Nano Pesticides and Nanosensors in Agriculture PDF

Nano pesticides and nanosensors in agriculture Pesticides and herbicides are used extensively in agricultural production throughout the world to protect plants against pests, fungi, and weeds. They are beneficial in terms of crop protection, disease control, food and material prote...

Nano pesticides and nanosensors in agriculture Pesticides and herbicides are used extensively in agricultural production throughout the world to protect plants against pests, fungi, and weeds. They are beneficial in terms of crop protection, disease control, food and material protection. But at the same time, it is toxic to humans, animals and non-target species. They have cumulative effects on the human body and lead to several diseases, ranging from chronic common cough and cold to bronchitis and cancer of the skin, eye, kidney, and prostate gland. Pesticides are widely distributed in drinking waters, groundwaters, and soils. Commonly Used Pesticides: a) Organochlorine Insecticides: for example, endosulfan, aldrin, and Heptachlor. b) Herbicides: for example Atrazine, Diuron and Molinate. c) Organophosphorus Insecticides: for example, Chlorpyrifos and Diazinon. ✓ Pesticides are susceptible to degradation using zero-valent Iron (ZVI). 26 Contd…. Nanopesticids stand for pesticides formulated in nanomaterials to find applications in the agricultural field, whether specially fixed on a hybrid substrate, encapsulated in a matrix or functionalized nanocarriers for external stimuli or enzyme-mediated triggers. The nanopesticide formulations can increase water solubility, and bioavailability and protect agrochemicals against environmental degradation, revolutionizing the control of pathogens, weeds, and insects in the crops. Nanoparticles have high surface to volume ratio, and they are able to linked with other compounds and be used as carrier. Hence, they can be used as nanocarriers or as active ingredients or both. Nanoformulations usually consist of several surfactants, polymers or inorganic (e.g. metal) NPs in the nanometre size range. Nanoparticle-associated pesticides show higher performance in terms of effectiveness, targeted delivery and action with reduced management costs. 27 Contd…. A nanocarrier enables the controlled release of an active compound stored at the core, so that the adequate concentration of this active compound could be preserved during the whole period of insect growth. 28 Contd…. Nanosensors in agriculture: Nanosensors are nanoscale element devices that are engineered to identify a particular molecules/organisms known as the analyte and could be molecules (dyes/colours, toxicants, pesticides, hormones, antibiotics, vitamins, etc.), biomolecules (enzymes, DNA/RNA, allergens, etc.), ions (metals, halogens, surfactants, etc.), gas/vapour (oxygen, carbon dioxide, volatile compounds, water vapors, etc.), organisms (bacteria, fungi, viruses) and environment (humidity, temperature, light, pH, weather, etc.). A typical nanosensor device operation contains three basic components: 1) Sample preparation 2) Recognition: Certain molecules/elements recognize the analytes within the sample. They could be antibodies, aptamers, chemical legends enzymes, etc., and have high affinity, specificity, and selective characteristics to their analytes to quantify them to acceptance levels. 3) Signal transduction: for example, optical, electrochemical, piezoelectric, pyroelectric, electronic, and gravimetric biosensors. 29 The component of nanosensors in agriculture 30 Contd…. These sensors are highly specific, handy, cost-effective, and detect at a level much lower as compared to their macroscale analogs. 31 Nanosensors for Pesticide Detection In general, an optical sensor is composed of a recognition element that is specific for the particular residual pesticidal particle and can network with the other constituent, the transducer, which is employed to produce the signal for the binding of a particular pesticide residue to the sensor. Also, electrochemical nanosensors appear to be an effective tool meant for pesticide detection. Various categories of nanomaterials comprising nanoparticles, nanocomposites and nanotubes are widely found to be engaged in electrochemically determining the residual pesticidal particles. 32 Nanosensors for Detecting Plant Pathogens The most widely used biosensing components for analysing pathogens are bacterial receptors, antibodies, and lectins, owing to their adaptability of amalgamation into biosensors. Nanoparticle-centred “chemical nose” biosensors necessitate the amendment of the surface of the nanoparticle with several ligands where an individual ligand is liable for a distinctive communication with the objective. The mechanism: The addition of nanoparticles to the bacteria leads to the development of aggregates encompassing the bacteria. This process of aggregation promotes a change of colour induced by a swing in localized surface plasmon resonance. The components of the bacterial cell wall which are responsible for this kind of aggregation are teichoic acids in Gram-positive and lipopolysaccharides and phospholipids in Gram-negative bacteria. These aggregation patterns are unique and are motivated by the occurrence of extracellular polymeric substances on the bacterial surface. These varying in patterns are accountable for offering discernible colorimetric responses. 33 Nanofertilizers in agriculture Nanofertilizers are nutrients that are encapsulated or coated within nanomaterial in order to enable controlled release, and its subsequent slow diffusion into the soil. The use of nanoscale fertilizers may help to minimise nutrient loss by leaching/run-off and reduce its fast degradation and volatility, thus enhancing the nutrient quality and the fertility of the soil, and promoting crop productivity in the long run The high surface area to volume ratio and the high penetration ability of nanofertilizers make them a suitable alternative to chemical fertilizers. The composition of nanofertilizers can facilitate: 1. Efficient nutrient uptake and soil fertility restoration. 2. Ultra-high absorption and increased photosynthesis. 3. Increased production and reduced soil toxicity. 4. Increased plant health and reduced environmental pollution. 34 Contd…. Examples of Nanofertilizers: Nano-Zinc: Zinc oxide nanoparticles can provide zinc more efficiently to plants, addressing zinc deficiency in crops. Nano-Phosphorus: Phosphorus nanoparticles or nanocarriers can reduce the fixation of phosphorus in soil, making it more available to plants. Nano-Nitrogen: Encapsulation of nitrogen fertilizers in nanoparticles can minimize nitrogen losses through volatilization and leaching. 35 Contd…. https://doi.org/10.1016/j.eti.2021.101658 36 Nanosensors for Detection of Heavy Metals Heavy metal ions like Pb2+, Hg2+, Ag+, Cd2+, and Cu2+ from different resources have a precarious influence on human beings as well as their surroundings. Optical chemical sensors that are frequently targeted for heavy metal detection fit into a cluster of chemical sensors that primarily employ electromagnetic radiation for engendering a diagnostic signal in an element known as the transduction element. The interactions between the sample and the radiation change a specific optical consideration that can be interrelated to the concentration of an analyte. Colourimetric approaches are advantageous due to their simple operation, economically feasible, transportable instrumentation, and easy-to-use applications. Several compounds are used for stabilizing nanosensors, such as polysaccharides citrates, different polymers, and proteins to improve the attributes of the nanosensors. Fluorescent quantum dots-based sensors are an efficient tool for sensing numerous metal ions. 37 Contd…. The introduction of magnetic nanomaterials (Fe3O4) into the quantum dot- based fluorescence sensors offers several additional advantages owing to their high specific surface area, special magnetic properties, magnetic operability, and low toxicity. 38 Nanomaterials for air and water pollution control The three major applications of nanotechnology in the fields of environment can be classified: 1) Remediation and purification of contaminated material 2) pollution detection (sensing and detection). 3) pollution prevention. Air pollution can be controlled with nano-adsorptive materials, nanocatalysis, and nano filters. Water pollution, nanofiltration and nano sorbents techniques are used. Nanotechnology for clean water: 1) Remediation is the process of removing, minimising or neutralising the water contaminants that can damage human health or ecosystems. 2) Remediation technologies can be divided into three categories, thermal, physicochemical and biological methods. 3) An advanced method that can be used is nanomaterials, with enhanced affinity, capacity and selectivity for heavy metals and other contaminants. 39 Contd…. The advantages of using nanomaterials in water remediation are their higher reactivity, larger surface contact and better disposal capability. Water remediation with iron nanomaterial: ✓ Zero valent Iron (ZVI) is classified into two types: (1) nanoscale ZVI (nZVI) and (2) reactive nanoscale iron product (RNIP). ✓ nZVI particles have a diameter of 100–200 nm composed of iron (Fe) with a valence of zero, whereas RNIP particles consist of 50/50 wt % Fe and Fe3O4. ✓ ZVI has high reactivity to a large number of contaminants, including Cu2+, chlorinated hydrocarbons, CrO22- and NO3-. ✓ Nano-iron could be substituted with other metals. Metals such as zinc and tin have the ability to reduce contaminants such as iron. 40 Contd…. Water remediation with ferritin: Iron stored inside protein ✓ Ferritin is an iron-containing protein that is able to control the formation of mineralized structures. Ferritin has the ability to remediate toxic metals and chlorocarbon un. ✓ The advantages of ferritin over ordinary iron catalysts are: (1) ferritin does not react under photoreduction; and visible light or solar radiation (2) it is also more stable. 41 Nanotechnology in water pollution treatment The major mechanisms used to remove contaminants from contaminated water through nanotechnology include nanofiltration and nano-sorbents. Nanofiltration: 1. Nanofiltration is a membrane process used in water pollution treatment for drinking water and wastewater. 2. Nanofiltration is a low-pressure membrane technique used to separate substances measuring 0.001-0.1 micrometre. 3. Nanofiltration is an effective method used to remove biological pollutants, turbidity, and inorganic compounds. Also, to soften hard water, remove dissolved organic materials, and trace contaminants from surface water, treatment of wastewater, and pre-treatment during the desalination of seawater. 42 Contd…. Nano Sorbents: Nano-sorbents can be used as separation techniques in the process of water purification to eradicate inorganic and organic matter from contaminated matter. Nanoparticles are effective sorbents due to their large surface area and can be enhanced with different reactor compounds to improve their affinity towards specific compounds. 43 Nanotechnology in air pollution treatment Nanotechnology can be used to treat and remedy air pollution through strategies such as the use of nano-adsorptive materials for adsorption, degradation by nanocatalysis, and the use of nano filters to filter and separate air pollutants. Use of Nano-Adsorptive Materials to Adsorb Air Pollutants: ✓ Nano adsorbents: carbon nanostructures have high selectivity, capacity, and affinity due to their physical characteristics, including average pre-diameter, the volume of the pores, and high surface area. ✓ Nano-adsorbents have unique properties that enable effective interactions with organic compounds through non-covalent bonds, including hydrogen bonding, electrostatic forces, hydrophobic interactions, and van der Waal forces. ✓ Carbon nanotubes have been used as adsorbent materials in environmental protection because of their characteristics, including high electrical and thermal conductivity, high strength, the unique potential for adsorption, and high hardness 44 Contd…. Degradation by Nanocatalysis: ✓ Nanotechnology can be used to prevent air pollution in indoor environments in a variety of ways. Semiconducting materials photocatalytic remediation is one effective strategy used to manage indoor pollution through nanotechnology. Reaction mainly occurs on the active surface, which is the significant catalyst structure. A decrease in the size of the catalyst leads to an increase in the surface area to increase the efficiency of the reaction. ✓ Nano-catalysts are considered appropriate materials for improving air quality and reducing pollutants in the air. For instance, titanium dioxide nanoparticles have photocatalytic properties to produce self-cleaning coatings used to decontaminate environmental pollutants, including nitrogen oxides, into materials that have low toxicity levels. Carbon nanostructures, including CNTs and graphene nanosheets, have been utilized to increase titanium dioxide’s photocatalytic effectiveness by facilitating the easy movement of electrons. 45 Contd…. Use of Nano Filters for Separation and Filtration Purposes: ✓ Nano filters are structured membranes with small pores to separate several contaminants from the exhaust to control air pollution by capturing gas pollutants. ✓ Filter media coated with nanofiber is mainly used in industrial plants to remove dust and filter the inlet air for gas turbines. ✓ Silver and copper nanoparticle filters are extensively used in air filtration technology as antimicrobial agents for the removal of biological aerosols such as viruses, bacteria, and fungi that cause infections. 46 Classes of nanomaterials in the removal of organic pollutants from environment Nano-photocatalysts: The term ‘‘photocatalysis’’ refers to the processes where light is used to excite the photocatalyst and accelerate the rate of the reaction, in which the photocatalyst remains unaltered. Nano photocatalysts are photocatalysts with 1 nm and 100 nm of size, in the presence of light, can accelerate the reactions. Nano-sized metals, zero-valent forms, monometallic oxides, bimetallic oxides, semiconductors can be used for the degradation of contaminants in the wastewater such as organic dyes or heavy metal ions. 47 Contd…. Nanophotocatalysts are highly capable of enhancing the mineralization of highly toxic and complex organic substances even at 25 ℃. These nano-sized materials are highly effective in mineralizing and degrading a wide range of organic Contaminants. In mineralization, the complex organic pollutants were decomposed into simpler compounds, whereas the decomposed compounds were completely destructed in the degradation stage, resulting in the formation of much simpler compounds like H2O, CO2. 48 Contd…. Water and Air remediation using nanosize semiconductor photocatalyst: Examples of photocatalysts: 1. Titanium dioxide (TiO2) 2. Zinc oxide (ZnO) 3. Iron oxide (Fe2O3) Photocatalysts are able to oxidize organic pollutants into nontoxic materials. The advantage of using Titanium dioxide (TiO2) for water remediation: 1. low toxicity. 2. high photoconductivity. 3. high photostability. 4. Excellent chemical and biological stability. 5. easily available and inexpensive materials. The advantage of using ZnO for water remediation: ZnO photocatalysts are able to detect and remediate contaminants from water. 49 Contd…. Nano and micromotors: A typical nano-motor is a nano-scale device which is having the ability to convert energy into movement. The nano-motors are capable of generating the forces in the order of few piconewtons. The important aspects of nano and micromotors are their high operational speed, movement specificity, and ability to self-mix. Micro/nanomotors are environmentally friendly and have attractive power units. 50