Effects Of Citric Acid Content Research Articles

Effect of citric acid content on magnetic property of magnetite particles for detecting virus

Effect of citric acid content on magnetic property of magnetite particles for detecting virus

Chromium removal capability, water resistance and mechanical behavior of foams based on cellulose nanofibrils with citric acid

Cellulose is a natural polysaccharide with beneficial adsorbent characteristics and a correct ecologically alternative material to design new adsorbents for water remediation contaminated with pollutants, such as metal ions that are toxic and nocive against biological systems. In this contribution, we confected foams based on cellulose nanofibrils (CNFs) with citric acid, an organic tricarboxylic acid from biosources, via a freeze-drying approach. Also, we investigated the effect of citric acid content and heat finishing treatment on the activation of crosslinking reactions in the foams. The increase of citric acid content causes slight enlargement of pore size and reduction of the activation energy for the thermal decomposition of amorphous cellulose in the foams. The heat treatment significantly affects only the cellulose releasing rate in water. The mechanical behavior of the CNF foams is changed after wetting. The CNF foams presented a two-step mechanism for the chromium adsorption kinetic, involving a pseudo-second-order and intraparticle diffusion in neutral pH via reversible physisorption. Besides the metal adsorption capacity, the foams presented suitable water resistance to be applied as adsorbant in aqueous media, releasing low cellulose content via Fickian diffusion with an initial burst effect. • Cellulose foams with citric acid as green adsorbents for heavy metals. • Eco-friendly preparation of cellulose foams via freeze-drying. • Thermodynamic and kinetics for the chromium adsorption by cellulose foams. • Cellulose releasing of cellulose foams as a water resistance test. • The effect of citric acid content on cellulose foam properties.

Preparation and properties of jute stick particleboard using citric acid–glycerol mixture as a natural binder

The application of citric acid and glycerol as natural binder was investigated for the manufacturing of jute stick particleboard in this study. The effects of citric acid content (0–30 wt%), citric acid and glycerol mixture (ratio of CA–G), and pressing temperatures on the properties of jute stick particleboard were investigated. Citric acid-bonded jute stick particleboard had good mechanical properties and dimensional stability when citric acid concentration was 20 wt% at pressing temperature of 200 °C. By addition of glycerol concentration (40/60), the properties were further increased. The modulus of rupture (MOR) and thickness swelling (TS) values of CA–G (40/60) bonded jute stick particleboard were 19.67 N/mm2 and 9%, respectively, which satisfy the minimum requirement for type-18 of particleboard JIS A 5908 (2003). FTIR analysis confirmed the formation of ester linkage by polymerization reaction between carboxyl groups and alcohol groups. Citric acid and glycerol polymer reacted with jute stick particles and produced cross-linked networks with enhanced properties, hence improved the adhesiveness during particleboard production. It could be concluded that citric acid and glycerol mixture can be a potential natural binder for the production of jute stick particleboard.

Citric acid cross-linked chitosan for inhibiting oxidative stress after nerve injury.

Scaffold design is particularly important and necessary for soft tissue repair such as nerve tissue repair. In this article, we designed and manufactured a macroporous chitosan-based hydrogel with excellent cell compatibility and antioxidant properties. Here, the chitosan (CS) based hydrogel is obtained by repeated freezing and thawing using citric acid (CA) as a cross-linking agent. We have evaluated the effects of citric acid content on the physical and chemical properties of hydrogels through mechanical properties and scanning electron microscopy. CA-CS hydrogel shows a macroporous structure, as the citric acid increases, the mechanical strength increases and the pore size decreases. In vitro cell experiments show that CA-CS hydrogel partakes positive effects on cell survival, adhesion and proliferation, as well as antioxidant properties. All results provide a basis for the construction of porous chitosan-based hydrogels, while demonstrating a promising approach to deal with oxidative stress in nerve injury.

Fabrication, characterization, and antibacterial properties of citric acid crosslinked PVA electrospun microfibre mats for active food packaging

In this study, electrospun poly(vinyl alcohol) (PVA) microfibre mats incorporated with clove oil (CO) with high water‐stability and water absorption ability were prepared through a heat‐induced in situ cross‐linkage with citric acid (CA). The effects of CA content on the electrospinning solution properties and physical properties of the crosslinked microfibre mats were investigated. The Fourier transform infrared spectroscopy showed that the esterification could occur between hydroxyl groups on the PVA and carboxyl groups on citric acid. The established strong interactions of citric acid and PVA after crosslinking improved the thermal stability, mechanical properties, contact angle, and water stability. The bacterial growth kinetics and the disk diffusion assay proved that the PVA/CA/CO microfibre mats had an obvious inhibitory effect on E. coli and S. aureus. The results showed the PVA/CA/CO microfibre mats would be a promising package material for food products.

High quality sugarcane bagasse-citric acid particleboards

The productivity of Indonesian sugarcane plantation, especially in East Java province reached 1.186.515 tonnes in 2017. Sugarcane liquid is extracted as sugar raw material and set aside sugarcane bagasse as waste of about 30% from total sugarcane weight. Usually sugarcane bagasse is burned to operate boiler in sugarcane mill. Meanwhile, the utilization of sugarcane bagasse, combine with citric acid for high quality particleboards production would be highly recommended. In this study, effect of citric acid content and pressing temperature on sugarcane particleboards properties were analysed. The size and target density of particleboards were 300 x 300 x 9 mm and 0.8 g/cm3, respectively. Citric acid liquid (59%) were sprayed onto sugarcane particles, with varied citric acid content (10, 15, 20 % of sugarcane particle weight). To evaporate water, sugarcane particles which already contain citric acid were pre-dried in oven of 80°C for 6h until the moisture content in sugarcane particles-citric acid was less than 3%. Subsequently, the boards were produced under pressing temperature of 180°C and 200°C, for 10 min. The physical properties of boards produced using 25% citric acid and pressed at 200°C (thickness swelling 4.43%; water absorption 29.48%) were superior than the others boards. The infrared (IR) spectra analysis showed the presence of ester linkage, representing that the carboxyl groups of citric acid had reacted with the hydroxyl groups of the sugarcane particles, providing the boards good physical properties. The boards mechanical properties were fulfilled the requirement of the JIS A 5908:2003 for particleboards type 18 (modulus of rupture 21.88 N/mm2, modulus of elasticity 3944 N/mm2, internal bond 1.03 N/mm2, screw withdrawal 393 N).

Effect of citric acid content and extractives treatment on the manufacturing process and properties of citric acid-bonded Salacca frond particleboard

This study focused on the effect of an extractive treatment and the application of citric acid on the properties of particleboard made from Salacca frond. In general, extractives have a negative effect on the bondability of synthetic resin. However, the effect of extractives on the bonding mechanism of citric acid as the biobased adhesive is unclear. Unextracted and extracted Salacca frond were used as the raw materials. A hot water extractive treatment was conducted by boiling the particles for 2 h. The boards were manufactured under the following conditions: citric acid content of 0%; 10%; 20% weight percent (wt%), pressing temperature of 180 °C, and pressing time of 10 min. The target density was set at 0.8 g cm-3. The results showed that the addition of citric acid resulted in an increase in the physical and mechanical properties of the particleboard. Interestingly, when a 20% citric acid content was applied, there were no siginificant differences in the physical or mechanical properties of the particleboards made from unextracted and extracted particles. Based on these results, it was concluded that when citric acid is used as adhesive, the hot-water extractive treatment of Salacca frond is not needed.

KARAKTERISTIK PAPAN PARTIKEL DARI LIMBAH KULIT KACANG TANAH DENGAN PEREKAT ALAMI ASAM SITRAT DENGAN PELARUT ASAP CAIR

Binderlessboard is one of the potential eco friendly products that can be developed. Utiliation of natural adhesives for non-wood composite is still very limited. Therefore, this research is focused on effects of citric acid content and pressing time on characteristics of particleboard made from peanut shell including its durability to dry wood termite attacks. Peanut shell particles were used as raw materials. Citric acid dissolved in liquid smoke which functioned as a water substitute solvent under a certain ratio and the concentration of the solution was adjusted to 60%. The use of liquid smoke is expected to increase the durability of the particleboard. Factors used in this research were citric acid content (10-30% based on dry weight particles) and pressing time (10 minutes and 15 minutes). Properties of particleboard were analyed based on Japanese Industrial Standard (JIS) A 5908 for particleboard. The dry wood termite resistance was then analyzed for its weight loss and mortality after 4 weeks. The results showed that the best particleboard was obtained from the treatment of 30% citric acid content with 15 minutes of pressing time where only the modulus of rupture and modulus of elasticity did not met the requirement of JIS A 5908 type 8 with the thickness swelling were 3.276%, water absorption were 44,991%, internal bonding were 4.679 kgf / cm², modulus of rupture were 26.822 kgf / cm², and modulus of elasticity were 8,986,058 kgf / cm². The best value of weight loss and mortality of dry wood termites on particleboard was obtained in a combination of 30% citric acid content with 10 minutes pressing time were 1.083% and 38.67% respectively.

Polyvinyl Alcohol (PVA)/Starch Bioactive Packaging Film Enriched with Antioxidants from Spent Coffee Ground and Citric Acid

The bioactive packaging polyvinyl alcohol (PVA)/starch films were prepared by incorporating combined antioxidant agents i.e. extracted spent coffee ground (ex-SCG) and citric acid. Effect of citric acid content on chemical compatibility, releasing of antioxidant, antibacterial activities, and physical and mechanical properties of PVA/starch incorporated ex-SCG (PSt-E) films was studied. The results of ATR-FTIR spectra showed that antioxidant agents of ex-SCG can penetrate into the film and the ester bond of blended films by citric acid was also observed. The presence of ex-SCG increased efficiency of antioxidant release and antimicrobial activity. The PSt-E film incorporated 30 wt% citric acid showed minimum inhibitory concentration against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). The incorporation of ex-SCG and citric acid into film showed a synergistic effect on antibacterial activity. The water resistance and kinetic moisture sorption improved with incorporation of citric acid. The tensile strength and biodegradability of samples were in range of 5.63–7.44 MPa and 65.28–86.64%, respectively. Based on this study, PSt-E film incorporated 30 wt% citric acid can be applied as novel food packaging materials.

Determination of In Situ Esterification Parameters of Citric Acid-Glycerol Based Polymers for Wood Impregnation

The development of wood treatments is of increasing industrial importance. A novel technique for improving the properties of lodgepole pine and white pine through modification of the microstructure is described. The present investigation is devoted to the synthesis and determination of in situ parameters of citric acid and glycerol based polymers for wood impregnation. This solvent free approach is environmentally friendly and achieved through an esterification condensation reaction under acidic conditions. Crude glycerol and citric acid reactants were cross-linked via a curing process at 160 °C creating a polymer with only water as the byproduct. The ester bonds and crosslinking levels were controlled using different catalysts and citric acid contents and related to the reaction time and temperature. The nature of bonding within the polymers and at the wood cell walls was determined by FT-IR analysis. The thermal properties such as glass transition temperature (Tg) were studied using TGA/DSC and the effect of citric acid content and catalyst type determined. Dimensional stability of impregnated wood samples improved above 50% for each sample with HCl and p-TSA catalysts compared to control samples. FTIR spectra were studied to show the presence of the ester linkages of the polymer in situ at the wood cell walls. Bonding between the polymer and wood macromolecules were observed by scanning electron microscopy and interpreted as evidence of chemical bonds at the wood cells. When prepared using a catalyst, the polymer was intimately incorporated into wood structure significantly improving the substrate dimensional stability. Enhanced stability makes this approach of particular interest for exterior wood products especially as a green renewable option for the wood industry.

Utilization of sweet sorghum bagasse and citric acid for manufacturing of particleboard I: Effects of pre-drying treatment and citric acid content on the board properties

Recently, the investigation of wood-based composites produced using agricultural waste and natural adhesives has become very important due to the decreased wood resources and fossil resource reserves. In this study, sweet sorghum bagasse and citric acid were used as the raw material and natural adhesive, respectively, for the experimental manufacture of particleboards. A pre-drying treatment of sprayed particles was performed to observe the effect of the pre-pressing moisture content of sprayed particles on the physical properties of the particleboards. In addition, the effect of the citric acid content on the physical properties of the particleboards was investigated. The boards were manufactured under the pressing conditions of 200°C for 10min. The citric acid content was varied in the range of 0–30wt%. The board size and target density were 300×300×9mm and 0.8g/cm3, respectively. Particleboards manufactured using phenol formaldehyde (PF) resin and polymeric 4,4′-methylenediphenyl isocyanate (pMDI) were used as references. The physical properties of boards prepared using pre-dried particles were superior to those of the boards prepared using non-dried particles. The physical properties of boards improved with increasing citric acid content up to 20wt%. The physical properties of boards bonded with 20wt% citric acid satisfied the requirement of the JIS A 5908 (2003) 18 type. In addition, the properties of these boards were comparable to those of boards bonded using PF resin and pMDI. Infrared (IR) spectral analysis suggested the presence of ester linkages, indicating that the carboxyl groups of citric acid had reacted with the hydroxyl groups of the sorghum bagasse to give the boards good physical properties. Consequently, it was concluded that pre-drying treatment of the particles and a citric acid content of 20wt% were effective in manufacturing particleboards composed of sweet sorghum bagasse and citric acid.

Properties of polyvinyl alcohol/xylan composite films with citric acid

Composite films of xylan and polyvinyl alcohol were produced with citric acid as a new plasticizer or a cross-linking agent. The effects of citric acid content and polyvinyl alcohol/xylan weight ratio on the mechanical properties, thermal stability, solubility, degree of swelling and water vapor permeability of the composite films were investigated. The intermolecular interactions and morphology of composite films were characterized by FTIR spectroscopy and SEM. The results indicated that polyvinyl alcohol/xylan composite films had good compatibility. With an increase in citric acid content from 10% to 50%, the tensile strength reduced from 35.1 to 11.6MPa. However, the elongation at break increased sharply from 15.1% to 249.5%. The values of water vapor permeability ranged from 2.35 to 2.95×10−7g/(mm2h). Interactions between xylan and polyvinyl alcohol in the presence of citric acid become stronger, which were caused by hydrogen bond and ester bond formation among the components during film forming.

Effect of citric acid content on the structural and magnetic properties of SrFe 12O 19 thin films

Strontium hexaferrite SrFe 12O 19 thin films have been synthesized on the Si (100) substrate using spin coating sol–gel process. The influence of different citric acid to metal ions (CA/MN) molar ratios of 0.5, 1 and 1.5 on the formation of SrFe 12O 19 was investigated. Fourier transform infrared analysis and theoretical calculations were conducted to determine and help control the concentration of metal citrates in solution precursors. X-ray diffraction, scanning electron microscopy and vibrating sample magnetometer techniques were also applied to evaluate the composition, microstructure, crystallite size and magnetic properties of the SrFe 12O 19 thin films. The results showed that single phase strontium hexaferrite thin films with optimum physical properties can be obtained from the solution with the CA/MN molar ratio of 1 after calcination at 800 °C. The SrFe 12O 19 thin films synthesized with the CA/MN molar ratio of 1 exhibited crystallite size of 42 nm and isotropically magnetic properties of M s = 267.5 kA/m (at 795.8 kA/m), M r = 134 kA/m, and H c = 341.4 kA/m.

Effect of citric acid content on synthesis of LiNi 1/3Mn 1/3Co 1/3O 2 and its electrochemical characteristics

LiNi 1/3Mn 1/3Co 1/3O 2 has been synthesized using different citric acid (chelating agent) contents to study the effect on morphology and electrochemical characteristics of the powdered compound synthesized. The citric acid content is expressed as R′ which is the ratio of citric acid to metal ions. The processing with large value of R′ yields the powder having particle size of about 200 nm. X-ray diffraction (XRD) analysis shows the powder has single phase layered rhombohedral structure. First cycle coulombic efficiency of the powder prepared with R′ = 3, is ∼93% in the voltage range of 4.6–2.5 V.