SO2 Gas Research Articles

Preparation of an innovative series of respiratory nano-filters using polystyrene fibrous films containing KCC-1 dendrimer and ZnO nanostructures for environmental assessment of SO2, NO2 and CO2.

Air pollution has become a major challenge that threatens human health. The use of respiratory filters is one of the proposed solutions. In this study, using polystyrene (PS) fibers and various nanomaterials, improved respiratory filters were fabricated to remove air pollutants. In this context, ZnO nanoparticles (ZnO NPs) integrated into dendritic structures of KCC-1 silica were used to improve the filters' ability to absorb pollutants. For the first time, the removal of gasses by modified filters with a novel polymeric nanocomposite (PS/ZnO-KCC-1) stabilized on the surface of respiratory filters was investigated. Moreover, two different methods including stabilized- and solution-based techniques were used to prepare the filters with different amounts of ZnO NPs and their efficiency was evaluated. All synthesized nanocomposites and developed filters were characterized by FT-IR, FESEM, TGA and XRD methods. The successful stabilization of nanostructures on the fibers was proved and the performance of the fibers was investigated with some tests, such as pressure drop and removal of suspended particles and CO2 (89%), NO2 (86%), and SO2 (83%) gases. PS/KCC-1-ZnO (5%) has better performance than other prepared fibers. The results showed that the removal of suspended particles in the filter containing ZnO and KCC-1 (M5) nanostructures was improved by 18% compared to the filter consisting of polystyrene fibers. The pressure drop increased with the addition of nanostructures and reached 180 Pa in the M5 filter. The filter containing ZnO NPs showed antibacterial activity against Staphylococcus (S.) aureus and Escherichia (E.) coli as Gram-positive and Gram-negative model bacteria using the Agar disk-diffusion method. Based on the results, the use of improved respiratory filters is recommended as an effective solution for combating air pollution and protecting human health.

Chemisorption of SO2 and NO2 gas over Na0.4MnO2 in ambient conditions: an experimental and theoretical study

Na0.4MnO2 could effectively capture SO2 and NO2 gas from lean sources in ambient conditions.

Adsorption and sensing performance of air pollutants on a β-TeO2 monolayer: a first-principles study.

Two-dimensional (2D) β-TeO2 is a novel semiconductor with potential applications in electronic circuits due to its air-stability and ultra-high carrier mobility. In this study, we explore the possibility of using a 2D β-TeO2 monolayer for the detection of gaseous pollutants including SO2, NO2, H2S, CO2, CO, and NH3 gas molecules based on first-principles calculations. The adsorption properties including the adsorption energy, adsorption distance and charge transfer indicate that the interaction between 2D β-TeO2 and the six gases is via a physisorption mechanism. Among the six gas adsorption systems, the SO2 adsorption system has the most negative adsorption energy and the largest charge transfer. In addition, the adsorption of SO2 obviously changes the electrical conductivity of the β-TeO2 monolayer because the band gap decreases from 2.727 eV to 1.897 eV after adsorbing SO2. Our results suggest that the 2D β-TeO2 should be an eminently promising SO2 sensing material.

Effects of atmospheric pollution on human health in Port Harcourt: Its implication on urban planning

This study examined the health implication of atmospheric pollution in Port Harcourt. The study adopted both experimental research design and ex-post facto designs. This involved direct field measurements of air pollutants (Sulphur (IV) Oxide, Nitrogen Oxide, Carbon Monoxide, and PM10) and archival medical data of air borne diseases in Port Harcourt. The study area was stratified into four zones using existing land use types. In each of the four zones, three most heavily congested traffic intersections were selected for monitoring the air pollutants. The data generated were analysed using multiple regression statistical tool at 0.05 level of significance. The study revealed that the concentration of air pollutants measured in parts per million for SO2 (0.24), NO2 (0.06), CO (33.1) and PM10 (2.65) in Port Harcourt metropolis exceeded WHO standards for SO2 (±0.00-0.01), NO2 (±0.03-0.06), CO (±3-10) and PM10 (±0.9-1.12). The study revealed that air borne diseases were on the increase in Port Harcourt metropolis. During the rainy season, there was a low prevalence of Air borne diseases in Port Harcourt and this could be attributed to the rainfall which reduces dust and fine particles. At F values of 8.59 and 10.871 respectively, SO2, and PM10 had a significant effect on the occurrence of air borne diseases in Port Harcourt metropolis at P<0.05. As such, SO2, and PM10 gases were responsible for the increase in cardiovascular diseases, reduced lung function, asthma, irritation of the eyes, cough, nausea in Port Harcourt metropolis. To mitigate the effects of atmospheric pollution on human health, urban planning strategies should focus on promoting sustainable transportation options (such as public transit, cycling, and walking), increasing green spaces and planting trees to improve air quality, promoting energy-efficient buildings, and implementing regulations to reduce emissions from industrial sources. Incorporating measures to improve air quality into urban planning decisions can help create healthier and more livable cities for residents.

DFT study on adsorption properties of TM(Ni, Co)Nx -doped graphene for high-temperature sensing of SF6 decomposed gases

Gas sensing is the key to online monitoring SF6 decomposition gases in gas-insulated switchgear (GIS) fault diagnosis. However, the gas sensors for high-temperature sensing of SF6 decomposed gases are still lacking. In this paper, the adsorption performance of TM(Co, Ni)Nx-doped graphene as gas-sensing materials for the SF6 decomposed gases of SO2, SOF2, and SO2F2 were studied by DFT calculations, especially for the case at high temperatures. The adsorption energy (Eads), adsorption distance (D), transferred charge (Qt), and molecular dynamics simulations were performed to study the gas adsorption ability of TMN2-doped graphene. The electronic structures were clarified by analysis of the density of states (DOS), the partial density of states (PDOS), electron density difference, and molecular orbitals. The molecular dynamics simulations at 873 K indicated the high thermodynamic stability of TM(Co, Ni)Nx-doped graphene, which promised their superior gas sensing performance to detect SF6 decomposed gases at high temperatures.

Dry desulphurisation of gas streams using KCC-1 mesoporous silica functionalised with deep eutectic solvents.

Sulphur dioxide, a toxic gas pollutant, is mainly generated by the combustion of fossil fuels and the smelting of sulphur-bearing mineral ores. Removal of SO2 gas or desulphurisation can be accomplished in industries using a variety of processes; the most efficient is wet flue gas desulphurisation (FGD). However, wet FGD has challenges, such as the requirement for wastewater treatment, excessive water usage, and the necessity for chloride protective coating. Despite having a lesser adsorption capacity than wet FGD, dry FGD can efficiently remove SO2 from the effluent gas stream and avoid the issues associated with wet FGD, provided that the sorbents are modified and regenerable. An alternative dry desulphurisation strategy by using fibrous mesoporous silica (KCC-1) modified with deep eutectic solvents (DES), choline chloride-glycerol (DES1) and choline chloride-ethylene glycol (DES2) is studied in this paper. KCC-1 modified with DES1 is found to increase SO2 adsorption capacity to 4.83 mg g-1, which is 1.73 times greater than unmodified KCC-1 and twice higher than KCC-1 modified with DES2 attributed to the sorbent's high porosity. Increasing reaction temperature and SO2 concentration reduce the adsorption capacity to 1.73 mg g-1 and 2.73 mg g-1, respectively. The Avrami kinetic model and the Toth isotherm model best reflect SO2 adsorption on the modified KCC-1, indicating that SO2 molecules are adsorbed exothermically in multilayer adsorption on a heterogeneous surface through a combination of physical and chemical processes. The higher SO2 adsorption capacity of the modified KCC-1 suggests that choline chloride-glycerol can provide additional sites for SO2 adsorption in dry FGD technology.

BP/GaN and BP/GaP core/shell nanowires: theoretical insights into photovoltaic and gas-sensing abilities.

DFT-based calculations were undertaken to, first, fully optimize and study the structural and electrical properties of bare BP nanowire (NW) in its hexagonal wurtzite (WZ) phase. The bare BP NW was found to have an indirect bandgap of 1.362 eV. Hence, the optimization of BP/GaN and BP/GaP core/shell nanowires (CSNWs) was performed to check if an indirect-to-direct band transition occurred. Both the CSNWs showed direct bandgaps of 0.225 eV and 1.252 eV, respectively. The Shockley-Queisser limits for the bare BP NW and BP/GaP CSNW were calculated and compared to gauge their respective photovoltaic efficiencies. The bare BP NW and BP/GaP CSNW yielded almost identical SQ efficiencies of 33.80% and 33.55%, respectively. However, as far as the nano- and micro-photovoltaic cell applications are concerned, the BP/GaP CSNW would be preferable, owing to its direct bandgap. Furthermore, the adsorption of some small oxide gases like carbon monoxide (CO), carbon dioxide (CO2), nitrogen dioxide (NO2) and sulfur dioxide (SO2) gases on BP/GaN and BP/GaP CSNWs was studied. On the basis of the charge transfer and work function mechanisms, NO2 and SO2 gases showed selectivity to be detected by both the CSNWs. However, the very highly escalated desorption times for these gases would reduce the repeatability of sensors. Conversely, both BP/GaN and BP/GaP CSNWs could find applications in the fabrication of entrapment devices for NO2 and SO2. The current-voltage (I-V) curves for the CSNWs before and after adsorption were also plotted and analyzed. The occurrence of negative differential conductance (NDC) can be observed in both the CSNWs. The CO2, NO2 and SO2 gases show significantly higher values of current than the pristine BP/GaN CSNW for voltages beyond 0.5 V. Thus, these gases are good proponents to be detected by BP/GaN CSNWs with negligible selectivity amongst them. However, CO@BP/GaN is a stand-out case with a characteristically unique NDC region at 0.9 V. In the case of BP/GaP CSNWs, CO and CO2 gases can be selectively detected, with a unique NDC region for CO at 0.9 V. Thus, the BP/GaP CSNW, in particular, stands out as an extremely versatile material that can be used to fabricate nano-photovoltaic and nano-sensing devices of the next generation.

Continuous multiphase Bunsen reactor of iodine-sulfur thermochemical water splitting cycles for hydrogen production: Experimental, Modelling and Design Insights

Thermochemical water splitting cycles (TWSCs) hold promise for sustainable H2 production in future energy systems, with Iodine-Sulfur (IS) and Nickel-Iodine-Sulfur (NIS) processes standing out as efficient options. The core of both these processes lies in the Bunsen reaction, underscoring the need to identify optimal operational conditions and plant solutions for this crucial reaction section. Thus, in this study, a continuous counter-current flow Bunsen reactor fed with 5 NL h−1 of SO2 was constructed and tested. An inventive aspect was the introduction of solid I2 pellets from the top to enhance saturation at the liquid-liquid interface between sulfuric and hydriodic product phases, promoting segregation. This ingenious design achieved nearly complete SO2 conversion and optimal H2SO4 and HI concentrations in the respective product phases, while avoiding undesirable byproduct formation. The study further advanced the modelling of the experimental reactor by employing innovative kinetic and liquid-liquid equilibrium description approaches, and demonstrating exceptional validation accuracy of R2 = 0.9988. Additionally, with the aim of obtaining design charts as a potential tool for Bunsen reactor design, a microscopic model describing the gas phase trend along bubble or packed Bunsen-type reactors was developed. The model’s dimensionless analysis revealed a characteristic times ratio (Bu) comprehensively describing all the phenomena occurring to the gas phase within the Bunsen reaction section, and identified an optimal Bu value of 0.4 for pure SO2 gas inlet. Overall, the study's innovative strategies and models contribute significantly to the advancement of Bunsen reactor engineering.

Highly selective capture of sulfur dioxide by low viscosity 1,2,4-triazole + [Emim]Cl deep eutectic solvents

Sulfur dioxide (SO2) is a toxic gas emitted from industrial waste gases, and its removal is crucial to improve the quality of the atmosphere and reduce the harm to human health. In this work, we investigated the absorption of SO2 by deep eutectic solvents (DESs) with low viscosity 1,2,4-triazole (Trtz) and 1-ethyl-3-methylimidazole chloride ([Emim]Cl) under different conditions. We briefly investigated the mechanism of sulfur dioxide absorption by DESs and measured the absorption performance of Trtz + [Emim]Cl DESs for SO2 at different molar ratios. The experimental results show that all Trtz + [Emim]Cl DESs have good capture performance for SO2, among which 298.2 K Trtz + [Emim]Cl (1:3) DES has an absorption capacity of 18.15 mol/kg (102.2 kPa) for SO2, surpassing most previously reported deep eutectic solvents. We found that the solubility of CO2 and N2 is much lower than that of SO2. The absorption capacity of DESs for SO2 is about 452 times that of CO2 and 1530 times that of N2.Therefore, this absorbent has extensive application prospects in the field of SO2 gas capture.

Enhanced SO2 resistance of NiFe/CeO2 catalyst by adding WS2 for CO-assisted selective catalytic reduction reaction

Selective catalytic reduction (SCR) is an effective NOx reduction method. Recently, research has been conducted on simultaneously removing NOx and CO using passive SCR technology that consumes CO gas that is normally generated in industrial combustion processes (designated as CO-SCR). SO2 gas in industrial flue gas can compete with NOx and CO, leading to catalyst deactivation and a shortened lifespan. Catalysts with resistance to the sulfur present in industrial processes are crucial for CO-SCR. Therefore, this study aimed to develop a catalyst resistant to the SO2 present in exhaust gas; specifically, WS2 which has excellent chemical stability, was added to a transition metal-based catalyst NiFe/CeO2 and the CO-SCR activity of the unmodified and WS2-incorporated catalysts (NiFe/CeO2 and NiFe/WS2-CeO2, respectively) were examined. NiFe/WS2-CeO2 (1 wt% WS2 content) exhibited a high NOx conversion rate of more than 80% in a sulfur atmosphere. The addition of WS2 to NiFe/CeO2 improved its CO adsorption capacity and catalytic reduction properties by 1.63 and 1.28 times, respectively, thereby promoting the catalytic performance. Fourier-transform infrared analysis revealed that NiFe/WS2-CeO2 was more resistant to sulfur poisoning than NiFe/CeO2. These findings can be leveraged to develop sulfur-resistant catalysts for eliminating NOx and CO from industrial flue gas.

Catalytic performance of mesoporous Mn-Co-Ti for o-xylene degradation: Mechanistic study under practical conditions

Catalytic combustion of volatile organic compounds from industrial flue gases at low temperatures remains a challenge. Herein, we developed a mesoporous Mn-Co-Ti catalyst for o-xylene degradation by a solvothermal strategy. The optimized Mn0.1Co-TiO2 catalyst possessed a nanoflower structures with a surface area of 83.1 m2/g and mesoporous volume of 0.1191 cm3/g. Mn-doping modulated the electronic interactions between Mn and Co, which promoted the formation of MnCo2O4.5 phase and increased Co3+ and Mn4+ content of the catalyst. The Mn0.1Co-TiO2 catalyst had an improved reduction capacity from 170 to 644 °C, with a maximum H2 consumption of 4.56 mmol/g. The Mn0.1Co-TiO2 catalyst achieved 50% o-xylene conversion at 193 °C at a GHSV of 60,000 h−1, whereas the equivalent catalyst prepared by impregnation required 315 °C for 50% o-xylene conversion. In the presence of NO, the generated NO2 accelerated o-xylene conversion because it promoted the generation of more Mn4+-O-Co3+ active sites and accumulation of intermediates such as maleate and acetate species. NH3 and H2O had slight inhibitory effects on o-xylene conversion, which were attenuated by abundant mesopores and redox ability of catalyst. SO2 gas caused inactive sulfates and chemical deactivation on catalyst surface, thus leading to excessive formation of benzoquinone products.

All-optical photoacoustic detection of SF6 decomposition component SO2 based on fiber-coupled UV-LED

An all-optical photoacoustic sensor for measuring the concentration of SF6 decomposition derivative SO2 was designed, whose detection limit was in the order of ppb-level. An UV-fiber and a single-mode fiber were utilized to transmit excitation light and probe light, respectively. The technical scheme of all-optical gas sensing has realized the competitive advantages of long-distance detection and anti-electromagnetic interference. As an UV-LED was the excitation light, the challenge of designing all-optical SO2 sensor was to effectively couple UV-LED with large divergence angle into an UV- fiber. Theoretical calculation and experiment have proved that the lens assembly as an effective strategy to realize the efficient coupling and beam collimation, which can achieve high excitation power and low solid photoacoustic background interference. The lens assembly with high focusing property was the key to improve the signal-to-noise ratio (SNR) by 5.2 times. To detect photoacoustic pressure with high sensitivity, a fiber optic cantilever acoustic sensor based on F-P interference was designed. Based on the demodulation algorithm of white light interference, dynamic cavity length of F-P was demodulated with high-resolution. Allan-Werle analysis result indicate that the detection limit of SO2 gas was 48 ppb with an averaging time of 100 s

Potential environmental and human health menace of spent graphite in lithium-ion batteries

The growing demand for lithium-ion batteries for portable electronics and electric vehicles results in a booming lithium battery market, leading to a concomitant increase in spent graphite. This research investigated the potential impacts of spent graphite on environmental and human health using standardized toxicity extraction and Life Cycle Impact Assessment models. The spent graphite samples were classified as hazardous waste due to the average nickel content of 337.14 mg/L according to Chinese regulations. Besides, cadmium and fluorine were the other elements that exceeded the regulations threshold. Easily ignored aluminum and heavy metal cobalt are other harmful elements according to the results of Life Cycle Impact Assessments. All the metallic harmful elements mainly exist in a transferable state. Thermogravimetry infrared spectrometry coupled with mass spectrometry was employed to recognize the emitted gases and explore gas emission behavior. Inorganic gases of CO, H2S, SO2, SO3, oxynitride, HCl, and fluoride-containing gases were detected. Sulfur-containing gases released from spent graphite were contributed by the residual sulfuric acid after leaching. The correlation between the evolution of emitted gases and the heating schedule was established simultaneously. The research comprehensively illustrates the pollution of spent graphite and provides assistance for the design of green recycling schemes for spent graphite.

Influence of gas impurities (SO2 and NOX) in flue gas on the carbonation and hydration of cement compacts

Flue gas with a typical CO2 concentration of 10–20 % is found to be potentially utilized for accelerating the curing process of cement compacts. However, the competitive effect of acid gas impurities (i.e. SO2 and NOX) contained in flue gas on carbonation behaviors remains unclear. In this work, multi-component gases (500 ppm SO2, 500 ppm NO2, 10 % O2, and 74.9 % N2) with a CO2 concentration of 15 % are simulated to study the carbonation reactivity of cement compacts after 2 h of curing. The influence of subsequent water curing on strength and microstructure development over time is also further investigated. The experimental results show that after exposure to CO2, the highly soluble acidic SO2 and NOX gases can considerably reduce the pH of cement compacts, and thus mitigate the carbonation efficiency. The dissolved SO2 can potentially compete with CO2 for calcium-bearing ion combination, leading to a reduction of ∼30 % in compressive strength. However, this inferior performance can be compensated by the progressive hydration reaction in subsequent water curing. The findings from this study highlight the essential consideration of gas impurities in flue gas CO2 curing, in particular their impact at an early age. Additionally, there is a need to explore the durability characteristics and interactions of gas impurities during high-temperature curing.

Ammonia release characteristics during desulfurization wastewater evaporation: Mechanisms and implications

This study investigated the mechanisms of ammonia release during desulfurization wastewater evaporation and its potential environmental impacts. A single droplet evaporation device (SDD) assessed the wastewater evaporation and ammonia release characteristics. Approximately 8.5 % of ammonia was released during the free water evaporation period (0–35 s). As the droplet underwent shell inflation-deflation and core-shell drying, the remaining ammonia was mainly released due to increased vapor pressure and poor thermal stability of ammonium salts. The wastewater properties, especially pH value, greatly influenced the release of ammonia. Alkaline wastewater exhibited a significantly higher ammonia release rate. Ammonia migration and transformation were studied in a 600 MW power plant. Approximately 9.2–11.7 % of ammonia was released, while the rest was retained in solid form within the evaporation product. Characterization techniques and DFT simulations showed that the released NH3 probably combines with fly ash due to the water vapor, HCl, SO3, and other acidic gases in the flue gas. Risk analysis suggested that ammonia release during evaporation would not significantly increase ammonia concentration in flue gas or hinder fly ash comprehensive utilization. However, when handling desulfurization wastewater with high-concentration ammonia, it was essential to consider the potential corrosion of downstream equipment caused by released ammonia.

Cu- and Al-Decorated Monolayer TiSe2 for Enhanced Gas Detection Sensitivity: A DFT Study.

The rapid industrial development has contributed to worsening global pollution, necessitating the urgent development of highly sensitive, cost-effective, and portable gas sensors. In this work, the adsorption of CO, CO2, H2S, NH3, NO, NO2, O2, and SO2 gas molecules on pristine and Cu- and Al-decorated monolayer TiSe2 has been investigated based on first-principles calculations. First, the results of the phonon spectrum and ab initio molecular dynamics simulations demonstrated that TiSe2 is dynamically stable. In addition, compared to pristine TiSe2 (-0.029 to -0.154 eV), the adsorption energy of gas molecules (excluding CO2) significantly decreased after decorated with Cu or Al (-0.212 to -0.977 eV in Cu-decorated TiSe2, -0.438 to -2.896 eV in Al-decorated TiSe2). Among them, NH3 and NO2 have the lowest adsorption energies in Cu and Al-decorated TiSe2, respectively. Further research has shown that the decrease in adsorption energy of gas molecules is mainly due to orbital hybridization and charge transfer between decorated Cu and Al atoms and gas molecules. These findings suggest that TiSe2 decorated with Cu and Al can effectively improve its sensitivity to NH3 and NO2, respectively, making it promising in gas sensing applications.

Study on atomization of grounding electrodes under the influence of magnetic field for dedusting and desulfurization of negative corona discharge

Corona discharge low-temperature plasma technology has good performance in treating dust and removing gaseous pollutants. In this paper, the dust and SO2 in the flue gas are removed by using the ground electrode atomization negative corona discharge device under the action of a magnetic field, and the discharge characteristics of the device, the removal efficiency of dust and sulfur dioxide, and its influencing factors are studied. The results show that the discharge characteristics and dust removal and desulfurization efficiency of the ground electrode atomization negative corona discharge under the action of a magnetic field are superior to the traditional l corona discharge and are almost affected by the extension of the operating time. Finally, the ground electrode atomization negative corona discharge under the action of a magnetic field is analyzed. The dust removal and desulfurization mechanism of corona discharge provide a reference for the development of dust removal and integrated desulfurization equipment.

Room temperature detection of sulfur dioxide using functionalized carbon nanotubes

The construction of a simple sensor structure sensitive to sulfur dioxide (SO2) based on multi-walled carbon nanotubes (MWCNTs) functionalized by nitric acid is described in this study. The functionalized MWCNTs were comparatively analyzed by X-ray diffraction, Raman, and FTIR spectroscopy methods, and their morphology was observed by scanning electron microscope (SEM). The sensitivity to 5 ppm SO2 gas is based on the change of resistance of functionalized MWCNTs. Tests on the fabricated sensor were performed at room temperature and defined that functionalized MWCNTs are sensitive to SO2 gas compared with the pristine MWCNTs.

A Novel Polyamino Acid Sulfur Dioxide Prodrug Synergistically Elevates ROS with β-Lapachone in Cancer Treatment

Due to the distorted redox balance, cancer cells are considered more vulnerable to excessive reactive oxygen species (ROS). In a variety of oxidative stress-related therapies, gas therapy has emerged as a new therapeutic strategy owing to its efficacy and biosafety. Herein, a newly-discovered gasotransmitter sulfur dioxide (SO2) and a tumor specific ROS generation agent β-lapachone (Lapa) were firstly combined for anticancer therapy. Firstly, amphiphilic glutathione (GSH) responsive polypeptide SO2 prodrug PEG-b-poly(Lys-DNs) was synthesized by ring opening polymerization of SO2-containing N-carboxyanhydride. Then, Lapa was encapsulated into the polymeric micelles with loading content of 8.6 % and loading efficiency of 51.6 %. The obtained drug-loaded nanoparticles (NPs(Lapa)) exhibited a fast release of Lapa and SO2 in the stimuli of 10 mM GSH in PBS. Subsequently, in vitro experiment showed that NPs(Lapa) exhibited obvious cytotoxicity towards 4 T1 cancer cells at a concentration of 2.0 μg/mL, which may be attributed to the depletion of intracellular GSH and upregulation of ROS level both by SO2 release and by the ROS generation from lapachone transformation. In vivo fluorescence imaging showed that the NPs were gradually enriched in tumor tissues in 24 h, probably due to the enhanced permeability and retention effect of NPs. Finally, NPs(Lapa) showed the best anticancer effect in 4 T1 tumor bearing mice with a tumor inhibiting rate (IRT) of 61 %, whereas IRT for free Lapa group was only 23.6 %. This work may be a new attempt to combine SO2 gas therapy with ROS inducer for anticancer therapy through oxidative stress.

Molecular modeling of Si60 fullerene and Nb-doped Si60 fullerene nanomaterials for SO2, NO2 and CO2 gas sensing

CO2, NO2 and SO2 are by-products from the petrochemical industries that have been associated with both global warming and several respiratory dysfunctions. Hence, several efforts are being put forth to detect their excesses at minimal concentrations. In this regard, this study presents a theoretical analysis based on quantum and molecular mechanical calculations of the sensing efficacy of silicon nanostructures towards the effective detection of these gases at low concentrations. To enhance the attributes of the nanomaterial, transition metal (Nb) was endohedrally doped on the silicon Si60 nanomaterial to enhance the surface conductivity and sensitivity. The results indicate that the metal-doped nanostructures have improved sensitivity towards the studied gases. The adsorption of NO2, SO2 and CO2 followed a declining trend; NO2@NbdopSi59 > SO2@NbdopSi59 > CO2@NbdopSi59 > NO2@Si60 > SO2@Si60 > CO2@Si60 respectively. The computed adsorption enthalpies were found to be −25.36, −136.26 and −183.67 kcal/mol respectively for CO2@NbdopSi59, NO2@NbdopSi59 and SO2@NbdopSi59 systems. Comparatively, SO2 and NO2 preferred to be adsorbed on Si60 than CO2. The results of other electronic properties such as energy gap and conductivity were also found to be in tandem with the adsorption and stability studies. The sensing mechanism and computed desorption times were also found to be within 1.02 s to 2.72 s, clearly indicating a quick desorption from the metal-doped surface. Contrary, desorption from the pristine nanocluster was found to be slower due to strong chemisorption bonds between the gases and surface. While the electronic properties affirmed the conducting and stable nature of the surfaces, molecular dynamics simulation was further employed for stability evaluation. These results also unveiled the stable nature of the nanocluster and confirmed that the studied metal-doped nanoclusters possess the ideal properties to be employed as sensors for SO2 NO2 and CO2 gases.