Chitosan-Aluminum Monostearate Composite Dispersion Characteristics

2012 ◽  
Vol 528 ◽  
pp. 233-236
Author(s):  
Kotchamon Yodkhum ◽  
Thawatchai Phaechamud
Keyword(s):  
Particle Size ◽  
Fatty Acid ◽  
Ph Value ◽  
Flow Behavior ◽  
Mixing Time ◽  
Buffer Solution ◽  
Solution Ph ◽  
Conjugate System ◽  
Mean Particle Size ◽  
Chitosan Concentration

Fatty acids have been used as additive for modifying chitosan-based system particularly in hydrophobic manner. Generally, techniques for preparing chitosan-fatty acid conjugate system are take time, involved with high temperature and high shear force and need some surfactants. In this study, alternative technique for simply blending chitosan with fatty acid was performed by taking advantage of ionization of metal stearate and chitosan in acidic condition. Metal stearate used in this study, aluminum monostearate (Alst), was dispersed in chitosan dissolved in lactate buffer solution pH 4.5 with various concentrations of chitosan. Physicochemical properties such as pH value, viscosity and rheology, morphology and particle size of the dispersions were characterized. The pH value and viscosity of the chitosan solutions was higher as the chitosan concentration was increased. For the dispersions, their pH value was not changed by mixing time but their viscosity was decreased by mixing time. All dispersions exhibited Newtonian flow behavior. Larger mean particle size of the dispersions was observed when the mixing time was longer. At higher chitosan concentration, mean particle size of the aggregated chitosan-stearate particles was smaller than the lower chiotsan concentration systems

scholarly journals Using lipase Candida rugosa as a catalyst for the biodiesel production from Tra fish (Pangasius hypophtalmus) oil

2015 ◽  
Vol 18 (1) ◽  
pp. 29-39
Author(s):  
Nhu Thi Tuyet Nguyen ◽  
Nguyen Thi Nguyen ◽  
Hoa Ngoc Phan
Keyword(s):  
Fatty Acid ◽  
Fish Oil ◽  
Specific Activity ◽  
Candida Rugosa ◽  
Free Water ◽  
Acid Value ◽  
Biodiesel Production ◽  
Molar Ratio ◽  
Buffer Solution ◽  
Solution Ph

In this work, lipase from Candida rugosa (LCR) was used as a catalyst for the transesterification reaction of fish oil with methanol. The research process consists of three stages: determine the material properties and the activity of the enzyme from Candida rugosa, transeter of fish oil with methanol catalyzed by the enzyme lipase, evaluation indicators of the quality of biodiesel obtained. Fish oil contains 62% unsaturated fatty acid, acid value of 2.2 mg KOH/g. Activity and specific activity of enzyme were respectively 1064 U/mg enzyme and 2782 U/mg protein. Factors affecting the efficiency of conversion of fatty acid methyl esters - FAME were investigated: the molar ratio of methanol/fish oil, ratio of enzyme/fish oil, temperature reaction, pH reaction, concentration of buffer and reaction time. Yield of biodiesel conversion was 92.65% with optimal conditions: rate of methanol/fish oil was 4:1, the ratio of enzyme/substract was 2%, reaction temperature was 40°C, additional 10% buffer solution pH 7 with 96 hour response time. Products biodiesel obtained FAME components accounted for 98.94%; density at 15°C is 0.8816 g/ml; no free water and glycerine, consistent with the original standard biodiesel (B100) (TCVN 7717:2007). However, the acid value of 1.7 mg KOH products/g higher than the allowable value.

The associations between high-density lipoprotein mean particle size and its fatty acid composition

2013 ◽  
Vol 7 (2) ◽  
pp. 235-245 ◽  
Author(s):  
Amirnader Emami Razavi ◽  
Morteza Pourfarzam ◽  
Mohsen Ani ◽  
Gholam Ali Naderi
Keyword(s):  
Particle Size ◽  
Fatty Acid Composition ◽  
Fatty Acid ◽  
High Density Lipoprotein ◽  
Acid Composition ◽  
Density Lipoprotein ◽  
High Density ◽  
Mean Particle Size

Preparation and Characterization of Danazol Nanoparticles for Dissolution Improvement

2018 ◽  
Vol 9 (SPL1) ◽  
Author(s):  
Luma Safa el-din Al-Hassnaui
Keyword(s):  
Particle Size ◽  
Phosphate Buffer ◽  
Phosphate Buffer Solution ◽  
Amorphous State ◽  
Volume Ratio ◽  
In Vitro Dissolution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Freeze Dried

Danazol is a synthetic steroid used for endometriosis treatment, haslow bioavailability as it is practically insoluble in water. This study has been carried out to prepare and characterize danazol nanoparticles by nanoprecipitation method at a different polymer to drug ratios of 0.5:1,1:1,2:1 and 3:1 using different polymers of CMC-30 and various grades of HPMC and PVP,as stabilizers. Variables that might affect the particle size as polymer type,polymer to drug ratio,temperature of precipitation,addition rate of danazol solution,volume ratio,time of stirring,concentrationof drug,have been investigated. The particle size of the prepared formulas has been in the nano-sized except those using CMC and the best formula has beenF20 at a polymer to drug ratio of0.5:1 which has given the smallest particle sizeof 33nm.The investigations of the drug–stabilizer compatibility havebeen studied by FTIR and DSC,crystalline state by XRD,size,and shape of nanoparticles by FESEM and the results showed that there has been no interaction between the danazol and stabilizer and there has been a partial conversion of danazol from crystalline to an amorphous state with a size below 100nm. Most of the studied factors havebeen found affect the particle size of the nanoparticles.The Entrapment efficiency has been (91.3% ± 0.4) in the (F20). The solubility study revealed that 6.75,4.97 and 5.1 folds increased of solubility of danazol for nanoparticles than that for raw in distilled water,0.1N HCl and in phosphate buffer of pH 6.8.The simple capsule has been prepared by incorporation of freeze-dried of F20 with lactose as a filler and the in vitro dissolution study has been conducted using 0.1N HCl (pH 1.2) with 2% w/v Brij-35,phosphate buffer solution(pH 6.8) with 2% w/v Brij-35as dissolution media. Within 30 minutes,100% of the danazol has been released from the nanoparticle capsule in both dissolution media compared to the raw and physical blend capsules as controls havebeen nearly complete in 120 minutes.One can conclude that Antisolvent method is an easy,efficient method to prepare danazol nanoparticles with an intense effect on solubility and faster in vitro dissolution rate than raw drug and its physical blend with stabilizer.

The Effect of Aging Temperature and pH Value of Aging Solution on the Microstructure of ZrO2-SiO2 Aerogels

2016 ◽  
Vol 697 ◽  
pp. 368-371 ◽  
Author(s):  
Ying Chen Qiao ◽  
Xiao Lei Li ◽  
Jian He ◽  
Hui Ming Ji ◽  
Zhu Rui Shen ◽  
...  
Keyword(s):  
Particle Size ◽  
Specific Surface ◽  
Size Distribution ◽  
Surface Area ◽  
Specific Surface Area ◽  
Alkaline Solution ◽  
Aging Temperature ◽  
Pore Volume ◽  
Ph Value ◽  
Solution Ph

ZrO2-SiO2 gels were prepared by prehydrolysis method with sol-gel process. Then,the wet gels were aged at different temperatures (60,110,170 °C) in ethanol or alkaline solution (pH=8). Finally, the monolithic ZrO2-SiO2 aerogels were obtained by supercritical fluid drying. N2 adsorption-desorption, scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FT-IR) were used to characterize the microstructure of aerogels. The aim of this research is to study the effect of aging temperature and pH value of aging solution on the microstructure of ZrO2-SiO2 aerogels. The results show that the specific surface area and pore volume of ZrO2-SiO2 aerogels aging in alkaline solution (pH=8) is lower than that of aging in the ethanol. And there is a shift of the pore size distribution towards larger values. This is because the cross-linking reaction in alkaline solution enlarges the particle size. As the aging temperature increases, the specific surface area and pore volume decrease and the particle size distribution of ZrO2-SiO2 aerogels is more uniform.

Study on the Removal Effect of Chromium(VI) in Wastewater by Rice Husk

2014 ◽  
Vol 1073-1076 ◽  
pp. 825-828 ◽  
Author(s):  
Xue Min Dai ◽  
Shu Na Wang ◽  
Xia Wang
Keyword(s):  
Particle Size ◽  
Rice Husk ◽  
Ph Value ◽  
Removal Rate ◽  
Experimental Studies ◽  
Optimal Conditions ◽  
Solution Ph ◽  
Adsorption Time ◽  
Chromium Vi

Rice husk was used as an adsorbent to study the adsorption of Cr (VI) from wastewater, Based on the experimental studies on influences of the particle size of rice husk, solution pH value, adsorption time, temperature and rice husk dose, the optimal conditions of the adsorption were determined as follows: temperature of 35°C, pH of 2, the particle size of rice husk in the range of 80-100 mesh, adsorption time of 3h, dose of 30g/0.2g. Under the optimal conditions, the removal rate of chromium from wastewater by rice husk can reach 91%.

scholarly journals Effects of Buffer Concentration on the Sensitivity of Silicon Nanobelt Field-Effect Transistor Sensors

Sensors ◽  
2021 ◽  
Vol 21 (14) ◽  
pp. 4904
Author(s):  
Chi-Chang Wu ◽  
Min-Rong Wang
Keyword(s):  
Field Effect ◽  
Field Effect Transistor ◽  
Crystalline Silicon ◽  
Ph Value ◽  
Buffer Concentration ◽  
Buffer Solution ◽  
Solution Ph ◽  
Effect Transistor ◽  
Response Current ◽  
Biomolecule Sensing

In this work, a single-crystalline silicon nanobelt field-effect transistor (SiNB FET) device was developed and applied to pH and biomolecule sensing. The nanobelt was formed using a local oxidation of silicon technique, which is a self-aligned, self-shrinking process that reduces the cost of production. We demonstrated the effect of buffer concentration on the sensitivity and stability of the SiNB FET sensor by varying the buffer concentrations to detect solution pH and alpha fetoprotein (AFP). The SiNB FET sensor was used to detect a solution pH ranging from 6.4 to 7.4; the response current decreased stepwise as the pH value increased. The stability of the sensor was examined through cyclical detection under solutions with different pH; the results were stable and reliable. A buffer solution of varying concentrations was employed to inspect the sensing capability of the SiNB FET sensor device, with the results indicating that the sensitivity of the sensor was negatively dependent on the buffer concentration. For biomolecule sensing, AFP was sensed to test the sensitivity of the SiNB FET sensor. The effectiveness of surface functionalization affected the AFP sensing result, and the current shift was strongly dependent on the buffer concentration. The obtained results demonstrated that buffer concentration plays a crucial role in terms of the sensitivity and stability of the SiNB FET device in chemical and biomolecular sensing.

Removal of Perfluorooctanoate from Water by Polyaluminium Chloride Coagulation

2012 ◽  
Vol 610-613 ◽  
pp. 1784-1788
Author(s):  
Liu Yang ◽  
Li Zhao ◽  
Peng Yu Liu ◽  
Zong Shuo Li ◽  
Qing Chang
Keyword(s):  
Ph Value ◽  
Removal Rate ◽  
Mixing Time ◽  
Model Solution ◽  
Neutral Solution ◽  
Solution Ph ◽  
Polyaluminum Chloride ◽  
Ph Values ◽  
Coagulation Process ◽  
Slow Mixing

The removal of perfluorooctanoate （PFOA） and turbidity from model solution by coagulation was investigated. A polyaluminum chloride (PACl) was used as a coagulant in the coagulation process. The effects of coagulant dose, slow mixing time, solution pH value and initial turbidity on the removal of both PFOA and turbidity from water were studied. It was found that the removal rate of PFOA in water increase along with the increase in slow mixing time, initial turbidity and PAC dose. The removal rate of PFOA is more effective at the near neutral solution pH values and the high initial turbidity. The removal percents of PFOA exceed 80% at the optimal condition. The removal mechanism was speculated to be the electrostatic interaction and hydrophobic interaction in coagulation process.

A Transient Simulation for Analysis of Volume Transition of pH-Sensitive Hydrogel in Micro-Channel

2009 ◽  
Vol 74 ◽  
pp. 25-28
Author(s):  
Hua Zou ◽  
Hua Li
Keyword(s):  
Ph Value ◽  
External Solution ◽  
Ionic Species ◽  
Ph Sensitive ◽  
Swelling Behavior ◽  
Bathing Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Smart Hydrogel ◽  
Ph Sensitive Hydrogel

Based on Donnan’s equilibrium, a simple chemo-mechanical model is developed to study the transient swelling behavior of the pH-sensitive hydrogel for design and optimization of smart hydrogel-based BioMEMS device. The model is mathematically composed of several governing equations, including Fick’s law which describes the diffusion process in the buffer solution, the fixed charge density formula associated with pH value of the buffer solution, and mechanical equation which gives the swelling ratio responding to pH. The model also considers several chemical conditions, including Donnan’s equilibrium condition which gives Donnan partitioning ratio relating to the concentrations of ionic species in the interior hydrogel and the external solution, the electroneutrality condition in the interior hydrogel and bathing solution as well. The model is capable of predicting the kinetics process of the smart hydrogel immersed in buffer solution with change in pH. The simulation of the diffusion-swelling behavior of the pH-sensitive hydrogel is presented, and the responsive deformation of the smart hydrogel to the solution pH is discussed in detail.

Research on Microbial Degradation of Bamboo Lignin for Extraction of Natural Bamboo Fiber

2013 ◽  
Vol 650 ◽  
pp. 273-278
Author(s):  
He Li ◽  
Guo Ying Zhou ◽  
Jian Liu ◽  
Sheng Jie Wang
Keyword(s):  
Microbial Degradation ◽  
Ph Value ◽  
Orthogonal Experiment ◽  
Bamboo Fiber ◽  
Ammonium Tartrate ◽  
Optimal Conditions ◽  
Buffer Solution ◽  
Solution Ph ◽  
Natural Bamboo Fiber ◽  
Liquid Quantity

This study optimizes on the technological conditions for extraction of natural bamboo fiber by means of microbial degradation of bamboo lignin. Results show that by the orthogonal experiment, we have studied out optimal conditions for combining three strains with fermentation to produce enzyme: 10.0 g/L glucose, 0.2 g/L ammonium tartrate, 4.5 buffer solution pH value and 20.0/250 ml loading liquid quantity. In these above four factors, the primary and secondary factors affecting enzyme production are: carbon source > pH value > loading liquid quantity > nitrogen source. Meanwhile, the experiment has studied the influence of single factor on lignin degradation: at the temperature of 37 °C, about 4 x 107spore concentration, adding 1.5 mg/L veratryl alcohol and introducing air at the efflux rate of 1 L/min are bamboo crude fiber optimal conditions for microbial selective degradation of lignin.

scholarly journals Skin Penetration of Ubiquinone (Co-Q10) In Nanoemulsion Delivery System Using Virgin Cocunut Oil (Vco)

2018 ◽  
Vol 8 (2) ◽  
Author(s):  
Tristiana Erawati M ◽  
Widji Soeratri ◽  
Noorma Rosita
Keyword(s):  
Droplet Size ◽  
Delivery System ◽  
Ph Value ◽  
Coconut Oil ◽  
Tween 80 ◽  
Skin Penetration ◽  
Acetate Buffer Solution ◽  
Buffer Solution ◽  
Solution Ph ◽  
Droplet Morphology

Ubiquinone (co-Q10) is a topical anti-aging with low solubility in water, so its penetration into the skin is also low. To increase its penetration ubiquinone (co-Q10) was loaded in the nanoemulsion delivery system using virgin coconut oil (VCO) as oil phase. Ubiquinone (co-Q10) in nanoemulsion formula consists of; ubiquinone (co-Q10), Tween 80, Span 80, ethanol 96%, VCO and acetate buffer solution pH 4.2 ± 0.5 with concentration; 1%; 18.66%; 1.92%; 3.42%; up to 100%, respectively. The characteristics of ubiquinone (co-Q10) nanoemulsion were observed in terms of droplet morphology by transmission electron microscope (TEM) and droplet size by particle analyzer, the pH and viscosity value. The ubiquinone (co-Q10) penetration test in the nanoemulsion system was compared with the emulsion on the rat skin. Result of this research showed the droplet morphology of ubiquinone (co-Q10) in nanoemulsion was spherical. The droplet size was 93.2 ± 2.78 nm. The pH value was 4.12 ± 0.02, and the viscosity was 8.5 cPas. Penetrasi of ubiquinone (co-Q10) in nanoemulsion was deeper (269 ± 48.12 and 993 ± 36.49 μm) than in emulsion (26.33 ± 6.43 and 110.33 ± 9.124 μm), after 2 and 6 hours sample application.

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