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"Ozonization"
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Ozonation of Cowpea Grains: Alternative for the Control of ICallosobruchus maculatus/I and Maintenance of Grain Quality
Nowadays, the modified atmosphere with ozone is one of the main alternatives for controlling insect pests in stored grains, as it allows grain quality to be maintained while causing no environmental damage. In light of this, the purpose of this study was to assess the toxicity of ozone to C. maculatus in cowpea grains as well as how it affects the physiological and physical properties of the grains. The toxicity was determined by estimating lethal doses (mg/g) at the top and bottom of the fumigation chamber for 50% and 95% of adult insects (LD[sub.50] and LD[sub.95]). Cowpea grain samples were removed after being exposed to ozone, and the effect of ozonation on the physical and physiological quality of the grains was assessed. The electrical conductivity, water content, and germination were all examined in this manner. The lethal doses LD[sub.50] were 65.97 and 45.52 mg/g when the insects were distributed at the top and bottom of the fumigation chamber, respectively. As a result, ozone toxicity was higher at the bottom than at the top. The increase in ozone doses resulted in a decrease in water content. The germination rate exceeded 90% in both locations where ozone was applied. The electrical conductivity remained constant, ranging between 152.01 and 239.59 S cm[sup.−1] g [sup.−1]. The findings indicate that ozone is toxic to C. maculatus but has no effect on grain quality. Ozone may therefore be used to manage C. maculatus in cowpea that has been stored.
Journal Article
Zn in Aqueous Solution
In this paper, Zn(0)-catalyzed ozonation degradation of acid orange 7 (AO7) and its impact factors including solution pH, Zn loading, and AO7 initial concentration were investigated through a series of bath experiments. The results demonstrated that Zn could markedly accelerate the degradation of AO7 by ozone (O.sub.3) and the degradation efficiency of AO7 increased by 77 and 71 % within 30 min as compared with those in the systems of O.sub.3 alone and Zn/air, respectively. The reuse of Zn resulted in a slight decline in AO7 degradation, suggesting that a coating of ZnO on the surface of Zn particles weakened Zn catalytic activity. The optimal removal of AO7 was achieved in a wide pH range of 4 to 10, and a lower or higher pH was not conducive to the degradation of AO7. In addition, the degradation efficiency of AO7 increased with Zn loading but decreased with AO7 initial concentration. The introduction of free radical scavengers into the system of AO7/Zn/O.sub.3 confirmed that O.sub.2.sup.*-, rather than *OH, was the main free radicals responsible for the rapid removal of AO7. The degradation of AO7 by O.sub.3 assisted with Zn could be well expressed with pseudo-first-order kinetic model.
Journal Article
Photocatalytic Degradation of Crystal Violet Catalysts
Crystal violet (CV) is an organic chloride salt and a triphenylmethane dye commonly used in the textile processing industry, also being used as a disinfectant and a biomedical stain. Although CV is widely used, it is carcinogenic to humans and is retained by industrial-produced effluent for an extended period. The different types of metal oxide (MO[sub.x]) have impressive photocatalytic properties, allowing them to be utilized for pollutant degradation. The role of the photocatalyst is to facilitate oxidation and reduction processes by trapping light energy. In this study, we investigated different types of metal oxides, such as titanium dioxide (TiO[sub.2]), zinc oxide (ZnO), zirconium dioxide (ZrO[sub.2]), iron (III) oxide (Fe[sub.2]O[sub.3]), copper (II) oxide (CuO), copper (I) oxide (Cu[sub.2]O), and niobium pentoxide (Nb[sub.2]O[sub.5]) for the CV decomposition reaction at ambient conditions. For characterization, BET and Raman spectroscopy were applied, providing findings showing that the surface area of the anatase TiO[sub.2] and ZnO were 5 m[sup.2]/g and 12.1 m[sup.2]/g, respectively. The activity tests over TiO[sub.2] and ZnO catalysts revealed that up to ~98% of the dye could be decomposed under UV irradiation in <2 h. The decomposition of CV is directly influenced by various factors, such as the types of MO[sub.x], the band gap–water splitting relationship, and the recombination rate of electron holes.
Journal Article
SBA-15 Templated Mesoporous MnO.sub.x for Catalytic Ozonation of Toluene
[gamma]-MnO.sub.2, [beta]-MnO.sub.2 and Mn.sub.2O.sub.3 with mesoporous structure were prepared as catalysts by using SBA-15 as hard template at different calcination temperatures. The catalysts were characterized by XRD, HRTEM, N.sub.2 adsorption-desorption, XPS, FTIR. The activity of three catalysts for catalytic ozonation of toluene followed the order of [beta]-MnO.sub.2 > [gamma]-MnO.sub.2 > Mn.sub.2O.sub.3. The results showed that the mesoporous [beta]-MnO.sub.2 exhibited the best catalytic performance because it has the highest average oxidation state of Mn and the most abundant surface adsorbed oxygen. Specifically, the toluene conversion could reach to 100% and the CO.sub.2 selectivity could reach up to 83% at 70-90 mg/m.sup.3 of toluene concentration over the catalyst. It can be inferred that reaction mechanism consists of two cycles including ozone decomposition and toluene adsorption on active sites of [beta]-MnO.sub.2, which obeys L-H mechanism. The active oxygen (O*) produced in the first cycle can oxidize the toluene molecule adsorbed in the second cycle. Simultaneously, the mesoporous [beta]-MnO.sub.2 had good stability, which reflected that it showed good performance on the catalytic ozonation of toluene during the 47-day test. In summary, this work makes it possible to remove VOCs for reality.
Journal Article
Effect of Gaseous Ozone and Storage Time on Polyphenolic Profile and Sugar Content in Fruits of Selected IVaccinium corymbosum/I L. Genotypes
One of the best sources of antioxidant and health-promoting bioactive substances is the fruit of V. corymbosum. A potent oxidizing agent, ozone (O[sub.3]), can effectively eliminate bacteria. The application of ozone gas to V. corymbosum fruit during storage had a favorable impact on the fruit’s phenolic component and sugar content in the current investigation. After 7 days of storage, phenolic content in all highbush blueberry cultivars and clones tested increased on average by 28.60%, including anthocyanins by 34%. After 14 days of storage, an average increase of 16.50% in phenolic compounds was observed, including a 20.53% increase in anthocyanins. Among all the tested varieties, clone BOR-21 treated with a dose of 0.01 mL·L[sup.−1] ozone for 30 min after 14 days had the highest TPC—143.73 mg·100 g[sup.−1] f.w. The sugar content of berries treated with a dose of 0.01 mL·L[sup.−1] ozone for 30 min, on day 7 and day 14 of storage increased by 9.2% and 6.3%, respectively. On day 7, the highest amount of total sugar (22.74 g·100 g[sup.−1]) was observed in Duke cultivar after being exposed to 0.01 mL·L[sup.−1] ozone for 15 min. The ozonation treatments enhanced the fruit’s saturation with nutrients, which raises the fruit’s value as food.
Journal Article
Photo-Ozonation of Multiclass Pharmaceuticals in Model Water: Kinetic Comparison of UV-C, Osub.3 and UV/Osub.3 Under Selected pH Conditions
The removal of four representative pharmaceuticals—sulfamethoxazole (SMX), carbamazepine (CBZ), diclofenac (DCF) and ibuprofen (IBU)—was investigated in a model aqueous solution using UV-C photolysis, ozonation and a hybrid UV/O[sub.3] process. UV-C and UV/O[sub.3] experiments were conducted at initial pH 3, 6 and 8, whereas single ozonation was applied at pH 6 as a near-neutral reference. The processes were compared in terms of removal efficiency, apparent pseudo-first-order kinetics and kinetic enhancement. UV-C photolysis showed pronounced compound selectivity, with efficient removal of DCF and SMX but limited transformation of CBZ and IBU. Ozonation markedly improved the removal of ozone-reactive compounds, particularly CBZ and DCF. Under near-neutral conditions, UV/O[sub.3] provided high removal efficiencies for all target compounds after 30 min. Kinetic analysis showed that UV/O[sub.3] enhancement was compound-specific: apparent synergy was observed for CBZ and IBU, with SF values of 1.43 and 1.24, respectively, whereas SMX showed a subadditive response. DCF was rapidly removed under UV/O[sub.3] but was excluded from the main SF comparison because its concentration approached the lowest calibrated concentration level. These results indicate that UV/O[sub.3] is especially useful for poorly UV-susceptible pharmaceuticals.
Journal Article
Mn
In this work, Ce-doped Mn/[gamma]-Al.sub.2O.sub.3 catalysts (Mn (Ce.sub.x)/[gamma]-Al.sub.2O.sub.3) with different Ce/Mn molar ratios were prepared for catalytic ozonation of pollutants in petroleum refinery wastewater (PRW). Results showed that compared to Mn/[gamma]-Al.sub.2O.sub.3 catalyst, the performances of Mn (Ce.sub.x)/[gamma]-Al.sub.2O.sub.3 catalysts were notably improved, especially Mn (Ce.sub.0.20)/[gamma]-Al.sub.2O.sub.3 catalyst demonstrated the highest activity and improved stability for the degradation of PRW (> 97% of chemical oxygen demand (COD) in PRW was removed and the molecules of petroleum-derived pollutants were almost completely degraded in 1.5 h treatment, and the catalyst showed no obvious decrease in activity after 5 cycles). The results of catalyst characterization confirmed that doping Ce changed the growth characteristics of the catalysts, increased the content of active phase [alpha]-MnO.sub.2 in the catalysts and led to the growth of [alpha]-MnO.sub.2 along crystal planes (310) preferentially, prevented catalyst particles from growing, and also enhanced the dispersion of those catalyst particles. Moreover, electron paramagnetic resonance (EPR) experiments revealed that Mn (Ce.sub.0.20)/[gamma]-Al.sub.2O.sub.3 catalyst promoted the production of more hydroxyl radicals (*OH) and superoxide anion (*O.sub.2.sup.-). The influences of catalyst dose, O.sub.3 concentration and pH on the degradation were also investigated. This work provided a theoretical basis and an experimental reference for the preparation of highly active Mn-based catalysts for deep ozonation of PRW by HCOP.
Journal Article
Mn /gamma-Al.sub.2O.sub.3 Catalysts with Notably Improved Performances for Catalytic Ozonation of Pollutants in Petroleum Refinery Wastewater
In this work, Ce-doped Mn/[gamma]-Al.sub.2O.sub.3 catalysts (Mn (Ce.sub.x)/[gamma]-Al.sub.2O.sub.3) with different Ce/Mn molar ratios were prepared for catalytic ozonation of pollutants in petroleum refinery wastewater (PRW). Results showed that compared to Mn/[gamma]-Al.sub.2O.sub.3 catalyst, the performances of Mn (Ce.sub.x)/[gamma]-Al.sub.2O.sub.3 catalysts were notably improved, especially Mn (Ce.sub.0.20)/[gamma]-Al.sub.2O.sub.3 catalyst demonstrated the highest activity and improved stability for the degradation of PRW (> 97% of chemical oxygen demand (COD) in PRW was removed and the molecules of petroleum-derived pollutants were almost completely degraded in 1.5 h treatment, and the catalyst showed no obvious decrease in activity after 5 cycles). The results of catalyst characterization confirmed that doping Ce changed the growth characteristics of the catalysts, increased the content of active phase [alpha]-MnO.sub.2 in the catalysts and led to the growth of [alpha]-MnO.sub.2 along crystal planes (310) preferentially, prevented catalyst particles from growing, and also enhanced the dispersion of those catalyst particles. Moreover, electron paramagnetic resonance (EPR) experiments revealed that Mn (Ce.sub.0.20)/[gamma]-Al.sub.2O.sub.3 catalyst promoted the production of more hydroxyl radicals (*OH) and superoxide anion (*O.sub.2.sup.-). The influences of catalyst dose, O.sub.3 concentration and pH on the degradation were also investigated. This work provided a theoretical basis and an experimental reference for the preparation of highly active Mn-based catalysts for deep ozonation of PRW by HCOP. Graphical
Journal Article