Experimental and computational phase behavior analysis of the PGME+CO2 and PGMEA+CO2 mixture at high pressures

권영택,Dhamodharan Duraisami,최환,심성원,변헌수 한국화학공학회 2022 Korean Journal of Chemical Engineering Vol.39 No.10

The vapor+liquid equilibrium (VLE) for the 2-components of propylene glycol monomethyl ether (PGME) and propylene glycol monomethyl ether acetate (PGMEA) in high pressure (HP) supercritical carbon dioxide (S-CO2) was evaluated. The solubility data determination was performed by the synthetic method at T=(313.2 to 393.2) K and p=(1.92 to 16.5) MPa. The obtained results indicated that the solubility of S-CO2 was found to increase monotonically with the increase of system temperature and mole fraction of PGME and PGMEA in binary (solute+solvent) mixtures. The solubility curve of PGME and PGMEA in the PGME+S-CO2 and PGMEA+S-CO2 models increases in connection with the increasing T at a steady pressure. The PGME+S-CO2 and PGMEA+S-CO2 models reveal type-I phase behavior (PB). The critical properties were achieved by Joback and Aspen plus method. Moreover, the experimental result adequately correlated with the Peng-Robinson equation of state (P-R E-O-S). Root mean square deviation (RMSD) for the PGME+S-CO2 [Joback: kij=0.0, hij=0.060, Aspen: kij=0.0, hij=0.065] and PGMEA+S-CO2 [Joback: kij=0.0, hij=0.0, Aspen: kij=0.0, hij=0.0] systems using two factors determined at 353.2 K was 9.07% (Joback), 10.98% (Aspen) and 4.03% (Joback), 4.78% (Aspen), respectively.

Synthesis of an antibiotic-preserving antimicrobial tetracycline-loaded gellan gum gel

Paramasivam Gokul,Dhamodharan Duraisami,Kishore Somasundaram Chandra,변헌수 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9

Gels play a significant role in our daily lives as they provide stability and desired features to various items of regular use, such as cosmetics, pharmaceuticals, household items, and agricultural products. However, a microbial attack on gels commonly occurs during gel-based formulations. Antibiotic-loaded gels can reportedly be stored for a long time. In this study, we fabricated a tetracycline-loaded gellan gum (TC/GG) gel and assessed its long-term stability against microbial attack. Morphological analyses revealed a firm and smooth texture with multifold bumpy surfaces on the GG and TC/GG gels. Fourier transform infrared spectroscopic analysis showed that the gel was well hydrated and thus suitable for releasing antibiotics. The feasibility of inhibiting microorganisms was qualitatively examined using the disk diffusion method. Interestingly, the unloaded GG gel itself exhibited an antimicrobial effect, while the loaded TC/GG gel showed a better antibacterial effect on S. aureus than on E. coli. TC/GG can be used to store and protect gels from microbial attacks for a long duration. In addition, it is suitable for storing bioactive agents, which are used in the biomedical field.

Numerical and experimental investigations on the mechanical behavior of additively manufactured novel composite materials for biomedical applications

Dhinakaran Veeman,Duraisami Dhamodharan,Mohankumar Subramaniyan,G.J. Surendhar,Chunhui Yang,Hun-Soo Byun 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.125 No.-

Polymer composites have a great scope which provides improvised mechanical and chemical propertiesthan matrix material. Although most composite materials are relatively strong, they are not sustainable. The sustainability and reusability of the material is significantly affected by the incorporation of nondegradablefillers. Bael bark is a naturally occurring material with numerous medical properties; in thisstudy, Bael bark was dried, synthesized and converted into nano-filler for integrating them in polylactide(PLA) matrix. PLA is a widely used biopolymer in the biomedical sector. The filler and matrix material areboth biodegradable; therefore, the resulting composite is also expected to be biodegradable. This studyaims to develop a composite comprising Bael bark and PLA, which is a better alternative to PLA in termsof strength and sustainability. Bael bark-reinforced PLA matrices were synthesized with different Baelbark compositions, i.e., 5 wt.%, 10 wt.%, 15 wt.%, and 20 wt.%. Subsequently, the resulting compositeswere subjected to filament characterization tests such as single fiber tensile test (SFTT), scanning electronmicroscopy (SEM), and X-ray diffraction (XRD). Notably, all extruded composites exhibited a uniform distributionof filler materials. Tensile, compression, and flexural tests were also conducted on the additivelyfabricated samples. The tensile strength, compressive strength and Flexural strength of composite specimenswere higher than neat PLA material, with increments of 39%, 33.8%, and 33.9%, respectively, for thecomposite made with 15 wt.% composites. Using a commercial finite element code ABAQUS, numericalsimulations were performed on tensile, compression and flexural specimens. The simulation resultsare in good agreement with the experimental results.

Development of Antibiotic-Protected Antimicrobial Tetracycline-Loaded GU (Guar Gum) Gel for Long-Term Storage

Paramasivam Gokul,Dhamodharan Duraisami,변헌수 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.3

Gels are widely used in our everyday lives, spanning personal care, cosmetics, oral care, food and beverages, household products, medical supplies, electronics, and arts and crafts. Their adaptable characteristics contribute to improved product performance, user satisfaction, and overall convenience. However, generation of microbial invasion is a common obstacle observed on gels and its formulations. Antibiotic loaded on gels is a better alternative to chemical-based preservative for long-term storage of gels. In this research, the gel was fabricated with two diff erent components with guar gum (GU) and tetracycline (TC) and its antimicrobial ability was tested over a period of time. We conducted morphological analyses that revealed a solid and rough surface on both GU and reduced sign of microbial attack on TC/GU-based gels. Identifi cation of functional groups is observed using Fourier transform infrared (FTIR) spectroscopy that confi rms the gel is well hydrated and make it suitable to deliver antimicrobial agents. Antimicrobial ability performed by antibiotics was tested using disc diff usion method. The unloaded GU gel does not exhibit an observed antimicrobial property, whereas GU/TC gel reveals a better antibacterial effi ciency on S. aureus compared to E. coli . Our fi ndings suggest that GU/TC gel can eff ectively safeguard gels from microbial attacks during long-term storage. Furthermore, this GU/TC gel can be used as a drug transport system for bioactive agents in biomedical applications.

Synthesis and Characterization of Silver Nanoparticles from Marine Streptomyces parvisporogenes KL3 for Effective Antibacterial and Larvicidal Applications

Thirumurugan Durairaj,Dhamodharan Duraisami,Thanigaivel Sundaram,Vadivalagan Chithravel,Vijayakumar Ramasamy,변헌수 한국화학공학회 2024 Korean Journal of Chemical Engineering Vol.41 No.4

Recent studies have emphasized the application of nanoscience and nanotechnology to disease prevention, diagnosis, and treatment. This study examined the use of marine actinobacteria in the synthesis of silver nanoparticles (AgNPs). UV–Vis spectrophotometry, Fourier infrared spectroscopy, X-ray diff raction, scanning electron microscopy, and energy dispersive X-ray spectroscopy were used to characterize the primary structure, crystalline nature, functional groups, shape, and elemental signal of the synthesized AgNPs. The mean particle diameter of the AgNPs was measured, and the size was found to be between 23 and 27 nm. The antibacterial activity of the AgNPs was evaluated; it showed enhanced inhibitory activity against Escherichia coli , Bacillus subtilis , and Klebsiella pneumoniae . At an AgNP concentration of 40 g/mL, the test pathogen growth was completely inhibited. The larvicidal property of the synthesized AgNPs showed enhanced activity against An. stephensi (LC5017.511 and LC9050.572), A. aegypti (LC50 22.481 and LC90 61.920), and Cx. quinquefasciatus (LC50 29.548 and LC90 73.123). By analyzing the phenotypic data, the 16S rRNA gene sequence, and the phylogenetic data, the probable isolate was also determined to be Streptomyces parvisporogenes KL3. The study results prove that biosynthesized AgNPs can be used as eff ective antibacterial and larvicidal agents in drug formulation.

Anticorrosive efficiency and adsorption characteristics of natural plant gums on mild steel exposed to the Diesel/Saline water biphasic system

Palanisamy Raji,Jayaprakash Jayapriya,Dhamodharan Duraisami,변헌수 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.9

Metallic equipment and structures that come in contact with a variety of petroleum products, solvents, water, the atmosphere, and soil in the oil and gas industry are highly prone to a range of corrosion phenomena, which escalate the risk of serious accidents. The use of green corrosion inhibitors in oil and gas can significantly reduce the maintenance and service costs. This study focuses on the anti-corrosive behavior of natural exudate gums, such as Azadirachta indica (G1), Moringa oleifera (G2), Prosopis juliflora (G3) and Prunus dulcis (G4). These gums were evaluated as corrosion inhibitors on mild steel against the diesel/saline water biphasic system by the weight loss method and electrochemical techniques. The inhibition efficiency was high at 93.86, 95.75, 92.42, and 90.02% at the highest tested concentration (5,000 ppm) for the gums G1, G2, G3, and G4, respectively. Among the investigated natural gums, the lowest corrosion rate (29.36 mm yr−1) and highest inhibition efficiency (95.75%) were achieved with Moringa oleifera (G2) at 5,000 ppm. The activation energy of the corrosion inhibition process (4.00–38 kJmol−1) was higher than that of the uninhibited system (1.8 kJmol−1), indicating that the inhibited systems possessed higher energy barriers and followed the Langmuir adsorption process. Our corrosion test results validate that the Moringa oleifera gum can serve as an effective eco-friendly corrosion inhibitor for mild steel in the biphasic system of diesel/saline water.