scholarly journals Influence of pH and ionic strength on the aggregation behaviors of xylan rich hemicelluloses with alkaline lignins

BioResources ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. 7608-7622
Author(s):  
Guichun Hu ◽  
Jinguang Hu ◽  
Honglei Chen ◽  
Shunxi Song ◽  
Fuqiang Chu
Keyword(s):  
Particle Size ◽  
Self Assembly ◽  
Main Chain ◽  
Ph Value ◽  
Low Ph ◽  
Ph Values ◽  
Wide Range ◽  
Nacl Concentration ◽  
Aggregation Behaviors ◽  
Influence Of Ph

The evolution of xylan-rich hemicelluloses (XH) aggregation behaviors in the presence of alkaline lignins (AL) under a wide range of pH values and NaCl concentration were investigated via dynamic light scattering and turbidity measurements. XH isolated from wheat straw contain a xylose backbone with arabinose side chains and a small amount of phenol groups. XH tend to aggregate in solution due to their low ratio of arabinose to xylose and hydrophobic phenol groups. AL interact with XH through the phenol groups bonded to the hemicellulose main chain to form an AL-XH complex. As the pH value decreases, the particle size and turbidity of AL, XH and their bonded complex all increase. The size of the AL-XH complex agglomerate is greater than the size of a XH at the same pH value, which indicates that the self-assembly of lignin molecules initiate the aggregation of XH. The particle size and turbidity of XH and AL-XH complexes increase as the XH concentration increase. At low pH values, e.g., 6.0, the particle size of the AL-XH complex more obviously increases compared to the XH particles. The size and turbidity of the AL, XH, and AL-XH complex agglomerates increased as the NaCl concentration increased.

scholarly journals Microstructure and Properties of Self-Assembly Graphene Microcapsules: Effect of the pH Value

Nanomaterials ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 587 ◽  
Author(s):  
Yan-Dong Guo ◽  
Jun-Feng Su ◽  
Ru Mu ◽  
Xin-Yu Wang ◽  
Xiao-Long Zhang ◽  
...  
Keyword(s):  
Electron Microscope ◽  
Photoelectron Spectroscopy ◽  
Self Assembly ◽  
Chemical Engineering ◽  
Ph Value ◽  
Liquid Paraffin ◽  
Energy Dispersive Spectrometer ◽  
Core Material ◽  
Microstructure And Properties ◽  
Ph Values

Graphene has attracted attention in the material field of functional microcapsules because of its excellent characteristics. The content and state of graphene in shells are critical for the properties of microcapsules, which are greatly affected by the charge adsorption equilibrium. The aim of this work was to investigate the effect of pH value on the microstructure and properties of self-assembly graphene microcapsules in regard to chemical engineering. Microcapsule samples were prepared containing liquid paraffin by a self-assembly polymerization method with graphene/organic hybrid shells. The morphology, average size and shell thickness parameters were investigated for five microcapsule samples fabricated under pH values of 3, 4, 5, 6 and 7. The existence and state of graphene in dry microcapsule samples were analyzed by using methods of scanning electron microscope (SEM), transmission electron microscope (TEM) and X-ray photoelectron spectroscopy (XPS). Fourier Transform Infrared Spectoscopy (FT-IR) and Energy Dispersive Spectrometer (EDS) were applied to analyze the graphene content in shells. These results proved that graphene had existed in shells and the pH values greatly influenced the graphene deposition on shells. It was found that the microcapsule sample fabricated under pH = 5 experienced the largest graphene deposited on shells with the help of macromolecules entanglement and electrostatic adherence. This microcapsules sample had enhanced thermal stability and larger thermal conductivity because of additional graphene in shells. Nanoindentation tests showed this sample had the capability of deforming resistance under pressure coming from the composite structure of graphene/polymer structure. Moreover, more graphene decreased the penetrability of core material out of microcapsule shells.

scholarly journals The Influence of pH Values on the Crystallite Size of ZnO by Solvothermal Synthesis

2017 ◽  
Vol 2 (2) ◽  
pp. 118 ◽  
Author(s):  
Ahmadi Jaya Permana ◽  
Dian Wulandari ◽  
Hartati Hartati ◽  
Harsasi Setyawati ◽  
Mochammad Zakki Fahmi
Keyword(s):  
Heat Treatment ◽  
Zinc Oxide ◽  
Crystallite Size ◽  
Solvothermal Synthesis ◽  
Solvothermal Method ◽  
Ph Value ◽  
Semiconductor Material ◽  
X Ray ◽  
Ph Values ◽  
Influence Of Ph

 Zinc oxide (ZnO) is a semiconductor material that widely used in various applications due to its unique properties. Synthesis of ZnO by solvothermal method has been conducted with controlled pH values. The variations of pH value were 10, 11 and 12 by adjusting NaOH content. Crystall structure of the synthesis products after heat treatment at 110oC and 600oC has characterised by X-ray Diffratometer (XRD). Crystallite size of ZnO was measured by Scherrer equation. Crystall phase of ZnO has been observed on all pH value variations at 110 oC with 22,98-37,06 nm of crystallite size, whereas ZnO has been observed on all pH value variations at 600 oC with 41,39-71,77 nm of crystallite size.Keywords: ZnO, pH values, crystallite size, solvothermal

Influence of pH on the Morphology and Luminescence Properties of Europium-Doped Hydroxyapatite Nanoparticles

2011 ◽  
Vol 391-392 ◽  
pp. 1132-1137
Author(s):  
Su Ping Huang ◽  
Jun Zhu ◽  
Ke Chao Zhou
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Doping Concentration ◽  
Ph Value ◽  
Luminescence Properties ◽  
X Ray Diffraction ◽  
X Ray ◽  
Inductively Coupled ◽  
Ph Values ◽  
Influence Of Ph

Luminescence behaviors and morphology of Eu3+doped hydroxyapatite synthesized under different pH values were well investigated by X-ray diffraction (XRD), scanning electronic microscopy (SEM), X-ray photoelectron spectroscopy (XPS), Inductively Coupled Plasma (ICP) (ICP–PLASMA 1000), and photoluminescence (PL) spectroscopy. Results revealed that With pH values increased from 6.5 to 10.0, the morphology of nano-Eu:HA particles changes from rod particles to equiaxed particles. The actual doping concentration and aspect ratio of Eu3+-doped HA decreased with the increasing of pH value. At the same time, the fluorescence intensity also tends to weakly lower with the increasing of pH value, which indicated that the luminescence properties mainly depended on the actual Eu3+doping concentration, the influences of morphology on the luminescence properties were slight.

Two novel mixed Eu3+/Y3+ Ln MOFs: influence of pH on the topology, Eu/Y ratio and energy transfer

CrystEngComm ◽  
2014 ◽  
Vol 16 (25) ◽  
pp. 5681-5688 ◽  
Author(s):  
Yu Zhang ◽  
Weiwei Ju ◽  
Xiao Xu ◽  
Yun Lv ◽  
Dunru Zhu ◽  
...  
Keyword(s):  
Energy Transfer ◽  
Ph Value ◽  
Ph Values ◽  
Influence Of Ph

Two mixed europium–yttrium MOFs with different interesting structures and doping proportions have been successfully synthesized by adjusting the pH values. The pH value largely affects the topologies and Eu/Y ratios of the two compounds.

Microcapsule Particle Size and Size Distribution and its Influencing Factors

2013 ◽  
Vol 746 ◽  
pp. 118-122 ◽  
Author(s):  
Zhao Hui Zhen ◽  
Zheng Shun Wang
Keyword(s):  
Particle Size ◽  
Size Distribution ◽  
Influencing Factors ◽  
Large Particle ◽  
Ph Value ◽  
Low Ph ◽  
Formaldehyde Resin ◽  
Melamine Formaldehyde ◽  
Large Particle Size ◽  
Rough Surface Morphology

The paper studied the microcapsule particle size, size distribution and its influencing factors with melamine formaldehyde resin (MF-resin) as wall and CVL as core. The results indicated that the microcapsules mean particle size decreased, size distribution became narrow with the increase of emulsifying time and shear rate. Low pH value would make the microcapsules have rough surface morphology and large particle size.

scholarly journals Original Research. Evaluation of Dental Erosion in a Group of Romanian Children Diagnosed with Gastroesophageal Reflux Disease

2017 ◽  
Vol 2 (s1) ◽  
pp. 17-20
Author(s):  
Krisztina Mártha ◽  
Alexandru Ogodescu ◽  
Daniela Eșian ◽  
Cristina Bica ◽  
Eugen Bud
Keyword(s):  
Gastroesophageal Reflux Disease ◽  
Gastroesophageal Reflux ◽  
Reflux Disease ◽  
Ph Value ◽  
Statistical Significance ◽  
Dental Erosion ◽  
Low Ph ◽  
Original Research ◽  
Ph Values ◽  
Dmft Index

AbstractGastroesophageal reflux disease (GERD) is a very common digestive disorder, which occurs when the acidic contents of the stomach returns into the esophagus to some extent, reaching the mouth, thereby increasing the frequency of dental erosion and caries. Since saliva plays a huge role in oral homeostasis, it is important to examine the role of this parameter in the appearance of the above mentioned oral lesions. The aim of our study was evaluate the oral condition of children suffering from reflux disease and to assess the relationship between salivary pH and the incidence of dental erosion and caries. In this prospective study we examined 25 children diagnosed with GERD, referred for hospitalization. Bedside intra-oral examination (DMFT index, gingival index) and strip method pH value determination was performed. We observed that patients with low pH values had increased caries frequency, and dental erosion was also noticeable. Statistical significance was determined comparing the DMFT index in groups with different pH values. We concluded that the high number of erosions is closely related to gastroesophageal reflux disease, as a consequence of the low pH value, which represents the main cause of oral manifestations in GERD.

scholarly journals Studying the influence of properties of initial ZrO2-(7 %)Y2O3 powders on properties of ceramic products

2019 ◽  
pp. 44-50
Author(s):  
N. V. Zhirenkina ◽  
M. A. Mashkovtsev ◽  
N. V. Obabkov ◽  
I. F. Zakirov
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Zirconium Oxide ◽  
Ph Value ◽  
Slip Casting ◽  
Mechanical Grinding ◽  
Influence Of Properties ◽  
Influence Of Ph ◽  
Research Show

The paper focuses on the possibility of forming ceramic products by the method of slip casting without the stage of mechanical grinding of powders. We studied the influence of pH value of hydroxides precipitation and hydrothermal treatment on the properties of ZrO2-(7 %)Y2O3 powders, and on the mechanical properties of ceramic products made from synthesized ZrO2-(7 %)Y2O3 powders without a grinding stage. Findings of research show that the quality of ceramic products based on zirconium oxide is more influenced by the specific surface area, rather than the particle size of the initial powders

scholarly journals Metal extraction from Cetraria islandica (L.) Ach. lichen using low pH solutions

2008 ◽  
Vol 73 (4) ◽  
pp. 405-413 ◽  
Author(s):  
Ana Cuculovic ◽  
Mirjana Pavlovic ◽  
Dragan Veselinovic ◽  
Scepan Miljanic
Keyword(s):  
Complex Formation ◽  
Acid Rain ◽  
Metal Ion ◽  
Metal Content ◽  
Ph Value ◽  
Low Ph ◽  
Metal Extraction ◽  
Ph Values ◽  
All Solutions ◽  
Extraction Of Metals

Extraction of metals (K, Al, Ca, Mg, Fe, Cu, Ba, Zn, Mn and Sr) from dry Cetraria islandica (L.) Ach. lichen was performed using solutions similar to acid rain (solution A H2SO4-HNO3-(NH4)2SO4 and solution B H2SO4- -HNO3-(NH4)2SO4-NH4NO3). The pH values of these solutions were 2.00, 2.58, 2.87, 3.28, and 3.75. Five consecutive extractions were performed with each solution. In all solutions, the extracted metal content, except Cu and Ca, was the highest in the first extract. The highest percentage of the metals desorbed in the first extraction was obtained using solutions with low pH values, 2.00, 2.58, and 2.87. The lowest percentage in the first extraction was obtained using solutions with pH 3.28 and pH 3.75, indicating influence of the H+ ion on the extraction. According to the results obtained, the investigated metals form two groups. The first group includes K, Al, Ca, Mg, and Fe. They were extracted in each of the five extractions at each of the pH values. The second group includes Ba, Zn, Mn, Cu, and Sr, which were not all extracted at each pH value. The first group yielded three types of extraction curves when the logarithms of extracted metal amounts were plotted as a function of the number of successive extractions. These effects indicate that three different positions (centers) of metal ion accumulation exist in the lichen (due to sorption, complex formation, or other processes present in the tissues).

Influence of pH on the Morphology of Yttrium Oxide Hydroxide Nitrate Nanocrystal

2007 ◽  
Vol 336-338 ◽  
pp. 2176-2178 ◽  
Author(s):  
Zhang Lian Hong ◽  
Huang Guo ◽  
Li Xia Peng ◽  
Min Quan Wang
Keyword(s):  
Hydrothermal Method ◽  
Yttrium Oxide ◽  
Ph Value ◽  
High Ph ◽  
Ph Values ◽  
Starting Solution ◽  
Primary Mechanism ◽  
Oxide Hydroxide ◽  
Influence Of Ph

Yttrium oxide hydroxide nitrate (Y4O(OH)9NO3), which was prepared by polyvinyl alcoholassisted hydrothermal method from the Y(NO3)3 and KOH starting solution, was characterized by XRD and FE-SEM. The results revealed that pH value of the starting solution is an important factor which determines the morphology and size of the products. The obtained products varied from lamina microprisms to circular nanorods when the pH value increased from 7.0 to 8.0. In the high pH value above 8.0, the size of nanorods decreased with increasing pH value. A primary mechanism was proposed to explain the evolution of morphology and size of Y4O(OH)9NO3 products prepared under various pH values.

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