scholarly journals Improved production of titanate nanotubes by hydrothermal method for adsorption of organic dyes

Author(s):  
Ayman H. Zaki ◽  
Sara Adel ◽  
Mahmoud M. Abd El-hafiez ◽  
Ahmed A. Abdel-Khalek

Abstract Background Increasing the yield of nanomaterials using the same reactor size and fixing most of the reactants and conditions will greatly improve the production process by saving time, energy and efforts. Titanate nanotubes are mainly prepared by hydrothermal process, in which TiO2 powder reacts with NaOH at certain conditions to form the desired nanotubes. It was reported that it is a must to use high concentrations of NaOH (10 N) to enable the tubular form formation, and the amount of NaOH from the stoichiometry point of view is much higher than that of TiO2; this means excess amounts of NaOH are not used and washed off. This work was designed to improve the production yield by making use of this excess amount of NaOH. Results More than 60 g of sodium titanate nanotubes was prepared using simple hydrothermal method. The prepared nanotubes were characterized by X-ray powder diffraction, high-resolution transmission electron microscopy, Fourier-transform infrared spectroscopy and BET surface area analysis. The adsorption capacity of these nanotubes was tested against three commonly used dyes: methyl orange, crystal violet and thymol blue. The samples showed great affinity toward crystal violet and lower activity toward methyl orange and thymol blue, where they achieved more than 90% removal efficiency under different experimental conditions. Conclusions Sodium titanate nanotubes were prepared in large amounts using modified hydrothermal method. The obtained nanotubes efficiently removed crystal violet from water. This improved synthesis of titanate nanotubes will reduce the total cost of nanomaterials production, and subsequently the treatment process, since titanate nanotubes are used in adsorption and photocatalysis processes.

2019 ◽  
Vol 7 (2) ◽  
pp. 240-246
Author(s):  
Kaur Harpreet ◽  
Kaur Harpreet ◽  
Vandana Kamboj ◽  
Vandana Kamboj

Water is the most crucial thing to mankind and so its contamination by various agencies is posing a threat to the natural balance. So, in the present work, the efficiency of various adsorbents derived from plant waste, to remove different dyes from aqueous solution was evaluated. Parameters for study were contact time, concentration and pH. Various combinations of plant ashes were used for the study. It was found that adsorbent prepared from the combination of orange peels, pomegranate and banana peels ashes, exhibited good adsorption capacity for methylene blue, congo red and crystal violet. All these dyes were completely removed from the aqueous solution while methyl orange was not removed. Congo red was removed completely within 40 min of contact with the adsorbent while methyl orange took 3 hrs to be removed to the extent of 48% only. The adsorption coefficient of congo red was found to be 2.33 while value for methylene blue and crystal violet was 1 and 1.66 respectively. The characterization of adsorbent was done by Scanning Electron Microscopy and IR spectroscopy. SEM image revealed the surface of adsorbent to be made of differential pores. From the results it became evident that the low-cost adsorbent could be used as a replacement for costly traditional methods of removing colorants from water.


2013 ◽  
Vol 864-867 ◽  
pp. 404-407
Author(s):  
Shi Zhao Kang ◽  
Tan Wu ◽  
Xiang Qing Li ◽  
Yi Lun Zhou ◽  
Jin Mu

Core-shell montmorillonite-TiO2 colloids were prepared in a hydrothermal process and characterized with transmission electron microscope, powder X-ray diffraction analysis, Brunauer-Emmett-Teller analysis and UV-vis spectra. Afterwards, their photocatalytic activity was investigated under UV irradiation using methyl orange as a model contaminant. In addition, the stability of the core-shell montmorillonite-TiO2 colloids was investigated by repeatedly performing methyl orange photocatalytic degradation experiments. The results indicate the as-prepared core-shell montmorillonite-TiO2 colloids are a highly efficient photocatalyst for the degradation of organic dyes in water. And this photocatalytic activity remains almost unchanged after eight successive cycles.


2019 ◽  
Vol 19 (2) ◽  
pp. 486 ◽  
Author(s):  
Nguyen Thi Thuong ◽  
Nguyen Thi Tuyet Nhi ◽  
Vo Thi Cam Nhung ◽  
Hoang Ngoc Bich ◽  
Bui Thi Phuong Quynh ◽  
...  

A number of harmful effects on the ecosystem, the life of humankind, and living species caused by dye-contaminated wastewater have urged the development for an efficient and cost-efficient treatment method for colored effluents. The cellulose-based adsorbents have been considered as a facile and efficient approach to remove hazardous pollutants because of the abundance of inexpensive agricultural wastes in Viet Nam. This study aims to investigate the elimination of methylene blue (MB) and crystal violet (VL) from wastewater using a fixed-bed column of pre-treated durian peel. Examined variables in the process are bed depths (2–6 cm), flow rate (5–20 mL/min), and influent dye concentrations (200–600 mg/L). The highest adsorption amount of pre-treated DP was 235.80 mg/g and 527.64 mg/g, respectively, on a 600 mg/L of methylene blue and crystal violet achieved within a bed height of 4 cm and a flow rate of 10 mL/min. Accordingly, the breakthrough curves were constructed and modeled using the relevant theoretical models under the effects of different experimental conditions. Pre-treated durian peel was found to exhibit high adsorption capacity for cationic dye in an initial concentration of 200–600 mg/L with complete removal being obtained.


2010 ◽  
Vol 63 (2) ◽  
pp. 293 ◽  
Author(s):  
Jeffrey S. Church ◽  
Keith Fincher ◽  
Xingdong Wang

Sodium titanate nanotubes were prepared hydrothermally and sodium ions were exchanged for hydrogen ions by washing with water and further treatment with HCl. No anatase or rutile was produced during the exchange. Photo-catalysts were prepared by calcination and their activity was compared in UV-A and simulated sunlight by bleaching methyl orange, which does not adsorb onto the catalyst’s surface. Only photo-catalysts with low sodium content were capable of bleaching the dye. More photo-oxidation occurred in simulated sunlight suggesting that the dye is absorbing visible light and transferring this energy to the TiO2. The preparation of highly active photo-catalysts from sodium titanate nanotubes may well depend on optimizing their preparation to minimize sodium content without the formation of rutile.


2010 ◽  
Vol 177 ◽  
pp. 82-85
Author(s):  
Zhong Sheng Chen ◽  
Wei Ping Gong ◽  
Teng Fei Chen ◽  
Guo Lin Huang ◽  
Wen Yuan Xu

Titanate nanotubes (TNTs) were prepared by treatment of anatase-TiO2 nanoparticles in mild hydrothermal conditions. TNTs were characterized by XRD, TEM, FT-IR and BET specific surface area technique. It was found that nanotubes might be NaxH2-xTi3O7 and were formed during the hydrothermal process, rather than during the treatment process with acid solution. The formation mechanism of TNTs can be explained as 3D→2D→1D. After hydrothermally reacting at 130°C for 48h, the as-prepared products exhibit hollow nanotubes with open ends, more than 100 nm in length, 10 nm in outer diameters, large BET surface area and pore volume, which may lead to potential photocatalysis and absorption application.


2018 ◽  
Vol 51 ◽  
pp. 13-23 ◽  
Author(s):  
Song Dong Yuan ◽  
Shi Qiang Chen ◽  
Xing Zhu ◽  
Peng Xiong ◽  
Yan Fei Yang ◽  
...  

In this paper, a tunable TiO2nanorod cross-link structure with ultra-high surface area (up to 109.81 m2/g) has been successfully prepared via hydrothermally treating elongated sodium titanate nanotubes. XRD, SEM, HRTEM and BET analysis were employed to characterize the morphology and inner structure of the samples. The preparation conditions (the hydrothermal temperatures and the pH values of the solutions) of the obtained TiO2products were systematically studied. The maximum length of nanorod reaches to 1 μm while the lateral size could be limited less than 10 nm. The surface area can be easily tuned by modifying the stirring rate during the hydrothermal process. In addition, the photocatalytic performance of synthesized TiO2nanorods were also measured, and the nanorod structure with ultra-high surface area showed much better photocatalytic activity than the sample produced without stirring process, which can be attributed to the influence of the large difference in specific surface area of the obtained TiO2products.


2019 ◽  
pp. 240-246
Author(s):  
Kaur Harpreet ◽  
Vandana Kamboj

Water is the most crucial thing to mankind and so its contamination by various agencies is posing a threat to the natural balance. So, in the present work, the efficiency of various adsorbents derived from plant waste, to remove different dyes from aqueous solution was evaluated. Parameters for study were contact time, concentration and pH. Various combinations of plant ashes were used for the study. It was found that adsorbent prepared from the combination of orange peels, pomegranate and banana peels ashes, exhibited good adsorption capacity for methylene blue, congo red and crystal violet. All these dyes were completely removed from the aqueous solution while methyl orange was not removed. Congo red was removed completely within 40 min of contact with the adsorbent while methyl orange took 3 hrs to be removed to the extent of 48% only. The adsorption coefficient of congo red was found to be 2.33 while value for methylene blue and crystal violet was 1 and 1.66 respectively. The characterization of adsorbent was done by Scanning Electron Microscopy and IR spectroscopy. SEM image revealed the surface of adsorbent to be made of differential pores. From the results it became evident that the low-cost adsorbent could be used as a replacement for costly traditional methods of removing colorants from water.


Catalysts ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 117
Author(s):  
Zahir Muhammad ◽  
Farman Ali ◽  
Muhammad Sajjad ◽  
Nisar Ali ◽  
Muhammad Bilal ◽  
...  

Degradation of organic dyes and their byproducts by heterogeneous photocatalysts is an essential process, as these dyes can be potentially discharged in wastewater and threaten aquatic and xerophyte life. Therefore, their complete mineralization into nontoxic components (water and salt) is necessary through the process of heterogeneous photocatalysis. In this study, Zr/CrO2 (Zirconium-doped chromium IV oxide) nanocomposite-based photocatalysts with different compositions (1, 3, 5, 7 & 9 wt.%) were prepared by an environmentally friendly, solid-state reaction at room temperature. The as-prepared samples were calcined under air at 450 °C in a furnace for a specific period of time. The synthesis of Zr/CrO2 photocatalysts was confirmed by various techniques, including XRD, SEM, EDX, FT-IR, UV-Vis, and BET. The photocatalytic properties of all samples were tested towards the degradation of methylene blue and methyl orange organic dyes under UV light. The results revealed a concentration-dependent photocatalytic activity of photocatalysts, which increased the amount of dopant (up to 5 wt.%). However, the degradation efficiency of the catalysts decreased upon further increasing the amount of dopant due to the recombination of holes and photoexcited electrons.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Garima Rathee ◽  
Amardeep Awasthi ◽  
Damini Sood ◽  
Ravi Tomar ◽  
Vartika Tomar ◽  
...  

Abstract It would be of great significance to introduce a new biocompatible Layered Double Hydroxide (LDH) for the efficient remediation of wastewater. Herein, we designed a facile, biocompatible and environmental friendly layered double hydroxide (LDH) of NiFeTi for the very first time by the hydrothermal route. The materialization of NiFeTi LDH was confirmed by FTIR, XRD and Raman studies. BET results revealed the high surface area (106 m2/g) and the morphological studies (FESEM and TEM) portrayed the sheets-like structure of NiFeTi nanoparticles. The material so obtained was employed as an efficient adsorbent for the removal of organic dyes from synthetic waste water. The dye removal study showed >96% efficiency for the removal of methyl orange, congo red, methyl blue and orange G, which revealed the superiority of material for decontamination of waste water. The maximum removal (90%) of dyes was attained within 2 min of initiation of the adsorption process which supported the ultrafast removal efficiency. This ultrafast removal efficiency was attributed to high surface area and large concentration of -OH and CO32− groups present in NiFeTi LDH. In addition, the reusability was also performed up to three cycles with 96, 90 and 88% efficiency for methyl orange. Furthermore, the biocompatibility test on MHS cell lines were also carried which revealed the non-toxic nature of NiFeTi LDH at lower concentration (100% cell viability at 15.6 μg/ml). Overall, we offer a facile surfactant free method for the synthesis of NiFeTi LDH which is efficient for decontamination of anionic dyes from water and also non-toxic.


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