Imaging Spectrometer for Air Atmosphere Pollutant Monitoring by Satellite

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Content

Shark-Inspired MEMS Chemical Sensor for Heavy Metal Detection

3D Graphene Hydrogel based Air Pollutant Sensing

Light Field Imaging Spectrometer for Air Atmosphere Pollutant Monitoring by Satellite

3

Heavy metal contamination is considered to be one of the most dangerous pollutants of water pollution, due to its non-biodegradable nature. The contamination can come from many sources, including urban, industrial, mining and agricultural sources.

Sources of heavy metal contamination

*Figure downloaded from Internet.

Background

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Disadvantages

of conventional monitoring method:

time-consuming, labor-intensive sample

collection.

unpredictable reactions during

transportation.

experimental facilities restricted to

centralized place.

requirement of well-trained personnel.

Sample Collection

Sample Transportation

Laboratory Analysis

Result Generation

Conventional Water Quality Monitoring

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In nature, some marine animals possess remarkably keen olfactory sensing system, among which shark has well reputed smelling capacity as its olfactory organs are highly responsible for perceiving and analyzing odorant information to initiate food searching.

Image of lemon shark Ventral view of the head of lemon shark

*Figure downloaded from Internet. Zeiske et al.

Inspiration

Olfactory organ

where in, incurrent nostril; or, olfactory rosette; nf, nasal flap; en, excurrent nostril.

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Cross-sectional SEM image of olfactory rosette of lemon sharkwhere ic, inlet chamber; r, raphe; ol, olfactory lamella; im, inner lamellar margin;

sf, secondary fold; cw, cavity wall; pc, peripheral canal.

Inside the olfactory cavity, a large number of olfactory lamellae aggregate a rosette layout to form internal gap system between opposite-facing lamellae for water circulation. Such structure will significantly increase the chances of odorant molecules to be captured by olfactory sensing system.

Zeiske et al.

Inspiration

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Reference Electrode (RE)

Working Electrode (WE)

Counter Electrode (CE)

Contact Pad

Microfluidic Channel

Assembly Mark

Inlet

Outlet

Reaction Chamber

Schematic drawing of proposed MEMS chemical sensor with top part (microfluidic channel) and bottom part (sensor base).

Concept

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A

(A) Schematic drawing and (B) photograph of our fabricated MEMS chemical sensor. (C) SEM image

of shark’s olfactory sensors and (D) SEM image of micropillar electrode array, which mimics the morphological arrangement of shark’s olfactory sensors.

Zeiske et al.

C D

Concept

B

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A B

(A)Square wave stripping voltammograms for increasing concentration of Pb under optimized conditions

(B) Its calibration curve.

Lead (Pb) detection with square wave anodic stripping voltammetry

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A B

(A)Square wave stripping voltammograms for increasing concentration of Cu under optimized conditions

(B) Its calibration curve.

Copper (Cu) detection with square wave anodic stripping voltammetry

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Content

Shark-Inspired MEMS Chemical Sensor for Heavy Metal Detection

3D Graphene Hydrogel based Air Pollutant Sensing

Light Field Imaging Spectrometer for Air Atmosphere Pollutant Monitoring by Satellite

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Graphene under ambient conditions has been observed to display p-type behavior due to the electron withdrawing nature of adsorbed water or oxygen containing moisture, inducing a hole-like carrier concentration.

3D graphene hydrogels have larger surface areas than 2D counterparts. It is favorable for gas absorption and therefore gives higher sensitivity and detection limit for gas.

Background

3D graphene hydrogels

2D graphene sheet

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Drop cast of 3D graphene hydrogelon electrodes

Use wire bonding for electrode Gas sensing test

electrode

Compare the sensing properties of 3D graphene hydrogel and 2D graphene sheet, Hypothesis: 3D graphene can improve the performance

3D graphene hydrogels were synthesized by one step hydrothermal method. (ACS Nano, 2010, 4, 4324 )

3D Graphene Hydrogel based Gas Sensor

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SEM images of synthesized 3D graphene hydrogel

Resistance increases when gas concentration increases

Detection of NO2 by 3D Porous Graphene Hydrogel

Contents

Shark-Inspired MEMS Chemical Sensor for Heavy Metal Detection

3D Graphene Hydrogel based Air Pollutants Sensing

Light Field Imaging Spectrometer for Air Atmosphere Pollutant Monitoring by Satellite

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Background

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• Spectral Imaging –I(x,y, λ)–Spectral fingerprints of atmosphere pollutants (NO,NO2,SO…)

• NTU nano-satellites projects–Miniature instrumentation

Concept

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Thank you !

June 29, 2015 SMART CENSAM 19