Showing papers on "Cyanide published in 2023"

Optical Sensing of Toxic Cyanide Anions Using Noble Metal Nanomaterials

Abstract: Water toxicity, one of the major concerns for ecosystems and the health of humanity, is usually attributed to inorganic anions-induced contamination. Particularly, cyanide ions are considered one of the most harmful elements required to be monitored in water. The need for cyanide sensing and monitoring has tempted the development of sensing technologies without highly sophisticated instruments or highly skilled operations for the objective of in-situ monitoring. Recent decades have witnessed the growth of noble metal nanomaterials-based sensors for detecting cyanide ions quantitatively as nanoscience and nanotechnologies advance to allow nanoscale-inherent physicochemical properties to be exploited for sensing performance. Particularly, noble metal nanostructure e-based optical sensors have permitted cyanide ions of nanomolar levels, or even lower, to be detectable. This capability lends itself to analytical application in the quantitative detection of harmful elements in environmental water samples. This review covers the noble metal nanomaterials-based sensors for cyanide ions detection developed in a variety of approaches, such as those based on colorimetry, fluorescence, Rayleigh scattering (RS), and surface-enhanced Raman scattering (SERS). Additionally, major challenges associated with these nano-platforms are also addressed, while future perspectives are given with directions towards resolving these issues.

Imidazole-derived new colorimetric/fluorometric chemosensor for the sensitive recognition of CN− ions: Real-time application in food samples and fluorescence bio-imaging

Abstract: On account of the supreme toxicity of CN− ions in the physiological systems, it is essential to develop a sensitive chemosensor to detect cyanide ions. Herein, we designed a new 5-(3-(4,5-diphenyl-1H-imidazol-2-yl)-2-hydroxybenzylidene)-2,2-dimethyl-1,3-dioxane-4,6-dione (BMA) sensor, which exhibits tremendous colorimetric as well as fluorometric behaviour towards CN− ions. This could be due to the nucleophilic attack of CN− ions on the dione-vinyl site, which induces intramolecular charge transfer (ICT) capabilities. The cyanide recognition mechanism of BMA was verified by optical experiments such as UV–visible and fluorescence spectroscopy, NMR, and mass analysis. Moreover, the structural characterization was done by 1H NMR titration and HRMS analysis, and the molecular orbital interactions were studied by TDDFT calculations. The sensor BMA exhibited a rapid response towards CN− ions (10 sec) with low detection limit (7.87 nM), great pH stability in the physiologically applicable pH range (6–12) and had good sensitivity and selectivity towards CN− ions. Encouraged by these detection properties, we successfully used sensor BMA to determine CN− ions in real water and food samples. To validate the colorimetric behavior of the sensor BMA, test paper strip experiments were carried out in the laboratory. We also extensively studied the effect of the sensor in Escherichia coli (E.coli) bacterial cells.

A synthetic porphyrin as an effective dual antidote against carbon monoxide and cyanide poisoning

Abstract: Significance In fire accidents, highly toxic gases such as carbon monoxide (CO) and hydrogen cyanide (HCN) are simultaneously generated during the combustion of building materials. When inhaled, these two gases strongly bind to hemoglobin, cytochromes, and other hemes in the living organisms, thus inhibiting aerobic respiration. To date, there is no therapeutic approach to overcome simultaneous poisoning with CO and HCN. Here, we invented a synthetic heme model compound (hemoCD-Twins) to provide emergency life-saving treatment. This compound captures CO and cyanide inhaled into animals with a single injection and is rapidly eliminated via urinary excretion. With an immediate antidotal effect, high degree of safety, and storage stability, hemoCD-Twins has great potential to be a ready-to-use antidote against fire gas poisoning.

Graphene Metasurface Inspired Cyanide Detecting Sensor with Encoding capabilities of Two, Three, and Four Bits

Abstract: In this paper, we have proposed graphene metasurfaces capable of achieving an encoding of 4 bits. A graphene metasurface placed over a glass substrate is presented. The proposed graphene metasurface can also be applied for the detection of Sodium Cyanide (NaCN), Potassium Cyanide (KCN), and Hydrogen Cyanide (HCN). The detection capacity of all three graphene metasurface sensor (GMSS) structures has been investigated and the structure with higher functionality has been identified. In addition, the device as a sensor has been investigated based on several parameters and it has been observed that the proposed device generates comparatively higher results. The proposed device has multifunctionality and can be employed either as a sensor or as an encoder. We claim that this is the first graphene metasurface inspired 4-bit encoding device as per our knowledge and can be employed in various applications. The anti-counterfeiting, dynamic information encryption, information authentication, optical data storage, and other related fields stand to benefit greatly from the proposed tunable GMSS and its information encryption and anticounterfeiting applications.

Binding of exogenous cyanide reveals new active-site states in [FeFe] hydrogenases

Abstract: [FeFe] hydrogenases are highly efficient metalloenyzmes for hydrogen conversion. Their active site cofactor (the H-cluster) is composed of a canonical [4Fe-4S] cluster ([4Fe-4S]H) linked to a unique organometallic di-iron subcluster ([2Fe]H). In [2Fe]H the two Fe ions are coordinated by a bridging 2-azapropane-1,3-dithiolate (ADT) ligand, three CO and two CN− ligands, leaving an open coordination site on one Fe where substrates (H2 and H+) as well as inhibitors (e.g. O2, CO, H2S) may bind. Here, we investigate two new active site states that accumulate in [FeFe] hydrogenase variants where the cysteine (Cys) in the proton transfer pathway is mutated to alanine (Ala). Our experimental data, including atomic resolution crystal structures and supported by calculations, suggest that in these two states a third CN− ligand is bound to the apical position of [2Fe]H. These states can be generated both by “cannibalization” of CN− from damaged [2Fe]H subclusters as well as by addition of exogenous CN−. This is the first detailed spectroscopic and computational characterisation of the interaction of exogenous CN− with [FeFe] hydrogenases. Similar CN−-bound states can also be generated in wild-type hydrogenases, but do not form as readily as with the Cys to Ala variants. These results highlight how the interaction between the first amino acid in the proton transfer pathway and the active site tunes ligand binding to the open coordination site and affects the electronic structure of the H-cluster.

Effect of Doping TiO2 NPs with Lanthanides (La, Ce and Eu) on the Adsorption and Photodegradation of Cyanide—A Comparative Study

Abstract: Free cyanide is a highly dangerous compound for health and the environment, so treatment of cyanide-contaminated water is extremely important. In the present study, TiO2, La/TiO2, Ce/TiO2, and Eu/TiO2 nanoparticles were synthesized to assess their ability to remove free cyanide from aqueous solutions. Nanoparticles synthesized through the sol–gel method were characterized by X-ray powder diffractometry (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), Fourier-transformed infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), and specific surface area (SSA). Langmuir and Freundlich isotherm models were utilized to fit the adsorption equilibrium experimental data, and pseudo-first-order, pseudo-second-order, and intraparticle diffusion models were used to fit the adsorption kinetics experimental data. Cyanide photodegradation and the effect of reactive oxygen species (ROS) on the photocatalytic process were investigated under simulated solar light. Finally, reuse of the nanoparticles in five consecutive treatment cycles was determined. The results showed that La/TiO2 has the highest percentage of cyanide removal (98%), followed by Ce/TiO2 (92%), Eu/TiO2 (90%), and TiO2 (88%). From these results, it is suggested that La, Ce, and Eu dopants can improve the properties of TiO2 as well as its ability to remove cyanide species from aqueous solutions.

Ensiling Cyanide Residue and In Vitro Rumen Fermentation of Cassava Root Silage Treated with Cyanide-Utilizing Bacteria and Cellulase

Abstract: Cyanide is a strong toxin in many tropical forage plants that can negatively affect ruminants. The aim of this study is to determine the cyanide removal efficiency, silage quality, and in vitro rumen fermentation of fresh cassava roots ensiled without an additive (control) and with Acremonium cellulase (AC), two cyanide-utilizing bacterial inoculants (Enterococcus feacium KKU-BF7 (BF7) and E. gallinarum KKU-BC10 (BC10)), and their combinations (BF7 + BC10, AC + BF7, AC + BC10 and AC + BF7 + BC10). A completely randomized design was used with eight treatments × four small-scale silo replicates. Additionally, extra silage samples (seven silos/treatment for individually opening after 0, 1, 3, 5, 7, 15, and 30 days of ensiling) were added to observe the changes in the total cyanide concentration and pH value. The fresh cassava root contained an optimal number of lactic acid bacteria (105 colony forming units/g fresh matter), and the contents of dry matter (DM) and total cyanides were 30.1% and 1304 mg/kg DM, respectively. After 30 days of ensiling, all silages demonstrated a low pH (<3.95; p < 0.01). Cyanide content ranged from 638 to 790 mg/kg DM and was highest in the control (p < 0.01). The addition of BF7 + BC10 increased the crude protein (CP) content (p < 0.01). The addition of AC decreased the fibrous contents (p < 0.01). The control had less acetic acid and propionic acid contents (p < 0.01) and a greater butyric acid content (p < 0.01). However, the degrees of in vitro DM digestibility (IVDMD) and gas production were similar among treatments. Methane production ranged between 29.2 and 33.3 L/kg IVDMD (p < 0.05), which were observed in the AC + BC10 and BF7 + BC10 treatments, respectively. Overall, our results suggested that the cyanide removal efficiency after 30 days of ensiling with good-quality cassava-root silage was approximately 39% of the initial value. The enterococci inoculants and/or AC could improve the ensiling process and cyanide removal efficiency (increasing it to between 47 and 51% of the initial value). The novel enterococci inoculants (BF7 + BC10) were associated with a decreased cyanide content and an increased CP content. They appeared to promote the methanogenesis potential of the cassava root silage. More research is required to validate the use of cyanide-utilizing bacterial inoculants in cyanogenetic plants, bioenergy fermentation, and livestock.

Comparative Study of the Effect of Doping ZnTiO3 with Rare Earths (La and Ce) on the Adsorption and Photodegradation of Cyanide in Aqueous Systems

Abstract: Cyanide is a highly toxic compound that can pose serious health problems to both humans and aquatic organisms. Therefore, the present comparative study focuses on the removal of total cyanide from aqueous solutions by photocatalytic adsorption and degradation methods using ZnTiO3 (ZTO), La/ZnTiO3 (La/ZTO), and Ce/ZnTiO3 (Ce/ZTO). The nanoparticles were synthesized by the sol-gel method and characterized by X-ray powder diffractometry (XRD), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy (EDS), Diffuse reflectance spectroscopy (DRS), and Specific surface area (SSA). The adsorption equilibrium data were fitted to the Langmuir and Freundlich isotherm models. Adsorption kinetics were also evaluated using the pseudo-first-order and pseudo-second-order models and the intraparticle diffusion model. Likewise, the photodegradation of cyanide under simulated sunlight was investigated and the reusability of the synthesized nanoparticles for cyanide removal in aqueous systems was determined. The results demonstrated the effectiveness of doping with lanthanum (La) and cerium (Ce) to improve the adsorbent and photocatalytic properties of ZTO. In general, La/ZTO showed the maximum percentage of total cyanide removal (99.0%) followed by Ce/ZTO (97.0%) and ZTO (93.6%). Finally, based on the evidence of this study, a mechanism for the removal of total cyanide from aqueous solutions using the synthesized nanoparticles was proposed.

First-Principles Calculations with Six Structures of Alkaline Earth Metal Cyanide A(CN)2 (A = Be, Mg, Ca, Sr, and Ba): Structural, Electrical, and Phonon Properties

Abstract: This work examines six structures (P4̅3m, P42nm, R3m, P21/c, R3̅m, and C2/m) of alkaline earth metal cyanide A(CN)2 (A = Be, Mg, Ca, Sr, and Ba) using first-principles calculations. The symmetries of P4̅3m, P42nm, and R3m reflect a variation of Pn3̅m, previously reported as occurring on Be(CN)2 and Mg(CN)2 in X-ray diffraction studies, while the symmetries of P21/c, R3̅m, and C2/m were selected from the P3̅m1 symmetry found using Mg(OH)2 as the initial structures, with −OH being replaced by −CN. The band structure, density of states, and phonon properties of all A(CN)2 structures were then investigated using density functional theory (DFT), with a generalized gradient approximation (GGA) applied for the exchange and correlation energy values. The simulation results for the phonon spectra indicate that the stable structures are Be(CN)2 (P4̅3m, P42nm, and C2/m), Mg(CN)2 (P4̅3m, P42nm, and C2/m), Ca(CN)2 (P21/c), Sr(CN)2 (P21/c and R3̅m), and Ba(CN)2 (R3̅m) at 0 GPa. For the effects of high pressure, Ca(CN)2 and Sr(CN)2 were thus found to be stable as C2/m at pressures above 10 and 3 GPa, respectively, while Ca(CN)2 is as stable as R3̅m above 15 GPa. In the calculated band structures, all of the compounds with the C2/m structure demonstrated good conductivity, while the other structures have a band gap range of 2.83–6.33 eV.

Phthalimide‐Based Off‐On‐Off Fluorosensor for Cascade Detection of Cyanide Ions and Picric Acid

Abstract: Novel methods that can be utilized to identify and detect harmful environmental pollutants still need to be proposed. This article describes the effective design and development of a turn-on photoluminescence probe, T1 [(E)-5-((2-hydroxybenzylidene) amino) isoindoline-1, 3-dione], which is selective and sensitive towards CN− ions having detection limit nM to μM range. When exposed to CN− ions, Probe T1 displays a strong fluorescence response under a 365 nm UV light irradiation with a noticeable low to high intense cyan color photoluminescence visible to the naked eye. For the practical utility of the present probe T1, a paper strips-based test kit experiment has been demonstrated as a portable and displayable photonic device for on-site detection of CN− ions. Furthermore, the T1-CN− adduct has been applied for detecting explosive nitroaromatic compounds, especially PA, based on the photoluminescence quenching mechanism. Using CN− ions, and PA as chemically encoded inputs and corresponding optical output, a molecular logic gate has been constructed. Further, probe T1 has been employed as a bio-analytical tool to map intercellular CN− ions in live cells. This study invokes a novel approach for designing and developing efficient and selective sensors employing well-known fluorescent probes as signaling units with prior photophysical knowledge.

Single Organic Ligands Act as a Bifunctional Sensor for Subsequent Detection of Metal and Cyanide Ions, a Statistical Approach toward Coordination and Sensitivity.

Abstract: The detection of key ions in environmental samples has garnered significant attention in recent years in the pursuit of a cleaner environment for living organisms. Bifunctional and multifunctional sensors, as opposed to single-species sensors, have emerged as a rapidly developing field. Many reports in the literature have documented the use of bifunctional sensors for the subsequent detection of metal and cyanide ions. These sensors, consisting of simple organic ligands, form coordination compounds with transition metal ions, resulting in clear visible or fluorescent changes that facilitate detection. In some cases, a single polymeric material can act as a ligand and coordinate with metal ions, forming a complex that serves as a sensor for cyanide ion detection in biological and environmental samples through various mechanisms. Nitrogen is the most dominant coordinating site in these bifunctional sensors, with the sensitivity of the sensors being directly proportional to the denticities of ligands for metal ions, while for cyanide ions the sensitivity was found independent of the denticity of the ligands. This review covers the progress made in the field over the past fifteen years (2007-2022), with most ligands detecting copper (II) and cyanide ions, but with the capability to detect other metals such as iron, mercury, and cobalt as well.