Papers by Keyword: Acetic Acid

Abstract: Chemical inertness of pristine carbon nanotubes (CNTs) poses challenges on their biocompatibility. In this paper, surface modification of pristine (5, 5) single-walled carbon nanotube (SWCNT) was explored through substitutional Boron (B) and Nitrogen (N) doping forming a C₃₈NB isomer. The electronic topology and binding mechanism of acetic acid adsorption on the isomer was then examined in the context of first-principles Density Functional Theory (DFT). Accordingly, high abundance of localized electrons between the substitutional doping sites indicates chemical binding of the substitutional atoms with the SWCNT. These are further supported by the calculated bond angles. When the acid was adsorbed on the C₃₈NB isomer, spontaneous charge redistributions were observed which are attributed to the oxidation caused by the O atoms and the charge acceptance of the C atoms. Topological analyses revealed that the net charge transfers for all considered configurations were towards the acid. In addition, the Lowest Unoccupied Molecular Orbital (LUMO) and Highest Occupied Molecular Orbital (HOMO) revealed the nonuniform distribution of electronic charges near the Fermi level. Finally, calculations of the electron localization function (ELF) showed that there was no orbital hybridization between the acid and the isomer. Further, the absence of localized electrons between their interaction points implied a physical binding mechanism. The results of the study could be used for future opto-electronic experiments and electrochemical biosensing applications of CNTs.

Abstract: To activate the early-age hydraulic reactivity of steel slag powder (SS), a method of using acetic acid (AA)-anhydrous alcohol solution to modify the SS via dry chemical modification technology was proposed. The compressive strength and hydraulic reactivity of SS pastes and SS blended cement pastes were investigated, then the mineral composition, surface morphology and specific surface area of unmodified SS and AA modified SS were characterized. The results show that calcite, portlandite and dicalcium ferrite in SS react with AA to produce calcium acetate and pores in the modified process, thus leading to AA modified SS with the greater specific surface area and rougher surface. Water is easier to absorb onto the surface of modified SS and enters the inner of SS particles along the pores, resulting in higher dissolution heat and reaction heat of active minerals in SS. The result show that, the higher 72 h cumulative hydration heat, the 3 d, 7 d and 90 d compressive strengths of AA modified SS pastes and AA modified SS blended cement pastes are obtained, compared to the unmodified pastes.

Abstract: Corrosion is the main problem in the processing of crude oil containing soap emulsion by using acetic acid based demulsifier. This study aims to analyze corrosion of API 5L Gr B steel pipe in the solution of 90% brine and 10% crude oil with addition of 2000 ppm of acetic acid based demulsifier at various concentration of amine based organic inhibitor. Corrosion testing was conducted using weight loss coupon. SEM and EDS analysis were performed to investigate corroded specimen. The weight loss results indicate that amine based organic inhibitor made the steel resistant to corrosion with an inhibitor effectiveness of up to 96.67% at a concentration of 40 ppm. SEM observation following with EDS analysis identifying the presence of inhibitor and corrosion product protection layer.

Abstract: Acid treatment of mordenite was conducted using acetic acid to increase the Si/Al ratio. The acid treatment of mordenite by acetic acid was performed using sonication. The various time of treatments was used to investigate the effect of sonication in acid treatment of mordenite. Mordenite and all samples after treatment were characterized by ICP, FT-IR, XRD, and ammonia adsorption to measure their acidity. The Si/Al ratio of mordenite was increased from 11.33 to 17.31, 19.47, and 20.58 respectively for 3, 6, and 9 h of sonication. This result was supported by the T‒O bond vibration of samples which shift to higher wavenumber. The increase of the Si/Al ratio was followed by the decrease of acidity. The XRD test result revealed partial loss of mordenite framework after acid treatment. The results indicated that the sonication method can be used for acid treatment of mordenite.

Abstract: Siwalan (Borassus flabellifer L.) is a palm family that is widely planted in the Tuban area of ​​East Java. Siwalan sap has a relatively high sugar content of about 10-15 g / 100 ml. The sap is obtained by tapping the inflorescences. In general, siwalan sap is used for fresh drinks or alcoholic beverages with maximum storage in 3 days. Based on the sugar content in the sap of siwalan, acetic acid products can be made through fermentation of glucose to ethanol, then the ethanol is fermented into acetic acid. Acetic acid is widely used as a preservative of food and health drinks. The purpose of this research is to study the effect of ethanol fermentation aerobic pH on acetic acid product. Anaerobic fermentation uses saccharomyces cereviceae to produce ethanol, and aerobic fermentation uses acetobacter aceti for acetic acid production. In aerobic ethanol fermentation using pH 3; 3.5; 4 and 5. The concentration of ethanol was analyzed using GC ULTRA Scientific Gas Chromatography, DSQ II detector, and MS 220 column. Acetic acid produced from the aerobic fermentation process was analyzed using an alkalimetric method. Anaerobic fermentation uses Saccharomyces cereviceae with 1-day log phase, while aerobic fermentation uses acetobacter aceti with a 5 day log phase. Aerobic fermentation to produce acetic acid was observed in 5 days to obtained maximum acetic acid concentration, the highest acetic acid concetration is about 2.595 g/l and yield of acetic acid is obtained 0.519% (b/v) at pH 5. Low acetic acid concentration due to low intitial sugar content in siwalan sap.

Abstract: In many cases, acetic acid is categorized as hazardous to health. A high-performance sensor for detecting acetic acid is urgently required. This study aims to observe the characteristics of quartz crystal microbalance (QCM) coated with polyacrylamide as an acetic acid sensor. For this purpose, we prepared the sensor by firstly coating with 1-dodecanethiol (using self-assembled-monolayers or SAM technique) followed subsequently by glutaraldehyde and polyacrylamide (PAM).As results, the sensors showed less sensitivity to humidity changes, which is one of the basic prerequisites for a stable sensor to an environment. We also obtained that the sensor showed relatively fast response time and high sensitivity to acetic acid vapor of about 96 seconds and 12.9 Hz/(mgL^-1), respectively. Further research, however, is still required to improve the sensitivity and specificity by choosing more selective polymers.

Abstract: Acetic acid is a clear liquid with a strong smell of acids. The danger of inhaling acetic acid vapors may cause irritation of the nose and throat. At high vapor levels, acetic acid may cause respiratory inflammation and can cause eye irritation and eye damage permanently. New detection methods of acetic acid are urgently required especially for practical applications. In this study, the acetic acid vapor sensor was developed by depositing polyethyleneimine (PEI) layer onto the two QCM substrates using well-known self-assembled monolayers (SAM) method. As results, the sensor was less sensitive to humidity. The sensor also showed high sensitivity and limit of detection limit (0.85 mg/L) to acetic acid.

Abstract: The study presents the extraction of collagen, a product of high value, from fleshings form hides. After testing several collagen extraction procedures we have proposed the simple and effective method to extract collagen from collagen-containing wastes of the leather industry. The unified method is based on the extraction of collagen using acetic acid in the presence of EDTA and included two repeated extraction stages. Qualitative analysis of the collagen using the disk-electrophoresis method showed a different ratio of monomers, dimers and other proteins.

Abstract: The present investigation is on the effect of red mud on the mechanical properties and durability of the geopolymer paste in sulphuric and acetic acid solution. Red mud and fly ash were used to form the geopolymer paste along with the alkalies. The variation of red mud in the paste composition was from 0% to 90%. Cylindrical shaped specimens of 1 inch diameter and 1 inch height were prepared. The specimens were immersed in 5% sulphuric acid and 5% acetic acid for 1, 7, 14, 28, 56 and 84 days and tested for weight loss, visual deformation, strength loss and colour of the solvent, based on the procedure specified by ASTM C 267 – 01. SEM/EDX Tests were performed on the geopolymer specimens. Test results show that initially, the strength of the geopolymer increased upon the addition of red mud. The strength was maximum when the percentage of red mud was 30%. The maximum strength obtained was 38 MPa for the paste containing 30% red mud using 10M alkali solution as against 31.69 MPa, when only fly ash was used. Geopolymer paste containing 30% and 50% red mud showed better resistance to acid attack. The strength loss was minimum for the samples containing 30% red mud in both inorganic and organic acid i.e. sulphuric and acetic acid.

Abstract: Polyvinyl Alcohol (PVA) is a biocompatible polymer with high mechanical strength used in the biomedical industry. While its features have biological properties, it lacks cell recognition sites that affect the entirety of cell proliferation and movement. To address this issue, gelatin (GEL) is added to the system to increase biomimetic properties. PVA and GEL nanofibers, produced from electrospinning, could provide new characteristics for tissue engineering applications. At present, aqueous solution of N,N-dimethylformamide (DMF), dimethyl sulfoxide (DMSO), and many other hazardous organic solutions are used in fabricating both PVA, GEL and PVA-GEL nanofibers, but it poses a great threat on sites that the solvent was unable to evaporate, affecting cell viability and motility. In this study, a new solvent system of deionized water, formic acid and glacial acetic acid was used to replace the current toxic solvent system utilized in electrospinning such polymers. Increasing amounts of formic acid and deionized water decreased further the fiber diameter of the PVA-GEL nanofibers. Further refinement in solution (PVA:GEL ratio) and process parameters (tip-to-collector distance and flow rate) produced much finer nanofibers, leading to a decrease in fiber diameter distribution. It is conclusive that a new alternative solvent system can be used in electrospinning PVA-GEL nanofibers that are non-toxic and exhibits much lower fiber diameter (≈20 nm) than the conventional solvents used before.