Preparation of Deep Hydrodesulfurzation Catalysts for Diesel Fuel using Organic Matrix Decomposition Method

Author(s):  
Hamid Audah AlMegren ◽  
Sergio Gonzalez-Cortes ◽  
Yu Huang ◽  
Haoyi Chen ◽  
Yangdong Qian ◽  
...  

In this work, a series of supported CoMo or NiMo HDS catalysts have been prepared based on the organic-metal matrix decomposition method and tested for diesel deep HDS with minimum hydrogen consumption under relatively low hydrogen partial pressure conditions. The aim is to develop a HDS catalyst which can reduce sulphur in diesel fuel from 5000ppm down to 50 ppm in a single pass with minimum hydrogen consumption under the conditions of 340oC, 35 bar, LHSV 1.2 h-1 with low H2/oil ratio. The catalysts preparation process was monitored and the resultant catalyst samples before and after the HDS performance test have been characterised, some interesting results have been obtained. The presence of citric acid as organic additive/dispersing agent/chelating agent in the impregnation solution improved HDS activity compared to the equivalent CoMo catalyst prepared without citric acid, The order of activity of the cobalt precursors is Co citrate > Co acetate > Co nitrate.

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 25 ◽  
Author(s):  
Maria Gandolfi ◽  
Paola Taddei ◽  
Anna Pondrelli ◽  
Fausto Zamparini ◽  
Carlo Prati ◽  
...  

The aim of the study was to investigate the effects of several decalcifying agents used as irrigant solutions in endodontic treatment on collagen and mineral components of dentin. Coronal dentin discs from five caries-free human third molars with a smear layer were treated for one minute with a chelating solution (1% Ethylenediaminetetraacetic acid (EDTA), 10% EDTA, 17% EDTA, 10% citric acid). Mineralization degree (Ca/N and P/N atomic ratios, IR Iapatite/Iamide II and I1410(carbonate)/I554(phosphate) spectroscopic ratios) and possible collagen rearrangements (collagen infrared (IR) amide II e III shifts) were evaluated by environmental scanning electron microscopy (ESEM)/energy dispersive X-ray spectroscopy (EDX) and IR spectroscopy before and after treatment (T0) and after ageing (T24h and T2m) in simulated body fluid (SBF). At T0, analysis showed that the highest demineralizing effect was achieved using a 10% citric acid solution and 10% EDTA, while the smallest effect was observed when using 17% EDTA. No significant collagen modifications were detected upon treatment with 1% EDTA, while subtle changes were observed after the other treatments. At T24h or T2m, analyses showed the highest remineralization values for 1% EDTA and the lowest for 10% citric acid, mainly at T2m. The samples treated with 17% EDTA showed slight collagen rearrangements upon remineralization. In conclusion, the highest demineralizing effect was observed for 10% EDTA and 10% citric acid. Collagen rearrangement was found for all the treatments except for 1% EDTA. The highest remineralization capability in SBF values was recorded for 1% EDTA and the lowest for 10% citric acid. A slight collagen rearrangement upon remineralization was still present in 17% EDTA-treated samples. Clinical use as a chelating agent in the endodontic therapy of citric acid and concentrated EDTA solutions should be reconsidered.


2021 ◽  
Vol 16 ◽  
pp. 155892502110034
Author(s):  
Xiongfang Luo ◽  
Pei Cheng ◽  
Wencong Wang ◽  
Jiajia Fu ◽  
Weidong Gao

This study establishes an eco-friendly anti-wrinkle treating process for cotton fabric. Sodium hydroxide-liquid ammonia pretreatment followed by 6% (w/w) PU100 adding citric acid pad-cure-dry finishing. In this process, citric acid (CA) was used as the fundamental crosslinking agent during finishing because it is a non-formaldehyde based, cost-effective and well wrinkle resistance agent. Environmental-friendly waterborne polyurethane (WPU) was used as an additive to add to the CA finishing solution. Six commercial WPUs were systematically investigated. Fabric properties like wrinkle resistance, tensile strength retention, whiteness, durable press, softness, and wettability were well investigated. Fourier transform infrared spectra and X-ray diffraction spectra were also measured and discussed before and after adding waterborne polyurethane. Tentative mechanism of the interaction among the WPU, CA, and modified cotton fabrics is provided. The effect of cotton fabric pretreatment on fabric performance was also investigated. After the eco-process’s treatment, the fabric wrinkle resistant angle was upgraded to 271 ± 7°, tensile strength retention was maintained at 66.77% ± 3.50% and CIE whiteness was elevated to 52.13 ± 3.21, which are much better than the traditional CA anti-wrinkle finishing based on mercerized cotton fabrics. This study provides useful information for textile researchers and engineers.


Author(s):  
Mariacarla Gonzalez ◽  
Razvigor Ossikovski ◽  
Tatiana Novikova ◽  
Jessica Ramella-Roman

2021 ◽  
Vol 15 ◽  
pp. 117863022110375
Author(s):  
Derebew Aynewa ◽  
Zemichael Gizaw ◽  
Aklilu Feleke Haile

Background: Meat safety is important for public health. As part of the meat chain abattoirs are required to give attention to meat hygiene and safety in order to minimize hazards. Therefore, the current study was conducted to evaluate the bacteriological quality of sheep carcasses, knowledge and hygienic practices of workers in a selected abattoir and to determine the effect level of 2.5% citric acid spray on total coliforms and aerobic bacteria load of raw sheep carcasses surfaces. Methods: A cross-sectional study design with structured questionnaire and observational checklists observation were used. A systematic random sampling technique was employed. A total of 50 sample swabs (25 swabs before citric acid spray and 25 after citric acid spray) were randomly taken from brisket, flank and rump of sheep’s carcasses. Swabs were moistened with buffered peptone water (BPW) and samples were taken by rubbing 100 cm2 (10 cm × 10 cm) area delineated by sterile aluminum template. In addition, we administered a structured questionnaire and an observational checklists to assess knowledge and hygienic practices of workers. Bacteriological quality of sheep carcasses were analyzed using the methods described by the US bacteriological analytical manual. Results: The mean count for aerobic bacteria of the sheep carcasses before and after citric acid spray were 7.2log10 CFU/ml and 6.4log10 CFU/ml, respectively. The test results also showed that 21 (84%) and 15 (60%) of the swab samples were positive before and after spraying citric acid, respectively. The mean counts for coliform bacterial of the sheep carcasses before and after citric acid spray were 3.5log10 CFU/ml and 2.9log10 CFU/ml, respectively. The mean total aerobic and coliform counts before and after citric acid spray were significantly different ( P < .05). Regarding the hygiene condition of workers, all the respondents reported that they always washed their hands with soap before and after entering the slaughtering room and 23 (53.5%) of the workers reported that they used hot water. Thirty-one (72.1%) of the workers reported that they do not used soap to wash hands after visiting toilet. Thirty-five (81.4%) of the production workers did not wear mouth mask while handling and distribute meat/carcass. On the other hand, all of the workers wore capes, gowns and boots at the time of the observation and only 18 (18.6%) of the production workers wore gloves at the time of the survey. Conclusion: The current study revealed that significant proportion of sheep carcasses were positive for total aerobic bacteria and total coliform. Moreover, the study also showed that spraying of sheep carcasses with 2.5% citric acid significantly reduced the total coliform and aerobic counts. However, we did not assessed how much spray results to this effect. Therefore, we recommended further studies to determine how much spray of 2.5% citric acid significantly reduce bacterial contamination of sheep carcasses. In addition, the abattoir has to follow the food hazard analysis critical control point (HACCP) system to minimize meat contamination during harvesting and processing. The abattoir has to also implement strict operation laws to improve hygiene conditions of the workers. In addition, the abattoir can minimize meat contamination using 2.5% citric acid as a decontaminant.


Author(s):  
Jalil Derakhshan ◽  
Majid Moatamedzadeh ◽  
Rostam Golmohammadi ◽  
Mohammad Babamiri ◽  
Maryam Farhadian

Introduction: Fatigue is the exhaustion of the body or spirit that can be caused by stress, excessive work, drug use, physical or mental illness. Fatigue is a factor in reducing productivity and incidents. Therefore, measuring fatigue is important. The aim of this study was to determine the fatigue measurement based on subjective and objective indices. Method: A cross-sectional study was performed on 120 male and female students. By simulating the real environment of each person in the 50 and 70dB pressure levels for 40 minutes, before and after exposure to noise, the amount of mental fatigue was measured using the subjective index Visual Analog Scale (VAS) and the objective index continuous performance test (CPT).  The results were analyzed using paired t-test and Spearman correlation coefficient in SPSS 20 software. Results: Measurement results with both self-declaration scale and continuous performance test showed that mental exhaustion  was increased significantly after exposure to the mentioned pressure level, but the results of two methods were not consistent with each other. Conclusion: Considering that the VAS self-declaration scale is a subjective method, it seems that the mismatch of the two methods is more related to the ineffectiveness of this scale. Therefore, it is suggested that re-examination has to be done with more precise methods such as electroencephalogram.


2010 ◽  
Author(s):  
G. K. Er ◽  
S. W. Lan ◽  
V. P. Iu ◽  
Jane W. Z. Lu ◽  
Andrew Y. T. Leung ◽  
...  

2019 ◽  
Vol 130 ◽  
pp. 01009
Author(s):  
Fandi Dwiputra Suprianto ◽  
Willyanto Anggono ◽  
Teng Sutrisno ◽  
Daniel William Gunawan ◽  
Gabriel Jeremy Gotama

Fuel oil is one of the important parts to support daily activities. The demand for fuel oil is increasing every year. Therefore, the search for the latest energy source is continuously conducted. Carica papaya L. seed oil is investigated as a renewable energy source replacement part of petroleum diesel fuel. C. papaya seed oil obtained through the extraction process using soxhlet method with n-hexane solvent. Then produce methylester by means of transesterification using 1 % NaOH catalyst and 20 % methanol of the weight of the oil and stirred at 400 rpm for 1 h. A mixture consisting of 10 % C. papaya seed biodiesel and 90 % petroleum diesel fuel, called CPSB-10, produces fuel properties that meet the specified standards by the Indonesian Directorate General of Oil and Gas. From the result of the performance test in a diesel test engine, the maximum brake power and brake thermal are consecutively 30.6 kW and 140.23 N m, the lowest sfc is 268 g kW–1 h–1, and the highest brake thermal efficiency is 32 %.


Catalysts ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 795 ◽  
Author(s):  
Hua-Ping Ren ◽  
Shao-Peng Tian ◽  
Si-Yi Ding ◽  
Gui-Qiu Huang ◽  
Min Zhu ◽  
...  

Ni-C/SiO2 and Ni-G/SiO2 catalysts were prepared by a complexed-impregnation method using citric acid and glycine as complexing agents, respectively. Ni/SiO2 was also prepared by the conventional incipient impregnation method. All the catalysts were comparatively tested for carbon dioxide reforming of methane (CDR) at P = 1.0 atm, T = 750 °C, CO2/CH4 = 1.0, and GHSV = 60,000 mL·g−1·h−1. The results showed that Ni-C/SiO2 and Ni-G/SiO2 exhibited better CDR performance, especially regarding stability, than Ni/SiO2. The conversions of CH4 and CO2 were kept constant above 82% and 87% after 20 h of reaction over Ni-C/SiO2 and Ni-G/SiO2 while they were decreased from 81% and 88% to 56% and 59%, respectively, over the Ni/SiO2. The characterization results of the catalysts before and after the reaction showed that the particle size and the distribution of Ni, as well as the interactions between Ni and the support were significantly influenced by the preparation method. As a result, an excellent resistance to the coking deposition and the anti-sintering of Ni was obtained over the Ni-C/SiO2 and Ni-G/SiO2, leading to a highly active and stable CDR performance.


Catalysts ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 619 ◽  
Author(s):  
Xuqiang Zhao ◽  
Li Qin ◽  
Michael Gatheru Waigi ◽  
Pengfei Cheng ◽  
Bing Yang ◽  
...  

The availability of bound residues of polycyclic aromatic hydrocarbons (PAHs), in reference to their parent compounds, can be enhanced by microbial activity and chemical reactions, which pose severe risks for the ecosystems encompassing contaminated soils. Considerable attention has been raised on how to remove these bound residues from PAH-contaminated soils. This paper provides a novel application of Fenton oxidation in the removal of bound residues of model PAHs, such as naphthalene (NAP), acenaphthene (ACP), fluorene (FLU) and anthracene (ANT), from naturally contaminated soils. The citric acid-enhanced Fenton treatment resulted in the degradation of bound PAH residues that followed pseudo-first-order kinetics, with rate constants within 4.22 × 10−2, 1.25 × 10−1 and 2.72 × 10−1 h−1 for NAP, FLU, and ANT, respectively. The reactivity of bound PAH residues showed a correlation with their ionization potential (IP) values. Moreover, the degradation rate of bound PAH residues was significantly correlated with H2O2-Fe2+ ratio (m/m) and H2O2 concentrations. The highest removal efficiencies of bound PAH residues was up to 89.5% with the treatment of chelating agent oxalic acid, which was demonstrated to be superior to other acids, such as citric acid and hydrochloric acid. This study provides valuable insight into the feasibility of citric acid-Fenton and oxalic acid-Fenton treatments in rehabilitating bound PAH residues in contaminated soils.


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