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Ammi visnaga is a biennial or annual herbaceous plant belonging to the family Apiaceae. For the first time, silver nanoparticles were synthesized using an extract of this plant. Biofilms are a rich source of many pathogenic organisms and, thus, can be the genesis of various disease outbreaks. In addition, the treatment of cancer is still a critical drawback for mankind. The primary purpose of this research work was to comparatively analyze antibiofilms against Staphylococcus aureus, photocatalytic activity against Eosin Y, and in vitro anticancer activity against the HeLa cell line of silver nanoparticles and Ammi visnaga plant extract. The systematic characterization of synthesized nanoparticles was carried out using UV–Visible spectroscopy (UV-Vis), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), dynamic light scattering (DLS), zeta potential, and X-ray diffraction microscopy (XRD). The initial characterization was performed with UV-Vis spectroscopy, where a peak appeared at 435 nm, which indicated the SPR band of the silver nanoparticles. AFM and SEM were performed to determine the morphology and shape of the nanoparticles, while EDX confirmed the presence of Ag in the spectra. The crystalline character of the silver nanoparticles was concluded with XRD. The synthesized nanoparticles were then subjected to biological activities. The antibacterial activity was evaluated by determining the inhibition of the initial biofilm formation with Staphylococcus aureus using a crystal violet assay. The response of the AgNPs against cellular growth and biofilm formation was found to be dose dependent. Green-synthesized nanoparticles showed 99% inhibition against biofilm and bacteria, performed excellent anticancer assay with an IC50 concentration of 17.1 ± 0.6 µg/mL and 100% inhibition, and photodegradation of the toxic organic dye Eosin Y up to 50%. Moreover, the effect of the pH and dosage of the photocatalyst was also measured to optimize the reaction conditions and maximum photocatalytic potential. Therefore, synthesized silver nanoparticles can be used in the treatment of wastewater contaminated with toxic dyes, pathogenic biofilms, and the treatment of cancer cell lines.

Benzodiazepines like nitrazepam are extensively used, both as prescribed medications and as illicit drug substitutes, and therefore detection is of prime importance. In this work, the electrochemical detection of nitrazepam using a graphitic carbon nitride (g-C3N4) modified electrode was investigated. The nitrogen-rich carbon material i.e., g-C3N4 was easily synthesized by the thermal condensation method using melamine as a precursor. The platinum electrode was modified by synthesized material and its electrochemical activity was tested using a three-electrode set-up. The cyclic voltammetry and electrochemical impedance spectroscopy confirmed the effective detection of nitrazepam. The detection at different concentrations was analyzed using CV and differential pulse voltammetry (DPV). The detection limit of 0.02 µM was found with the linear dynamic range of nitrazepam. A repeatability experiment was conducted to check the stability of the proposed electrode. This study confirms the potential use of g-C3N4 as an effective and stable electrode material for the detector in the field of pharmaceuticals and health care.

The main aim of this work is to establish a sensor MESH network using an ESP-MESH networking protocol with the ESP32 MCU (a Wi-Fi-enabled microcontroller) for indoor and outdoor air quality monitoring in real time. Each sensor node is deployed at a different location on the college campus and includes sensor arrays (CO2, CO, and air quality) interfaced with the ESP32. The ESP-MESH networking protocol is a low-cost, easy-to-implement, medium-range, and low-power option. ESP32 microcontrollers are inexpensive and are used to establish the ESP-MESH network that allows numerous sensor nodes spread over a large physical area to be interconnected under the same wireless network to monitor air quality parameters accurately. The data of different air quality parameters (temperature, humidity, PM2.5, gas concentrations, etc.) is taken (every 2 min) from the indoor and outdoor nodes and continuously monitored for 72 min. A custom time-division multiple-access (TDMA) scheduling scheme for energy efficiency is applied to construct an appropriate transmission schedule that reduces the end-to-end transmission time from the sensor nodes to the router. The performance of the MESH network is estimated in terms of the package loss rate (PLR), package fault rate (PFR), and rate of packet delivery (RPD). The value of the RPD is more than 97%, and the value of the PMR and PER for each active node is less than 1.8%, which is under the limit. The results show that the ESP-MESH network protocol offers a considerably good quality of service, mainly for medium-area networks.

Hydrazine is a well-known carcinogen and can cause several other adverse effects on human health such as respiratory issues, irritation of the eyes, liver and kidney problems, and dermal corrosion. An effective method is needed to detect the carcinogenic reagent like hydrazine. Tin oxide (SnO2)-modified graphitic carbon nitride (g-C3N4) decorated with well-crystallized silver (Ag) nanoparticles (denoted as Ag@SO-gCN) was fabricated by a biogenic/green approach and characterized by standard techniques. A fluorine-doped tin oxide (FTO) support/substrate was coated with Ag@SO-gCN by the doctor-blade technique, and employed as the working electrode (denoted as Ag@SO-gCN/FTO) for the electrochemical detection of carcinogenic hydrazine (Hz) as a model analyte at room temperature. The dual electrochemical techniques of linear sweep voltammetry (LSV) and cyclic voltammetry (CV) were used for the detection of hydrazine (denoted as Hz). The Ag@SO-gCN/FTO sensor shows an effective current response in the detection of Hz in solutions. The concentration of Hz was very efficiently monitored using LSV and CV under different conditions. The sensor shows a low limit of detection (LOD), high sensitivity and selectivity, and good linear range. The sensitivity and LOD of this sensor using LSV are 2.01 μA μM−1 cm−2 and 0.164 ± 0.013 μM, respectively. However, the fabricated Hz sensor using CV showed a sensitivity of 2.305 μA μM−1 cm−2 and LOD of 0.143 ± 0.011 μM. This study thus provides an innovative Ag@SnO2-g-C3N4-based electrochemical sensor as an effective device for the successful detection of hazardous chemicals.

Antibiotics and organic dyes are both significant causes of water pollution, and their removal from, or degradation in, water systems can be difficult. To address this issue, SnO2-modified TiO2 nanocomposites (STOs) were fabricated using a sonication-impregnation method. The prepared STOs (STO-1, STO-2, and STO-3) were characterized through various techniques including powder X-ray diffraction, Fourier-transform infrared spectroscopy, UV–vis diffuse reflectance spectroscopy, photoluminescence, high resolution-transmission electron microscopy, and X-ray photoelectron spectroscopy. The fabricated STOs exhibited narrowing of their bandgap and enhanced absorption in the UV and visible region. The STOs were further tested for their use in the photocatalytic degradation of tetracycline hydrochloride (TC) under visible light irradiation and were found to be very suitable for this application. The adsorption of TC on the STOs reached nearly 56%–62% after 15 min in the dark, while the vast majority degraded (81%–95%) within 20 min of visible light exposure. The narrowed band-gap and surface-based properties played a significant role in improving the adsorption-degradation efficiency of TC by extending the absorption spectrum and enhancing the separation efficiency of charge carriers. Moreover, the degradation of MB and CR was performed using STO-1 and displayed over 97% and 90% degradation, respectively. Thus, an effective method to utilize a non-noble photocatalyst to efficiently degrade antibiotics and organic dyes was achieved.

In this work, a completely non-intrusive type alternating current (a.c) voltagemeasurement system based on the novel capacitively coupled technique isproposed. In literature, most of the reported capacitive coupling techniquerequire a direct contact of sensor to the ground potential of power system.Human operator, whose body is in contact with the ground must touch thecapacitive sensor to provide the power system ground. The reliability ofthose types of approach is limited, as the human operator must be in directcontact to a conductive part of the sensor. Also, there is the effect of nature ofimpedance exist between the body of the human operator and the ground,which is not taken care by most of the existing methods. In this work, a new method regardless of the variations in the impedance exist between themeasurement unit and the ground potential through the earth, is proposed.Simulation analysis has been conducted in detail to validate the proposedapproach. A prototype measurement system has been developed and thentested for a line voltage (200 to 250 V), at 60 Hz. The capacitance outputw.r.t applied voltage was linear and the worst-case non-linearity error wasrecorded as

Green synthesis has gained extensive attention in material science because of its sustainability and eco-friendliness in producing a wide range of nanomaterials. This study demonstrated the photocatalytic and antimicrobial abilities of green synthesized silver-embedded zinc oxide nanocomposites (Ag@ZnO NCs). Zinc oxide with a unique mesoporous ellipsoidal morphology in size range of 0.59 ± 0.11 × 0.33 ± 0.09 µm (length × width) was synthesized using the aqueous extract of goji berry (ZnO-GB) by calcination in the air. Powder X-ray diffraction (XRD) revealed the formation of a hexagonal phase of wurtzite (WZ) structure. The average crystallite size of ZnO-GB was 23.74 ± 4.9 nm as calculated using Debye–Scherrer’s equation. It also possesses higher thermal stability with the surface area, pore-volume, and pore size of 11.77 m2/g, 0.027 cm3/g, and 9.52 nm, respectively. Furthermore, different mesoporous Ag@ZnO NCs embedded with face-centered cubic (fcc) silver nanoparticles (Ag NPs) in the range of 90–160 nm were synthesized by GB extract as a reducing and capping agent on the surface of ZnO-GB after calcination. The immobilization of Ag NPs was confirmed by XRD, X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), FE-transmission electron microscopy (FE-TEM), and energy-dispersive X-ray spectroscopy (EDS). It was found that Ag0.2@ZnO NC (0.2 wt% of Ag) showed excellent photocatalytic degradation of both methylene blue (MB) (cationic) and congo red (CR) (anionic) dyes under simulated solar irradiation. The photocatalytic degradation of 99.3 ± 0.35% MB and 98.5 ± 1.3% CR occurred in 90 and 55 min, respectively, at room temperature by Ag0.2@ZnO NC. Besides, these NCs also showed broad-spectrum antibacterial activity against both Gram-positive and Gram-negative bacteria. The mechanistic concept of generating reactive oxygen species (ROS) by electron and hole charge (e‾/h+) carriers seems to be responsible for the photocatalytic degradation of commercial dyes and antibacterial activities by Ag@ZnO NCs. Thus, these as-prepared green Ag@ZnO NCs are promising candidates as photocatalysts for industrial/wastewater treatment as well as in antimicrobial therapeutics.

Carbon quantum dots (CQDs), the intensifying nanostructured form of carbon material, have exhibited incredible impetus in several research fields such as bio-imaging, bio-sensing, drug delivery systems, optoelectronics, photovoltaics, and photocatalysis, thanks to their exceptional properties. The CQDs show extensive photonic and electronic properties, as well as their light-collecting, tunable photoluminescence, remarkable up-converted photoluminescence, and photo-induced transfer of electrons were widely studied. These properties have great advantages in a variety of visible-light-induced catalytic applications for the purpose of fully utilizing the energy from the solar spectrum. The major purpose of this review is to validate current improvements in the fabrication of CQDs, characteristics, and visible-light-induced catalytic applications, with a focus on CQDs multiple functions in photo-redox processes. We also examine the problems and future directions of CQD-based nanostructured materials in this growing research field, with an eye toward establishing a decisive role for CQDs in photocatalysis, bio-imaging, and bio-sensing applications that are enormously effective and stable over time. In the end, a look forward to future developments is presented, with a view to overcoming challenges and encouraging further research into this promising field.

Silver-titania nanocomposites (Ag-TiO2 NCs) have unique functional attributes due to their photocatalytic and antibacterial properties. In this study, titania nanoparticles (TiO2-NPs) were successfully in-situ decorated with silver nanoparticles (Ag-NPs) using the aqueous extract of goji berries (Lycium barbarum L.) as a bioreducing and stabilizing agent. Different Ag-TiO2 NCs were synthesized by treating different concentrations of silver nitrate with a specific concentration of TiO2-NPs in the presence of fruit extract. The green-synthesized NCs were characterized using several techniques viz., ultraviolet–visible spectrophotometry, X-ray diffractometry (XRD), scanning electron microscopy, field-emission transmission electron microscopy (FE-TEM), Fourier transform infrared spectroscopy, and X-ray photoelectron spectroscopy. XRD analysis revealed the formation of face-centered cubic (fcc) crystals, and FE-TEM analysis revealed the embedment of Ag-NPs throughout the surface of TiO2-NPs. The average size of Ag-NPs on TiO2-NPs increased from 11.2 ± 3.05 nm to 16.4 ± 4.5 nm with an increase in the concentration of silver ions, and the morphology of Ag-NPs was predominantly quasi-spherical and hexagonal. These NCs exhibited an excellent photocatalytic degradation of an azo dye, methylene blue (MB). The synthesized Ag-TiO2 NCs (3:1) showed higher photocatalytic degradation efficiency of ∼ 93.4% for MB in 130 min under visible light irradiation. Ag-TiO2 NCS also exhibited good antibacterial activities towards Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative). Therefore, the formation of Ag-NPs on the surface of TiO2-NPs to form Ag-TiO2 NCs exhibits eco-friendly photocatalytic degradation of azo dye contaminants as well as antibacterial activity.

The Fuel cells are probable to rapidly develop a source of low to zero-emission power generation for applications in portable technologies, electric and rechargeable automobiles. This is the matter of concern for renewable energy that is attractive and noteworthy owing to growing power demand. The uncertainty of the increasing oil values and eco-friendly difficulties will be the prime concern in future. Amongst the several renewable energy sources fuel cell is the advance alternative energy solution and it is attaining more popularity by virtue of its advanced effectiveness, purity and cost-effective source of power. Hence, this book chapter presents a comprehensive review of the design and fabrication of nanostructured material for fuel cell application. In accumulation, thorough metal-metal oxides fabrication and effective role of fuel cell in energy-related issues. This chapter also focuses on the working principle, its advantages, disadvantages, in transportation, industrial and commercial applications of fuel cell.

Development of advanced materials with a benign environmentally friendly approach for heterogeneous visible light photocatalysis is always preferable. An environmentally favorable approach was used to anchor silver nanoparticles (Ag NPs) to tin oxide-decorated-graphitic carbon nitride (SnO2-g-C3N4) using a biofilm as a green reducing tool for the biogenic synthesis of 1–6 mM Ag@SnO2-g-C3N4 nanostructures (NSs). The fabricated NSs were characterized using sophisticated techniques. The developed Ag@SnO2-g-C3N4 NSs showed a well-defined spherical-shaped Ag NPs anchored to SnO2-g-C3N4 NSs. The synthesized NSs were applied for photocatalytic degradation of hazardous dyes and photoelectrochemical studies. A comparative investigation of Ag@SnO2-g-C3N4 NSs for the visible light-assisted photocatalytic degradation of Methylene blue (MB), Congo red (CR), and Rhodamine B (RhB) was performed. The photocatalytic degradation of MB, CR, and RhB reached ∼99% in 90 min, ∼98% in 60 min, and ∼94% in 240 min, respectively. T...

Narrow band gap zinc oxide (ZnO) nanoparticles (NPs) were synthesized using unboiled and boiled leaf extracts of Costus woodsonii. The as-synthesized NPs were characterized using a range of techniques. The as-synthesized ZnO NPs were crystalline with a hexagonal wurtzite structure similar to the commercial ZnO (ZnO-C). The maximum absorbance was observed at ~390 nm for ZnO-C and the as-synthesized ZnO NPs (ZnO-UL and ZnO-BL) showed a red shift, i.e. ~448 nm to ~462 nm, hence, a lower band gap of ~2.68–2.77 eV. The band gap energy of the as-synthesized ZnO NPs was lower than that of commercial ZnO. The surface of ZnO was coated/modified with the components of the leaf extract. The as-synthesized ZnO NPs showed similar particle sizes and were spherical in shape. These studies confirmed the green synthesis of ZnO NPs using Costus woodsonii and the significantly reduced band gap (Eg = ~2.68 eV to ~2.77 eV) of the as-synthesized ZnO NPs compared to the ZnO-C (Eg = 3.18 eV).

The use of biomass for functional nanomaterial is fascinating. Costus woodsonii was used as a green approach to synthesize zinc oxide (ZnO) nanoparticles from its bulb (flower). The as-synthesized ZnO nanoparticles were characterized by X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Fourier transform infrared (FT-IR) spectroscopy, UV-Vis diffuse reflectance spectroscopy (UV-Vis DRS), and transmission electron microscopy (TEM). XRD showed that the commercial ZnO (C-ZnO) and as-synthesized ZnO nanoparticles were of high purity and displayed a hexagonal wurtzite and well crystalline structure. XPS confirms that Zn was in the + 2 chemical state. FT-IR spectroscopy showed some additional peaks on the as-synthesized ZnO only due to a surface coating of the components of the bulb extract. TEM revealed the morphology, particle size, and high purity of the ZnO nanoparticles. The UV-Vis DRS of the as-synthesized ZnO showed a red shift compared to C-ZnO, which was attributed to the surface coating of the as-synthesized ZnO nanoparticles. These studies confirmed the synthesis of ZnO nanoparticles with a lower band gap, i.e., Eg = 2.66–2.79 eV. Therefore, phytogenic synthesis could be a new or alternate pathway for the synthesis of different types of novel nanomaterials with unique characteristics without altering the basic and fundamental structure.

The rapid progress of state-of-the-art carbon-based metals as a catalyst is playing a central role in the research area of chemical and materials engineering for effective visible-light-induced catalytic applications. Numerous admirable catalysts have been fabricated, but significant challenges persist to lower the cost and increase the action of catalysts. The development of carbon-based nanostructured materials (i.e., activated carbon, carbon nitride, graphite, fullerenes, carbon nanotubes, diamond, graphene, etc.) represents an admirable substitute to out-of-date catalysts. Significant efforts have been made by researchers toward the improvement of various carbon-based metal nanostructures as catalysts. Moreover, incredible development has been achieved in several fields of catalysis, such as visible-light-induced catalysis, electrochemical performance, energy storage, and conversion, etc. This review gives an overview of the up-to-date developments in the strategy of design and fabrication of carbon-based metal nanostructures as photo-catalysts by means of several methods within the green approach, including chemical synthesis, in situ growth, solution mixing, and hydrothermal approaches. Moreover, the photocatalytic effects of the resulting carbon-based nanostructure classifications are similarly deliberated relative to their eco-friendly applications, such as photocatalytic degradation of organic dye pollutants.

The aerogels are porous with low density structures and have been explored in the range of applications including catalysis, thermal insulators, solar energy uses, piezoelectric, energy conversions-storage, low-temperature glass formation, sensors, adsorption, and photocatalysis. A variety of aerogels with unusual architect have been developed such as organic aerogels, nonsilica oxide aerogels, chalcogenide aerogels, carbon aerogels, and others. In the present chapter, we have tried to compile a brief research associated with the development of aerogels and their composites and used in the various applications of present need of water pollution and its remediation. Additionally, we have discussed the problems with the different examples of aerogels as sensors, adsorbents, and photocatalysts.

Over the last decade, the assortment of metal, metal-oxide materials fabricated using several chemical and physical techniques have increased significantly. This chapter presents a notable explanation of the progressive development of the solid materials known as aerogels. Metal, metal-oxides aerogels can have unusual properties, such as, high surface area, low density, low thermal conductivity, and good optical translucency. This combination of properties makes aerogels attractive materials for use in applications ranging from lightweight structural, insulating or shock absorbing materials especially in aeronautics, microelectronics, sensing applications, and purification systems. These aerogels materials have been fabricated using extensive variability of techniques, such as, incorporation of metal nanoparticles or carbon-based substituents into the sol-gel matrix and surface modification of the matrix following gelation. This chapter presents brief introduction, basic properties, and fabrication process of metal, metal oxides aerogels, and further various techniques for the purification systems has been discussed.

Metaheuristic algorithms are found to be more effective and helpful in working out on complex problems (e.g., optimization and mining, etc.). This chapter presents a survey with a brief overview of the cuckoo algorithm, its latest developments, as well as recommendation for the applications in various disciplines. The presented survey analyzes the algorithm search insight, its Levy flight strategy, and search mechanism efficiency. It was found that despite being capable of solving various complex and multimodal problems researcher further improves cuckoo search algorithm performance. The chapter presents the cuckoo search algorithm, and explains the variants and hybrids of the cuckoo algorithm. Further, the chapter unveils various complex problems of science and engineering where the algorithm can be applied successfully with better convergence and global optimization results.

There is an unremarkable development in human life by industrialization and modernization which consequences the harmful contamination in the fresh water. This contamination is rapidly growing by the use of a variety of organic dyes, inorganic and other harmful pollutants like chemicals, pesticides, soil erosion, etc. which causes the quality of fresh and clean water continuously degraded. To get an access of clean water removal of contaminants is a major challenge for the water industries. It is a high demand to develop useful material in water treatment with high separation capacity, low-priced, porosity, and recyclability. Adsorption, coagulation, oxidative-reductive degradation and membrane separation, etc. have been developed for water/waste water treatment. Adsorption is found to be one of the most widely used method in water treatment. Variety of different adsorbents and their hybrids are used for the removal of pollutants from water. Recently, investigation on remediation of water involves the use of nanomaterials with high purifying capability. Metal and metal oxide nanomaterials are one of the important and excellent reagents for the decontamination of water/waste water treatment. The present chapter is a compilation of various adsorbents based on metal and metal oxide nanomaterials for decontamination of water/waste water available till date.