scholarly journals Anisotropic Oxidative Growth Of Goethite-Coated Sand Particles In Column Reactors During 4-Chloronitrobenzene Reduction by Fe(II)/Goethite

2022 ◽  
Author(s):  
Adel Soroush ◽  
R. Lee Penn ◽  
William Arnold
Keyword(s):  
Iron Oxides ◽  
Nitroaromatic Compounds ◽  
Important Class ◽  
Sand Particles ◽  
Coated Sand ◽  
Groundwater Pollutants

Reduction of nitroaromatic compounds (NACs), an important class of groundwater pollutants, by Fe(II) associated with iron oxides, a highly reactive reductant in anoxic aquifers, has been studied widely, but there...

scholarly journals Nitroaromatic Compounds, from Synthesis to Biodegradation

2010 ◽  
Vol 74 (2) ◽  
pp. 250-272 ◽  
Author(s):  
Kou-San Ju ◽  
Rebecca E. Parales
Keyword(s):  
Nitro Group ◽  
Aromatic Amines ◽  
Environmental Remediation ◽  
Oxidative Degradation ◽  
Nitroaromatic Compounds ◽  
Important Class ◽  
Industrial Chemicals ◽  
Evolutionary Origins ◽  
The Stability ◽  
The U.S

SUMMARY Nitroaromatic compounds are relatively rare in nature and have been introduced into the environment mainly by human activities. This important class of industrial chemicals is widely used in the synthesis of many diverse products, including dyes, polymers, pesticides, and explosives. Unfortunately, their extensive use has led to environmental contamination of soil and groundwater. The nitro group, which provides chemical and functional diversity in these molecules, also contributes to the recalcitrance of these compounds to biodegradation. The electron-withdrawing nature of the nitro group, in concert with the stability of the benzene ring, makes nitroaromatic compounds resistant to oxidative degradation. Recalcitrance is further compounded by their acute toxicity, mutagenicity, and easy reduction into carcinogenic aromatic amines. Nitroaromatic compounds are hazardous to human health and are registered on the U.S. Environmental Protection Agency's list of priority pollutants for environmental remediation. Although the majority of these compounds are synthetic in nature, microorganisms in contaminated environments have rapidly adapted to their presence by evolving new biodegradation pathways that take advantage of them as sources of carbon, nitrogen, and energy. This review provides an overview of the synthesis of both man-made and biogenic nitroaromatic compounds, the bacteria that have been identified to grow on and completely mineralize nitroaromatic compounds, and the pathways that are present in these strains. The possible evolutionary origins of the newly evolved pathways are also discussed.

The use of dispersible clays to reduce water repellency of sandy soils

Soil Research ◽  
1989 ◽  
Vol 27 (4) ◽  
pp. 797 ◽  
Author(s):  
M Ma'shum ◽  
JM Oades ◽  
ME Tate
Keyword(s):  
Organic Matter ◽  
Sandy Soils ◽  
Water Repellency ◽  
Cetyl Alcohol ◽  
Water Repellent ◽  
Fine Grained ◽  
Naturally Occurring ◽  
Rapid Control ◽  
Sand Particles ◽  
Coated Sand

Water-repellency in sandy soils is determined by the amount of hydrophobic organic matter coating the sand particles and the specific surface area of the sands. The hydrophobic state can be simulated by coating hydrophilic sand with cetyl alcohol. Admixture of finely particulate materials with either naturally occurring water-repellent sands or the model cetyl alcohol-coated sand markedly reduced the water-repellency. Dispersible sodic clays were more effective than calcium saturated clays in reducing water-repellency, suggesting that the addition of dispersible, fine-grained illites and kaolinites couid play an important role in the rapid control of water-repellent soils in field situations.

scholarly journals Removal of mutagen X “MX” from drinking water using reduced graphene oxide coated sand particles

2019 ◽  
Vol 17 (2) ◽  
pp. 827-837
Author(s):  
Mahtab Bagheban ◽  
Ali Mohammadi ◽  
Majid Baghdadi ◽  
Mehran Janmohammadi ◽  
Maryam Salimi
Keyword(s):  
Drinking Water ◽  
Graphene Oxide ◽  
Reduced Graphene Oxide ◽  
Reduced Graphene ◽  
Sand Particles ◽  
Coated Sand

scholarly journals Effect of Bovine Manure on Fecal Coliform Attachment to Soil and Soil Particles of Different Sizes

2007 ◽  
Vol 73 (10) ◽  
pp. 3363-3370 ◽  
Author(s):  
Andrey K. Guber ◽  
Yakov A. Pachepsky ◽  
Daniel R. Shelton ◽  
Olivia Yu
Keyword(s):  
Clay Fraction ◽  
Free Cell ◽  
Organic Coating ◽  
Bacterial Attachment ◽  
Fecal Coliforms ◽  
Clay Particles ◽  
Soil Particles ◽  
Soil Fractions ◽  
Sand Particles ◽  
Coated Sand

ABSTRACT Manure-borne bacteria can be transported in runoff as free cells, cells attached to soil particles, and cells attached to manure particles. The objectives of this work were to compare the attachment of fecal coliforms (FC) to different soils and soil fractions and to assess the effect of bovine manure on FC attachment to soil and soil fractions. Three sand fractions of different sizes, the silt fraction, and the clay fraction of loam and sandy clay loam soils were separated and used along with soil samples in batch attachment experiments with water-FC suspensions and water-manure-FC suspensions. In the absence of manure colloids, bacterial attachment to soil, silt, and clay particles was much higher than the attachment to sand particles having no organic coating. The attachment to the coated sand particles was similar to the attachment to silt and clay. Manure colloids in suspensions decreased bacterial attachment to soils, clay and silt fractions, and coated sand fractions, but did not decrease the attachment to sand fractions without the coating. The low attachment of bacteria to silt and clay particles in the presence of manure colloids may cause predominantly free-cell transport of manure-borne FC in runoff.

Study on Resin Coated Sand Proppant Used for Oil Production

2012 ◽  
Vol 524-527 ◽  
pp. 1910-1914 ◽  
Author(s):  
Tao Chen ◽  
Guo Zhen Wang ◽  
Jie Gao ◽  
Yan Dan Yang ◽  
Rui Ma ◽  
...  
Keyword(s):  
Hydraulic Fracturing ◽  
Coupling Agent ◽  
Oil Production ◽  
Promising Method ◽  
Short Term ◽  
Sand Particles ◽  
The Cost ◽  
Coated Sand

A method of preparing precured resin coated sand particles was developed. The effects of resins dosages, plasticizer and coupling agent on the sphericity, roundness, crush resistance and flow conductivity of pre-cured resin coated sand were also discussed. Compared with raw sand, the sphericity and roundness of this resin coated sand particles is higher. It also possessed excellent properties to company sample, such as better resistance to crushing, as well as higher short term flow conductivity. By use of the resin coated sand, the cost could be reduced, and the yield of raw oil will be increased. It is a promising method of modified sand in field of hydraulic fracturing treatment.

Chemical Classification and Particle Sizing of Foundry Sands

1985 ◽  
Vol 43 ◽  
pp. 388-389
Author(s):  
D.S. DeMiglio
Keyword(s):  
Image Analysis ◽  
Energy Dispersive Spectrometer ◽  
Image Analysis System ◽  
Representative Sampling ◽  
Foundry Sands ◽  
Large Atomic Number ◽  
Backscattered Electron ◽  
Sand Particles ◽  
Analysis System ◽  
Reclamation System

Much progress has been made in recent years towards the development of closed-loop foundry sand reclamation systems. However, virtually all work to date has determined the effectiveness of these systems to remove surface clay and metal oxide scales by a qualitative inspection of a representative sampling of sand particles. In this investigation, particles from a series of foundry sands were sized and chemically classified by a Lemont image analysis system (which was interfaced with an SEM and an X-ray energy dispersive spectrometer) in order to statistically document the effectiveness of a reclamation system developed by The Pangborn Company - a subsidiary of SOHIO.The following samples were submitted: unreclaimed sand; calcined sand; calcined & mechanically scrubbed sand and unused sand. Prior to analysis, each sample was sprinkled onto a carbon mount and coated with an evaporated film of carbon. A backscattered electron photomicrograph of a field of scale-covered particles is shown in Figure 1. Due to a large atomic number difference between sand particles and the carbon mount, the backscattered electron signal was used for image analysis since it had a uniform contrast over the shape of each particle.

Gold liposomes

1996 ◽  
Vol 54 ◽  
pp. 898-899
Author(s):  
James F. Hainfeld
Keyword(s):  
Direct Methods ◽  
Important Class ◽  
Double Bonds ◽  
Membrane Phospholipids ◽  
Essential Ingredient ◽  
Lipid Structures

Lipids are an important class of molecules, being found in membranes, HDL, LDL, and other natural structures, serving essential roles in structure and with varied functions such as compartmentalization and transport. Synthetic liposomes are also widely used as delivery and release vehicles for drugs, cosmetics, and other chemicals; soap is made from lipids. Lipids may form bilayer or multilammellar vesicles, micelles, sheets, tubes, and other structures. Lipid molecules may be linked to proteins, carbohydrates, or other moieties. EM study of this essential ingredient of life has lagged, due to lack of direct methods to visualize lipids without extensive alteration. OsO4 reacts with double bonds in membrane phospholipids, forming crossbridges. This has been the method of choice to both fix and stain membranes, thus far. An earlier work described the use of tungstate clusters (W11) attached to lipid moieties to form lipid structures and lipid probes.

Selective oxidation of aniline into azoxybenzene catalyzed by Nb-peroxo@iron oxides at room temperature

2020 ◽  
Vol 44 (21) ◽  
pp. 8710-8717
Author(s):  
André L. D. Lima ◽  
Humberto V. Fajardo ◽  
André E. Nogueira ◽  
Márcio C. Pereira ◽  
Luiz C. A. Oliveira ◽  
...  
Keyword(s):  
Iron Oxides ◽  
Selective Oxidation ◽  
Room Temperature ◽  
High Selectivity

Nb-peroxo@iron oxides show high selectivity and activity in aniline conversion to azoxybenzene.

Pilot Plant Data for Synthetic Iron Oxides

1952 ◽  
Vol 44 (3) ◽  
pp. 449-449
Author(s):  
C DeWitt ◽  
M Livingood ◽  
K Miller
Keyword(s):  
Iron Oxides ◽  
Pilot Plant ◽  
Plant Data
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