The purpose of this investigation was to study the factors affecting the electrolytic production of hydrogen peroxide from hydrogen and oxygen. The mechanism of this reaction throws light on the production and chemistry of hydrogen peroxide, electrochemistry of hydrogen, oxygen and water and the mechanism of corrosion. This investigation involved the study of the formation and decomposition of hydrogen peroxide at the cathode of an electrolytic cell. Zinc, mercury, magnesium alloy F-S-l, aluminum, lead and activated carbon electrodes in 5 N sodium hydroxide, 0.1018 N sodium hydroxide, and 0.01018 N potassium hydroxide, saturated ammonium chloride and 0.043 N phosphoric acid were studied. / M.S.

This research investigated the efficacy of chlorine dioxide (ClO₂), ultraviolet (UV) irradiation, UV in combination with chlorine dioxide (UV/ClO₂), and UV in combination with hydrogen peroxide (UV/H₂O₂) for decolorizing three reactive azo dyes (sultan red, indigo blue and cypress green) and treated textile-manufacturing wastewater. The objective was to determine the best treatment for reducing color to the Virginia Pollutant Discharge Elimination System (VPDES) permit level of 300 American Dye Manufacturers Institute (ADMI) units. The effects of the three chemical oxidation treatments provided color reduction for all three dyes. The results suggested UV/H₂O₂ and UV/ClO₂2 treatments provided maximum color reduction of the red and blue dyes, and UV/H₂O₂ was the most effective for maximum reduction of the green dye. A research goal was to provide predictive models of the wastewater effluent for the treatment processes, including the UV exposure time required to reach the 300 ADMI permit value and the effective ClO₂ dose necessary to achieve the 300 units. The results of the investigations regarding the effluent indicated that UV/H₂O₂ and UV/ClO₂ (5 mg/L) provided reduction to 300 units in less than 10 minutes UV exposure when the initial effluent color was less than 500 ADMI units. Without the addition of oxidant, contact times longer than 10 minutes were required for UV to decolorize these effluents to 300 ADMI units. Chlorine dioxide dosages between 10 and 30 mg/L both with and without UV irradiation achieved the same results. / Master of Science

The influence of solution pH, DOC concentration, the relative molecular weight distribution of DOC, and the source of DOC were investigated for their effects on the removal of complexed Fe(II) by alum coagulation and/or KMn04 and H20 2 oxidation. The differentiation between particulate, colloidal, and soluble iron species was achieved through the use of 0.2 urn filters and 100K ultrafilters. Results from oxidation and ultrafiltration studies indicated incomplete complexation of the Fe(II) by DOC in solution. Following the addition of either oxidant, uncomplexed Fe(II) was oxidized to Fe (III) which was either complexed by high molecular weight DOC or formed colloidal iron oxides, both of which were efficiently removed by alum coagulation. Alum coagulation alone, however, was ineffective for removing Fe(II) in the presence of DOC. Results revealed the formation of particulate iron species to be a function of DOC source. The formation of colloidal iron was dependent upon DOC concentration and DOC source. The adsorption of DOC by iron oxides was observed to accompany the formation of colloidal iron species. / Master of Science

No / The human epidermis holds an autocrine acetylcholine production and degradation including functioning membrane integrated and cytosolic butyrylcholinesterase (BuchE). Here we show that BuchE activities increase 9-fold in the presence of calcium (0.5 × 10-3 M) via a specific EF-hand calcium binding site, whereas acetylcholinesterase (AchE) is not affected. 45Calcium labelling and computer simulation confirmed the presence of one EF-hand binding site per subunit which is disrupted by H2O2-mediated oxidation. Moreover, we confirmed the faster hydrolysis by calcium-activated BuchE using the neurotoxic organophosphate O-ethyl-O-(4-nitrophenyl)-phenylphosphonothioate (EPN). Considering the large size of the human skin with 1.8 m2 surface area with its calcium gradient in the 10¿3 M range, our results implicate calcium-activated BuchE as a major protective mechanism against suicide inhibition of AchE by organophosphates in this non-neuronal tissue

No / Numerous factors may influence the incidence of diabetes in the population. The production of reactive oxygen species (ROS) is elevated in diabetes patients. Based on the reported involvement of reactive species and nitrate/nitrite in diabetes, this present study has examined in the alkaline Comet assay, the effect of different levels of NaNO2 in the presence of the oxygen radical generating agent, hydrogen peroxide (H2O2). Peripheral lymphocytes from diabetic and non-diabetic Caucasians and Asians of both sexes were studied in vitro. Endogenous factors (e.g., sex, age, body mass index-BMI) and exogenous factors (lifestyle factors e.g., smoking and drinking habits, diet) were taken into account. A preliminary study in two individuals showed that DNA damage remained constant over a wide dose range of NaNO2 (1-75 mM), but when H2O2 was added at a constant concentration of 50 ¿M per dose of NaNO2, there was an increase in DNA damage corresponding with the varying levels of NaNO2 investigated. This was also seen with the 44 individuals (non-diabetic, n = 24; type 1 diabetic, n = 11; type 2 diabetic, n = 9) investigated. NaNO2 was capable of inducing a significant level of DNA damage in lymphocytes (p<0.001), but only with the addition of H2O2. When levels of DNA damage were analysed in terms of the different variables there were few significant differences in damage between diabetic and non-diabetic subjects, or other sub-population groups, and no statistically significant differences in susceptibility were observed between subject covariates using regression techniques.

Yes / The development of cardiovascular disease (CVD) is the main cause of death among chronic kidney disease (CKD) patients (1). Endothelial injury and dysfunction are critical steps in atherosclerosis, a major CVD (2). Increased production of reactive oxygen species (ROS) has been associated with the pathogenesis of cardiovascular diseases such as atherosclerosis, hypertension and heart failure (3). However, hydrogen peroxide (H2O2) modulates endothelial cell function by intricate mechanisms. Ambient production of O2.− and subsequently H2O2 at low levels, maintained via basal activity of pre-assembled endothelial NAD (P) H oxidases (4). Endothelial cells play an important regulatory role in the circulation as a physical barrier and as a source of a variety of regulatory substances. Dysfunction of the vascular endothelium is thus leading to atherosclerosis which is characterised by overexpression of adhesion molecule expression, comprising vascular cell adhesion molecule 1(VCAM1). This adhesion molecule has been found to be up-regulation in human atherosclerotic lesions. The aim of this study is to evaluate the effect of H2O2 on the endothelial cells adhesion molecules expression. Primary cultures of Human Umbilical Vascular Endothelial Cells (HUVECs) will be maintained in endothelial growth medium supplemented with penicillin-streptomycin and supplement mix of fetal calf serum in a 37C humidified incubator in an atmosphere of 5% v/v CO2. HUVECs will be treated with in the presence and absences of 50 μM of H 2O2 for 2, 6, 12 and 24 h. Intracellular superoxide anion production in HUVECs will be detected by using p-Nitro Blue Tetrazolium (NBT) assay to demonstrate whether H2O2 induce the generation of superoxide anions intracellularly in HUVECs. The formation of blue formazan will be measured spectrophotometrically at 570 nm. Total RNA will be extracted from non-treated and treated cells and RNA quantity and quality will be checked by OD260/280 measurements. VCAM-1 mRNA expression will be assessed using RT-PCR. Our results show that H2O2 could potentially significantly induce EC activation through increased mRNA expression of ICAM-1 adhesion molecules in cultured HUVECs. Treatment with N-acetyl cysteine (NAC) (bulk/nano form) could significantly attenuate the effect of H2O2 administration on adhesion molecule protein expression. This strongly suggests the role of ROS in the endothelial cell damage sustained. Future work is to find reliable methods to test endothelial function. Non-invasive studies such as brachial ultrasound testing are also needed to determine its predictive value as a potential predictor for cardiovascular disease.

No / In the search for an efficient and economical method to treat a leachate generated from a controlled municipal solid waste landfill site (Jebel Chakir) in the region of greater Tunis in Tunisia, ozone alone and ozone combined with hydrogen peroxide were studied. The leachate was characterised by high COD, low biodegradability and intense dark colour. A purpose-built reactor, to avoid foaming, was used for the study. It was found that ozone efficacy was almost doubled when combined with hydrogen peroxide at 2 g/L but higher H2O2 concentrations gave lower performances. Enhancement in the leachate biodegradability from about 0.1 to about 0.7 was achieved by the O3/H2O2 system. Insignificant changes in pH that may due to buffering effect of bicarbonate was found. A small decrease in sulphate concentrations were also observed. In contrast, chloride concentration declined at the beginning of the experiment then increased to reach its initial value. Estimates of the operating costs were made for comparison purposes and it was found that the O3/H2O2 system at 2 g/L H2O2 gave the lowest cost of about 3.1 TND (2.3 USD)/kg COD removed.

京都大学 / 新制・課程博士 / 博士(工学) / 甲第25298号 / 工博第5257号 / 京都大学大学院工学研究科物質エネルギー化学専攻 / (主査)教授 村田 靖次郎, 教授 近藤 輝幸, 教授 中村 正治 / 学位規則第4条第1項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DFAM

Compared to unmodified carbons and even some metal materials, nitrogen-doped carbons have been found to exhibit better performance for reducing oxygen-oxygen bonds, a key step in electroreduction of both O2 (an important reaction in energy applications) and H2O2 (an important reaction in sensing and biosensing). Previous studies from our lab revealed that thermal decomposition of urea in the presence of carbon fiber (CF) results in N-doped that exhibited good electrocatalytic properties for H2O2 reduction. However, previous methods of sealing ultramicroelectrodes (UMEs) made from N-doped CF using laser heating of borosilicate capillaries and epoxy seemed to affect surface nitrogen contents and electrocatalytic properties. In this work, we evaluate paraffin sealing as a strategy for preparing UMEs in a way that minimizes effects on important surface nitrogen species so that electrocatalytic properties of the N-doped CF towards H2O2 reduction can be retained.

The implementation of nitrate-free emulsions in Boliden's blasting operations prompted an in-depth investigation into the accumulation of drill cuttings following drilling activities. This master's thesis aimed to understand the contributing factors and quantify drill cuttings, particularly in view of the planned introduction of a new explosive compound. The focal points of the study were the Boliden Kankberg and Garpenberg mines, where a rich variety of data sources were harnessed. The research encompassed a thorough literature review highlighting enduring challenges in drilling and factors that influenced cuttings transport. The study delved into the complex relationships between drilling parameters, including drilling angle, rate of penetration, lithology, and other variables, examining their role in drill cuttings generation and hole evenness. This thesis was a response to the planned introduction of nitrate-free emulsions in Boliden's blasting operations, catalyzed by concerning observations at the Kankberg mine. These observations revealed a significant presence of residual drill cuttings, which raised concerns about their potential impact on blasting effectiveness. The primary focus was on the Kankberg and Garpenberg mines, allowing for a comprehensive exploration of data mainly obtained by filming the drill holes after drilling. A noteworthy aspect of the study was the development and application of a MATLAB-based image processing code to estimate the volume of residual drill cuttings in drill holes. This quantitative approach served as a robust foundation for the investigation. One key finding of the investigation was the disparity in drill cuttings accumulation between the investigated holes in Garpenberg and Kankberg. The "Working from Backwards" approach, employed at the Kankberg mine, underscored the critical importance of controlled drilling angle and rate of penetration in mitigating drill cuttings and achieving uniform drilling outcomes. While this research shed light on these factors, further exploration was needed to fully grasp their intricacies and identify additional variables influencing drill cuttings and hole evenness. These findings offered vital guidance for the development of strategies and practices to enhance drilling operations in the future. Additionally, cluster analysis results emphasized the pivotal role of lithological characteristics in drill cuttings generation. The study provided practical recommendations, including the identification of lithological variations through enhanced mapping, the adjustment of drilling parameters, and the optimization of drilling methods tailored to specific lithologies. / <p>Successful</p>