Application of hydroxyapatite and its modified forms as adsorbents for water defluoridation: an insight into process synthesis

2020 ◽  
Vol 36 (3) ◽  
pp. 369-400 ◽  
Author(s):  
Suja George ◽  
Dhiraj Mehta ◽  
Virendra Kumar Saharan
Keyword(s):  
Water Treatment ◽  
Groundwater Resources ◽  
Sol Gel ◽  
Synthesis Method ◽  
Fluoride Removal ◽  
Synthesis Methods ◽  
Removal Capacity ◽  
Specific Catalytic Activity ◽  
Physical And Chemical ◽  
Modified Forms

AbstractFluorosis is a major scourge in many countries caused by prolonged consumption of drinking water with high fluoride content found in groundwater resources. Hydroxyapatite (Hap) and its composite forms are excellent biomaterials that recently gained attention as efficient adsorbents, owing to its physical and chemical nature as it can substitute both cationic and anionic complexes present in an aqueous solution in its atomic arrangement. Its biological nature, biocompatibility and biodegradability along with its chemical characteristics such as crystallinity, stability, ion adsorption capability and highly specific catalytic activity make it suitable for a variety of applications especially in water treatment for fluoride removal. This review describes various techniques for synthesis of a wide variety of biogenic, synthetic, composite and modified forms of Hap for application in water defluoridation. Hap derived from natural sources or synthesized using conventional methods, hydrothermal, sol-gel or advanced sonication-cum-precipitation technique varied in terms of its crystallinity, structure, size, etc., which affect the fluoride removal capacity. The advantage and disadvantages of various synthesis methods, process parameters and product characteristics have been compiled, which may help to identify a suitable synthesis method for a desired Hap product for potential application and future perspectives in water treatment.

scholarly journals Magnetic iron oxide/clay nanocomposites for adsorption and catalytic oxidation in water treatment applications

2020 ◽  
Vol 18 (1) ◽  
pp. 1148-1166
Author(s):  
Ganjar Fadillah ◽  
Septian Perwira Yudha ◽  
Suresh Sagadevan ◽  
Is Fatimah ◽  
Oki Muraza
Keyword(s):  
Iron Oxide ◽  
Water Treatment ◽  
Photocatalytic Oxidation ◽  
Low Cost ◽  
Synthesis Method ◽  
Chemical Oxidation ◽  
Magnetic Iron Oxide ◽  
Oxidation Processes ◽  
Recent Developments ◽  
Physical And Chemical

AbstractPhysical and chemical methods have been developed for water and wastewater treatments. Adsorption is an attractive method due to its simplicity and low cost, and it has been widely employed in industrial treatment. In advanced schemes, chemical oxidation and photocatalytic oxidation have been recognized as effective methods for wastewater-containing organic compounds. The use of magnetic iron oxide in these methods has received much attention. Magnetic iron oxide nanocomposite adsorbents have been recognized as favorable materials due to their stability, high adsorption capacities, and recoverability, compared to conventional sorbents. Magnetic iron oxide nanocomposites have also been reported to be effective in photocatalytic and chemical oxidation processes. The current review has presented recent developments in techniques using magnetic iron oxide nanocomposites for water treatment applications. The review highlights the synthesis method and compares modifications for adsorbent, photocatalytic oxidation, and chemical oxidation processes. Future prospects for the use of nanocomposites have been presented.

scholarly journals Sol-Gel Synthesis of the Double Perovskite Sr2FeMoO6 by Microwave Technique

Materials ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 3876
Author(s):  
Jesús Valdés ◽  
Daniel Reséndiz ◽  
Ángeles Cuán ◽  
Rufino Nava ◽  
Bertha Aguilar ◽  
...  
Keyword(s):  
Particle Size ◽  
Hydrothermal Synthesis ◽  
Microwave Radiation ◽  
Structural Characteristics ◽  
Sol Gel ◽  
Synthesis Method ◽  
Double Perovskite ◽  
Synthesis Methods ◽  
X Ray ◽  
Sol Gel Synthesis

The effect of microwave radiation on the hydrothermal synthesis of the double perovskite Sr2FeMoO6 has been studied based on a comparison of the particle size and structural characteristics of products from both methods. A temperature, pressure, and pH condition screening was performed, and the most representative results of these are herein presented and discussed. Radiation of microwaves in the hydrothermal synthesis method led to a decrease in crystallite size, which is an effect from the reaction temperature. The particle size ranged from 378 to 318 nm when pH was 4.5 and pressure was kept under 40 bars. According to X-ray diffraction (XRD) results coupled with the size-strain plot method, the product obtained by both synthesis methods (with and without microwave radiation) have similar crystal purity. The Scanning Electron Microscopy (SEM) and Energy Dispersive X-ray Spectroscopy (EDS) techniques showed that the morphology and the distribution of metal ions are uniform. The Curie temperature obtained by thermogravimetric analysis indicates that, in the presence of microwaves, the value was higher with respect to traditional synthesis from 335 K to 342.5 K. Consequently, microwave radiation enhances the diffusion and nucleation process of ionic precursors during the synthesis, which promotes a uniform heating in the reaction mixture leading to a reduction in the particle size, but keeping good crystallinity of the double perovskite. Precursor phases and the final purity of the Sr2FeMoO6 powder can be controlled via hydrothermal microwave heating on the first stages of the Sol-Gel method.

scholarly journals Review on the Synthesis Methods of Nano-Tungsten Oxide Dihydrate Colloid

2021 ◽  
Vol 335 ◽  
pp. 03008
Author(s):  
Khizar Mushtaq ◽  
Pui May Chou ◽  
Chin Wei Lai
Keyword(s):  
Particle Size ◽  
Tungsten Oxide ◽  
Sol Gel ◽  
Synthesis Method ◽  
Transition Element ◽  
Cost Effective ◽  
Processing Parameters ◽  
Synthesis Methods ◽  
Cost Effective Method ◽  
Future Work

Tungsten being a transition element, forms oxide compounds of various oxidation states that enables it to form nanocolloids of tungsten oxide dihydrate. Multiple methods have been used in recent years to synthesize nano tungsten oxide dihydrate, including sol-gel synthesis, electrochemical deposition, hydrothermal synthesis and anodization. However, a universally accepted synthesis method for this material is not offered. The most appropriate method and its corresponding processing parameters for the synthesis of nano tungsten oxide dihydrate colloids were presented in the present study. The objective of the present study was to investigate the effect of processing parameters, i.e. applied voltage, temperature and anodizing duration on the particle size of nanocolloids. It is found that anodization is the easiest, efficient, and cost-effective method to synthesize the colloidal solution of nano tungsten oxide dihydrate. Conducting the synthesis at room temperature at a voltage of 50 V for 60 minutes yields the product with particle size of 40 – 60 nm, which can be used in wide array of applications. This paper also highlights the research gaps for future work and gives recommendations to extend this study particularly for the industrial application of tungsten oxide.

New inorganic (an)ion exchangers with a higher affinity for arsenate and a competitive removal capacity towards fluoride, bromate, bromide, selenate, selenite, arsenite and borate

2011 ◽  
Vol 11 (5) ◽  
pp. 505-515 ◽  
Author(s):  
Natalia Chubar
Keyword(s):  
Sol Gel ◽  
Synthesis Method ◽  
Cost Effective ◽  
Ionic Species ◽  
Adsorptive Capacity ◽  
Ion Exchangers ◽  
Inorganic Ion Exchangers ◽  
Inorganic Ion ◽  
Removal Capacity ◽  
Hydrous Oxides

Highly selective materials and effective technologies are needed to meet the increasingly stronger drinking water standards for targeted ionic species. Inorganic ion exchangers based on individual and mixed-metal hydrous oxides (or mixed adsorbents that contain inorganic ion exchangers in their composition) are adsorptive materials that are capable of lowering the concentrations of anionic contaminants, such as H2AsO4−, H3AsO3, F−, Br−, BrO3−, HSeO4−, HSeO3− and H3BO3, to 10 μg/L or less. To achieve a higher selectivity towards arsenate, a new ion exchanger based on Mg–Al hydrous oxides was developed by a novel, cost-effective and environmentally friendly synthesis method via a non-traditional (alkoxide-free) sol-gel approach. The exceptional adsorptive capacity of the Mg–Al hydrous oxides towards H2AsO4− (up to 200 mg[As]/gdw) is due to the high affinity of this sorbent towards arsenate (steep equilibrium isotherms) and its fast adsorption kinetics. Because of the mesoporous (as determined by N2 adsorption and SEM) and layered (as determined by XRD and FTIR) structure of the ion-exchange material as well as the abundance of anion exchange sites (as determined by XPS and potentiometric titration) on its surface the material demonstrated very competitive (or very high) removal capacity towards other targeted anions, including fluoride, bromide, bromate, selenate, selenite, and borate.

scholarly journals Synthesis Methods of Obtaining Materials for Hydrogen Sensors

Sensors ◽  
2021 ◽  
Vol 21 (17) ◽  
pp. 5758
Author(s):  
Izabela Constantinoiu ◽  
Cristian Viespe
Keyword(s):  
Spin Coating ◽  
Sol Gel ◽  
Synthesis Method ◽  
Pulsed Laser ◽  
Laser Deposition ◽  
Synthesis Methods ◽  
Sensitive Area ◽  
Hydrogen Sensors ◽  
Hydrogen Detection ◽  
Co Precipitation

The development of hydrogen sensors has acquired a great interest from researchers for safety in fields such as chemical industry, metallurgy, pharmaceutics or power generation, as well as due to hydrogen’s introduction as fuel in vehicles. Several types of sensors have been developed for hydrogen detection, including resistive, surface acoustic wave, optical or conductometric sensors. The properties of the material of the sensitive area of the sensor are of great importance for establishing its performance. Besides the nature of the material, an important role for its final properties is played by the synthesis method used and the parameters used during the synthesis. The present paper highlights recent results in the field of hydrogen detection, obtained using four of the well-known synthesis and deposition methods: sol-gel, co-precipitation, spin-coating and pulsed laser deposition (PLD). Sensors with very good results have been achieved by these methods, which gives an encouraging perspective for their use in obtaining commercial hydrogen sensors and their application in common areas for society.

scholarly journals Green Synthesis and Applications of ZnO and TiO2 Nanostructures

Molecules ◽  
2021 ◽  
Vol 26 (8) ◽  
pp. 2236
Author(s):  
Rosana A. Gonçalves ◽  
Rosimara P. Toledo ◽  
Nirav Joshi ◽  
Olivia M. Berengue
Keyword(s):  
Green Synthesis ◽  
Sol Gel ◽  
Cost Effective ◽  
Synthesis Methods ◽  
Green Approach ◽  
Oxide Nanostructures ◽  
Co Precipitation ◽  
Physical And Chemical ◽  
Synthesis Approach ◽  
Tio2 Nanostructures

Over the last two decades, oxide nanostructures have been continuously evaluated and used in many technological applications. The advancement of the controlled synthesis approach to design desired morphology is a fundamental key to the discipline of material science and nanotechnology. These nanostructures can be prepared via different physical and chemical methods; however, a green and ecofriendly synthesis approach is a promising way to produce these nanostructures with desired properties with less risk of hazardous chemicals. In this regard, ZnO and TiO2 nanostructures are prominent candidates for various applications. Moreover, they are more efficient, non-toxic, and cost-effective. This review mainly focuses on the recent state-of-the-art advancements in the green synthesis approach for ZnO and TiO2 nanostructures and their applications. The first section summarizes the green synthesis approach to synthesize ZnO and TiO2 nanostructures via different routes such as solvothermal, hydrothermal, co-precipitation, and sol-gel using biological systems that are based on the principles of green chemistry. The second section demonstrates the application of ZnO and TiO2 nanostructures. The review also discusses the problems and future perspectives of green synthesis methods and the related issues posed and overlooked by the scientific community on the green approach to nanostructure oxides.

scholarly journals Literature Review: Synthesis Methods of NiFe2O4 Nanoparticles for Aqueous Battery Applications

2021 ◽  
Vol 4 (2) ◽  
pp. 42-52
Author(s):  
Fatih Izzul Haq ◽  
◽  
Muhammad Aldin Nur Zein ◽  
Rachel Gabriella ◽  
Silmi Ridwan Putri ◽  
...  
Keyword(s):  
Literature Review ◽  
Industrial Production ◽  
Sol Gel ◽  
Synthesis Method ◽  
Synthesis Methods ◽  
Calcination Process ◽  
Aqueous Battery ◽  
Pulsed Wire Discharge ◽  
Effective Synthesis ◽  
Nife2o4 Nanoparticles

Today, the application of NiFe2O4 nanoparticles is increasing in the field of technology that is in great demand, thereby increasing the demand for industrial production. The use of NiFe2O4 nanoparticles can be applied in various technologies, including aqueous batteries. Therefore, an effective method for industrial production is needed. This paper aims to discuss and compare a more efficient method in the synthesis of NiFe2O4. The research method used is a literature review of 62 papers. There are several NiFe2O4 synthesis methods, namely Coprecipitation, Citrate Precursor Technique, Mechanical Alloying, Hydrothermal, Sonochemistry, Reverse Micelle, Sol-Gel, and Pulsed Wire Discharge. The results show that the effective synthesis method of NiFe2O4 is Hydrothermal. This is because the hydrothermal method is economically feasible, environmentally friendly, and has no requirement of high temperatures in the calcination process to produce the final product. The nanoparticle size is around 29.39 nm. This paper is expected to assist in selecting the synthesis method of NiFe2O4.

scholarly journals Progress in Synthesis of Conductive Polymer Poly(3,4-Ethylenedioxythiophene)

2021 ◽  
Vol 9 ◽  
Author(s):  
Shisong Nie ◽  
Zaifang Li ◽  
Yuyuan Yao ◽  
Yingzhi Jin
Keyword(s):  
Electrochemical Polymerization ◽  
Synthesis Method ◽  
Conductive Polymer ◽  
Synthesis Methods ◽  
High Quality ◽  
Research Directions ◽  
Energy Conversion And Storage ◽  
Physical And Chemical ◽  
And Storage ◽  
Coupling Polymerization

PEDOT is the most popularly used conductive polymer due to its high conductivity, good physical and chemical stability, excellent optical transparency, and the capabilities of easy doping and solution processing. Based on the advantages above, PEDOT has been widely used in various devices for energy conversion and storage, and bio-sensing. The synthesis method of PEDOT is very important as it brings different properties which determine its applications. In this mini review, we begin with a brief overview of recent researches in PEDOT. Then, the synthesis methods of PEDOT are summarized in detail, including chemical polymerization, electrochemical polymerization, and transition metal-mediated coupling polymerization. Finally, research directions in acquiring high-quality PEDOT are discussed and proposed.

scholarly journals Advances in Laser Ablation Synthesized Silicon-Based Nanomaterials for the Prevention of Bacterial Infection

Nanomaterials ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1443
Author(s):  
Marina Martínez-Carmona ◽  
María Vallet-Regí
Keyword(s):  
Laser Ablation ◽  
Bacterial Infection ◽  
Laser Treatment ◽  
Sol Gel ◽  
Synthesis Method ◽  
Synthesis Methods ◽  
Bulk Materials ◽  
Chemical Methods ◽  
Physical Methods ◽  
Silicon Based

Nanomaterials have unique properties and characteristics derived from their shape and small size that are not present in bulk materials. If size and shape are decisive, the synthesis method used, which determines the above parameters, is equally important. Among the different nanomaterial’s synthesis methods, we can find chemical methods (microemulsion, sol-gel, hydrothermal treatments, etc.), physical methods (evaporation-condensation, laser treatment, etc.) and biosynthesis. Among all of them, the use of laser ablation that allows obtaining non-toxic nanomaterials (absence of foreign compounds) with a controlled 3D size, has emerged in recent years as a simple and versatile alternative for the synthesis of a wide variety of nanomaterials with numerous applications. This manuscript reviews the latest advances in the use of laser ablation for the synthesis of silicon-based nanomaterials, highlighting its usefulness in the prevention of bacterial infection.

scholarly journals DETERMINATION OF THE SIZES OF PARTICLES OF SUPERCONDUCTING CUPRATE Y3Ba5Cu8OX BY MEANS OF DIFFERENT METHODS

2020 ◽  
Vol 4 ◽  
pp. 10-13
Author(s):  
Anastasiia Bolotnikova
Keyword(s):  
Particle Size ◽  
Size Structure ◽  
Solid Phase ◽  
Sol Gel ◽  
Synthesis Method ◽  
Precipitation Method ◽  
Phase Method ◽  
Synthesis Methods ◽  
Scherrer Formula ◽  
Co Precipitation

The superconducting cuprate Y3Ba5Cu8Ox was obtained with the help of sol-gel technology (sample C), co-precipitation of hydroxocarbonates (sample B) and solid-phase synthesis methods (A). Based on the results of scanning electron microscopy and methods based on the analysis of X-ray diffraction data: the Williamson-Hall construction and the Scherrer formula, features of the microstructure of the synthesized samples are established. The smallest particle size has a sample that has been synthesized by the sol-gel method. The tendency to aggregation and sedimentation for this sample is the smallest. The sample obtained by the co-precipitation method has larger grains and a higher tendency to aggregate. The size of the microparticles and the tendency to aggregate for the sample synthesized by the solid-phase method are greatest. The morphology of particles was studied using three methods: SEM, Scherrer and Williamson-Hall formulas and the following results were found: particle size depends on the synthesis method, but a relatively narrow size distribution within one synthesis method remains, the value of crystal lattice microdeformation for samples increases in a line: C sample– A sample– B sample. Thus, the work was carried out for determining the size, structure and morphology of superconducting phases. It expands knowledge in the field of research of superconducting compounds

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