scholarly journals Nanocellulose extraction and surface modification toward active packaging applications

2017 ◽  
Author(s):  
◽  
Ying Wu
Keyword(s):  
Surface Modification ◽  
Sulfuric Acid ◽  
Surface Charge ◽  
Acid Hydrolysis ◽  
Average Particle Size ◽  
Deep Eutectic Solvent ◽  
Dry Mass ◽  
Active Packaging ◽  
Average Particle ◽  
Hemicellulose Removal

Cellulose nanocrystals (CNCs) have attracted growing interest as a renewable nanomaterial. The main objective of this study was to explore the extraction of CNCs from switchgrass and surface modification of CNCs into antimicrobially active nanomaterials for active packaging application. Switchgrass was first fractionated via different pretreatment/pulping methods (i.e., acid-chlorite pretreatment, organosolv pretreatment, and deep eutectic solvent (DES) pretreatment), yielding high cellulose-enriched pulp (greater than 75.53 percent cellulose). Acid-chlorite pretreatment was the most effective for delignification, removing 97.80 percent lignin from switchgrass. In contrast, DES pretreatment was more effective for hemicellulose removal (greater than 79.55 percent xylan). Fourier transform infrared (FTIR) spectra also showed significant lignin and hemicellulose removal and enrichment of cellulose after pretreatment. Post-treatment with NaOH and H2O2 bleached organosolv and DES pulp, making them more suitable for CNCs extraction via sulfuric acid hydrolysis. The yields of CNCs extracted from the resulting pulps ranged from 30.52 to 35.82 percent (based on the dry mass of pulp loaded) via sulfuric acid hydrolysis with the highest yield observed with mildly post-treated ChCl: FA pulp. The surface charge of the prepared CNCs ranged from -20.30 to -26.70 mV. And the average particle size ranged from 63.55 to 222.20 nm. Surface modification by grafting polyethyleneimine (PEI) onto the surface of CNCs with carboxylic groups endowed CNCs with antimicrobial activity, especially toward Gram-positive bacteria Bacillus megaterium. The modified CNCs (CNCs-PEI) showed positive surface charge, indicating successful cationization. FTIR also confirmed the presence of PEI on surface modified CNCs. Incorporation of CNCs-PEI by 5 percent into PVA film improved its mechanical strength remarkably. This study demonstrated successful extraction of CNCs from switchgrass and development of antimicrobially active CNCs via surface modification toward active packaging applications. Antimicrobially active CNCs have great potential to be used as a multifunctional nanomaterial for advanced applications.

Application of nanocrystalline structure modifi ed layers on coldworking tool

2021 ◽  
pp. 37-43
Author(s):  
S.S. Samotugin ◽  
V.I. Lavrinenko ◽  
Yu.S. Samotugina ◽  
O.A. Khristenko ◽  
O.N. Shicheva ◽  
...  
Keyword(s):  
Fracture Toughness ◽  
Particle Size ◽  
Surface Modification ◽  
Structure Formation ◽  
Cold Working ◽  
Average Particle Size ◽  
Nanocrystalline Structure ◽  
Cutting Edge ◽  
Average Particle ◽  
Plasma Surface

The regularities of the structure formation and changes in the fracture toughness parameters of the Kh12M steel are studied for various technological variants of plasma surface modification. The possibility for the formation of nanocrystalline martensite-carbide structure with average particle size of 50...150 nm in the surface volumes at the cutting edge of cold-working tool is shown.

Effects of Dissolving Agents on Particle Size Reduction of Titanium Dioxide Synthesized by Solution Combustion Technique

2016 ◽  
Vol 690 ◽  
pp. 236-239
Author(s):  
Oratai Jongprateep ◽  
Rachata Puranasamriddhi
Keyword(s):  
Particle Size ◽  
Titanium Dioxide ◽  
Sulfuric Acid ◽  
Nitric Acid ◽  
Average Particle Size ◽  
Average Particle ◽  
Particle Sizes ◽  
Solution Combustion ◽  
Initial Reagent ◽  
Combustion Technique

High photocatalytic activity of nanoparticulate titanium dioxide has attracted worldwide attention. Synthesis techniques of the nanoparticles, however, often require high energy supply or costly initial reagents. Solution combustion technique is an energy-effective technique capable of synthesizing nanosized titanium powders. This research aimed at utilizing a less expensive initial reagent in synthesis of nanoparticulate titanium dioxide by the solution combustion technique. The research also examined effects of dissolving agents on chemical composition and particle sizes of the synthesized powders. A low-cost initial reagent, titanium dioxide with average particle size of 154 nanometers, was dissolved in sulfuric acid or dispersed in nitric acid prior to the combustion. Experimental results revealed that the pure anatase phase titanium dioxide was successfully obtained in powders prepared from both sulfuric acid and nitric acid. The average particle size of the powder prepared from sulfuric acid was 77 nanometers, while that of the powder prepared from nitric acid was 117 nanometers. The difference in particle sizes was attributed to solubility of the initial reagent in the acid. Complete solution of initial reagent in sulfuric acid was the main factor attributed to finer particle size.

scholarly journals Effect of Particle Size on the Hydraulic Characteristics of Mechanically and Biologically Treated Waste

2020 ◽  
Vol 2020 ◽  
pp. 1-13
Author(s):  
Zhenying Zhang ◽  
Xiufeng Pan ◽  
Jiahe Zhang ◽  
Hui Xu
Keyword(s):  
Particle Size ◽  
Large Scale ◽  
Void Ratio ◽  
Average Particle Size ◽  
Dry Mass ◽  
Dry Density ◽  
Average Particle ◽  
Vertical Permeability ◽  
The Difference ◽  
Reduce Emissions

Mechanical biological treatment (MBT) is a waste processing technology that helps conserve resources and reduce emissions harmful to the environment. The treatment of municipal solid waste (MSW) using MBT is a hot topic in environmental geotechnical engineering. Permeability tests were carried out on MBT waste using a compression and permeability combined apparatus and a large-scale vertical permeability apparatus taking the influence of particle size into consideration. The permeability of samples with smaller particle sizes was found to be lower for the same pressure and dry mass (%) of component. The best-fit line between the logarithmic permeability and variables such as the dry density was linear. As the dry density increased or the void ratio decreased, the permeability of samples with smaller particles decreased more. The logarithmic permeability increased with the increase in the average particle size and void ratio. The permeabilities of MBT waste corresponding to particle size ranges of 0–10, 0–20, and 0–40 mm were 10−10–10−5, 10−8–10−4, and 10−5–10−3 m/s, respectively. The difference between MBT waste and MSW was analyzed in terms of their permeability. The results of MBT waste were compared with those reported in previous studies to provide reference for the permeability analysis of MBT landfills.

scholarly journals Development of Ultradeformable Liposomes with Fatty Acids for Enhanced Dermal Rosmarinic Acid Delivery

Pharmaceutics ◽  
2021 ◽  
Vol 13 (3) ◽  
pp. 404
Author(s):  
Thirapit Subongkot ◽  
Tanasait Ngawhirunpat ◽  
Praneet Opanasopit
Keyword(s):  
Fatty Acids ◽  
Oleic Acid ◽  
Surface Charge ◽  
Size Distribution ◽  
Rosmarinic Acid ◽  
Average Particle Size ◽  
Skin Penetration ◽  
Laser Scanning Microscopy ◽  
Confocal Laser ◽  
Average Particle

This study aimed to develop ultradeformable liposomes (ULs) with fatty acids, namely, oleic, linoleic, and linolenic acid, to improve the skin penetration of rosmarinic acid. This study also investigated the vesicle-skin interaction and skin penetration pathway of ULs with fatty acids using the co-localization technique of multifluorescently labeled particles. The prepared ULs were characterized in terms of size, surface charge, size distribution, shape, % entrapment efficiency (% EE), and % loading efficiency (% LE). The prepared ULs with fatty acids had an average particle size between 50.37 ± 0.3 and 59.82 ± 17.3 nm with a size distribution within an acceptable range and exhibited a negative surface charge. The average % EE and % LE were 9 and 24.02, respectively. The in vitro skin penetration study found that ULs with oleic acid could significantly increase the skin penetration of rosmarinic acid compared to ULs. According to confocal laser scanning microscopy observations, this study suggested that UL vesicles attach to the skin before releasing the entrapped drug to penetrate the skin. These findings suggested that ULs with oleic acid penetrated the skin via the transfollicular pathway as a major penetration pathway.

Controlling the Nanostructural Characteristics of TiO2 Nanoparticles Derived from Ilmenite Mineral of Bangka Island through Sulfuric Acid Route

2013 ◽  
Vol 391 ◽  
pp. 34-40 ◽  
Author(s):  
Hanum Latifa ◽  
Akhmad Herman Yuwono ◽  
F. Firdiyono ◽  
Nurul Taufiqu Rochman ◽  
Sri Harjanto ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Iron Powder ◽  
Sol Gel ◽  
Average Particle Size ◽  
Volume Ratio ◽  
Average Particle ◽  
Processing Conditions ◽  
Calcination Time ◽  
Titanyl Sulfate ◽  
Minor Elements

The ilmenite mineral (FeO.TiO2) from Bangka Island-Indonesia is an important source for synthesizing TiO2nanoparticles. However, the process is rather difficult since this mineral still contains many impurities and minor elements. Therefore, controlling the synthesizing route parameters is essential for obtaining the desired TiO2nanoparticle characteristics. In the current work, we proposed a modified process involving the use of sulfuric acid through sol-gel method to provide titanyl sulfate (TiOSO4) solution as the inorganic precursor. For investigation purposes, several parameters were varied including volume ratio of water and titanyl sulfate, addition of iron powder (seeding) and dextrin coagulant, calcination time and temperature. The results showed that TiO2nanoparticles can be succesfully synthesized using TiOSO4precursor derived from Bangka ilmenite. Under all processing conditions, the resulting TiO2nanoparticles have sphere-like shape and were indexed as the anatase TiO2phase. The results also showed that the average particle size was reduce from 96 188 nm to 32 40 nm when the volume ratio of water and titanylsulfate was increased from 3:1 to 6:1. The addition of iron powder as seeding has improved the purity of TiO2to ~ 95.01 wt%, in comparison to that of without seeding, which is ~92.78 wt%.

scholarly journals Preparation and Characterization of Nanocrystalline Cellulose from Cassava Stem Wastes by Electromagnetic Induction

2021 ◽  
Vol 16 (2) ◽  
pp. 109-117
Author(s):  
Lia Lismeri ◽  
Hertantri Yulia Rahmi ◽  
Nada Afifah Gomiyati ◽  
Yuli Darni ◽  
Panca Nugrahini Febriningrum ◽  
...  
Keyword(s):  
Acid Hydrolysis ◽  
Electromagnetic Induction ◽  
Average Particle Size ◽  
Nanocrystalline Cellulose ◽  
Raw Material ◽  
Induction Treatment ◽  
Average Particle ◽  
Cellulose Content ◽  
Naoh Solution ◽  
Cassava Stem

Cassava stems were one of the largest agricultural by products in Indonesia, especially in Lampung Province. It is known that cassava stems have a fairly high lignocellulose content, especially cellulose which reaches 39.29%. The high cellulose content in cassava stems has great potential to be used as raw material for Nanocrystalline Cellulose (NCC). The preparation of nanocrystalline cellulose consists of four main stages, namely: pre-hydrolysis, delignification, bleaching, and acid hydrolysis. The pre-hydrolysis stage was carried out by boiling a solution of CH3COOH and cassava stem powder for 60 minutes at a temperature of 105oC. Cassava stem powder was then delignified using a 25% NaOH solution heated to a temperature of 105oC for 1 hour. The bleaching stage used a 3.5% NaOCl solution at a temperature of 50oC for 60 minutes and was carried out twice. The last step is acid hydrolysis using 2.5N HCl solution for 15 minutes at a temperature of 105oC, then the electromagnetic induction treatment is varied with temperature variations of 30oC, 50oC, and 70oC for 60 minutes. The prepared nanocrystalline cellulose were tested for lignocellulose, XRD and PSA. From the test results, the best variation of nanocrystal cellulose preparation was acid hydrolysis treatment with 70oC electromagnetic induction for 60 minutes, namely an increase in the percentage of cellulose 62.93%, crystallinity 90.68%, and an average particle size of 18.04µm with some particles measuring nanometers. From the results of the research, it was concluded that electromagnetic induction increased crystallinity and decreased the size of nanocrystalline cellulose.

scholarly journals Synthesis of Cellulose Nanocrystals (CNCs) from Brewer’s Spent Grain Using Acid Hydrolysis: Characterization and Optimization

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Bisrat Yihun Matebie ◽  
Belachew Zegale Tizazu ◽  
Aseel A. Kadhem ◽  
S. Venkatesa Prabhu
Keyword(s):  
Acid Hydrolysis ◽  
Acid Concentration ◽  
Cellulose Nanocrystals ◽  
Average Particle Size ◽  
Cellulose Nanocrystal ◽  
Average Particle ◽  
Hydrolysis Time ◽  
Solid Ratio ◽  
Spent Grain ◽  
Hydrolysis Conditions

This study is aimed at utilizing brewery’s spent grain (BSG) byproduct for the synthesis of cellulose nanocrystals (CNCs) using acid hydrolysis and optimizing the hydrolysis parameters (hydrolysis time, temperature, liquid-solid ratio, and acid concentration). Alkali and bleaching treatment were done to remove hemicellulose and lignin from BSG. Optimization process was performed using central composite design (CCD) to obtain optimum value of cellulose nanocrystal (CNC) yield. The maximum cellulose nanocrystal (CNC) yield of 43.24% was obtained at optimum hydrolysis conditions of 50°C, 51 wt% acid concentration, 41 min, and liquid-solid ratio of 19 ml/g. The raw brewery spent grain; alkali-treated fiber, bleached fiber, and obtained CNC were characterized using scanning electron microscopy (SEM), XRD, particle analyzer, FTIR, and differential scanning calorimeter (DSC). The characterization results indicated that the obtained cellulose nanocrystal (CNC) has rod-like whisker shape with crystallinity of 76.3% and an average particle size of 309.4 nm.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

A New Method for Direct Determination of the Recoilless Fraction with Application to Magnetic Nanoparticles

2002 ◽  
Vol 721 ◽  
Author(s):  
Monica Sorescu
Keyword(s):  
Room Temperature ◽  
Average Particle Size ◽  
Direct Determination ◽  
Average Particle ◽  
Lattice Method ◽  
Recoilless Fraction ◽  
Single Room ◽  
Magnetite Particles ◽  
Physical Mixtures

AbstractWe propose a two-lattice method for direct determination of the recoilless fraction using a single room-temperature transmission Mössbauer measurement. The method is first demonstrated for the case of iron and metallic glass two-foil system and is next generalized for the case of physical mixtures of two powders. We further apply this method to determine the recoilless fraction of hematite and magnetite particles. Finally, we provide direct measurement of the recoilless fraction in nanohematite and nanomagnetite with an average particle size of 19 nm.

Determination of grinding parameters of fenugreek seed

1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh
Keyword(s):  
Particle Size ◽  
Energy Consumption ◽  
Moisture Content ◽  
Specific Energy ◽  
Feed Rate ◽  
Average Particle Size ◽  
Specific Energy Consumption ◽  
Average Particle ◽  
Fenugreek Seeds ◽  
Fenugreek Seed

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  

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