Smart Sensors, Measurement and Instrumentation 35 Md Eshrat E. Alahi Subhas Chandra Mukhopadhyay Smart Nitrate Sensor Internet of Things Enabled Real-Time Water Quality Monitoring Smart Sensors, Measurement and Instrumentation Volume 35 Series Editor Subhas Chandra Mukhopadhyay School of Engineering Macquarie University Sydney, NSW Australia TheSmartSensors,MeasurementandInstrumentationseries(SSMI)publishesnew developments and advancements in the fields of Sensors, Instrumentation and Measurement technologies. The series focuses on all aspects of design, develop- ment, implementation, operation and applications of intelligent and smart sensors, sensor network, instrumentation and measurement methodologies. The intent is to cover all the technical contents, applications, and multidisciplinary aspects of the field, embedded in the areas of Electrical and Electronic Engineering, Robotics, Control, Mechatronics, Mechanical Engineering, Computer Science, and Life Sciences,aswellasthemethodologiesbehindthem.Withinthescopeoftheseries are monographs, lecture notes, selected contributions from specialized conferences and workshops, special contribution from international experts, as well as selected PhD theses. Indexed by SCOPUS and Google Scholar. More information about this series at http://www.springer.com/series/10617 Md Eshrat E. Alahi (cid:129) Subhas Chandra Mukhopadhyay Smart Nitrate Sensor Internet of Things Enabled Real-Time Water Quality Monitoring 123 Md EshratE. Alahi SubhasChandra Mukhopadhyay Shenzhen Institute of Advanced Schoolof Engineering Technology,Chinese Academy ofSciences MacquarieUniversity Shenzhen University Town Sydney,NSW,Australia Shenzhen Guangdong,China ISSN 2194-8402 ISSN 2194-8410 (electronic) Smart Sensors, Measurement andInstrumentation ISBN978-3-030-20094-7 ISBN978-3-030-20095-4 (eBook) https://doi.org/10.1007/978-3-030-20095-4 ©SpringerNatureSwitzerlandAG2019 Thisworkissubjecttocopyright.AllrightsarereservedbythePublisher,whetherthewholeorpart of the material is concerned, specifically the rights of translation, reprinting, reuse of illustrations, recitation, broadcasting, reproduction on microfilms or in any other physical way, and transmission orinformationstorageandretrieval,electronicadaptation,computersoftware,orbysimilarordissimilar methodologynowknownorhereafterdeveloped. The use of general descriptive names, registered names, trademarks, service marks, etc. in this publicationdoesnotimply,evenintheabsenceofaspecificstatement,thatsuchnamesareexemptfrom therelevantprotectivelawsandregulationsandthereforefreeforgeneraluse. The publisher, the authors and the editors are safe to assume that the advice and information in this book are believed to be true and accurate at the date of publication. Neither the publisher nor the authors or the editors give a warranty, expressed or implied, with respect to the material contained hereinorforanyerrorsoromissionsthatmayhavebeenmade.Thepublisherremainsneutralwithregard tojurisdictionalclaimsinpublishedmapsandinstitutionalaffiliations. ThisSpringerimprintispublishedbytheregisteredcompanySpringerNatureSwitzerlandAG Theregisteredcompanyaddressis:Gewerbestrasse11,6330Cham,Switzerland Preface Nitrate-Nisanaturallyoccurringioniccompoundthatisapartofnature’snitrogen cycle.Nitrate-Narereadilylosttogroundandsurfacewaterasaresultofintensive agriculture, industrial wastes, and disposal of human and animal sewage. The impactofelevatednitrate-Nconcentrationsonwaterqualityhasbeenidentifiedasa critical issue of a healthy environment for the future. Presently, water quality managers follow the traditional measurement systems that involve physically col- lecting thesamplingwater fromremotesites andtesting itinthelaboratory.These methodsareexpensive,requiretrainedpeopletoanalysethedataandproducemuch chemical waste. Therefore, low-cost ion-imprinted polymer (IIP)-coated impedimetric nitrate-N sensor was developed, and the detection range of nitrate-N was 1–10 (mg/L). The selectiveIIPmaterialwassensitivetonitrate-Nionsinanaqueousmedium,andthe results are validated through standard UV spectrometric methods. Micro- electromechanical system (MEMS)-based interdigital sensor and sensing system was also developed to measure nitrate-N, and the range was 0.01–0.5 (mg/L). The graphite/PDMS-based low-cost sensor was also fabricated, and the sensor was characterized to measure nitrate-N in the range of 1–70 (mg/L). Temperature compensation was added for both the sensors (MEMS and graphene), and Wi-fi connectivity was provisioned in the system to transfer the measured data in real time. An improved LoRa-based sensing system (solar-panel- and rechargeable- battery-powered) was developed and trialled in the field successfully which can measure the nitrate-N concentration in real time and transfer the data to IoT cloud server to overcome the limitations of laboratory-based sensing system. Chapter 1 discusses the background and the introduction of the research. The importance of nitrate sensor and in-situ-based sensing system with real-time monitoring has been discussed. There are varieties of detection methods available fornitrate.Someofthemarelaboratory-based,andsomeofthemcanbeusedinthe sampling locations. The advantages and shortcomings of those methods are dis- cussed in Chap. 2. Chapter 3 discusses the principle of interdigital capacitive sensor,andthedetectionmethodofelectrochemicalimpedancespectroscopy(EIS). Chapter 4 discusses the low-range nitrate measurement, the temperature v vi Preface compensation technique which is employed in the developed sensor and the elec- tronics of the IoT-enabled smart sensing system. Chapters 5, 6 and 7 discuss the varieties of the sensor and their fabrication technique, validation methods and development of the in situ IoT-enabled sensing system. Chapter 8 discusses the conclusion of the research, limitations of the current research and prospects. This book is originated from a Ph.D. research done at Macquarie University, NSW, Australia. The aim of this work is to develop low-cost IoT-enabled smart nitrate sensor for the detection of nitrate as contamination in natural water. The authors are highly grateful to the colleagues who had a significant contribution to thiswork:Dr.AnindyaNag,Dr.NasrinAfsarimanesh,Dr.KrishanthiJayasundera, Dr. Keith Imrie, Dr. Fahmida Wazed Tina and Van Nguyen Thi Phuoc. Special thanks to Macquarie University, Australia, and Massey University, New Zealand, for providing research facilities. We would also extend our thanks to our families for their support, motivation and encouragement throughout the work. Shenzhen, China Dr. Md Eshrat E. Alahi Sydney, Australia Prof. Subhas Chandra Mukhopadhyay Contents 1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 2 Literature Review . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.2 Detection Methodologies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.3 Electrochemical Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 2.4 Potentiometric Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8 2.5 Amperometric Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 2.6 Voltammetric Detection. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.7 Chromatography Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 2.8 Biosensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 2.9 Flow-Injection Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 2.10 Electromagnetic Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20 2.10.1 Planar Electromagnetic Sensor . . . . . . . . . . . . . . . . . . . 20 2.10.2 Planar Interdigital Sensor . . . . . . . . . . . . . . . . . . . . . . . 22 2.11 Fibre-Optic Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 2.12 Commercial Sensors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27 2.13 Challenges and Future Opportunities . . . . . . . . . . . . . . . . . . . . . 28 2.14 Internet of Things (IoT). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30 2.15 Existing Sensor Nodes for IoT. . . . . . . . . . . . . . . . . . . . . . . . . . 31 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 3 Interdigitated Senor and Electrochemical Impedance Spectroscopy (EIS) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.2 Planar Interdigital Sensors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 3.3 Novel Planar Interdigital Sensors . . . . . . . . . . . . . . . . . . . . . . . . 45 3.4 Electrochemical Impedance Spectroscopy (EIS) . . . . . . . . . . . . . 46 vii viii Contents 3.4.1 Basic Principles of EIS. . . . . . . . . . . . . . . . . . . . . . . . . 47 3.4.2 Data Representation in Nyquist Plot and Bode Plot . . . . 48 3.4.3 Randle’s Electrochemical Cell Equivalent Circuit Model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 3.5 Chapter Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 4 Temperature Compensation for Low Concentration Nitrate Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 4.2 Experimental Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4.2.1 MEMS-Based Sensor . . . . . . . . . . . . . . . . . . . . . . . . . . 54 4.2.2 Temperature Measurement . . . . . . . . . . . . . . . . . . . . . . 55 4.2.3 Nitrate Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . 55 4.3 Sensing System. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 4.3.1 Block Diagram of the Sensing System. . . . . . . . . . . . . . 57 4.3.2 The Signal Generator . . . . . . . . . . . . . . . . . . . . . . . . . . 57 4.3.3 Frequency Response Analysis Circuit . . . . . . . . . . . . . . 58 4.3.4 Controlling of Pump and Solenoid Valve. . . . . . . . . . . . 60 4.3.5 IoT-Based Smart System. . . . . . . . . . . . . . . . . . . . . . . . 61 4.4 Results and Discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62 4.4.1 Measurement of Temperature . . . . . . . . . . . . . . . . . . . . 62 4.4.2 Nitrate Measurement and Standard Equation Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65 4.4.3 Stream Water Testing. . . . . . . . . . . . . . . . . . . . . . . . . . 68 4.4.4 Data in Cloud Server . . . . . . . . . . . . . . . . . . . . . . . . . . 68 4.4.5 Comparison of Impedance Measurement by LCR and the Developed System. . . . . . . . . . . . . . . . 69 4.4.6 Improvement of Temperature Compensation . . . . . . . . . 71 4.5 Chapter Summary. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 5 Graphite/PDMS Capacitive Sensor for Nitrate Measurement . . . . . . 73 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73 5.2 Fabrication of the Printed Sensors . . . . . . . . . . . . . . . . . . . . . . . 73 5.3 Experimental Setup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78 5.4 Comparative Analysis of Two Different Sensors. . . . . . . . . . . . . 79 5.5 Temperature and Nitrate-N Measurement . . . . . . . . . . . . . . . . . . 79 5.6 IoT-Enabled Smart Sensing System . . . . . . . . . . . . . . . . . . . . . . 80 5.7 Results and Discussion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81 Contents ix 5.7.1 Comparative Analysis. . . . . . . . . . . . . . . . . . . . . . . . . . 81 5.7.2 Nitrate Measurement. . . . . . . . . . . . . . . . . . . . . . . . . . . 83 5.7.3 Temperature Measurement . . . . . . . . . . . . . . . . . . . . . . 83 5.8 Summarize . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88 6 Preparation and Characterization of the Selectivity Material of Nitrate Sensor. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91 6.2 Ion Imprinting Polymerisation . . . . . . . . . . . . . . . . . . . . . . . . . . 91 6.2.1 Types of Imprinting Process . . . . . . . . . . . . . . . . . . . . . 92 6.2.2 Monomers, Cross-Linkers, Solvents and Initiator for the Imprinting Procedure . . . . . . . . . . . . . . . . . . . . . 93 6.3 Polymerisation Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 6.3.1 Bulk Polymerisation . . . . . . . . . . . . . . . . . . . . . . . . . . . 94 6.3.2 Precipitation Polymerisation . . . . . . . . . . . . . . . . . . . . . 95 6.3.3 Suspension Polymerisation . . . . . . . . . . . . . . . . . . . . . . 95 6.3.4 Surface (Emulsion) Polymerisation . . . . . . . . . . . . . . . . 95 6.4 Materials and Methods . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 6.4.1 Chemicals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 6.4.2 Apparatus . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 96 6.4.3 Synthesis of Nitrate Imprinted Polymer Coating. . . . . . . 96 6.4.4 Functionalizing the Polymer Coating. . . . . . . . . . . . . . . 98 6.4.5 Sorption Study. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98 6.4.6 Static Sorption Time. . . . . . . . . . . . . . . . . . . . . . . . . . . 99 6.4.7 Selectivity Test. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99 6.4.8 A Binding Procedure of Coated Sensor . . . . . . . . . . . . . 99 6.4.9 EIS Measurement of the Coated Sensor. . . . . . . . . . . . . 100 6.4.10 Unknown Sample Measurement . . . . . . . . . . . . . . . . . . 101 6.4.11 Reusability Testing. . . . . . . . . . . . . . . . . . . . . . . . . . . . 102 6.4.12 Non-linear Least Square Curve Fitting. . . . . . . . . . . . . . 102 6.4.13 Comparison of Coated Sensor and ISE . . . . . . . . . . . . . 102 6.5 Results and Discussions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 6.5.1 Sorption Studies. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103 6.5.2 Uptake Kinetics Studies . . . . . . . . . . . . . . . . . . . . . . . . 103 6.5.3 Study of Selectivity Test. . . . . . . . . . . . . . . . . . . . . . . . 104 6.5.4 pH-Dependent Binding Profile . . . . . . . . . . . . . . . . . . . 106 6.5.5 Calibration Standard. . . . . . . . . . . . . . . . . . . . . . . . . . . 106 6.5.6 Unknown Sample Measurement . . . . . . . . . . . . . . . . . . 107 6.5.7 Reusability of the Sensor . . . . . . . . . . . . . . . . . . . . . . . 108