scholarly journals Applications of Modified Biochar-Based Materials for the Removal of Environment Pollutants: A Mini Review

2020 ◽  
Vol 12 (15) ◽  
pp. 6112 ◽  
Author(s):  
Jung Eun Lee ◽  
Young-Kwon Park
Keyword(s):  
Iron Oxides ◽  
Functional Groups ◽  
Advanced Oxidation Process ◽  
Catalyst Support ◽  
Environmental Pollutants ◽  
Metal Catalyst ◽  
Modified Biochar ◽  
Eutrophic Water ◽  
Iron Iron ◽  
Titanium Dioxides

The biochar treated through several processes can be modified and utilized as catalyst or catalyst support due to specific properties with various available functional groups on the surface. The functional groups attached to the biochar surface can initiate active radical species to play an important role, which lead to the destruction of contaminants as a catalyst and the removal of adsorbent by involving electron transfer or redox processes. Centering on the high potential to be developed in field applications, this paper reviews more feasible and sustainable biochar-based materials resulting in efficient removals of environmental pollutants as catalyst or support rather than describing them according to the technology category. This review addresses biochar-based materials for utilization as catalysts, metal catalyst supports of iron/iron oxides, and titanium dioxide because the advanced oxidation process using iron/iron oxides or titanium dioxides is more effective for the removal of contaminants. Biochar-based materials can be used for the removal of inorganic contaminants such as heavy meals and nitrate or phosphate to cause eutrophication of water. The biochar-based materials available for the remediation of eutrophic water by the release of N- or P-containing compounds is also reviewed.

Ice nucleation activity of iron oxides via immersion freezing and an examination of the high ice nucleation activity of FeO

2021 ◽  
Vol 23 (5) ◽  
pp. 3565-3573
Author(s):  
Esther Chong ◽  
Katherine E. Marak ◽  
Yang Li ◽  
Miriam Arak Freedman
Keyword(s):  
Iron Oxides ◽  
Functional Groups ◽  
Ice Nucleation ◽  
Mechanical Processing ◽  
Immersion Freezing ◽  
Nucleation Activity ◽  
Ice Nucleation Activity

FeO has enhanced ice nucleation activity due to functional groups that are exposed upon mechanical processing.

Microstructure, Stiffness and Corrosion of Bare and Phosphated Specimens Made by Sintering of Structured Iron-Iron Oxide Spheres

2020 ◽  
Vol 405 ◽  
pp. 411-416
Author(s):  
Miriam Kupková ◽  
Martin Kupka ◽  
Renáta Oriňáková ◽  
Radka Gorejová
Keyword(s):  
Iron Oxide ◽  
Iron Oxides ◽  
Metallic Iron ◽  
Galvanic Corrosion ◽  
Iron Phosphate ◽  
Reduction Reaction ◽  
Diffusion Control ◽  
Iron Oxide Particles ◽  
Flow Through ◽  
Iron Iron

Granulated iron oxide particles were incompletely reduced to structured particles comprised metallic iron and residual iron oxides. Structured particles were pressed into prismatic compacts and sintered. Some of sintered specimens were subsequently phosphatized and calcined. Specimens with an iron phosphate coating were found stiffer than specimens without coating. In Hanks' solution, a galvanic corrosion was induced by more noble iron oxides coupled to a less noble metallic iron. This could explain higher corrosion potentials and higher rates of iron dissolution in comparison with a pure iron. The coating of specimens with iron phosphates shifted corrosion potentials towards more negative values and slowed down the dissolution of iron. This was most likely caused by a reduction in oxygen flow through the coating to iron-oxide cathodes, which has enhanced the influence of diffusion control on the kinetics of reduction reaction.

Development of Efficient Metal Catalyst Support

2007 ◽  
Vol 561-565 ◽  
pp. 547-550 ◽  
Author(s):  
Shouichi Muraoka ◽  
Kazuhiro Kitamura ◽  
Satoshi Kishi ◽  
Tatuo Nakazawa ◽  
Yasuo Shimizu
Keyword(s):  
Aluminum Oxide ◽  
Oxide Layer ◽  
Catalyst Support ◽  
Wire Mesh ◽  
Metal Catalyst ◽  
Oxide Surface ◽  
Low Oxygen ◽  
Metallic Catalyst ◽  
Aluminum Oxide Layer ◽  
Aluminum Oxide Surface

A new wire mesh metallic catalyst support has been studied by using a stainless heat resistant steel of including aluminum. This catalyst support was improved for the metal honeycomb catalyst support that had been put to practical use. The wire mesh catalyst support was made in the following procedures. First, it was made from flat plate made by the stainless steel from the machining. Second, the low oxygen atmosphere in the heat treatment furnace did the aluminum extraction processing. Third, the aluminum oxide layer was made on the surface of catalyst support by furnace in air. Metal honeycomb catalyst has been made for several years by this method. The aim of this study was to evaluate the aluminum oxide layer on the surface of wire mesh catalyst support. The aluminum oxide surface was measured using scanning electron microscopy (SEM) and X-ray reflection diffraction (XRD). This catalyst support has the performance similar to the conventional metal honeycomb catalyst support.

scholarly journals Hybrid Advanced Oxidation Processes Involving Ultrasound: An Overview

Molecules ◽  
2019 ◽  
Vol 24 (18) ◽  
pp. 3341 ◽  
Author(s):  
JagannathanMadhavan ◽  
JayaramanTheerthagiri ◽  
DhandapaniBalaji ◽  
SallaSunitha ◽  
Choi ◽  
...  
Keyword(s):  
Organic Pollutants ◽  
Organic Contaminants ◽  
Advanced Oxidation Process ◽  
Anthropogenic Activities ◽  
Environmental Pollutants ◽  
Advanced Oxidation ◽  
Aqueous Environment ◽  
Physical Conditions ◽  
Chemical Utilization ◽  
Complete Mineralization

: Sonochemical oxidation of organic pollutants in an aqueous environment is considered to be a green process. This mode of degradation of organic pollutants in an aqueous environment is considered to render reputable outcomes in terms of minimal chemical utilization and no need of extreme physical conditions. Indiscriminate discharge of toxic organic pollutants in an aqueous environment by anthropogenic activities has posed major health implications for both human and aquatic lives. Hence, numerous research endeavours are in progress to improve the efficiency of degradation and mineralization of organic contaminants. Being an extensively used advanced oxidation process, ultrasonic irradiation can be utilized for complete mineralization of persistent organic pollutants by coupling/integrating it with homogeneous and heterogeneous photocatalytic processes. In this regard, scientists have reported on sonophotocatalysis as an effective strategy towards the degradation of many toxic environmental pollutants. The combined effect of sonolysis and photocatalysis has been proved to enhance the production of high reactive-free radicals in aqueous medium which aid in the complete mineralization of organic pollutants. In this manuscript, we provide an overview on the ultrasound-based hybrid technologies for the degradation of organic pollutants in an aqueous environment.

scholarly journals Risk Evaluation of Pyrolyzed Biochar from Multiple Wastes

2019 ◽  
Vol 2019 ◽  
pp. 1-28 ◽  
Author(s):  
Shem M. Ndirangu ◽  
Yanyan Liu ◽  
Kai Xu ◽  
Shaoxian Song
Keyword(s):  
Functional Groups ◽  
Risk Evaluation ◽  
Low Cost ◽  
Risk Index ◽  
Potential Ecological Risk ◽  
Pyrolysis Process ◽  
Air Oxidation ◽  
Net Benefit ◽  
Modified Biochar ◽  
Contaminated Food

This paper aims at demonstrating the significance of biochar risk evaluation and reviewing risk evaluation from the aspects of pyrolysis process, feedstock, and sources of hazards in biochar and their potential effects and the methods used in risk evaluation. Feedstock properties and the resultant biochar produced at different pyrolysis process influence their chemical, physical, and structural properties, which are vital in understanding the functionality of biochar. Biochar use has been linked to some risks in soil application such as biochar being toxic, facilitating GHGs emission, suppression of the effectiveness of pesticides, and effects on soil microbes. These potential risks originate from feedstock, contaminated feedstock, and pyrolysis conditions that favor the creation of characteristics and functional groups of this nature. These toxic compounds formed pose a threat to human health through the food chain. Determination of toxicity levels is a first step in the risk management of toxic biochar. Various sorption methods of biochar utilized low-cost adsorbents, engineered surface functional groups, and nZVI modified biochars. The mechanisms of organic compound removal was through sorption, enhanced sorption, modified biochar, postpyrolysis thermal air oxidation and that of PFRs degradation was through activation, photoactive functional groups, magnetization, and hydrothermal synthesis. Emissions of GHGs in soils amended with biochar emanated through physical and biotic mediated mechanisms. BCNs have a significance in reducing the health quotient indices for PTEs risk contamination by suppressing cancer risk arising from consumption of contaminated food. The degree of environmental risk assessment of HM pollution in biomass and biochars has been determined by using potential ecological risk index and RAC while organic contaminant degradation by EPFRs was considered when assessing the environmental roles of biochar in regulating the fate of contaminants removal. The magnitude of technologies’ net benefit must be considered in relation to the associated risks.

scholarly journals Parameter Optimisation of Carbon Nanotubes Synthesis via Hexane Decomposition over Minerals Generated fromAnadara granosaShells as the Catalyst Support

2012 ◽  
Vol 2012 ◽  
pp. 1-9 ◽  
Author(s):  
M. Z. Hussein ◽  
S. A. Zakarya ◽  
S. H. Sarijo ◽  
Z. Zainal
Keyword(s):  
Electron Microscopy ◽  
Carbon Nanotubes ◽  
Catalyst Support ◽  
Chemical Vapour ◽  
Total Iron ◽  
Metal Catalyst ◽  
Iron Loading ◽  
Transmission Electron ◽  
Synthesis Of Carbon Nanotubes ◽  
Anadara Granosa

The synthesis of carbon nanotubes (CNTs) by the chemical vapour deposition (CVD) method using natural calcite fromAnadara granosashells as the metal catalyst support was studied. Hexane and iron (Fe) were used as the carbon precursor and the active component of the catalyst, respectively. Response surface methodology (RSM) based on central composite design (CCD) was used to optimise the effect of total iron loading, the duration of reaction, and reaction temperature. The optimal conditions were total iron loading of 7.5%, a reaction time of 45 min, and a temperature of 850°C with a resulting carbon yield of 131.62%. Raman spectra, field-emission-scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) analyses showed that the CNTs were of the multiwalled type (MWNTs).

Purification of Multi-Walled Carbon Nanotubes Grown by Thermal CVD on Fe-Based Catalyst

2006 ◽  
Vol 48 ◽  
pp. 50-54 ◽  
Author(s):  
Th. Dikonimos Makris ◽  
L. Giorgi ◽  
R. Giorgi ◽  
Nicola Lisi ◽  
Elena Salernitano ◽  
...  
Keyword(s):  
Carbon Nanotubes ◽  
Catalyst Support ◽  
Secondary Phase ◽  
Metal Catalyst ◽  
Purification Method ◽  
Thermal Cvd ◽  
Aluminum Ions ◽  
Before And After ◽  
Multi Walled Carbon Nanotubes ◽  
Walled Carbon Nanotubes

Aiming at the purpose of using carbon nanotubes as secondary phase in composite materials, removal of metal catalyst, catalyst support and amorphous carbon is crucial to make the most of the required properties. A purification method was developed to remove the metal catalyst from multi-walled nanotubes grown by thermal CVD. A nanosized Fe-based catalyst, prepared by coprecipitation of iron and aluminum ions, followed by solid state reaction, was used to catalyze the growth. Carbon nanotubes were subjected to acid purification and a comparison between nitric acid and a mixture of nitric and hydrochloric acid for the removal of Fe and Fe oxides is provided. Morphological and spectroscopic analyses of the materials were performed, both before and after the purification processes.

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