Synthesis, Characterization, and Photocatalytic Activities of Graphene Oxide/metal Oxides Nanocomposites: A Review

Sustainable water processing techniques have been extensively investigated and are capable of improving water quality. Among the techniques, photocatalytic technology has shown great potential in recent years as a low cost, environmentally friendly and sustainable technology. However, the major challenge in the industrial development of photocatalyst technology is to develop an ideal photocatalyst which must have high photocatalytic activity, a large specific surface area, harvest sunlight and shows recyclability. Keeping these views, the present review highlighted the synthesis approaches of graphene/metal oxide nanocomposite, characterization techniques and their prominent applications in photocatalysis. Various parameters such as photocatalyst loading, structure of photocatalyst, temperature, pH, effect of oxidizing species and wavelength of light were addressed which could affect the rate of degradation. Moreover, the formation of intermediates during photo-oxidation of organic pollutants using these photocatalysts is also discussed. The analysis concluded with a synopsis of the importance of graphene-based materials in pollutant removal. Finally, a brief overview of the problems and future approaches in the field is also presented.

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Water quality monitoring: from conventional to emerging technologies

Water Science & Technology Water Supply ◽

10.2166/ws.2019.144 ◽

2019 ◽

Vol 20 (1) ◽

pp. 28-45

Author(s):

Umair Ahmed ◽

Rafia Mumtaz ◽

Hirra Anwar ◽

Sadaf Mumtaz ◽

Ali Mustafa Qamar

Keyword(s):

Machine Learning ◽

Water Quality ◽

Industrial Development ◽

Low Cost ◽

Research Work ◽

Water Quality Monitoring ◽

Machine Learning Techniques ◽

Rapid Urbanization ◽

Analysis Process ◽

Learning Techniques

Abstract The rapid urbanization and industrial development have resulted in water contamination and water quality deterioration at an alarming rate, deeming its quick, inexpensive and accurate detection imperative. Conventional methods to measure water quality are lengthy, expensive and inefficient, including the manual analysis process carried out in a laboratory. The research work in this paper focuses on the problem from various perspectives, including the traditional methods of determining water quality to gain insight into the problem and the analysis of state-of-the-art technologies, including Internet of Things (IoT) and machine learning techniques to address water quality. After analyzing the currently available solutions, this paper proposes an IoT-based low-cost system employing machine learning techniques to monitor water quality in real time, analyze water quality trends and detect anomalous events such as intentional contamination of water.

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Objectives of a Water Quality Monitoring Programme for the International River Basins in a Developing Country in Southern Africa – Mozambique

Water Science & Technology ◽

10.2166/wst.1984.0120 ◽

1984 ◽

Vol 16 (5-7) ◽

pp. 33-39

Author(s):

S J Hugman

Keyword(s):

Water Quality ◽

Water Resources ◽

Industrial Development ◽

Water Quality Monitoring ◽

Quality Data ◽

Sample Collection ◽

Water Quality Data ◽

Maximum Benefit ◽

Management And Development ◽

International Obligations

Mozambique lies on the south-east coast of Africa. Its Independence, in 1975, was particularly difficult and severely disrupted the economy. All its major rivers rise in neighbouring countries and several, in particular those from South Africa and Swaziland, are already heavily used before crossing the border. Since 1977 the National Water Directorate has been responsible for management and development of water resources. The Directorate includes a hydrology department which maintains field-teams throughout the country. Virtually no water quality data are available from before 1972, when irregular sample collection began. Since Independence, sampling has continued but the Directorate has redefined the objectives of the programme to obtain maximum benefit from very limited resources. These objectives were chosen for economic, hydrological and political reasons. The long-term objectives are to provide the data required for agricultural and industrial development projects, to manage and maintain the quality of Mozambique's water resources, and to meet international obligations. In practice, the capacity of the hydrological service is insufficient to meet these objectives. The targets for the existing programme were therefore chosen to satisfy the most important objectives and to be feasible with present resources. The routine programme is being completely operated by technicians who have no more than nine years schooling.

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Nanocomposite Materials Based on Electrochemically Synthesized Graphene Polymers: Molecular Architecture Strategies for Sensor Applications

Chemosensors ◽

10.3390/chemosensors9060149 ◽

2021 ◽

Vol 9 (6) ◽

pp. 149

Author(s):

André Olean-Oliveira ◽

Gilberto A. Oliveira Brito ◽

Celso Xavier Cardoso ◽

Marcos F. S. Teixeira

Keyword(s):

Conducting Polymers ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

Electrochemical Sensors ◽

Structural Characteristics ◽

Low Cost ◽

Large Specific Surface Area ◽

Molecular Architecture ◽

Sensor Applications

The use of graphene and its derivatives in the development of electrochemical sensors has been growing in recent decades. Part of this success is due to the excellent characteristics of such materials, such as good electrical and mechanical properties and a large specific surface area. The formation of composites and nanocomposites with these two materials leads to better sensing performance compared to pure graphene and conductive polymers. The increased large specific surface area of the nanocomposites and the synergistic effect between graphene and conducting polymers is responsible for this interesting result. The most widely used methodologies for the synthesis of these materials are still based on chemical routes. However, electrochemical routes have emerged and are gaining space, affording advantages such as low cost and the promising possibility of modulation of the structural characteristics of composites. As a result, application in sensor devices can lead to increased sensitivity and decreased analysis cost. Thus, this review presents the main aspects for the construction of nanomaterials based on graphene oxide and conducting polymers, as well as the recent efforts made to apply this methodology in the development of sensors and biosensors.

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Multi-Blockchain-Based IoT Data Processing Techniques to Ensure the Integrity of IoT Data in AIoT Edge Computing Environments

Sensors ◽

10.3390/s21103515 ◽

2021 ◽

Vol 21 (10) ◽

pp. 3515

Author(s):

Sung-Ho Sim ◽

Yoon-Su Jeong

Keyword(s):

Low Cost ◽

Third Party ◽

Monitoring And Control ◽

Constant Size ◽

Computing Environments ◽

Iot Devices ◽

Cloud Servers ◽

The Cost ◽

Processing Techniques ◽

And Control

As the development of IoT technologies has progressed rapidly recently, most IoT data are focused on monitoring and control to process IoT data, but the cost of collecting and linking various IoT data increases, requiring the ability to proactively integrate and analyze collected IoT data so that cloud servers (data centers) can process smartly. In this paper, we propose a blockchain-based IoT big data integrity verification technique to ensure the safety of the Third Party Auditor (TPA), which has a role in auditing the integrity of AIoT data. The proposed technique aims to minimize IoT information loss by multiple blockchain groupings of information and signature keys from IoT devices. The proposed technique allows IoT information to be effectively guaranteed the integrity of AIoT data by linking hash values designated as arbitrary, constant-size blocks with previous blocks in hierarchical chains. The proposed technique performs synchronization using location information between the central server and IoT devices to manage the cost of the integrity of IoT information at low cost. In order to easily control a large number of locations of IoT devices, we perform cross-distributed and blockchain linkage processing under constant rules to improve the load and throughput generated by IoT devices.

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Development and Characterization of a Novel Low-Cost Water-Level and Water Quality Monitoring Sensor by Using Enhanced Screen Printing Technology with PEDOT:PSS

Micromachines ◽

10.3390/mi11050474 ◽

2020 ◽

Vol 11 (5) ◽

pp. 474 ◽

Cited By ~ 1

Author(s):

Bei Wang ◽

Manuel Baeuscher ◽

Xiaodong Hu ◽

Markus Woehrmann ◽

Katharina Becker ◽

...

Keyword(s):

Water Quality ◽

Water Level ◽

Sheet Resistance ◽

Screen Printing ◽

Low Cost ◽

Conductive Polymer ◽

Water Quality Monitoring ◽

Physical Treatment ◽

Printing Technology ◽

Screen Printing Technology

A novel capacitive sensor for measuring the water-level and monitoring the water quality has been developed in this work by using an enhanced screen printing technology. A commonly used environment-friendly conductive polymer poly(3,4-ethylenedioxythiophene):poly (styrenesulfonate) (PEDOT:PSS) for conductive sensors has a limited conductivity due to its high sheet resistance. A physical treatment performed during the printing process has reduced the sheet resistance of printed PEDOT:PSS on polyethylenterephthalat (PET) substrate from 264.39 Ω/sq to 23.44 Ω/sq. The adhesion bonding force between printed PEDOT:PSS and the substrate PET is increased by using chemical treatment and tested using a newly designed adhesive peeling force test. Using the economical conductive ink PEDOT:PSS with this new physical treatment, our capacitive sensors are cost-efficient and have a sensitivity of up to 1.25 pF/mm.

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Smart and Low Cost Real Time Water Quality Monitoring System Using IoT

SSRN Electronic Journal ◽

10.2139/ssrn.3350297 ◽

2019 ◽

Author(s):

Jeba Anandh S ◽

Anandharaj M ◽

Aswinrajan J ◽

Karankumar G ◽

Karthik P

Keyword(s):

Water Quality ◽

Real Time ◽

Monitoring System ◽

Low Cost ◽

Water Quality Monitoring ◽

Quality Monitoring

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Comparison and verification of four field-based microbiological tests: H2S test, Easygel®, Colilert®, Petrifilm™

Journal of Water Sanitation and Hygiene for Development ◽

10.2166/washdev.2011.026 ◽

2011 ◽

Vol 1 (1) ◽

pp. 68-85 ◽

Cited By ~ 18

Author(s):

Patty Chuang ◽

Stephanie Trottier ◽

Susan Murcott

Keyword(s):

Water Quality ◽

Developing Countries ◽

Standard Method ◽

Low Cost ◽

Field Tests ◽

Single Test ◽

Total Water ◽

Microbiological Test ◽

Technical Capacity ◽

Larger Sample

The UN defines water supplies as ‘improved’ or ‘unimproved.’ These indicators are easy to measure, but do not reflect water quality, which requires laboratory or field tests. Laboratory and test availability, expense and technical capacity are obstacles for developing countries. This research compares and verifies four low-cost, field-based microbiological tests: the EC-Kit (Colilert® and Petrifilm™ tests), the H2S bacteria test, and Easygel®, against a standard method (Quanti-Tray®). The objectives are to: (1) verify the accuracy of the four field-based tests, (2) study the accuracy of these tests as a function of improved and unimproved sources; (3) recommend a single microbiological test, if appropriate, based on accuracy and cost, and/or (4) recommend a testing combination, if appropriate, based on accuracy and cost. The tests of 500+ total water samples from Capiz Province, Philippines and Cambridge, MA indicate that two-tests systems gave better results than a single test. Both the 100-mL H2S test + Petrifilm™ and the 20-mL H2S test + Easygel® combinations yield promising results, in addition to being inexpensive. None of the field-based tests should be used on their own. We recommend further verification of a larger sample size and scale be undertaken before these testing combinations are recommended for wider use.

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