Chemical sensors for environmental monitoring: Limitations, challenges and prospects

There is a window of opportunity now to tackle the challenges in environmental monitoring and respond to:

The most promising devices that could meet all these challenges are chemical sensors. A bibliographic search on SciFinder (for the period 2020-2022) combining the concepts "Chemical sensors" and "Environmental monitoring" leads to a rather “impressive” number of references: more than 180,000 papers published in peer-reviewed journals, 35,000 patents and 17,000 reviews.
However, with such a craze and despite undeniable progress in surface functionalization techniques, transduction mechanisms, and lab-on-chip design, the chemical sensors market is still limited.
This presentation concerns the limitations, challenges to be met and prospects of chemical sensors. What improvements need to be done to make them THE analytical devices of choice for environmental monitoring?

Najla Fourati is an Assistant Professor at Conservatoire National des Arts et Métiers (Cnam-Paris) since 2008. She obtained her PhD in Material Science in 1999, joined the Cnam Laboratory of Physics in 2000 and then the SATIE Laboratory in 2014. Her research is focused on the design and realization of electrochemical and surface acoustic wave sensors for selective detection of chemical analytes (pesticides, heavy ions, endocrine disruptors...) and biomolecules (proteins, cancers biomarkers, neurotransmitters ...) in simple and real media. She’s co-leader of the axis “Electrochemical and gravimetric bio and chemical sensors” at SATIE / Cnam.

Pressure retarded osmosis (PRO) Technology for sustainable osmotic power generation from desalination waste

Pressure retarded osmosis (PRO) is a membrane-based osmotically driven process that harnesses the energy of mixing between low-salinity and high-salinity streams for producing mechanical energy. In this PRO process, water permeates through a semipermeable membrane from a lower concentration feed solution into a higher concentration draw solution, partially pressurized, possibly brine. As a particular free energy, the salinity gradient energy from saline solutions with specific concentrations has lately been assured as a source of renewable energy. This work explores the latest advancements as well as different application of the PRO process along with the analysis of potential energy that is harvested from the salinity gradient resources in a multi-stage and single-stage PRO processes. A significant challenge faced by the PRO process is obtaining a suitable commercial membrane that consolidates the features of reverse osmosis membrane (for withstanding the hydraulic pressure) and forward osmosis membrane (to reduce the concentration polarization phenomenon). In order to address the above challenge, information on the advanced lab-fabricated membranes and commercially available membranes are presented in the current work. The huge possibility of PRO technology is introduced in the current work by interpreting the PRO desalination systems, process design, salinity gradient resource energy of pretreatment, and dual-stage PRO (DSPRO) process. It is expected that this work could help in extensively understanding the PRO process and therefore provide crucial information for stimulating further research and development.

Syed Javaid Zaidi is presently UNESCO Chair in Desalination and Water Treatment recently established in Qatar at Qatar University and Chair Professor of Chemical Engineering at the Center for Advanced Materials, Qatar University. He has 30 years of research and teaching experience in academia and industry research in four reputed institutions: Qatar University, University of Queensland Australia, King Fahd University of Petroleum & Minerals, and Ottawa University. He published more than 300 articles in reputed international journals, book chapters, conference proceedings/presentations, 15 patents and patent disclosures and authored a book on Reverse Osmosis System published by Elsevier. The focus of his research have been desalination and water treatment, membrane technology for energy and environment applications, conducting interdiscipilinary research in collaboration with reputed international institutions worldwide. He was the visiting scholar at the Massachussettes Institute of Technology, USA. He has supervised more than 50 graduate students, 100 Summer internship and Co-op students in Qatar, Saudi Arabia, and Australia contributing to research capacity building. He also have coordinated the establishment of Water Technology Unit at CAM. He is presently honorary member of Advisory Council of Arab Water Desalination (ARWDEX). He is the recipient of many national and international awards including Excellence in Research Award, Patent Award, Almari Prize for Scientific Research Innovation and Lifetime Achievement Award by Venus International Foundation.

Literature review on test systems for the identification of the effects of endocrine active substances on soil invertebrates

In the last 20 years, a considerable number of studies have addressed possible endocrine disrupting chemicals (EDCs) in the environment. However, little attention has been paid to endocrine effects on soil invertebrates. The aims of the present literature study are (1) to compile the existing knowledge of endocrine effects on soil invertebrates via a comprehensive and critical literature review, (2) to identify potentially useful test species and endpoints for evaluating and assessing the effects of endocrine active substances on soil organisms, and (3) to develop recommendations for suitable tests, based on criteria such as sensitivity and practicability. The compiled data set on the effects of potential EDCs on the development and reproduction of soil invertebrates does by far not cover the range of exposed soil organisms or those chemicals that (potentially) act as EDCs. In addition, there is an obvious lack of studies addressing EDC-specific endpoints. The available information on endocrinology of the relevant soil invertebrate groups and on endocrine disruptive effects on these organisms is relatively sparse, and the data are not sufficient to identify critical developmental periods with sufficient certainty. Thus, full life-cycle testing is required to identify potential adverse effects of EDCs on the most relevant groups of soil invertebrates. Actually, we propose to cover the effects of EDCs (and other chronic mode-of-actions (MOA)) in tests with specific endpoints and sufficiently long test durations. However, it is unlikely to start this kind of work with all four groups simultaneously because of limited resources. Acknowledging this it is proposed to start with those tests (species, methods), which scored best in the exercise previously described. Therefore, we propose to develop, validate and standardize life-cycle tests with reproductive endpoints (plus possible additional EDC-specific endpoints. The following four groups of organisms could be exposed and, thus, should be represented in the EDC-specific a test battery:

In addition, one further organism group should be mentioned, which has at least a potential to contain test species for EDCs: the nematodes. However, so far, the available information is not sufficient to recommend an EDC-focused test system. Instead, basic research should be perfor-med to better understand the ecological relevance of effects on and the sensitivity of nematodes. With regard to gastropods, the most suitable test species has to be identified before discussing test practicability and sensitivity. In short, both applied and basic research is highly needed. In detail, a step-wise approach is recommended in order to identify the effects of potential EDCs (and substances with other MOAs) on soil invertebrates.

Dr. Römbke has a Ph.D. and a Diploma in Biology from the University of Frankfurt a.M.. In 1994, he co-founded ECT Oekotoxikologie GmbH (located in Flörsheim/Germany) as a private contract research laboratory, where he is still one of two Managing Directors. Dr. Römbke is responsible for ecotoxicological effect and fate tests as well as the environmental risk assessment of chemicals (pesticides, heavy metals, pharmaceuticals) and mixtures (wastes, contaminated soils), working both for chemical industry and for national and international governmental authorities. He has published about 210 papers in indexed journals. Dr. Römbke is specialized in the taxonomy, biogeography and ecology of soil fauna, in particular Oligochaeta such as earthworms and Enchytraeidae. He is involved in several ecological and ecotoxicological field studies in Germany, other European countries and in Brazil (Amazonas, Parana), most recently the EU-FP7 project EcoFINDERS. Especially he is interested in the development and standardization of ecotoxicological test methods for CEN, ISO and OECD as well as in the international harmonization of methods for biological soil monitoring, serving e.g. as chair of ISO TC 190/SC4 (the committee responsible for biological methods).

Microalgae as polysaccharides producers – Challenges and recent developments

Marine organisms are one of the most underutilized biological resources. The extreme diversity of microalgae, unicellular photosynthetic organisms that are known to produce large quantities of polysaccharides, makes them very attractive for bioprospecting and potential exploitation as commercial sources of exopolysaccharides. Indeed, exopolysaccharides from microalgae have been poorly studied compared to those from bacteria, fungi, terrestrial plants or macroalgae. A french interdisciplinary research project with approaches of biochemistry, physico-chemistry, process engineering and microbiology was conducted between 2015 and 2021. Its main objective was to increase the level of knowledge about the production of soluble polysaccharides with original structures by microalgae from marine and freshwater environments. It intended to develop the scientific background necessary for the industrial exploitation of these exopolysaccharides as hydrocolloids and/or biological active agents and to evaluate economic and environmental impacts of large-scale production. Correlations between original and published structures of exopolysaccharides and the taxonomic affiliation of microalgae producers have been highlighted for the first time. The implementation of physiological stress strategy led to accumulation of exopolysaccharides during microalgae cultivation. After their depolymerization some polysaccharides have been sucessfully tested as anti-age care and slimming agent. Other ones revealed unusual texturant properties as fluid gel behavior.

Keywords : Exopolysaccharide, polysaccharide, microalgae, Cyanobacteria, photobioreactor

Philippe Michaud, Full Professor of biochemistry since 2005 is head of the "4Bio" research group at the Institut Pascal, an interdisciplinary research laboratory of Clermont Auvergne University. His scientific skills focuse on the development of bioprocesses for obtaining polysaccharides from various sources and analysis of structure-function relationships. He has published 215 research papers and 17 book chapters. He is the co-inventor of 14 patents, 3 them leading to industrial exploitation. He has been the advisor or co-advisor for 25 PhD students. Since 2005, he has been in charge of more than 15 national and international research projects, funded or co-funded by industry. He was the general secretary of International Forum on Industrial Bioprocesses between 2015 and 2018. He is deputy editor of Bioengineered, and associate or guest editors of numerous international journals. He has been nominated as Chevalier des palmes académiques of the French government in 2020.

Phosphogypsum (PG) is a waste or a by-product? Case of valorization of PG in construction materials

Phosphogypsum is a by-product resulting from the acidic attack of phosphate rock to produce phosphoric acid H3PO4. Huge quantities of phosphogypsum amounting up to 280 million tons are produced each year throughout the world. The Tunisian production rate exceeds 10 million tons per year. Actually, the only means of phosphogypsum management in Tunisia is its storage in dumps due to the heavy metals and radionuclides contents which potentially cause problems to the environment and human health. Different PG recovery processes have been proposed in the literature which can be environmentally safe and economically appealing. Through this work we proposed to address the question on how it can be valorized and whether it can be used in construction. This study, therefore, aimed to upgrade this waste into a value-added by-product.

Prof. Elaloui Elimame currently teaches at the Faculty of Sciences of Gafsa, University of Gafsa and a head of Applications of Material for Environment, Water and Energy Research laboratory. His research interests cover a wide area ranging from Physical Chemistry, Green Chemistry to Materials Chemistry. He is working in the Sol-Gel field since 1994, strongly focused on the synthesis of innovative materials that can be used in different application areas such as optoelectronics, photonics, and photocatalyis. For some years he has been interested in the valorization of waste such as Phosphogypsum and natural clays in building materials, wastewater treatment and in agriculture. He has co-published about 122 papers and 5 book chapters. He was the former President of the University of Gafsa from 2011 to 2017 and serves actually as Director of Applications of Material for Environment, Water and Energy Research laboratory (LR21ES15) based at the Faculty of Sciences of Gafsa (h-index 23).

Measuring Methane Emissions from Solid Waste Landfills: Side by Side Assessment of Ground-Based, Drone-Based, Satellite-Based Technologies

Anaerobic decomposition in municipal solid waste (MSW) landfills results in the generation and emissions of methane from these facilities. These emissions are a significant source of greenhouse gas emissions at the national and global level. Due to the heterogeneity, the spatial and temporal variability of emissions patterns, it has been very challenging to assign a total GHG emissions contribution of a given landfill. Currently, GHG contributions of each landfill are not based on measurements but estimated based on simplistic and often inaccurate first-order decay models and voluntarily reported to regulatory agencies. Due to the advances in sensor and remote sensing technologies, more and more methods are being developed to measure methane emissions from landfills. Amongst all currently available methods of measuring methane emissions from landfills, the tracer correlation technique is the most accurate method in terms of providing estimates of total methane emissions from landfills. The controlled tracer method is regarded as the benchmark to “ground-truth” any other technologies developed or designed to provide estimates of landfill emissions. The newly formed Methane Emission Reduction Initiative (MERI) at FAMU-FSU College of Engineering, Florida State University has the instrumentations and the capacity to perform the controlled tracer correlation testing. The vision of MERI is to (1) provide scientifically validated methodologies that measures emissions from landfills, and (2) revise and develop protocols for GHG emissions inventories for landfills The presentation will summarize the results of an extensive field campaign consisting of:

• Collecting ambient air methane concentrations measured during (1) SEM campaigns, (2) drone-based air monitoring campaigns, (3) a fixed array of continuous methane concentration sensors, and (4) from controlled tracer experiments at several landfills in the U.S.A.
• Using the collected data from each campaign/technology to determine independent estimates of total methane emissions from each Landfill.
• Verifying and validate the developed approaches by simultaneous tracer correlation method.
• Estimating the difference between measured emissions and regulatory acceptable GHG inventory methods.

Tarek Abichou: Tarek holds B.S., M.S., and Ph.D. degrees in Engineering from the University of Wisconsin Madison. Tarek is currently a Full Professor at Florida State University. He also an Executive Director of Resilient Infrastructure & Disaster Response Center (RIDER). His research, academic, and professional background have focused on the environmental geotechnics field, which combines the traditional geotechnical engineering discipline with environmental and natural resources applications. Professor Abichou has been involved in field, laboratory, and modeling studies of sustainable solid waste management systems for more than 30 years. He is currently involved in research investigating the mitigation of greenhouse gas emissions from landfills using bio-oxidation of methane. Recently, he has been involved in temporal and spatial characterization of methane emissions from landfills. He is also developing a gas generation model to inventory fugitive gas emission from landfills. He has been recently involved in research on the resilience of coastal communities and barrier islands to rising sea levels and how to incorporate the use of livable shorelines to enhance coastal resiliency. He is known for his research investigating the mitigation of greenhouse gas emissions from landfills using bio-oxidation of methane. He was also a full-time practicing civil and environmental engineer for more than five years.