2022-09

4th ICOASE 2022

This work is aimed to synthesize nanostructured boron nitride quantum dots (BNQDs) that act as photo-catalyst under UV light irradiation. The photocatalyst is applied to remove organic wastes via photodegradation. BNQDs were characterized using XRD, SEM-EDX, FTIR ,UV-Vis and fluorescence spectrophotometry. BNQDs have the energy gap close to 3.79eV. The results show that the obtained band gap value and band edges position are higher than the value of free energy for photo degradation at conduction and valance bands, this proves that the BNQDs is thermodynamically suitable to drive super oxide and hydroxyl radical production. BNQDs is employed to eliminate different pollutants including, dyes and pharmaceuticals. Kinetic was studied as well, the result of kinetic shows that the degradation of Amlodipine and tetracycline at peak 367nm and 375nm are of the second order with a R2 value of 0.98, 0.97 respectively, and first order kinetic in case of Congo red and toluidine blue at peak 497nm, 615nm respectively with a R2 value of 0.96 for both molecules. Reactive oxygen species (ROS) trapping experiments was performed to determine the active species in photo-catalysis mechanism. Based on experimental data we can conclude that active species h+, e-, O2-• and •OH have a significant effect on degradation yield. Regarding computational simulation, the crystal and electronic structures of the BNQDs have been calculated. The lattice parameters were measured with the Perdew-Burke-Ernzerhof (PBE) functional, and the energy gap (Eg) were calculated applying hybrid functionals including (Becke-3 Parameter-Lee-Yang-Parr) B3LYP and (Heyd–Scuseria–Ernzerhof) exchange–correlation functional HSE06. B3LYP provided better results and closer to the experimental data, given that 2eV as an indirect band gap and thus, B3LYP exchange function was utilized to analyze the band structures and density of states.

2021-08

2nd international conference on Nanotechnology& Nanoscience

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 calculate 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, with 16% and 8% of TB eliminated after one hour degradation with CP-BN and P-BN, respectively. 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 band and possible photocatalytic mechanism. Data from trapping experiments shows that both the hydroxyl radical and super oxide are responsible for degradation, but electron and hole at valance and conduction band was 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 bandgap (Eg) were calculated with the (PBE) as local functional of the generalized gradient approximations (GAA) in addition, hybrid functional 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.

2019-10

2018 International Conference on Advanced Science and Engineering (ICOASE)

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.

2018-12

Materials Science and Engineering

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

2018 International Conference on Advanced Science and Engineering (ICOASE)

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.