scholarly journals Influence of pH, Precursor Concentration, Growth Time, and Temperature on the Morphology of ZnO Nanostructures Grown by the Hydrothermal Method

2011 ◽  
Vol 2011 ◽  
pp. 1-9 ◽  
Author(s):  
G. Amin ◽  
M. H. Asif ◽  
A. Zainelabdin ◽  
S. Zaman ◽  
O. Nur ◽  
...  
Keyword(s):  
Zinc Oxide ◽  
Aspect Ratio ◽  
Ph Value ◽  
Precursor Concentration ◽  
Growth Time ◽  
Zno Nanostructures ◽  
Alkaline Ph ◽  
Starting Solution ◽  
Initial Ph ◽  
Influence Of Ph

We investigated the influence of the pH value, precursor concentration (C), growth time and temperature on the morphology of zinc oxide (ZnO) nanostructures. The pH of the starting solution was varied from 1.8 to 12.5. It was found that the final pH reaches an inherent value of 6.6 independently of the initial pH solution. Various ZnO structures of nanotetrapod-like, flower-like, and urchin-like morphology were obtained at alkaline pH (8 to 12.5) whereas for pH solution lower than 8 rod-like nanostructures occurred. Moreover, we observed the erosion of the nanorods for a pH value less than 4.6. By changing the concentrations the density and size were also varied. On going from a high (C>400 mM) to lower (C<25 mM)C, the resulted ZnO nanostructures change from a film to nanorods (NRs) and finally nanowires (NWs). It was also found that the length and diameter of ZnO NRs follow a linear relation with time up to 10 hours, above which no further increase was observed. Finally the effect of growth temperature was seen as an influence on the aspect ratio.

scholarly journals Hydrothermal Synthesis of Various Shape-Controlled Europium Hydroxides

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 529
Author(s):  
Hongjuan Zheng ◽  
Kongjun Zhu ◽  
Ayumu Onda ◽  
Kazumichi Yanagisawa
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Ph Value ◽  
Hydrothermal Temperature ◽  
X Ray ◽  
Hydrothermal Reactions ◽  
Starting Solution ◽  
Initial Ph ◽  
Shape Controlled ◽  
Scanning Electron

Eu(OH)3 with various shape-controlled morphologies and size, such as plate, rod, tube, prism and nanoparticles was successfully synthesized through simple hydrothermal reactions. The products were characterized by XRD (X-Ray Powder Diffraction), FE-SEM (Field Emission- Scanning Electron Microscopy) and TG (Thermogravimetry). The influence of the initial pH value of the starting solution and reaction temperature on the crystalline phase and morphology of the hydrothermal products was investigated. A possible formation process to control morphologies and size of europium products by changing the hydrothermal temperature and initial pH value of the starting solution was proposed.

scholarly journals Influence of pH on the dynamics of the wound process in the postoperative period

2021 ◽  
Vol 11 (2) ◽  
pp. 87-91
Author(s):  
А. М. Morozov ◽  
А. R. Armasov ◽  
А. N. Sergeev ◽  
S. V. Zhukov ◽  
Е. А. Sobol ◽  
...  
Keyword(s):  
Postoperative Period ◽  
Ph Value ◽  
Healing Process ◽  
Hydrogen Index ◽  
Biochemical Reactions ◽  
Postoperative Wound ◽  
Wound Exudate ◽  
Initial Values ◽  
Initial Ph ◽  
Influence Of Ph

The wound process is a set of stages that successively replace each other and as a result lead to epithelization of the skin and closure of the wound defect. The development of the wound process is influenced by the pH value of the wound contents, which determines the rate of all biochemical reactions occurring in the wound. In the course of the study, patients were measured for wound exudate in the postoperative period. It was noted that in patients with the initial values of the hydrogen index, which was 7, a more effective healing process of the postoperative wound was observed, while in patients with the initial pH value of 8, the wound process took a protracted character. 

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

scholarly journals Study on the effect of growth-time and seed-layers of Zinc Oxide nanostructured thin film prepared by the hydrothermal method for liquefied petroleum gas sensor application

BIBECHANA ◽  
2018 ◽  
Vol 16 ◽  
pp. 145-153
Author(s):  
Guna Nidha Gnawali ◽  
Shankar P Shrestha ◽  
Khem N Poudyal ◽  
Indra B Karki ◽  
Ishwar Koirala
Keyword(s):  
Thin Film ◽  
Zinc Oxide ◽  
Gas Sensor ◽  
Sheet Resistance ◽  
Measurement Unit ◽  
Growth Time ◽  
Zno Nanostructures ◽  
Liquefied Petroleum Gas ◽  
Nanostructured Thin Film ◽  
Seed Layers

Gas sensors are devices that can convert the concentration of an analytic gas into an electronic signal. Zinc oxide (ZnO) is an important n-type metal oxide semiconductor which has been utilized as gas sensor for several decades. In this work, ZnO nanostructured films were synthesized by a hydrothermal route from ZnO seeds and used as a liquefied petroleum gas (LPG) sensor. At first ZnO seed layers were deposited on glass substrates by using spin coating method, then ZnO nanostructured were grown on these substrates by using hydrothermal growth method for different time duration. The effect of growth time and seed layers of ZnO nanostructured on its structural, optical, and electrical properties was studied. These nanostructures were characterized by X-ray diffraction, scanning electron microscopy, optical spectroscopy, and four probes sheet resistance measurement unit. The sensing performances of the synthetic ZnO nanostructures were investigated for LPG.XRD showed that all the ZnO nanostructures were hexagonal crystal structure with preferential orientation. SEM reviled that the size of nanostructure increased with increase in growth time. Band gap and sheet resistance for ZnO nanostructured thin film decreased with increase in growth time. ZnO nanostructured thin film showed high sensitivity towards LPG gas. The sensitivity of the film is observed to increase with increase in no of seed layers as well as growth time. The dependence of the LPG sensing properties on the different growth time of ZnO nanostructured was investigated. The sensing performances of the film were investigated by measured change in sheet resistance under expose to LPG gas. BIBECHANA 16 (2019) 145-153

The Behaviors of Removing Silver Ions by Low-Cost Expanded Rice Husk, Nature Diatomite and Nature Bentonite as Sorbents

2012 ◽  
Vol 724 ◽  
pp. 472-475
Author(s):  
Xuan Liang ◽  
Xue Gang Luo ◽  
Xiao Yan Lin ◽  
Qiang Mei
Keyword(s):  
Adsorption Capacity ◽  
Rice Husk ◽  
Ph Value ◽  
Low Cost ◽  
Silver Ions ◽  
Maximum Adsorption Capacity ◽  
Removal Of Heavy Metals ◽  
Initial Ph ◽  
Influence Of Ph ◽  
By Products

Low cost industrial and agricultural by-products are promising materials for water pollution treatment such as removal of heavy metals. This work deals with removal of silver ions from solutions using expanded rice husk (ERH), nature diatomite (ND) and nature bentonite (NB). Firstly the influence of pH value of the solution on adsorption capacity for silver ions was studied, and then the effect of initial silver concentration on adsorbents adsorption capacity was investigated. The silver ions removal percentage increases with initial pH and achieves a maximum value of nearly 94% at pH= 5.0 ± 0.5 for ERH. The maximum adsorption capacity is 18.6 mg/g for ERH.

scholarly journals Factorial Design of Experiments for Optimization of Photocatalytic Degradation of Tartrazine by Zinc Oxide (ZnO) Nanorods with Different Aspect Ratios

2020 ◽  
Author(s):  
Andrew Skinner ◽  
Anthony DiBernardo ◽  
Arvid Masud ◽  
Nirupam Aich ◽  
Alexandre Pinto
Keyword(s):  
Zinc Oxide ◽  
Aspect Ratio ◽  
Photocatalytic Degradation ◽  
Factorial Design ◽  
Removal Efficiency ◽  
Rate Constant ◽  
Zno Nanorods ◽  
Order Rate Constant ◽  
Order Rate ◽  
Initial Ph

The photocatalytic degradation of the azo dye tartrazine using zinc oxide (ZnO) as photocatalyst under ultraviolet light was investigated using a 2<sup>4</sup> factorial design. The variables studied were the aspect ratio of ZnO nanorods, the ZnO load, the initial pH of tartrazine solution, and the H<sub>2</sub>O<sub>2</sub> volume. These variables were studied aiming to maximize the tartrazine removal efficiency and the pseudo-1<sup>st</sup>-order rate constant of the removal process. The ZnO aspect ratio was tuned by varying the Lewis base during the synthesis, hexamethylenetetramine (HMTA) was used to prepare ZnO with low aspect ratio (ZnO_LowAR), and NaOH was used to prepare ZnO with high aspect ratio (ZnO_HighAR). The microstructural characterizations indicated that ZnO_LowAR and ZnO_HighAR nanorods have similar structural, textural and optical properties. The only exception was the dimensions of the nanorods obtained, which could result in differences in the facets exposed on each type of nanorod surface. The factorial design revealed that ZnO aspect ratio, the initial pH of tartrazine solution, and the H<sub>2</sub>O<sub>2</sub> volume all have primary significant effects, whereas the ZnO load is not significant neither in the tartrazine removal efficiency nor in the pseudo-1<sup>st</sup>-order rate constant. Statistical models considering the coefficients of the significant interactions were obtained, leading to reasonable predicted results in comparison to the results experimentally obtained. The conditions leading to highest removal efficiency (~92%) and pseudo-1<sup>st</sup>-order rate constant (3.81 x 10<sup>-2</sup> min<sup>-1</sup>) were carried out with ZnO_HighAR, initial pH 7, and without H<sub>2</sub>O<sub>2</sub>, which outperformed the TiO<sub>2</sub> P-25 under the same conditions.

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.

Preparation and Characterization of Cerium Hydrate Fiber

2007 ◽  
Vol 336-338 ◽  
pp. 2182-2185
Author(s):  
Jia Ming Sung ◽  
Sung En Lin ◽  
Wen Cheng J. Wei
Keyword(s):  
Aspect Ratio ◽  
Ph Value ◽  
Ambient Pressure ◽  
Key Factors ◽  
Aging Period ◽  
Starting Solution ◽  
Sodium Hydrate ◽  
Heating Treatment ◽  
Novel Method

Cerium hydrate fiber (CHF), which showed an aspect ratio greater than 100, was synthesized by a novel method, which used the mixing of cerium nitrate (Ce(NO3)3), sodium hydrate (NaOH) and citric acid (C6H8O7) synthesized at a relative low temperature and ambient pressure. The precipitates were characterized by XRD, SEM and TEM. The results showed that in addition to fibers, two morphologies could be obtained depending on the synthesizing conditions. Aging time and formulation were two key factors for the control of the aspect ratio of the precipitates. By a heating treatment at 600oC for 2 h, the homogenous and well-crystallized cerium dioxide (CeO2) fiber can be fabricated. The effects of synthesis parameters, such as the concentration of the starting solution, aging period, and pH value were reported and discussed.

scholarly journals ADSORPSI ION LOGAM Fe DALAM LIMBAH TEKSTIL SINTESIS DENGAN MENGGUNAKAN METODE BATCH

2018 ◽  
Vol 2 (2) ◽  
pp. 68
Author(s):  
Muhammad Arief Karim ◽  
Heni Juniar ◽  
M. Fitria Putri Ambarsari
Keyword(s):  
Metal Ions ◽  
Metal Ion ◽  
Ph Value ◽  
Batch Process ◽  
Two Factors ◽  
The Matrix ◽  
Initial Ph ◽  
Stirring Time ◽  
Influence Of Ph ◽  
Predetermined Time

Adsorption is a process occurs in a fluid, either it is liquid or gas, bonded in a solid or liquid (absorbent agent, adsorbent) and eventually creates a thin layer or film (adsorbed agent, adsorbent) on its surface. In this study, the writer did the process of the adsorption of Fe metal ion to the adsorbent of carbide waste that has been processed into tablet with 3x5 mm size, adsorption was done with Batch process by stirring 15gr or adsorbent into 100ml of synthetic waste with 50rpm stirring speed. There are two factors that influence the decrease of Fe metal concentration in synthesis waste which is the influence of pH and time. This study used variables of adsorption time (1; 2; 3; 4; 5; 6) hours with pH (2.5; 4.1) for each hour with an initial concentration of Fe 800g metal ions. This study was conducted to obtain the optimum value of pH and concentration of final Fe metal ions with the comparison of initial pH ratio and predetermined time. Seen from the matrix results of the study, it can be concluded that the longer the stirring time the more metal ions are absorbed by the adsorbent of carbide waste and pH value also rises.

Influence of pH on Cadmium Removal from Wastewater by SSI

2012 ◽  
Vol 232 ◽  
pp. 935-938
Author(s):  
Jun Guo Li ◽  
Yan Shi ◽  
Na Bi ◽  
Yan Ping Feng
Keyword(s):  
Reaction Rate ◽  
Ph Value ◽  
Direct Reduction ◽  
Reaction Rate Constant ◽  
Cadmium Removal ◽  
First Order ◽  
Initial Ph ◽  
Apparent Reaction Rate Constant ◽  
Influence Of Ph ◽  
Apparent Reaction Rate

Spherical sponge iron (SSI) with high activity and intension could be prepared through direct reduction by hydrogen. pH value in solution increased despite initial pH because a large amount of H+ was depleted along with erosion battery reaction of SSI. It was suggested that initial pH has significant influence on pH value in solution and cadmium removal percentage by SSI. When the initial pH maintained at 2.03, cadmium removal percentages were only 10.17% and 22.00%, respectively, in 10min and 30min. While the initial pH was adjusted to 3.00, cadmium removal percentage could be elevated to 73.10% and 95.46% in similar libration time. Cadmium removal by SSI appeared to be the first-order reaction. When the initial pH was maintained at 2.03, the apparent reaction rate constant of cadmium removal by SSI was only 0.434 and 1.027 h-1, while which could be elevated to 5.882 and 5.249 h-1 when the initial pH was adjusted to 3.00.

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