Ozone Oxidation Treatment Research Articles

Preparation and performance of catalyst for organic peroxide wastewater treatment

To improve the oxidation pretreatment efficiency of wastewater from organic peroxides, a catalyst (CeO2-C catalyst) was developed using the calcination method with ceramic particles as the support. The crystalline structure and elemental composition of the CeO2-C catalyst were characterized by Scanning Electron Microscope (SEM), Energy Dispersive Spectrometer (EDS), and X-ray diffraction (XRD). This study explored the effects of CeO2 mass ratio, calcination temperature, and calcination time on the performance of the catalyst. The optimal preparation conditions were established through orthogonal experiments. Additionally, the synergistic effect of the catalyst on the ozone oxidation treatment of peroxide wastewater was investigated. The results indicated that the optimal preparation parameters were a CeO2 mass ratio of 4 %, a calcination temperature of 500 °C, and a duration of 5 h, respectively. After five cycles of reuse, the catalytic activity slightly decreased but remained relatively stable. With an ozone flow rate of 6 L/min, the CeO2-C/ozone catalytic oxidation process achieved a Chemical Oxygen Demand (COD) removal rate of 28.11 % in wastewater, and the B/C (the ratio of BOD concentration to COD concentration) of wastewater improved from 0.093 to 0.152. The calcination method proved effective for preparing the CeO2-C catalyst, which demonstrated significant catalytic performance and held promising application prospects in the oxidation pretreatment of organic peroxide wastewater.

Revealing the structural variation and degradation mechanism of cellulose during ozone oxidation treatment

Despite numerous studies on the use of ozone for the removal of non-cellulosic substances from lignocellulosic fibers, the mechanism underlying cellulose degradation and the oxidized group formation during ozone oxidation treatment remain unclear. This study focuses on the extraction of α-cellulose from flax fibers. The effect of ozone oxidation on the degree of polymerization (DP) and oxidized groups in α-cellulose under different operational conditions (ozone concentration, oxidation time, water pick-up value, initial pH value) were thoroughly investigated. Additionally, the quality of α-cellulose oxidized under different phases (gas and liquid) of ozone reaction was systematically compared. Results showed that the DP value of α-cellulose-O3-Gas-80% (130 mg·L−1·min−1, 15 min, WPV 80%, pH 2.0) was lower than that of α-cellulose-O3-Liquid (130 mg·L−1·min−1, 15 min, 1:30 g·mL−1, pH 2.0) and α-cellulose-O3-Gas-0% (130 mg·L−1·min−1, 15 min). However, the carboxyl and carbonyl contents showed the opposite trends. FTIR results showed a new peak (carboxyl peak) for α-cellulose and a reduction of hydrogen bonding interactions in molecules after ozone oxidation. In addition, the crystallinity and thermal stability of α-cellulose decreased after ozone oxidation, with α-cellulose-O3-Gas-80% exhibiting the most significant decline. SEM analysis showed that the morphology of α-cellulose was changed after ozone oxidation. This study provides some guidance to mitigate ineffective degradation of cellulose and assist in the selection of cellulose protectors during the process of extracting lignocellulosic fibers by ozone oxidation.

Inhibitory effects of antioxidant moieties in humic substances on phototransformation of chlortetracycline mediated by the algae extracellular organic matter

In algae rich waters, sunlight-driven transformation of antibiotics could be accelerated via sensitization by algae extracellular organic matter (EOM), and this photosensitization process will be affected by coexisting humic substances. In this study, we explored the effect and mechanism of humic substances on photodegradation of chlortetracycline (CTC) mediated by EOM. We found that humic substances exhibited a marked inhibitory effect on the EOM-mediated photodegradation of CTC. Given that humic substances exhibited little effects on the EOM-mediated formation of triplet state species, the quenching effect of humic substances on reactive species was excluded. The inhibitory effect of humic substances was mainly attributed to the back reduction of CTC oxidation intermediates by the antioxidant moieties in humic substances. The ozone oxidation treatment for humic substances was applied to destroy antioxidant moieties. After ozonation, the inhibitory effects of humic substances were greatly decreased, confirming the dominant role of antioxidant moieties in humic substances, which inhibited CTC photodegradation mediated by EOM via reducing oxidation intermediates of CTC. This back reduction was further verified to be exergonic via reactive Gibbs free energy, indicating the back reduction by humic substances of CTC oxidation intermediates could occur spontaneously. The present study will be helpful for predicting the fate and risk of CTC in algae rich water environments, and is of great significance for the study of phototransformation of other antibiotics.

Study on the Removal of Fluorescent Whitening Agent from Paper-Mill Wastewater Using the Submerged Membrane Bioreactor (SMBR) with Ozone Oxidation Process

In this study, paper-mill wastewater was treated using the Submerged Membrane Bioreactor (SMBR) process. In particular, the ozone oxidation treatment process is applied after SMBR to remove the fluorescent whitening agent, which is a trace pollutant and non-biodegradable. Fluorescent whitening agent concentration was indirectly measured by UV scanning and COD concentration. The concentration of COD before SMBR and ozone oxidation was 449.3 mg/L, and the concentration of treated water was 100.3 mg/ℓ. The COD removal efficiency of paper-mill wastewater through SMBR and the ozone oxidation process was about 77.68%. The optimized amount of ozone was required for the removal of the fluorescent whitening agent after SMBR was 95 mg·O3/ℓ calculated by UV scan results. Additionally, the optimized amount of required ozone to remove COD was calculated to 0.126 mg·COD/mg·O3.

Numerical modeling of mass transfer processes coupling with reaction for the design of the ozone oxidation treatment of wastewater

A computational model for an ozone oxidation column reactor used in dyeing wastewater treatment is proposed to represent, simulate, and predict the ozone bubble process. Considering the hydrodynamics, mass transfer, and ozone oxidation reaction, coupling modeling can more realistically calculate the ozone oxidation bubble process than the splitting methods proposed in previous research. The modeling is validated and shows great consistency with experimental data. The verified model is used to analyze the effect of operating conditions, such as the initial gas velocity and the ozone concentration, and structural conditions, such as multiple gas inlets. The ozone consumption is influenced by the gas velocity and the initial ozone concentration. The ozone’s utilization decreases with the increasing gas velocity while nearly the same at different initial ozone concentrations. Simulation results can be used in guiding the practical operation of dyeing wastewater treatment and in other ozonation systems with known rate constants in wastewater treatment.

Removal of organic and inorganic matters from secondary effluent using resin adsorption and reuse of desorption eluate using ozone oxidation

This study aimed to compare the effectiveness of MAER and L20 resin for the adsorption treatment of secondary effluent, and evaluate the applicability of ozone oxidation for the reuse of desorption eluate. Bench-scale adsorption experiments showed that the MAER resin exhibited higher efficiency than L20 resin in removal of COD within 600 treated bed volumes (BV), which declined from 32.5% to 14.1% in the first and sixth treatment loading of 100 BV. On the other hand, the L20 resin displayed obviously higher removal efficiency of total nitrogen (TN) than MAER resin within 600 BV, which dropped from 74.6% to 9.8% at the same condition. The ozone oxidation treatment could achieve desirable reuse of desorption eluate, although its chemical oxygen demand (COD) concentration increased gradually in line with the reuse numbers. The uptake of COD, TN and total phosphorus declined steadily by using ozone treated eluate as the regenerant in successive adsorption-desorption cycles, but increased obviously with a new batch of regenerant. Overall, the resin adsorption could efficiently remove organic and inorganic matters from secondary effluent, while the treatment loop including desorption eluate oxidation and eluate reuse could markedly enhance the concentration ratio of treated effluent.

Evaluation of Ultraviolet Light and Hydrogen Peroxide Enhanced Ozone Oxidation Treatment for the Production of Cellulose Nanofibrils

The oxidation of cellulose to modify the fiber surface is widely recognized as a promising strategy to improve the production of cellulose nanofibrils (CNFs) from pulp fibers. In this study, an eco...

Catalytic ozone oxidation treatment of wastewater from a pesticide enterprise

Catalytic ozone oxidation treatment of wastewater from a pesticide enterprise

Increase of Strength for CFRTP Fabricated with Carbon Fiber Fabrics and Polyamide6 Resin by Ozone Oxidation Treatment

Increase of Strength for CFRTP Fabricated with Carbon Fiber Fabrics and Polyamide6 Resin by Ozone Oxidation Treatment

Minimally-Invasive Transepidermal Potential Measurement System with Microneedle Salt Bridge

1. Background The epidermis, the surface layer of the skin, works as a barrier to protect inner organ against external stimulation. Malfunction of the skin barrier can be developed into skin diseases such as dry skin, dermatitis, etc. Thus, the evaluation of integrity of the skin barrier functions is required in medicine and cosmetics. The transepidermal potential (TEP), potential difference across the epidermis generated with ion localization, has been suggested to be related to the skin barrier functions1–3. In the TEP measurement, a pair of electrodes are required to be vertically aligned, where an inner electrode is set under the epidermis, while a surface electrode is on the skin. Conventionally, the inner electrode is placed on a wound, surgically exposed dermis1,3. As a non-invasive alternative to the wound, the inner electrode can be placed on a sublingual area for evaluation of the TEP variation2. For the measurement of absolute TEP, to juxtapose the inner and the surface electrodes is desirable for suppression of iR drop generated in dermis and other tissues. In this study, we developed a minimally invasive system for absolute TEP measurement with the inner electrode made of a fine microneedle (0.18 mm in diameter). The microneedle filled with agar works as a salt bridge, and the TEPs of a piece of porcine skin were measured. Furthermore, the inner and surface electrodes were integrated into a compact probe for the measurements of local skin barrier disruption based on TEP value. 2. Materials and methods A painless syringe needle with a plastic cartridge was purchased from Terumo (Nanopass 34G). Total length of the needle was 4 mm, the tip diameter was 0.18 mm, and the length of the lumen at the tip was ca. 0.7 mm. The needle surface was hydrophilized by an ozone oxidation treatment. 2 wt% of agarose in Ringer’s solution was injected to the preheated needle and its cartridge. Gelation of the agarose solution was induced at room temperature. The connecting hole was created on the side of the cartridge by a biopsy punch, and the conventional tubular salt bridge filled with Ringer’s solution in agar was connected through the hole. A silicone elastomer ring was equipped as a spacer to control the penetration depth of the needle within the subepidermal region. All the salt bridges were stored in Ringer’s solution until each measurement was conducted. 3. Results and discussion Figure 1(a) is a schematic diagram of the entire TEP measurement systems using two kinds of salt bridge electrodes. One electrode was a conventional tubular salt bridge (inner diameter: 3mm), and another was a needle-based salt bridge as shown in Figure 1(b). Both contained Ringer’s solution in agar, which has similar electrolyte composition to the tissue fluid. The tubular electrode is put on the target surface of skin, and its potential was measured against that of the needle electrode inserted to subepidermal regions. Figure 1(c) shows TEP measured for a piece of porcine skin using this system with changing the insertion point of the inner needle electrode (20 mm, 10 mm, and 2 mm from the target area). Stable potential ca. -15 mV for this sample was measured regardless of the position of needle electrode. This result motivated us to develop a compact device by integrating the tubule and needle electrodes for the local mapping of TEP. As shown in Figure 2(a), two thin Ag/AgCl electrodes were connected to the Ringer’s solution in agar filled inside and outside of the needle. The distance between the needle and the neighbor salt bridge was ca. 2 mm. The localized TEP measurement was demonstrated for the porcine skin partially disrupted by tape-stripping and defatting as indicated in the photographs of Figure 2(b). The potential measured by the sensor probe showed smaller potential for the area B (disrupted) than that of its adjacent areas A and C (undisrupted). As future works, the probe for a large animal with similar skin to human will be developed for more quantitative local TEP measurements. (Adapted from “Minimally-Invasive Transepidermal Potentiometry with Microneedle Salt Bridge”, Y. Abe et al.(submitted)) 1. Barker, A. T. et al., Am. J. Physiol. 242,R358–R366 (1982). 2. Kawai, E. et al., Exp. Dermatol. 17,688–692 (2008). 3. Dubé, J. et al., Tissue Eng. Part A 16, 3055–3063 (2010). Figure 1

Electronic structure characterization of an individual single-walled carbon nanotube by in situ electrochemical surface-enhanced Raman scattering spectroscopy.

We present an electronic structural analysis of an individual single-walled carbon nanotube (SWNT) by employing electrochemical surface-enhanced Raman scattering (SERS). An isolated SWNT was supported on a well-defined Au nanodimer structure, which possesses a localized surface plasmon resonance (LSPR) field at the nanogap, and highly intense SERS spectra were obtained for the SWNT at the gap region. The absolute potential of the Fermi level of the isolated SWNT in an ionic liquid was determined from the electrochemical potential dependence of the SERS intensity showing the dependence on the chirality of SWNTs. The electronic structural change in an isolated SWNT by ozone oxidation treatment was also analyzed. The results indicate that the electrochemical SERS technique is a powerful tool for detailed analysis of the electronic structure of isolated SWNTs.

連続炭素繊維強化ポリカーボネートのオゾン酸化処理による強度向上

The purpose of this study is to improve the mechanical properties of carbon fiber reinforced thermoplastics (CFRTP) using polycarbonate (PC) for a matrix resin. To achieve this purpose, we investigated the molding conditions of CFRTP and the surface modification method for the carbon fiber fabric (CFF) and PC sheet. Results of the examination of molding conditions, when the press pressure in the molding increased from 2 MPa to 10 MPa, flexural strength of CFRTP increased 50% compared with the original value. This reason would be due to the both things, namely increase of volume fraction (45%→57%) and decrease of void content (5.8%→3.4%) of CFRTP. In order to improve the adhesion between CFF and PC sheet, ozone oxidation treatment was adopted. This treatment was carried out for both CFF and PC sheet. In comparison with the untreated one, it was found that flexural strength and tensile strength increased 31% and 14%, respectively.

Using ozonation to eliminate the inhibition of soluble algal products (SAP) of Scenedesmus sp. LX1 on its growth in microalgal cultivation for biomass/bioenergy production

Water recycling is an effective way to reduce water consumption in the industrialization of microalgae-based biomass/bioenergy production. The soluble algal products (SAP) which inhibit the microalgae growth will accumulate in the recycled water. Therefore, the ozone oxidation treatment of SAP produced by Scenedesmus sp. LX1 was studied to reduce the inhibition of SAP. The experimental results showed that there was almost no change in the content of SAP (counted by dissolved organic carbon) after ozonation, but the inhibition of SAP on microalgae growth disappeared. The intrinsic growth rate (r) of Scenedesmus sp. LX1 in the cultivation solution containing untreated SAP was 0.52 d−1, and it rose to 0.95 d−1 after SAP was ozonized. The maximum population growth rate (Rmax) followed a similar trend, increasing from 9.19 × 105 to 13.0 × 105 cells mL−1 d−1. It was suggested that the changes of fluorescence and hydrophilic–hydrophobic/acid–base property of SAP after ozonation leads to the disappearance of SAP inhibition on microalgae growth.

Improvement in Mechanical Properties of Continuous Carbon Fiber Reinforced Thermoplastic Composites by Ozone Oxidation Treatment

Improvement in Mechanical Properties of Continuous Carbon Fiber Reinforced Thermoplastic Composites by Ozone Oxidation Treatment

Noble metal deposition modulation on amorphous photochromic diarylethene film

We investigated deposition modulation by noble metals on a photochromic diarylethene (DAE) film. Differences in color and sheet resistance (Rs) between the metal films deposited on the colored and colorless DAE films were observed. We observed Rs ratios of 106 for Ag, 107 for Cu, and 104 for Au. We found that the color and Rs differences were caused by the size differences in the metal nanocrystals on the deposited films. The difference in Rs was increased further after ozone oxidation treatment of the samples. We also demonstrated that this phenomenon can be applied to wiring in electronics and the crosstalk between adjacent wiring can be reduced by ozone oxidation treatment.

Effect of ozone treatment on the optical and electrical properties of HfSiO thin films

The effect of room temperature ozone oxidation treatment on thin HfSiO film grown by atomic layer deposition (ALD) has been investigated. The optical and electrical properties with different post-ozone oxidation time were characterized. The evolution of ozone interacting with HfSiO films was clearly illuminated. Ozone can repair the lossy chemical bonds and vacancies, resulting in the improvement of packing density and polarizability of HfSiO films. With more ozone entering the HfSiO films, the refractive index, dielectric constant, and interfacial properties can be greatly upgraded. Furthermore, the frequency dispersion of ALD-HfSiO film can be improved after O3 treatment time for 8 min.

Assessing the Effect of Inorganic Anions on TiO2-Photocatalysis and Ozone Oxidation Treatment Efficiencies

AbstractConsidering the application of AOPs might be limited for the treatment of industrial wastewater with high inorganic load, and that partial results reported to date regarding this particular are inconclusive, even opposite in some cases, the effect of inorganic anions on the oxidation efficiency of photocatalysis and ozonation has been further assessed with statistical significance. While the presence of sulphate and chloride did not appreciably affect the photocatalytic oxidation of phenol, nitrate significantly enhanced the removal of COD (≈ 8-15%). The addition of carbonate simply increased the pH, which strongly inhibited the photocatalytic process; whereas if pH=5 was kept constant, the reduction of the COD was not affected by the presence of carbonate. On the other hand, sulphate, chloride and nitrate did not significantly affect the degradation of phenol by ozonation; whereas the presence of carbonate apparently enhanced the reduction of COD. It is actually proved that this improvement in the efficiency of the treatment was produced by the pH buffering effect of these ions, rather than to its presence itself, which actually significantly reduced the removal of COD (5-10%) by radical scavenging action in comparison to when the treatment was performed in the absence of anions in the solution adjusting the pH to similar basic values (≈9.5-13.5). When ozonation was performed at a pH close to neutral (6.5 ± 0.2) or basic (12 ± 0.2), at which the indirect oxidation of hydroxyl radical is surely widely active, the results were significantly enhanced in any case (COD removal ≈ 70-75%), whether in the absence or the presence of these anions; despite the significant slight radical scavenging effect (COD removal ≈ 65-70%) that was attributed to the addition of carbonate.

Study on Oxidation Effect of Ozone on Petroleum-Based Pollutants in Water

The removal of petroleum-based pollutants from water by ozone is studied. The results indicate that the oxidation effect of ozone on the petroleum-based pollutants is associated with water temperature, pH, dosage of ozone and reaction time. The removal efficiency of petroleum-based pollutants increases with the rise of temperature, pH, amount of ozone and reaction time, and reaches 83% under the conditions that the ratio of ozone to petroleum-based pollutants is 1:1 and the reaction time is 10 min. GC/MS analysis reveals that the amount of petroleum-based pollutants in water is reduced 39% from the previous 61 organics to 37 organics, the total peak area is reduced 36% after ozone oxidation treatment. Therefore, ozone has an excellent effect on the removal of petroleum-based pollutants and can be applied in the treatment of petroleum wastewaters.

Treatment Rate Improvement of the Ozone Oxidation Method for Laundry Waste Water

Radioactive laundry waste water generated in nuclear power plants includes organic compounds to be removed, for which ozone oxidation treatment is a possibility. To verify the applicability, its total organic carbon concentration (TOC) lowering rate improvement was examined in 0.5x10-3 m3 batch and 3x10-2 m3 pilot equipment experiments. In the batch experiments, ozone at a concentration of 200g/Nm3 was dispersed into 0.5x10-3 m3 of Simulated Laundry Waste Water (SLWW) with TOC of 11 mM. Total organic carbon concentration was measured every hour to see the effects of the temperature, and the initial concentrations of both H2O2 and NaOH which were added to urge OH radical generation from ozone. In the pilot equipment experiments, 1x10-2 to 3x10-2 m3 of the SLWW were circulated using an ejector to disperse the ozone. The influences of the flow rate and the SLWW volume on lowering TOC were examined, because they were related to the ejector dispersion performance and the appropriate ozone addition per SLWW volume. Appropriate initial H2O2 and NaOH concentrations in the batch experiments were 14.7mM and ImM, respectively. Lowering of TOC became faster at higher temperatures, because ozone self-decomposition and OH radical diffusion to the organic compound molecules were promoted. Lowering of TOC also became faster at higher flow rates, while the influence of the volume became saturated.