Rice Husk-Derived Cellulose Nanofibers: A Potential Sensor for Water-Soluble Gases

Cellulose and its derivatives have evoked much attention in sensor technology as host-matrices for conducting materials because of their versatility, renewability, and biocompatibility. However, only a few studies have dealt with the potential utilization of cellulose as a sensing material without a composite structure. In this study, cellulose nanofibers (CNF) and 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-oxidized cellulose nanofibers (TOCNF) extracted from rice husks by using ultrasonic-assisted methods are introduced as a potential gas sensing material with highly sensitive performance. To fabricate nanocellulose-based films, CNF, TOCNF, and TOCNF with glycerol (TOCNF/G) were dispersed in water and applied on polyimide substrate with digital electrodes to form self-standing thin films by a drop-casting method. A transparent coating layer on the surface of the plate after drying is used for the detection of water-soluble gases such as acetone, ammonia, methane, and hydrogen sulfide gases at room temperature at 52% relative humidity. The sensor prototypes exhibited high sensitivity, and the detection limit was between 1 ppm and 5 ppm, with less than 10 min response and recovery time. The results indicate that both the CNF- and the TOCNF-coated sensors show good sensitivity toward ammonia and acetone, compared to other gases. A TOCNF/G-coated sensor exhibited minimum time in regard to response/recovery time, compared to a CNF-coated sensor. In this study, nanocellulose-based sensors were successfully fabricated using a low-cost process and a bio-based platform. They showed good sensitivity for the detection of various gases under ambient conditions. Therefore, our study results should further propel in-depth research regarding various applications of cellulose-based sensors in the future.

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Long-term evaluation of air sensor technology under ambient conditions in Denver, Colorado

Atmospheric Measurement Techniques ◽

10.5194/amt-11-4605-2018 ◽

2018 ◽

Vol 11 (8) ◽

pp. 4605-4615 ◽

Cited By ~ 29

Author(s):

Stephen Feinberg ◽

Ron Williams ◽

Gayle S. W. Hagler ◽

Joshua Rickard ◽

Ryan Brown ◽

...

Keyword(s):

Air Pollution ◽

Wind Direction ◽

Low Cost ◽

Geographic Location ◽

Field Evaluation ◽

Time Of Day ◽

Sensor Technology ◽

Ambient Conditions ◽

Data Completeness ◽

Sampling Campaign

Abstract. Air pollution sensors are quickly proliferating for use in a wide variety of applications, with a low price point that supports use in high-density networks, citizen science, and individual consumer use. This emerging technology motivates the assessment under real-world conditions, including varying pollution levels and environmental conditions. A seven-month, systematic field evaluation of low-cost air pollution sensors was performed in Denver, Colorado, over 2015–2016; the location was chosen to evaluate the sensors in a high-altitude, cool, and dry climate. A suite of particulate matter (PM), ozone (O3), and nitrogen dioxide (NO2) sensors were deployed in triplicate and were collocated with federal equivalent method (FEM) monitors at an urban regulatory site. Sensors were evaluated for their data completeness, correlation with reference monitors, and ability to reproduce trends in pollution data, such as daily concentration values and wind-direction patterns. Most sensors showed high data completeness when data loggers were functioning properly. The sensors displayed a range of correlations with reference instruments, from poor to very high (e.g., hourly-average PM Pearson correlations with reference measurements varied from 0.01 to 0.86). Some sensors showed a change in response to laboratory audits/testing from before the sampling campaign to afterwards, such as Aeroqual, where the O3 response slope changed from about 1.2 to 0.6. Some PM sensors measured wind-direction and time-of-day trends similar to those measured by reference monitors, while others did not. This study showed different results for sensor performance than previous studies performed by the U.S. EPA and others, which could be due to different geographic location, meteorology, and aerosol properties. These results imply that continued field testing is necessary to understand emerging air sensing technology.

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An Effective Optical Dual Gas Sensor for Simultaneous Detection of Oxygen and Ammonia

Sensors ◽

10.3390/s19235124 ◽

2019 ◽

Vol 19 (23) ◽

pp. 5124 ◽

Cited By ~ 3

Author(s):

Sajal Biring ◽

Annada Sankar Sadhu ◽

Moumita Deb

Keyword(s):

Gas Sensor ◽

Fluorescent Dyes ◽

Low Cost ◽

Simultaneous Detection ◽

High Sensitivity ◽

Eosin Y ◽

Practical Applications ◽

Sensing Material ◽

Dual Sensor ◽

Sensitivity And Selectivity

The development of a simple, low-cost sensor for the effective sensing of multiple gases in industrial or residential zones has been in high demand in recent days. In this article, we have proposed an optical sensor for the dual sensing of oxygen (O2) and ammonia (NH3) gases, which consists of oxygen and ammonia-sensitive fluorescent dyes coated individually on both sides of a glass substrate. An ethyl cellulose (EC) matrix doped with platinum (II) meso-tetrakis (pentafluorophenyl) porphyrin (PtTFPP) serves as the oxygen-sensing material, whereas the NH3-sensing material includes an eosin Y fluorescent indicator immobilized within a cellulose acetate (CA) matrix. Both the oxygen and ammonia-sensitive materials were excited by the same LED light source with a 405 nm peak wavelength, while the corresponding emissions were detected separately for the selective sensing of the gases under study. The dual gas sensor exhibits maximum sensitivities of around 60 and 20 for oxygen and ammonia gases, respectively. The high sensitivity and selectivity of the proposed optical dual sensor suggests the feasibility of the simultaneous sensing of oxygen and ammonia for practical applications.

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State-of-the-Art Optical Devices for Biomedical Sensing Applications—A Review

Electronics ◽

10.3390/electronics10080973 ◽

2021 ◽

Vol 10 (8) ◽

pp. 973

Author(s):

N. L. Kazanskiy ◽

S. N. Khonina ◽

M. A. Butt ◽

A. Kaźmierczak ◽

R. Piramidowicz

Keyword(s):

Optical Sensors ◽

Low Cost ◽

High Sensitivity ◽

Sensor Technology ◽

Biomedical Sensors ◽

Plasmonic Sensors ◽

Biomedical Sensing ◽

Sensing Applications ◽

Compact Size ◽

Pros And Cons

Optical sensors for biomedical applications have gained prominence in recent decades due to their compact size, high sensitivity, reliability, portability, and low cost. In this review, we summarized and discussed a few selected techniques and corresponding technological platforms enabling the manufacturing of optical biomedical sensors of different types. We discussed integrated optical biosensors, vertical grating couplers, plasmonic sensors, surface plasmon resonance optical fiber biosensors, and metasurface biosensors, Photonic crystal-based biosensors, thin metal films biosensors, and fiber Bragg grating biosensors as the most representative cases. All of these might enable the identification of symptoms of deadly illnesses in their early stages; thus, potentially saving a patient’s life. The aim of this paper was not to render a definitive judgment in favor of one sensor technology over another. We presented the pros and cons of all the major sensor systems enabling the readers to choose the solution tailored to their needs and demands.

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High Sensitivity of Ammonia Sensor through 2D Black Phosphorus/Polyaniline Nanocomposite

Nanomaterials ◽

10.3390/nano11113026 ◽

2021 ◽

Vol 11 (11) ◽

pp. 3026

Author(s):

Zuquan Wu ◽

Lei Liang ◽

Shibu Zhu ◽

Yifan Guo ◽

Yao Yao ◽

...

Keyword(s):

Electron Microscopy ◽

Low Cost ◽

Oxidative Polymerization ◽

High Sensitivity ◽

Fast Response ◽

Experimental Result ◽

Conjugation System ◽

Detection Range ◽

Sensing Material ◽

Response And Recovery

Recently, as a two-dimensional (2D) material, black phosphorous (BP) has attracted more and more attention. However, few efforts have been made to investigate the BP/polyaniline (PANI) nanocomposite for ammonia (NH3) gas sensors. In this work, the BP/PANI nanocomposite as a novel sensing material for NH3 detection, has been synthesized via in situ chemical oxidative polymerization, which is then fabricated onto the interdigitated transducer (IDTs). The electrical properties of the BP/PANI thin film are studied in a large detection range from 1 to 4000 ppm, such as conduction mechanism, response, reproducibility, and selectivity. The experimental result indicates that the BP/PANI sensor shows higher sensitivity and larger detection range than that of PANI. The BP added into PANI, that may enlarge the specific surface area, obtain the special trough structure for gas channels, and form the p–π conjugation system and p–p isotype heterojunctions, which are beneficial to increase the response of BP/PANI to NH3 sensing. Meanwhile, in order to support the discussion result, the structure and morphology of the BP/PANI are respectively measured by Fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV−vis), transmission electron microscopy (TEM), and field emissions scanning electron microscopy (SEM). Moreover, the sensor shows good reproducibility, and fast response and recovery behavior, on NH3 sensing. In addition, this route may offer the advantages of an NH3 sensor, which are of simple structure, low cost, easy to assemble, and operate at room temperature.

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Long-term evaluation of air sensor technology under ambient conditions in Denver, Colorado

10.5194/amt-2018-12 ◽

2018 ◽

Cited By ~ 3

Author(s):

Stephen Feinberg ◽

Ron Williams ◽

Gayle S. W. Hagler ◽

Joshua Rickard ◽

Ryan Brown ◽

...

Keyword(s):

Air Pollution ◽

Wind Direction ◽

Low Cost ◽

Geographic Location ◽

Field Evaluation ◽

Time Of Day ◽

Sensor Technology ◽

Ambient Conditions ◽

Data Completeness ◽

Sampling Campaign

Abstract. Air pollution sensors are quickly proliferating for use in a wide variety of applications, with a low price point that supports use in high density networks, citizen science, and individual consumer use. This emerging technology motivates the assessment under real-world conditions, including varying pollution levels and environmental conditions. A seven-month, systematic field evaluation of low-cost air pollution sensors was performed in Denver, Colorado over 2015–2016; the location chosen to evaluate the sensors in a high altitude, cool, and dry climate. A suite of particulate matter (PM), Ozone (O3), and nitrogen dioxide (NO2) sensors were deployed in triplicate, and were collocated with Federal Equivalent Method (FEM) monitors at an urban regulatory site. Sensors were evaluated for their data completeness, correlation with reference monitors, and ability to reproduce trends in pollution data, such as daily concentration values and wind-direction patterns. Most sensors showed high data completeness when data loggers were functioning properly. The sensors displayed a range of correlations with reference instruments, from poor to very high (e.g. hourly-average PM Pearson correlations with reference measurements varied from 0.01 to 0.86). Some sensors showed a change in response to laboratory audits/testing from before the sampling campaign to afterwards, such as the Aeroqual, where the O3 response slope changed from about 1.2 to 0.6. Some PM sensors measured wind-direction and time of day trends similar to those measured by reference monitors, while others did not. This study showed different results for sensor performance than previous studies performed by the U.S. EPA and others, which could be due to different geographic location, meteorology, and aerosol properties. These results imply that continued field testing is necessary to understand emerging air sensing technology.

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Low-Cost, High-Sensitivity Detection of Waterborne Al3+ Cations and F− Anions via the Fluorescence Response of a Morin Derivative Dye

Engineering Proceedings ◽

10.3390/i3s2021dresden-10166 ◽

2021 ◽

Vol 6 (1) ◽

pp. 29

Author(s):

Alhulw H. Alshammari ◽

Zahrah Alqahtani ◽

Faiz Bukhari Mohd Suah ◽

Syaza Atikah Nizar ◽

Alan Dunbar ◽

...

Keyword(s):

Phase Transfer ◽

Limit Of Detection ◽

Low Cost ◽

High Sensitivity ◽

Water Soluble ◽

Fibre Optic ◽

Long Term Stability ◽

Ion Sensing ◽

Lock In ◽

Fluorescence Spectrometer

Morin dye is known as a cheap and readily available selective ‘off → on’ fluorescent sensitiser when immobilised in a phase transfer membrane for the detection of Al3+ ions. Here, a morin derivative, NaMSA, which readily dissolves in water with good long-term stability is used in conjunction with a fibre-optic transducer with lock-in detection to detect Al3+ in drinking water below the potability limit. The combination of a water-soluble dye and the fibre-optic transducer require neither membrane preparation nor a fluorescence spectrometer yet still display a high figure of merit. The known ability to recover morin-based Al3+ cation sensors selectively by exposure to fluoride (F−) anions is further developed, enabling a complementary sensing of either fluoride anions, or aluminium cations, using the same dye with a sub-micromolar limit-of-detection for both ions. The sensor performance parameters compare favourably to prior reports on both aqueous aluminium and fluoride ion sensing.

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Nanomaterials-Based Electrochemical Immunosensors

Micromachines ◽

10.3390/mi10060397 ◽

2019 ◽

Vol 10 (6) ◽

pp. 397 ◽

Cited By ~ 7

Author(s):

Zhenguo Zhang ◽

Yulin Cong ◽

Yichun Huang ◽

Xin Du

Keyword(s):

Carbon Nanomaterials ◽

Low Cost ◽

High Sensitivity ◽

Detection Methods ◽

Sensor Technology ◽

Time Analysis ◽

Real Time Analysis ◽

Electrochemical Immunosensors ◽

Recent Developments ◽

Metal Nanomaterials

With the development of nanomaterials and sensor technology, nanomaterials-based electrochemical immunosensors have been widely employed in various fields. Nanomaterials for electrode modification are emerging one after another in order to improve the performance of electrochemical immunosensors. When compared with traditional detection methods, electrochemical immunosensors have the advantages of simplicity, real-time analysis, high sensitivity, miniaturization, rapid detection time, and low cost. Here, we summarize recent developments in electrochemical immunosensors based on nanomaterials, including carbon nanomaterials, metal nanomaterials, and quantum dots. Additionally, we discuss research challenges and future prospects for this field of study.

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Implementation of an innovative sensor technology for effective online water quality monitoring in the distribution network

Water Practice & Technology ◽

10.2166/wpt.2012.099 ◽

2012 ◽

Vol 7 (4) ◽

Cited By ~ 4

Author(s):

B. R. de Graaf ◽

F. Williamson ◽

Marcel Klein Koerkamp ◽

J. W. Verhoef ◽

R. Wuestman ◽

...

Keyword(s):

Water Quality ◽

Drinking Water ◽

Real Time ◽

Low Cost ◽

Distribution Network ◽

Warning System ◽

High Sensitivity ◽

Water Quality Monitoring ◽

Quality Monitoring ◽

Sensor Technology

For safe supply of drinking water, water quality needs to be monitored online in real time. The consequence of inadequate monitoring can result in substantial health risks, and economic and reputational damages. Therefore, Vitens N.V., the largest drinking water company of the Netherlands, set a goal to explore and invest in the development of intelligent water supply. In order to do this Vitens N.V. has set up a demonstration network for online water quality monitoring, the Vitens Innovation Playground (VIP). With the recent innovative developments in the field of online sensoring Vitens kicked off, in 2011, its first major online sensoring program by implementing a sensor grid based on EventLab systems from Optiqua Technologies Pte Ltd in the distribution network. EventLab utilizes bulk refractive index as a generic parameter for continuous real time monitoring of changes in water quality. Key characteristics of this innovative optical sensor technology, high sensitivity generic sensors at low cost, make it ideal for deployment as an early warning system. This paper describes different components of the system, the technological challenges that were overcome, and presents performance data and conclusions from deployment of Optiqua's EventLab systems in the VIP.

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Dual polymer networks: a new strategy in expanding the repertoire of hydrogels for biomedical applications

Journal of Materials Science Materials in Medicine ◽

10.1007/s10856-019-6316-9 ◽

2019 ◽

Vol 30 (10) ◽

Author(s):

Shathani Nkhwa ◽

Evren Kemal ◽

Neelam Gurav ◽

Sanjukta Deb

Keyword(s):

Biomedical Applications ◽

Low Cost ◽

Polymer Networks ◽

Water Soluble ◽

Biological Molecules ◽

Poly Vinyl Alcohol ◽

Dilute Solution ◽

Ambient Conditions ◽

Polymer Formation ◽

New Strategy

Abstract Inspired by the double network hydrogel systems we report the formulation of dual networks, which expands the repertoire of this class of materials for potential biomedical applications. The tough dual network hydrogels were designed through sequential interpenetrating polymer formation, applying green chemistry and low-cost methods, devoid of any initiator-activator complexes that may pose risks in biomedical applications. The dual networks were synthesized in two steps, firstly the water soluble poly(vinyl alcohol) was subjected to cryogelation that formed the first network, which was then expanded by intrusion of a dilute solution of sodium alginate and complexed with a solution of calcium chloride under ambient conditions and further freeze-thawed. These hydrogels are flexible, ductile and porous with the ability to absorb and retain fluids as well as possess the versatility to easily incorporate biological molecules/drugs/antibiotics to be applied in tissue matrices or drug delivery systems. The dual network hydrogels can be tailored to have varying mechanical properties, shapes, size, thickness and particularly can be made physically porous if required, to suit the users intended application.

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Optical Fiber Sensor for Heavy Chemical Detection: An Overview

Journal of Physics Conference Series ◽

10.1088/1742-6596/2075/1/012010 ◽

2021 ◽

Vol 2075 (1) ◽

pp. 012010

Author(s):

Nurul Athirah Mohamad Abdul Ghafar ◽

Arni Munira Markom ◽

Marni Azira Markom ◽

Ahmad Razif Muhammad

Keyword(s):

Optical Fiber ◽

Electromagnetic Interference ◽

Low Cost ◽

Optical Fiber Sensor ◽

High Sensitivity ◽

Electrochemical Analysis ◽

Detection Methods ◽

Fiber Sensor ◽

Sensor Technology ◽

Compact Size

Abstract Heavy metal contaminations such as mercury, lead, arsenic, cadmium, and zinc are becoming more serious and have become a hazard to human health. Due to their non-biodegradable nature, they can easily accumulate in the environment and cause toxicity even at low concentrations. Therefore, detecting the presence of these metal ions requires a highly sensitive sensing method. Traditional detection methods, such as electrochemical analysis, require complicated sample preparation, are costly, and typically require a lengthy measurement period. These days, optical fiber sensors have been acknowledged due to their unique characteristics such as compact size, high sensitivity, low cost, high flexibility, and immunity to electromagnetic interference. An overview of an optical fiber sensor technology for heavy chemical measurement is discussed in this paper. The sensing mechanisms are summarized, as well as the chemical water quality parameters and sensitivities.

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