Quantifying the chemical activity of cavitation bubbles in a cluster.

Acoustic cavitation bubbles drive chemical processes through their dynamic lifecycle in liquids. These bubbles are abundant within sonoreactors, where their behavior becomes complex within clusters. This study quantifies their chemical effects within well-defined clusters using a new laser-based method. We focus a laser beam into water, inducing a breakdown that generates a single cavitation bubble. This bubble undergoes multiple collapses, releasing several shockwaves. These shockwaves propagate into the surrounding medium, leading to the formation of secondary bubbles near a reflector, separated from the input laser beam. We evaluate the chemical activity of these bubble clusters of various sizes by KI dosimetry, and to gain insights into their dynamics, we employ high-speed imaging. Hydrophone measurements show that conversion from focused shockwave energy to chemical reactions increases to a maximum of 16.5%. Additional increases in shockwave energy result in denser bubble clusters and a slightly decreased conversion rate, falling to 14.9%, highlighting the key role of bubble dynamics in the transformation of mechanical to chemical energy and as a result in the efficiency of the sonoreactors. The size and frequency of bubble collapses influence the cluster's chemical reactivity. We introduce a correlation for predicting the conversion rate of cluster energy to chemical energy, based on the cluster's energy density. The maximum conversion rate occurs at a cluster energy density of 2500 J/L, linked to a cluster with an average bubble diameter of 91 µ m, a bubble density of 3500 bubbles/ml, and a bubble-to-bubble distance ratio of 8.

Ultrasound and sonochemistry enhance education outcomes: From fundamentals and applied research to entrepreneurial potential.

With this manuscript we aim to initiate a discussion specific to educational actions around ultrasonics sonochemistry. The importance of these actions does not just derive from a mere pedagogical significance, but they can be an exceptional tool for illustrating various concepts in other disciplines, such as process intensification and microfluidics. Sonochemistry is currently a far-reaching discipline extending across different scales of applicability, from the fundamental physics of tiny bubbles and molecules, up to process plants. This review is part of a special issue in Ultrasonics Sonochemistry, where several scholars have shared their experiences and highlighted opportunities regarding ultrasound as an education tool. The main outcome of our work is that teaching and mentorship in sonochemistry are highly needed, with a balanced technical and scientific knowledge to foster skills and implement safe protocols. Applied research typically features the use of ultrasound as ancillary, to merely enhance a given process and often leading to poorly conceived experiments and misunderstanding of the actual effects. Thus, our scientific community must build a consistent culture and monitor reproducible practices to rigorously generate new knowledge on sonochemistry. These practices can be implemented in teaching sonochemistry in classrooms and research laboratories. We highlight ways to collectively provide a potentially better training for scientists, invigorating academic and industry-oriented careers. A salient benefit for education efforts is that sonochemistry-based projects can serve multidisciplinary training, potentially gathering students from different disciplines, such as physics, chemistry and bioengineering. Herein, we discuss challenges, opportunities, and future avenues to assist in designing courses and research programs based on sonochemistry. Additionally, we suggest simple experiments suitable for teaching basic physicochemical principles at the undergraduatelevel. We also provide arguments and recommendations oriented towards graduate and postdoctoral students, in academia or industry to be more entrepreneurial. We have identified that sonochemistry is consistently seen as a 'green' or sustainable tool, which particular appeal to process intensification approaches, including microfluidics and materials science. We conclude that a globally aligned pedagogical initiative and constantly updated educational tools will help to sustain a virtuous cycle in STEM and industrial applications of sonochemistry.

Carbon capture, utilization and sequestration systems design and operation optimization: Assessment and perspectives of artificial intelligence opportunities.

Carbon capture, utilization, and sequestration (CCUS) is a promising solution to decarbonize the energy and industrial sectors to mitigate climate change. An integrated assessment of technological options is required for the effective deployment of CCUS large-scale infrastructure between CO2 production and utilization/sequestration nodes. However, developing cost-effective strategies from engineering and operation perspectives to implement CCUS is challenging. This is due to the diversity of upstream emitting processes located in different geographical areas, available downstream utilization technologies, storage sites capacity/location, and current/future energy/emissions/economic conditions. This paper identifies the need to achieve a robust hybrid assessment tool for CCUS modeling, simulation, and optimization based mainly on artificial intelligence (AI) combined with mechanistic methods. Thus, a critical literature review is conducted to assess CCUS technologies and their related process modeling/simulation/optimization techniques, while evaluating the needs for improvements or new developments to reduce overall CCUS systems design and operation costs. These techniques include first principles- based and data-driven ones, i.e. AI and related machine learning (ML) methods. Besides, the paper gives an overview on the role of life cycle assessment (LCA) to evaluate CCUS systems where the combined LCA-AI approach is assessed. Other advanced methods based on the AI/ML capabilities/algorithms can be developed to optimize the whole CCUS value chain. Interpretable ML combined with explainable AI can accelerate optimum materials selection by giving strong rules which accelerates the design of capture/utilization plants afterwards. Besides, deep reinforcement learning (DRL) coupled with process simulations will accelerate process design/operation optimization through considering simultaneous optimization of equipment sizing and operating conditions. Moreover, generative deep learning (GDL) is a key solution to optimum capture/utilization materials design/discovery. The developed AI methods can be generalizable where the extracted knowledge can be transferred to future works to help cutting the costs of CCUS value chain.

Characterization of the acoustic cavitation in ionic liquids in a horn-type ultrasound reactor.

Most ultrasound-based processes root in empirical approaches. Because nearly all advances have been conducted in aqueous systems, there exists a paucity of information on sonoprocessing in other solvents, particularly ionic liquids (ILs). In this work, we modelled an ultrasonic horn-type sonoreactor and investigated the effects of ultrasound power, sonotrode immersion depth, and solvent's thermodynamic properties on acoustic cavitation in nine imidazolium-based and three pyrrolidinium-based ILs. The model accounts for bubbles, acoustic impedance mismatch at interfaces, and treats the ILs as incompressible, Newtonian, and saturated with argon. Following a statistical analysis of the simulation results, we determined that viscosity and ultrasound input power are the most significant variables affecting the intensity of the acoustic pressure field (P), the volume of cavitation zones (V), and the magnitude of the maximum acoustic streaming surface velocity (u). V and u increase with the increase of ultrasound input power and the decrease in viscosity, whereas the magnitude of negative P decreases as ultrasound power and viscosity increase. Probe immersion depth positively correlates with V, but its impact on P and u is insignificant. 1-alkyl-3-methylimidazolium-based ILs yielded the largest V and the fastest acoustic jets - 0.77 cm3 and 24.4 m s-1 for 1-ethyl-3-methylimidazolium chloride at 60 W. 1-methyl-3-(3-sulfopropyl)-imidazolium-based ILs generated the smallest V and lowest u - 0.17 cm3 and 1.7 m s-1 for 1-methyl-3-(3-sulfopropyl)-imidazolium p-toluene sulfonate at 20 W. Sonochemiluminescence experiments validated the model.

Facile solvothermal synthesis of a MIL-47(V) metal-organic framework for a high-performance Epoxy/MOF coating with improved anticorrosion properties.

The vanadium-based metal-organic framework MIL-47 distinguishes itself among other MOFs for its distinctive structure and unique properties (e.g., flexible structure, high thermal stability, and high surface area). The synthesis of MIL-47 has been reported from various metal precursors, including vanadium(iii) chloride (VCl3) as a rich source of metal ions. Attempts have been made to include other starting materials, a step forward towards large-scale production. Synthesis from various solid materials is encouraged, seeking an economic and greener approach. In this study, vanadium pentoxide (V2O5), a readily abundant low-cost and thermodynamically stable metal source, was used to synthesize the MIL-47(V) framework via a facile solvothermal route. This precursor provides a controllable rate of metal ion production depending on the applied reaction conditions. In our method, the synthesis took place at a low temperature and reaction time (180 °C for 20 h, instead of 220 °C for 72 h), yielding MIL-47 microrods. Moreover, among its unique properties, the metal centers of MIL-47 oxidize under the influence of thermal or chemical treatments, preserving the framework structure. This unusual character is not commonly witnessed in comparable MOF structures. This property can be leveraged in anti-corrosion applications, whereby a redox reaction would sacrifice the framework components, protecting the metal in contact. However, the chemical stability of MIL-47 is doubted against a corrosive medium. Thus, an epoxy coating with 10 wt% MOF loading was incorporated in our investigation to extend the aluminum alloy (AA2024) surface protection for prolonged exposure duration. The uniformity of distribution of the prepared MOF within the epoxy matrix was confirmed using SEM/EDX. Electrochemical impedance spectroscopy (EIS) was used to evaluate the corrosion performance of the coated samples. The results showed that the inclusion of V-MOF offers extended corrosion prevention, over 60 days, for the AA2024 alloy against artificial seawater. The neat epoxy coating could not prevent the corrosion of AA2024 over two weeks of immersion, whereby pitting corrosion was clearly observed. The V-MOF could induce a series of redox reactions leading to the precipitation of vanadium on the cathodic sites of metal surfaces.

Scratching the Surface of the Protein Corona: Challenging Measurements and Controversies.

This Review aims to provide a systematic analysis of the literature regarding ongoing debates in protein corona research. Our goal is to portray the current understanding of two fundamental and debated characteristics of the protein corona, namely, the formation of mono- or multilayers of proteins and their binding (ir)reversibility. The statistical analysis we perform reveals that these characterisitics are strongly correlated to some physicochemical factors of the NP-protein system (particle size, bulk material, protein type), whereas the technique of investigation or the type of measurement (in situ or ex situ) do not impact the results, unlike commonly assumed. Regarding the binding reversibility, the experimental design (either dilution or competition experiments) is also shown to be a key factor, probably due to nontrivial protein binding mechanisms, which could explain the paradoxical phenomena reported in the literature. Overall, we suggest that to truly predict and control the protein corona, future efforts should be directed toward the mechanistic aspects of protein adsorption.

Multivariate metal-organic framework MTV-MIL-101 via post-synthetic cation exchange: is it truly achievable?

The post-synthetic exchange (PSE) method is a well-proven route to replace, modify, and add different functionalities to metal-organic frameworks (MOFs). Particularly, the solvent-assisted cation substitution (SACS) technique has been reported to prepare mixed-metal multivariate metal-organic frameworks (MTV-MOFs). However, such a technique does not apply to all types of MOFs. In 2013, Szilágyi et al. reported the achievement of the mixed-metal MTV-MIL-101 framework via PSE. Since then, a debate has been taking place about the validity of these findings. On the other hand, the attainment of the mixed-metal MIL-101 was reported to be obtainable through the direct synthesis, which is, to some, the only way to achieve it. Here, we settle this dispute by investigating Szilágyi's method not only as described, but also at extended conditions of time and different metal precursors: all attempts were vain. However, by reconsidering the refluxing solvent (dimethylformamide "DMF" instead of water) and the applied reaction conditions (110 °C-20 h), mixed-metal MIL-101(Cr/Fe) was achieved via a simple PSE method.

Sonoprocessing: From Concepts to Large-Scale Reactors.

Intensification of ultrasonic processes for diversified applications, including environmental remediation, extractions, food processes, and synthesis of materials, has received attention from the scientific community and industry. The mechanistic pathways involved in intensification of ultrasonic processes that include the ultrasonic generation of cavitation bubbles, radical formation upon their collapse, and the possibility of fine-tuning operating parameters for specific applications are all well documented in the literature. However, the scale-up of ultrasonic processes with large-scale sonochemical reactors for industrial applications remains a challenge. In this context, this review provides a complete overview of the current understanding of the role of operating parameters and reactor configuration on the sonochemical processes. Experimental and theoretical techniques to characterize the intensity and distribution of cavitation activity within sonoreactors are compared. Classes of laboratory and large-scale sonoreactors are reviewed, highlighting recent advances in batch and flow-through reactors. Finally, examples of large-scale sonoprocessing applications have been reviewed, discussing the major scale-up and sustainability challenges.

Solar Light Photoactive Floating Polyaniline/TiO2 Composites for Water Remediation.

In the present study, the development of innovative polyurethane-polyaniline/TiO2 modified floating materials applied in the sorption and photodegradation of rhodamine B from water matrix under solar light irradiation is reported. All the materials were fabricated with inexpensive and easy approaches and were properly characterized. The effect of the kind of polyaniline (PANI) dopant on the materials' behavior was investigated, as well as the role of the conducting polymer in the pollutant abatement on the basis of its physico-chemical characteristics. Rhodamine B is removed by adsorption and/or photodegradation processes depending on the type of doping agent used for PANI protonation. The best materials were subjected to recycle tests in order to demonstrate their stability under the reaction conditions. The main transformation products formed during the photodegradation process were identified by ultraperformance liquid chromatography-mass spectrometry (UPLC/MS). The results demonstrated that photoactive floating PANI/TiO2 composites are useful alternatives to common powder photocatalysts for the degradation of cationic dyes.

Sonochemical synthesis of porous gold nano- and microparticles in a Rosette cell.

We report the synthesis of Au nano- and microparticles that relies on α-D-glucose (C6H12O6) as the reducer and stabilizer in a Rosette cell under 20 kHz ultrasound irradiation. The chemical and physical effects of ultrasonic irradiation on the synthesis were investigated. The results showed that an optimum pH is required for the formation of insoluble Au(0) particles. Upon irradiation, low pH yielded Au nanoparticles while high pH resulted in microparticles. The Au surface capping by α-D-glucose hydroxyl and carbonyl groups was confirmed by Fourier transform infrared (FT-IR) spectroscopy. X-ray diffraction (XRD) analysis indicated that the Au particles crystallize within the face-centered-cubic (FCC) cell lattice. Moreover, continuous sonication reduced larger amounts of the Au precursor compared to the intermittent mode. Furthermore, tuning sonication time and mode influences the particle size and porosity as characterized by scanning and transmission electron microscopy. Our results shed a new light into the importance of the experimental and ultrasound parameters in obtaining Au particles of desired features through sonochemistry.

Photochemical Synthesis of Gold and Silver Nanoparticles-A Review.

Nanomaterials have supported important technological advances due to their unique properties and their applicability in various fields, such as biomedicine, catalysis, environment, energy, and electronics. This has triggered a tremendous increase in their demand. In turn, materials scientists have sought facile methods to produce nanomaterials of desired features, i.e., morphology, composition, colloidal stability, and surface chemistry, as these determine the targeted application. The advent of photoprocesses has enabled the easy, fast, scalable, and cost- and energy-effective production of metallic nanoparticles of controlled properties without the use of harmful reagents or sophisticated equipment. Herein, we overview the synthesis of gold and silver nanoparticles via photochemical routes. We extensively discuss the effect of varying the experimental parameters, such as the pH, exposure time, and source of irradiation, the use or not of reductants and surfactants, reagents' nature and concentration, on the outcomes of these noble nanoparticles, namely, their size, shape, and colloidal stability. The hypothetical mechanisms that govern these green processes are discussed whenever available. Finally, we mention their applications and insights for future developments.

Piezo-enhanced photocatalytic diclofenac mineralization over ZnO.

The degradation of diclofenac has been realized for the first time by a piezo-enhanced sonophotocatalytic approach based on ZnO. The sonophotocatalytic degradation showed a slight enhancement in the degradation of the parent compound, whereas strong synergistic effects were observed for the mineralization process when suitable ZnO morphologies are used, reaching 70% of complete degradation of 25 ppm diclofenac using 0.1 g/L ZnO in 360 min. Tests in a complex water matrix show enhanced diclofenac removal, outperforming a TiO2 benchmark photocatalyst. These promising experimental results promote this process as a good alternative to traditional degradation approaches for remediation of real water matrices.

Electron paramagnetic resonance of sonicated powder suspensions in organic solvents.

The chemical effects of the acoustic cavitation generated by ultrasound translates into the production of highly reactive radicals. Acoustic cavitation is widely explored in aqueous solutions but it remains poorly studied in organic liquids and in particular in liquid/solid media. However, several heterogeneous catalysis reactions take place in organic solvents. Thus, we sonicated trimethylene glycol and propylene glycol in the presence of silica particles (SiO2) of different sizes (5-15 nm, 0.2-0.3 µm, 12-26 µm) and amounts (0.5 wt% and 3 wt%) at an ultrasound frequency of 20 kHz to quantify the radicals generated. The spin trap 5,5-dimethyl-1-pyrrolin-N-oxide (DMPO) was used to trap the generated radicals for study by electron paramagnetic resonance (EPR) spectroscopy. We identified the trapped radical as the hydroxyalkyl radical adduct of DMPO, and we quantified it using stable radical 2,2,6,6-tetramethyl-1-piperidinyloxy (TEMPO) as a quantitation standard. The concentration of DMPO spin adducts in solutions containing silica size 12-26 µm was higher than the solution without particles. The presence of these particles increased the concentration of the acoustically generated radicals by a factor of 1.5 (29 µM for 0.5 wt% of SiO2 size 12-26 µm vs 19 µM for 0 wt%, after 60 min of sonication). Ultrasound produced fewest radicals in solutions with the smallest particles; the concentration of radical adducts was highest for SiO2 particle size 12-26 µm at 0.5 wt% loading, reaching 29 µM after 60 min sonication. Ultrasound power of 50.6 W produced more radicals than 24.7 W (23 µM and 18 µM, respectively, at 30 min sonication). Increased temperature during sonication generated more radical adducts in the medium (26 µM at 75 °C and 18 µM at 61 °C after 30 min sonication). Acoustic cavitation, in the presence of silica, increased the production of radical species in the studied organic medium.

Synthesis of a novel Ce(iii)/melamine coordination polymer and its application for corrosion protection of AA2024 in NaCl solution.

We present the synthesis of a new cerium(iii)-melamine coordination polymer (CMCP) by a mixed-solvothermal method and its characterization. Characterization techniques included Raman, Fourier Transformation Infra-Red (FTIR), X-Ray Diffraction (XRD) and Scanning Electron Microscope (SEM), in which the change in the electronic environment and the crystallinity were tracked. The characterization results confirm the coordination of cerium(iii) with melamine through -NH2 groups, instead of the N atoms of the triazine ring, for which we propose a mechanism of interaction. In addition, Biovia Materials Studio package was applied to determine and investigate the molecular structure of the CMCP. All simulations were done using COMPASS force-field theory and atom-based method for summation of electrostatic and van de Waals forces. The application of the CMCP for the corrosion inhibition of AA2024 in 3.5% NaCl solution was tested using the potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The results point out that the presence of cerium as cerium(iii) in the CMCP structure plays the fundamental role of inhibition, whereby the inhibition mechanism occurs by cathodic oxidation of Ce(iii) to Ce(iv) and cyclic reduction of Ce(iv) to Ce(iii) by melamine part of CMCP.

FeCrAl as a Catalyst Support.

The iron-chromium-aluminum alloy (FeCrAl) is an exceptional support for highly exothermic and endothermic reactions that operate above 700 °C in chemically aggressive environments, where low heat and mass transfer rates limit reaction yield. FeCrAl two- and three-dimensional structured networks-monoliths, foams, and fibers-maximize mass transfer rates, while their remarkable thermal conductivity minimizes hot spots and thermal gradients. Another advantage of the open FeCrAl structure is the low pressure drop due to the high void fraction and regularity of the internal path. The surface Al2O3 layer, formed after an initial thermal oxidation, supports a wide range of metal and metal oxide active phases. The aluminum oxide that adheres to the metal surface protects it from corrosive atmospheres and carbon (carburization), thus allowing FeCrAl to operate at a higher temperature. The top applications are industrial burners, in which compact knitted metal fibers distribute heat over large surface areas, and automotive tail gas converters. Future applications include producing H2 and syngas from remote natural gas in modular units. This Review summarizes the specific preparation techniques, details process operating conditions and catalyst performance of several classes of reactions, and highlights positive and challenging aspects of FeCrAl.

Sonophotocatalytic degradation of sodium diclofenac using low power ultrasound and micro sized TiO2.

The nonsteroidal anti-inflammatory drug sodium diclofenac (DC) is an emerging water pollutant which resists conventional wastewater treatments. Here the sonophotocatalytic degradation of DC was carried out using micrometric TiO2 (both pristine and Ag-decorated), UV-A irradiation and 20 kHz pulsed ultrasound. Sonophotocatalytic tests were compared with photolysis, sonolysis, sonophotolysis, sonocatalysis and photocatalysis data performed in the same conditions. A synergy index of over 2 was determined for tests with pristine TiO2, while values close to 1.3 were observed for Ag-TiO2. Reaction intermediates were studied by HPLC-MS, showing degradation mechanisms activated by hydroxyl radicals. Similar pathways were identified for photocatalytic and sonophotocatalytic tests, although the latter led to more oxidized compounds. Different reactor configurations (static and dynamic set ups) were studied. Sequential and simultaneous application of UV light and ultrasound led to similar performance. The role of water matrix was investigated using ultrapure and drinking water, showing marked detrimental effects of electrolytes on the DC degradation. Overall, the combined treatment proved more efficient than photocatalysis alone especially in demanding working conditions, like in drinking water matrices.

Intellectual contributions meriting authorship: Survey results from the top cited authors across all science categories.

Authorship is the currency of an academic career for which the number of papers researchers publish demonstrates creativity, productivity, and impact. To discourage coercive authorship practices and inflated publication records, journals require authors to affirm and detail their intellectual contributions but this strategy has been unsuccessful as authorship lists continue to grow. Here, we surveyed close to 6000 of the top cited authors in all science categories with a list of 25 research activities that we adapted from the National Institutes of Health (NIH) authorship guidelines. Responses varied widely from individuals in the same discipline, same level of experience, and same geographic region. Most researchers agreed with the NIH criteria and grant authorship to individuals who draft the manuscript, analyze and interpret data, and propose ideas. However, thousands of the researchers also value supervision and contributing comments to the manuscript, whereas the NIH recommends discounting these activities when attributing authorship. People value the minutiae of research beyond writing and data reduction: researchers in the humanities value it less than those in pure and applied sciences; individuals from Far East Asia and Middle East and Northern Africa value these activities more than anglophones and northern Europeans. While developing national and international collaborations, researchers must recognize differences in peoples values while assigning authorship.

Nano-MnO2 Decoration of TiO2 Microparticles to Promote Gaseous Ethanol Visible Photoremoval.

TiO2-based photocatalysis under visible light is an attractive way to abate air pollutants. Moreover, developing photocatalytic materials on a large-scale requires safe and low-cost precursors. Both high-performance TiO2 nanopowders and visible-light active noble metals do not match these requirements. Here, we report the design of novel Mn-decorated micrometric TiO2 particles. Pigmentary TiO2 replaced unsafe nano-TiO2 and firmly supported MnOx particles. Mn replaced noble metals such as Au or Ag, opening the way for the development of lower cost catalysts. Varying Mn loading or pH during the impregnation affected the final activity, thus giving important information to optimize the synthesis. Photocatalytic activity screening occurred on the gas-phase degradation of ethanol as a reference molecule, both under ultraviolet (UV) (6 h) and Light Emitting Diode (LED) (24 h) irradiation. Mn-doped TiO2 reached a maximum ethanol degradation of 35% under visible light after 24 h for the sample containing 20% of Mn. Also, we found that an acidic pH increased both ethanol degradation and mineralization to CO2, while an alkaline pH drastically slowed down the reaction. A strict correlation between photocatalytic results and physico-chemical characterizations of the synthesized powders were drawn.

Ultrasound-assisted impregnation for high temperature Fischer-Tropsch catalysts.

A fraction of the petroleum extracted from oil reservoirs contains associated natural gas. Rather than building infrastructure to recover low volumes of this natural gas, the industry flares or vents it to the atmosphere, which contributes to atmospheric greenhouse gas emissions but also reduces the air quality locally because it contains gaseous sulphur and nitrogen compounds. Converting the natural gas (NG) to hydrocarbons with a small-scale two-step gas-to-liquids process, is an alternative to flaring and venting. In the first step, NG reacts with oxygen to form syngas (Catalytic Partial Oxidation) and in the second step the syngas reacts over metallic catalysts to form higher paraffins at 210 °C to 300 °C-Fischer Tropsch synthesis (FT). For the first time, we synthesize bimetallic FeCo FT catalysts with ultrasound. An ultrasonic horn agitates the solution during the entire impregnation process. The active phase dispersion of the sonicated catalysts was superior to the catalyst synthesized without ultrasound, while reducing the impregnation time by a factor of three. We tested our catalysts in a lab-scale, fixed-bed reactor at 270 °C and 300 °C, and achieved 80% conversion over 3-days on stream and a 40% yield of C2+.

Sustainable manufacture of insect repellents derived from Nepeta cataria.

Malaria devastates sub-Saharan Africa; the World Health Organization (WHO) estimates that 212 million people contract malaria annually and that the plasmodium virus will kill 419 000 in 2017. The disease affects rural populations who have the least economic means to fight it. Impregnated mosquito nets have reduced the mortality rate but the Anopheles mosquitoes are changing their feeding patterns and have become more active at dusk and early morning rather than after 22h00 as an adaptation to the nets. Everyone is susceptible to the Anopheles at these times but infants and pregnant women are the most vulnerable to the disease. Plant-based mosquito repellents are as effective as synthetic repellents that protect people from bites. They are sustainable preventative measures against malaria not only because of their efficacy but because the local population can produce and distribute them, which represents a source of economic growth for rural areas. Here, we extract and test the essential oil nepetalactone from Nepeta cataria via steam distillation. Families in endemic areas of Burundi found them effective against bites but commented that the odor was pungent. An epidemiological study is required to establish its clinical efficacy.