2024-03

Catalysis Letters

Water pollution has become a major concern due to the rapid development of industrialization and rise in chemical use, which poses a great risk to humans and environment. Herein, a novel nanocomposite of metal-free boron nitride quantum dots (BNQDs) supported on graphitic carbon nitride (g-C3N4) photocatalyst (BNQDs@g-C3N4) was successfully synthesized using a facile and green approach. The prepared nanocomposite exhibited exceptional photocatalytic activity in the degradation of aqueous waste pollutants, including organic dyes and pharmaceuticals under visible light irradiation, its worth mentioning, the rate constant of tetracycline removal was 0.064 mol−.L.min−1. The experimental results indicated that the significantly boosted photocatalytic activity of the BNQDs@g-C3N4 composite proved the energy gap modulation by the construction of heterojunction between the BNQDs and g-C3N4 in s-scheme photocatalyst. Theoretical calculations were done to calculate the crystal, electronic structures, and properties of BNQDs@g-C3N4. Theoretical results showed that loading of BNQDs on g-C3N4 provides an extended band edges that are more applicable in visible light-based photocatalysis process. Additionally, it offers additional bands that facilitate the passage of electrons between the valance and conduction bands. Finally, a possible s-scheme mechanism of the charge separation improvement was proposed by analyzing the experimental results and theoretical calculations.

2024-03

Baghdad Science Journal (Baghdad Sci. J.) (Issue : 21) (Volume : 10)

This article focuses on Pelargonium graveolens, a fragrant medicinal plant from the Geraniaceae family. The study examines the plant's phytochemical composition, antioxidant activity, and mineral absorptivity, with the plant being grown indoors. The study also examined the plant's ash content and antioxidant activity using a variety of techniques, and the results demonstrated that P. graveolens is effective at absorbing lead. The plant contains eight different minerals, including Cu, Mn, Co, Ni, Pb, Mg, Fe, and Ca. Statistical analysis was used to determine the level of antioxidants present, using DPPH, reducing power, and total antioxidant capacity methods. The extraction process used a mixture of water, 70% ethanol and absolute ethanol solvents in varying ratios. To conclude, the study examines Pelargonium graveolens, a fragrant medicinal plant, for its antioxidant activity and mineral absorptivity.

2024-02

International Journal of Environmental Analytical Chemistry

In this study, a novel photocatalyst, Cu&Ni@FAU Faujasite type zeolite, was successfully prepared and characterised using various techniques, including XRD, SEM-EDX, FTIR, N2 adsorption-desorption isotherm, and UV-Vis spectrophotometry. Cu&Ni@FAU enhances the photocatalytic efficiency through several mechanisms, including the photo-Fenton-like process of H2O2, the electronic capture of KBrO3, and the reducing effect of NaBH4. Response surface methodology has been applied to study the impact of H2O2, KBrO3, and NaBH4 and their interactions on the photocatalysis of tetracycline. Furthermore, the efficiency of the photocatalysts and their kinetics were assessed for four different organic molecules, and it was found that the rate constant of tetracycline degradation was 0.054 M−1min−1. It is worth mentioning, Cu&Ni@FAU is temperature stable and shows maximum degradation at 70°C. Radical trapping experiments revealed that various reactive species played a role in the photodegradation process. The results show that hydroxyl radicals (OH•) and superoxide radicals (O2-•) are the dominant species in the photocatalysis mechanism. Additionally, electrons (e-) and holes (h+) had a moderate impact as active species, since the band edges of Cu&Ni@FAU is located between 2.86 eV at valance band (VB) and −0.38 eV at conduction band (CB).. To gain deeper insights into these processes, the study used density functional theory (DFT) simulation, which allowed for the calculation of electronic and vacuum band edges. This computational approach likely provided valuable information about the fundamental processes occurring during the photocatalysis process.

2023-02

RSC advances (Issue : 13)

To achieve the efficient removal of pharmaceutical wastes, novel photo-Fenton catalysts, iron-decorated boron nitride quantum dots (Fe@BNQDs) were prepared. Fe@BNQDs were characterized using XRD, SEM-EDX, FTIR, and UV-Vis spectrophotometry. The decoration of Fe on the surface of BNQDs enhanced the catalytic efficiency due to the photo-Fenton process. Photo-Fenton catalytic degradation of folic acid was investigated under UV and visible light. The influence of H2O2, catalyst dose, and temperature on the degradation yield of folic acid was investigated using Response Surface Methodology. Moreover, the efficiency of the photocatalysts and kinetics was investigated. Radical trapping experiments revealed that holes were the main dominant species in the photo-Fenton degradation mechanism and BNQDs played active roles because of their hole extraction ability. Additionally, active species such as e− and O2−˙ have a medium effect. The computational simulation was utilized to provide insights into this fundamental process, and for this purpose, electronic and optical properties were calculated.

2022-10

ACS OMEGA (Issue : 7) (Volume : 42)

In this paper, silver-loaded phosphorous and carbon co-doped boron nitride quantum dot (Ag@CP-BNQD) nanocomposites were synthesized using a co-precipitation method followed by a hydrothermal approach. The nanocomposites of Ag@CP-BNQDs were characterized by scanning electron microscopy, energydispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, of Ag@CP-BNQDs were characterized by scanning electron microscopy, energydispersive spectroscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and ultraviolet−visible spectrophotometry. The as-prepared Ag@CP-BNQDs were used for photocatalytic degradation of 10 common organic pollutants, including dyes, pharmaceuticals, and pesticides in aqueous solution under visible light irradiation. The high-performance photocatalysis of Ag@CP-BNQDs proved that Ag@CP-BNQDs is plasmonic and the n−p junction photocatalyst. Theoretical calculations were done to measure the crystals and electronic structures of Ag@CPBNQDs. Theoretical results showed that loading of Ag behaves as plasmonic sensitizers and co-catalysts and provides extra bands, which make electron movement easier between valance and conduction bands. The mechanism of the charge separation enhancement was postulated. Our findings might deepen our understanding of how sensitizer surface modification works in photodegradation applications.

2021-12

IRANIAN JOURNAL OF CATALYSIS (Issue : 4) (Volume : 11)

The goal of this research is to create nanostructured metal free phosphorous doped Boron nitride (P-BN) and phosphorous-carbon co-doped Boron nitride (CP-BN) that serve as photocatalysts when exposed to UV light. P-NPs were well diffused in aqueous solution. The nanostructured materials were characterized using XRD, SEM-EDX, and UV-Vis spectrophotometry. Based on the characterization results, phosphorous atoms were doped in the crystal structure of BN. The experimental data and theoretical calculations were used to measure the band gap energy, which was determined to be around 4.2 eV in the experimental case; for this purpose, both Tauc and Kubelka-Munk equations were utilized. Thus, photocatalysis degradation is limited to UV region. To examine the degradation effectiveness of photo-catalysts, toluidine blue (TB) was utilized; it was found that the basic medium was the best for degradation; 16% and 8% of TB were eliminated with CP-BN and P-BN, respectively after one hour degradation. Scavengers such as IPA, Na2C2O4, KBrO3, and ascorbic acid were added to trapping experiments to demonstrate the correct potential energy gap in valance and conduction bands and possible photocatalytic mechanism. Data from trapping experiments show that both the hydroxyl radical and super oxide are responsible for degradation, but electron and hole at valance and conduction bands were of low efficiency because of quick recombination. As regards computational study, the crystal and electronic structures of the P-BN and CP-BN have been studied. The lattice parameters were calculated with the Perdew-Burke-Ernzerhof (PBE), and the bandgaps (Eg) were calculated with the (PBE) as (non-local) instead of local (non-local functional generalized gradient approximations) (GAA). In addition, hybrid functional was also applied including (Becke-3 Parameter-Lee-Yang-Parr) B3LYP and (Heyd–Scuseria–Ernzerhof) exchange–correlation functional HSE06. Hybrid functional B3LYP provided better results and closer to the experimental data of the P-BN and CP-BN compound.

2021-06

Engineering, Technology & Applied Science Research (Issue : 3) (Volume : 11)

The current research aims to improve the cetane number of diesel extracted from the crude oil of Tawke region-Iraq Kurdistan. A specific mixture of chemical compounds was prepared which included m-nitrophenol, 4-nitro toluene, and nitrobenzene. The components' effects were investigated with regard to the cetane number, flash point, viscosity, and refractive index of diesel. The quantity of each compound mixed with diesel was prepared based on the statistical analysis of the experiment device (Box–Behnken Designs-BBDs). The tested mixture showed a good agreement and improvement of cetane and flash point and a very low effect on viscosity and refractive index. According to the statistical analysis, the main influence on cetane number and the flashpoint was from m-nitrophenol. The investigation showed that the best results were acquired from the samples of 25PPM 4-nitro toluene and 50PPM m-nitrophenol with a cetane number of 65.3. The correlation and the interaction of the regression equation were linear with all cases. It is worth mentioning that all additives positively influenced the cetane number in the regression equation. The sulfur content was measured as well, and the obtained weight percentage of sulfur was 0.8404%.

2021-03

Science Journal of University of Zakho (Issue : 1) (Volume : 9)

The kinetic of photo catalytic degradation of Congo red dye using semiconductor in aqueous solution of ZnO has been studied. All photochemical experiments have been carried out in quartz photo cell 25ml capacity and the solvent used for all experiment was distilled water (D. W). The influence of temperature has been investigated as well. Spectrophotometric method was utilized for this work. Degradation kinetic has been done for absorption peak of Congo red at 497 nm and 344 nm. Different method was applied for this purpose, and the results show that the degradation of Congo red was first order at 497nm and zero order at 344 nm. The degradation of CR dye were increased by increasing temperature from 20 oC to 40 oC and then degreased at 50 oC and this is due to desorption that occur at the semiconductor surface while; in case of 10 oC the rate constant was higher than 20 oC. However, when changing the concentration the rate constant dose not changed regularly, this perhaps due to the fact that it does not follow the same order throughout the degradation process, and it does not obey Arrhenius law of activation energy.

2020-08

Asian Journal of Applied Chemistry Research (Issue : 1) (Volume : 6)

Experimental design DoE (box behnken design BBD) and statistical analysis approaches were employed to determine the effect of Congo red dye (CR) concentration, photo catalyst dose (Fe+ 2) and follow of oxygen gas as an oxidant on the degradation of CR The results show that the concentration oppositely affects the degradation yield whereas the remaining two factors show positive effect, throughout all experiments oxygen molecule shows crucial role in their positive effect with p-value about 0.01 which is very significant value. The accepted regression model was linear with significance p-value 0.032 that mean all factors show good agreement in linear relationship and the interactions was not important. Degradation kinetics was also applied to investigate the effect of increasing dye concentration on degradation rate constant with and without photo catalyst dose and oxidant (O 2). It appears that the degradation of peak at 498nm is second order The result was in good agreement with that of statistical analysis that are 0.0435, 0.0545 and 5.4 M-min-with photo catalysis 12, 8 and 4 PPM dye, 4O 2 mL/min, 20PPM Fe+ 2 respectively, in case without photocatalyst the results were 0.0025 and 0.0207 M-min-with 12 and 4 PPM in turn.

2020-03

New journal of chemistry (Issue : 13) (Volume : 20)

The dispersibility of carbon dots in organic and/or aqueous solvents plays a critical role in various application fields. Amphiphilic carbon dots could find broader applications due to their hydrophilic and lipophilic properties. Here, a method is described for the preparation of amphiphilic carbon dots (CDs) from white berries as a carbon source. The CDs can be well dispersed both in organic and aqueous solvents. Fluorescence is strongly red-shifted upon going from an organic solvent (in CCl4 the emission is blue with a maximum at 450 nm) to an aqueous solvent (orange fluorescence with a maximum near 600 nm). Fluorescence is independent of the excitation wavelength which is uncommon in the carbon quantum dot family. Nitrite is found to quench fluorescence in water solution, but not other common metal cations and anions. In chloroform, the fluorescence is quenched by tetracycline. The linear part of the calibration plot for nitrite covers the 5 to 90 nM concentration range, with a 1.5 nM detection limit. The linear range for tetracycline extends from 10 to 150 mM.

2019-09

IEEE

The photo catalytic degradation of Congo red by oxidant's and semiconductors in suspension aqueous solution of ZnO, H 2 O 2 has been studied. This work has been done by assist of RSM (surface response methodology) for design of experiments and statistical calculations. All photochemical experiments have been carried out in quartz photo cell and the solvent used for all experiment was distilled water (D. W). The influence of hydrogen peroxide H 2 O 2 , zinc oxide and dye concentration has been studied by statistical analysis. The instrument used for experiments in this work is spectrophotometer in order to find the calculated and then predicted percentage of degradation, ANOVA analysis and other statistical parameters also has been measured. The result shows that the P-values are higher than 0.05 confidence level in all experiments this means that the parameter of this work does not make a sense on percentage of degradation. This is may be due to that the hydrogen peroxide (H 2 O 2 ) may work as oxygen provider to accelerate the photo degradation process. Meanwhile, Excess amount of H 2 O 2 , Could act as hydroxyl radical capture in the mineralization system. On the other hand; the best result was 19% degradation in case of 10ppm Congo red concentration, 5% H 2 O 2 and 0.1g/L ZnO.

2019-06

Science Journal of University of Zakho (Issue : 2) (Volume : 7)

his work investigates the electro-catalytic degradation of alizarinblack dye in an electrochemical cell using Fe as anode and Al as cathode. The influence of initial dye concentration, effect of salt, pH, change of temperature and effect ofchange of applied voltage have been studied in addition, the influence of semiconductor dose has studied as well. In the current work roughly total removal of 70 mg/L of dye occurred in 16 minonly. The results showedthat effect of both electrolyte concentration and applied voltage was positive if combined together and the rate of degradation in neutralmedium was the best for degradation of Alizarin black dye.

2019-03

Science Journal of University of Zakho (Issue : 1) (Volume : 7)

the effect of polarity of solvent on the viscosity and viscosity index of lubricating engine oil has been studied using ethanol as an example of polar solvent and toluene as an example of non-polar solvent at different solvent ratios and ambient temperature and additionally other experiments have been done at five different temperatures including 100 oC. So that, the activation energy of viscous flow (Ea) was calculated, and for this purpose Arrhenius viscosity-temperature dependence has been applied and the results were 42.128, 29.256 and 35.417 KJ/mole for lubricating engine oil mixed with ethanol, toluene and no additives in turn. It additionally shows that adding polar solvent to lubrication engine oil viscosity increases this may be due to the fact of strong inter molecular forces that found in polar molecules such as hydrogen bonding in ethanol makes the solution forces stronger as a result higher viscosity. However, adding non-polar solvent decreases viscosity because of small size of toluene and both paraffinic lubricating oil and toluene have same London dispersion inter molecular forces. Last not least, the result shows that engine oil mixed with non-polar molecule gives more temperature stability than that of polar molecule giving viscosity index (VI) 366 and 580 respectively.

2018-12

IOP Conference Series: Materials Science and Engineering (Issue : 1) (Volume : 454)

The photo degradation of Trifluralin by ultra violet light region has been studied in liquid phase. In this research, different concentration with different temperature has been investigated. The results have shown that increasing temperature lead to increases rate constant, but when we change concentration the rate constant dose not changed regularly. That may be due to the fact that it is not pure secondary order photo-degradation reaction. All thermodynamic parameters have been measured using second order kinetic plot and Arrhenius plot.

2018-09

IEEE

The photo-catalytic degradation of Toluidine Blue dye (TB) in aqueous suspension solution has been studied utilizing fluorescence light and using Zinc oxide (ZnO) as a semiconductor at variety working factors. The studied parameters were concentration of dye, semiconductor dose and the influence of pH. The result shows that expanding of ZnO dose from 20 to 60 mg/L increases the removal rate of TB dye. On the other hand, the adding of concentration from 5 to 15 mg/L show negative effect on the rate of photo-degradation. It has been denoted that the percentage of dye degradation come to the peak value at high acidic medium. 11 % of TB dye was adsorbed, in dark condition, by ZnO. In addition, the kinetics of degradation has been examined and the degradation was found to take after pseudo-first order kinetic model.