Ovidius University Annals of Chemistry最新文献_第9页

Optimization of process factors using the Taguchi method of DOE towards the hydrodeoxygenation of acetic acid 用DOE法对乙酸加氢脱氧工艺因素进行优化

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Ovidius University Annals of Chemistry Pub Date : 2020-01-01 DOI: 10.2478/auoc-2020-0008

A. Mashi, M. Rahama

{"title":"Optimization of process factors using the Taguchi method of DOE towards the hydrodeoxygenation of acetic acid","authors":"A. Mashi, M. Rahama","doi":"10.2478/auoc-2020-0008","DOIUrl":"https://doi.org/10.2478/auoc-2020-0008","url":null,"abstract":"Abstract This paper reports the optimization of process factors using the Taguchi method towards the conversion of acetic acid and ethanol yield during the hydrogenation of acetic acid over 4% Pt/TiO2. The acidity of 4% Pt/TiO2 was characterized using NH3-Temperature Programmed Desorption analysis (NH3-TPD). Afterwards, the effect of temperature on the hydrogenation of acetic acid as an individual feed was investigated. The reaction space explored in the following ranges: temperature 80-200 °C, pressure 10-40 bar, time 1-4 h, catalyst 0.1-0.4 g and stirring speed 400-1000 min−1 using 4% Pt/TiO2, was investigated for the optimization study, while the effect of temperature was studied in a temperature range of 145 to 200 °C. NH3-TPD analysis reveals that moderate acidity was suitable for the hydrogenation of acetic acid to ethanol. It was also found that 200 °C, 40 bar, 4 h, 0.4 g and 1000 min−1 for acetic acid conversion, and 160 °C, 40 bar, 4 h, 0.4 g and 1000 min−1 were the optimum conditions for ethanol production. In addition, the selectivity of ethanol was favored at lower temperatures which decreases with increasing temperature.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"90 1","pages":"38 - 43"},"PeriodicalIF":0.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89959247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Effect of acryloylation on superabsorbency of starch copolymers 丙烯酰化对淀粉共聚物高吸水性的影响

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Ovidius University Annals of Chemistry Pub Date : 2020-01-01 DOI: 10.2478/auoc-2020-0003

A. D. Mohammed, Yusuf Hassan

引用次数: 1

Consideration of phthalates distribution in underground water in some selected regions in Delta State, Southern Nigeria 对尼日利亚南部三角洲州某些选定地区地下水中邻苯二甲酸盐分布的考虑

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Ovidius University Annals of Chemistry Pub Date : 2020-01-01 DOI: 10.2478/auoc-2020-0009

O. Edjere, C. Ogwuche, U. Bassey, A. Rim-Rukeh

{"title":"Consideration of phthalates distribution in underground water in some selected regions in Delta State, Southern Nigeria","authors":"O. Edjere, C. Ogwuche, U. Bassey, A. Rim-Rukeh","doi":"10.2478/auoc-2020-0009","DOIUrl":"https://doi.org/10.2478/auoc-2020-0009","url":null,"abstract":"Abstract The choice of phthalates as plasticizers have been on the increase especially in household products. They are ubiquitous environmental pollutants due to their physical attribute. This study was carried out to determine the occurrence and level of phthalates in the groundwater in some regions of Delta State. Groundwater samples were collected from fourteen sampling points and analyzed using standard procedures. The obtained results showed that the concentration (µg/l) of six phthalate ester compounds present in the water samples was of the order: < 0.05 - 0.05 BBP, < 0.05 - 3.71 BEHP, < 0.05 - 0.54 DBP, < 0.05 - 0.55 DEP, < 0.05 - 0.13 DMP, and < 0.05 - 0.48 DnOP. BEHP was observed to be the major compound of the phthalate acid esters present in most sampling stations, whilst others, especially BBP, were found to be in low concentration and does not pose any immediate threat to human health. The presence of BEHP in most samples from different locations suggests an inflow of the phthalate to underground water, hence it becomes imperative for continuous monitoring and a call to various governments and environmental regulatory agencies to establish standards for phthalate esters in order to monitor its presence in the environment.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"374 1","pages":"44 - 48"},"PeriodicalIF":0.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76614777","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 2

The influence of extraction method on antioxidant potential of Tilia argentea flowers and bracts 提取方法对银椴花及苞片抗氧化能力的影响

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Ovidius University Annals of Chemistry Pub Date : 2020-01-01 DOI: 10.2478/auoc-2020-0004

Serap AYAZ SEYHAN, Z. Yilmaz, Deniz Çikla Yilmaz

引用次数: 1

Synthesis and characterization of magnetic oxide nanoparticles and corresponding thin films for wastewaters treatment 废水处理用磁性氧化物纳米颗粒及其薄膜的合成与表征

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Ovidius University Annals of Chemistry Pub Date : 2020-01-01 DOI: 10.2478/auoc-2020-0021

Lenuța Crintea Căpăţână, V. Muşat, S. Polosan, A. Cantaragiu, V. Bașliu, A. V. Dediu Botezatu, R. Dinică

{"title":"Synthesis and characterization of magnetic oxide nanoparticles and corresponding thin films for wastewaters treatment","authors":"Lenuța Crintea Căpăţână, V. Muşat, S. Polosan, A. Cantaragiu, V. Bașliu, A. V. Dediu Botezatu, R. Dinică","doi":"10.2478/auoc-2020-0021","DOIUrl":"https://doi.org/10.2478/auoc-2020-0021","url":null,"abstract":"Abstract Industrial wastewater can be properly treated using nanotechnologies and nanomaterials. This paper presents the synthesis and characterization of three series of magnetic nanoparticles (MNPs) and corresponding thin films, used for the degradation of organic compounds and removal of heavy metals from industrial wastewater. The samples were obtained by co-precipitation from a ferric (Fe3+) and ferrous (Fe2+) ions solution in a molar ratio of 2:1, at temperatures between 80-95 °C. The characterization of the samples was performed by scanning electron microscopy (SEM), and X-ray diffraction (XRD) methods. The magnetic nanoparticles were deposited on glass substrates by the centrifugal coating technique and the optical and magneto-optical activity was investigated by UV-Vis spectroscopy and magnetic circular dichroism technique (MCD). The effect of the investigated samples on the decomposition under UV irradiation of organic dyes was monitored by UV-Vis spectroscopy. Our preliminary results have shown that the magnetite and maghemite MNPs can be effective in UV degradation of methylene blue (MB) dye.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"25 1","pages":"122 - 131"},"PeriodicalIF":0.9,"publicationDate":"2020-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87892084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Activity and stability of urease enzyme immobilized on Amberlite resin 安培石树脂固定化脲酶的活性与稳定性

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Ovidius University Annals of Chemistry Pub Date : 2019-10-30 DOI: 10.20944/preprints201910.0348.v1

Jawad Kadhim Jawad Al-Shams, M. Hussein, H. Al-Hakeim

{"title":"Activity and stability of urease enzyme immobilized on Amberlite resin","authors":"Jawad Kadhim Jawad Al-Shams, M. Hussein, H. Al-Hakeim","doi":"10.20944/preprints201910.0348.v1","DOIUrl":"https://doi.org/10.20944/preprints201910.0348.v1","url":null,"abstract":"Abstract Immobilization of enzymes is a good field of study to extend the life of enzyme and reduce the cost of the chemical processes, such as separation processes. Urease is an important enzyme with medical and industrial applications. The aim of the present study is to prepare an immobilized urease on a strong cation exchange resin (Amberlite IR120 Na) and study its activity and stability. We monitored the release of Na ions in the collected fractions and searching for enzyme in the fractions as indicators of immobilization by ion exchange phenomenon. Sodium is determined by using atomic absorption spectroscopy technique, while the enzyme concentration was tested by Bradford’s method. Immobilized urease activity was evaluated by salicylate-hypochlorite method. The results indicated a complete immobilization of urease enzyme on the resin surface with reserving 92% of the activity of free enzyme. The immobilized urease enzyme on resin showed good stability and it has a 62% of its activity after 154 days of storage at room temperature. It is concluded that a new immobilized urease enzyme system is prepared with good enzyme activity and stability.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"46 1","pages":"1 - 4"},"PeriodicalIF":0.9,"publicationDate":"2019-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77415860","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3

Study of the influence of alcohols addition to gasoline on the distillation curve, and vapor pressure 研究了汽油中添加醇对蒸馏曲线和蒸汽压的影响

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Ovidius University Annals of Chemistry Pub Date : 2019-07-01 DOI: 10.2478/auoc-2019-0022

I. Niță, Elis Geacai, Sibel Osman, O. Iulian

引用次数: 1

Evaluation of the effect of a modified proprietary poultry feed on cholesterol excretion in laying birds 改性专有家禽饲料对产蛋鸟类胆固醇排泄影响的评价

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Ovidius University Annals of Chemistry Pub Date : 2019-07-01 DOI: 10.2478/auoc-2019-0020

C. Ikese, S. T. Ubwa, S. Adoga, S. Audu, M. Akor

{"title":"Evaluation of the effect of a modified proprietary poultry feed on cholesterol excretion in laying birds","authors":"C. Ikese, S. T. Ubwa, S. Adoga, S. Audu, M. Akor","doi":"10.2478/auoc-2019-0020","DOIUrl":"https://doi.org/10.2478/auoc-2019-0020","url":null,"abstract":"Abstract The effect of modified proprietary poultry feed on cholesterol excretion in laying birds was evaluated. The study sort to lower the cholesterol content of eggs at the point of their physiological formation via a modification of the proprietary feed fed to laying poultry birds. This was with a view to lower the net cholesterol content in their eggs, thereby lowering the cholesterol levels available in such eggs for intake upon consumption. A 20% rice bran modification of the proprietary feed was made. Animal subjects were divided into experimental and control groups and the mean total cholesterol in their faecal droppings where determined before and after varying their feeding programs. Whereas the experimental group was fed with the modified feed, the control group was maintained on the unmodified feed. Enzymatic colorimetric method was used for the determination of mean total cholesterol in the dried faecal droppings of each group of birds under investigation. The results showed that the mean total cholesterol excretion before and after the modified feed regimen were 5.97±0.16 mg/g and 9.99±0.47 mg/g respectively and were found to be significantly different when compared using a t-test at p > 0.05 and 49 degree of freedom The results also showed that the modified proprietary poultry feed increased total cholesterol excretion in the faecal droppings of laying birds fed with the modified feed by 67.3%, and this was found to be statistically significant at p > 0.05. Hence, a 20% rice-bran modification of the proprietary feed yields a modified feed with a proven potency in elevating total cholesterol excretion while producing no drastic deviation from the proximate composition of the unmodified proprietary feed and is thus likely to have no adverse effect on the productivity of laying birds.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"50 1","pages":"113 - 116"},"PeriodicalIF":0.9,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84636364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Occurrence and risk assessment of phenolic endocrine disrupting chemicals in shallow groundwater resource from selected Nigerian rural settlements 尼日利亚农村居民点浅层地下水中酚类内分泌干扰物的发生及风险评估

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Ovidius University Annals of Chemistry Pub Date : 2019-07-01 DOI: 10.2478/auoc-2019-0018

O. Onyekwere, C. J. Okonkwo, Azubuike Bright Okoroafor, C. J. Okonkwo

{"title":"Occurrence and risk assessment of phenolic endocrine disrupting chemicals in shallow groundwater resource from selected Nigerian rural settlements","authors":"O. Onyekwere, C. J. Okonkwo, Azubuike Bright Okoroafor, C. J. Okonkwo","doi":"10.2478/auoc-2019-0018","DOIUrl":"https://doi.org/10.2478/auoc-2019-0018","url":null,"abstract":"Abstract To date, limited information exists on the distribution of endocrine disrupting compounds in groundwater resources from African rural settlements. In view of this knowledge gap, the present study investigated the concentrations and potential health risks of phenolic endocrine disrupting chemicals (EDCs) in underground water samples obtained from eight rural settlements in Nigeria, West Africa. The water samples were obtained from domestic drinkable communal wells at Anambra (Mgbaukwu and Umudioka), Lagos (Bariga, Itire and Mushin), and Delta (Agbarho, Ikweghwu and Orhokpokpor) states representing the South-East, South-West and South-South Nigeria respectively. Samples were analyzed for 10 selected chlorinated, nitrogen-containing and alkyl phenolic compounds using gas chromatography coupled with flame ionization detector technique. At all understudied sites, selected phenolic compounds with the exception of 2-chlorophenol which was below detectable limits at 4 sites (Agbarho, Mgbaukwu, Umudioka site 1 and Mushin) were detected. The concentrations of the phenolic compounds in the samples from the different sites ranged between below detectable limits to 0.0904 ppm. Nonylphenol, 2,4-dinitrophenol and 2,4,6-trichlorophenol were predominant at EDCs in most sites when compared with the other phenolic contaminants. The calculated chronic daily intake (CDI) results for the exposed populations at the communities implies that the level of occurrence and daily intake of 2-nitrophenol, 2,4-dimethylphenol, 4-nitrophenol, 2-chlorophenol and bisphenol A were still below their respective oral reference doses. Nonylphenol and 2,4,6-trichlorophenol (risk quotient, RQ > 1) were identified as the major EDC contributors to potential health risk for exposed populations at the communities.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"39 1","pages":"101 - 107"},"PeriodicalIF":0.9,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"82933779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 8

Performance evaluation of a formulated infant food on some biological indices in Wistar rats 一种配方婴儿食品对Wistar大鼠某些生物学指标的性能评价

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Ovidius University Annals of Chemistry Pub Date : 2019-07-01 DOI: 10.2478/auoc-2019-0021

C. Ikese, S. T. Ubwa, P. A. Adie, S. Audu, Godwin Ejeke

{"title":"Performance evaluation of a formulated infant food on some biological indices in Wistar rats","authors":"C. Ikese, S. T. Ubwa, P. A. Adie, S. Audu, Godwin Ejeke","doi":"10.2478/auoc-2019-0021","DOIUrl":"https://doi.org/10.2478/auoc-2019-0021","url":null,"abstract":"Abstract Performance evaluation of a formulated infant food on some biological indices in Wistar rats was investigated. For rats fed separately with normal rat feed, formulated infant food and proprietary food, serum total protein and albumin were determined by colorimetric method, red blood cell (RBC) and differential white blood cell (WBC) counts were determined with a haemocytometer, packed cell volume (PCV) was by micro-haematocrit, haemoglobin (HGB) was determined using cyanomethaemoglobin method while mean cell volume (MCV) and mean cell haemoglobin (MCH) were calculated. The results obtained showed that, for Wistar rats fed with normal rat feed, the baseline values prior to the commencement of feeding trial for serum total protein, albumin, body weight, PCV, WBC, platelet count (PLT), RBC, HGB, lymphocyte count (LYM), MCH, MCV, neutrophil (NEU), and eosinophil (EOS) were 82.9 g/dL, 44.75 g/dL, 142.80g, 41.14%, 7.60×103 μL−1, 404.85×103 μL−1, 5.68×106 μL−1, 10.80 g/dL, 50.28 %, 18.42 pg, 59.28 fL, 45.57 %, and 2.57 % respectively. After the feeding trial, the serum total protein, albumin, body weight, PCV, WBC, PLT, RBC, HGB, LYM, MCH, MCV, NEU, and EOS in Wistar rats fed with the formulated infant food (the experimental group) were 79.6 g/dL, 50.65 g/dL, 169.18g, 40.14%, 5.77 ×103 μL−1, 309.85 ×103 μL−1, 6.85×106 μL−1, 12.45 g/dL, 52.85 %, 18.24 pg, 58.64 fL, 42.00 %, and 2.14% respectively and these were in most cases, either greater or comparable with their corresponding mean values of 69.1 g/dL, 44.40 g/dL, 177.97 g, 30.24%, 4.18×103 μL−1, 188.14×103 μL−1, 5.29×106 μL−1, 10.74 g/dL, 53.14 %, 20.37 pg, 57.61 fL, 38.85 %, and 4.57 % respectively in Wistar rats fed with the proprietary infant formula (the control group). This shows that the potential infant food has a more positive effect on most of the biological indices assessed than the proprietary infant food or a comparable effect at the least.","PeriodicalId":19641,"journal":{"name":"Ovidius University Annals of Chemistry","volume":"176 1","pages":"117 - 121"},"PeriodicalIF":0.9,"publicationDate":"2019-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79839870","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0