scholarly journals GEOCHEMICAL CHARACTERIZATION OF BANANA, BURITI PALM, JUTE AND COIR FIBRES FOR USE AS BIOGEOTEXTILES FOR EROSION CONTROL

2018 ◽  
Vol 26 (3) ◽  
pp. 202-215 ◽  
Author(s):  
Charles Izuchukwu Egbujuo ◽  
Michael A. Fullen ◽  
Antonio J. T. Guerra ◽  
Alexander Iheanyi Opara
Keyword(s):  
Heavy Metal ◽  
Heavy Metal Contamination ◽  
Erosion Control ◽  
X Ray Diffraction ◽  
Soil System ◽  
Geochemical Composition ◽  
X Ray ◽  
Jute Cloth ◽  
High Concentrations ◽  
Banana Leaf

Geochemical analysis of selected plant fibres used as geotextiles for erosion control was conducted to evaluate their geochemical composition and to determine the elements that could potentially be nutrients for plants or cause heavy metal contamination in soils. Analysis of the samples was performed using X-ray Diffraction and X-ray Fluorescence spectrometry. Results revealed that potassium concentrations varied from 3.63% in jute-mat (India)-50.73% in banana-leaf (São Romão, Brazil), with a mean of 27.17%. Similarly, calcium concentrations varied from 0.09% in banana-leaf (São Romão) –37.0% in banana-leaf/stem (Oleo, Brazil). Iron concentrations varied from 0.15% in banana-leaf/stem samples (Oleo) –4.47% in jute-cloth (India). Since banana-leaf/stem had the highest concentration of macro-nutrients, it is therefore proposed that banana-leaf has the highest potential for adding nutrients to the soil system when biodegraded. In addition, heavy metal analysis of the samples revealed that none of the fibres have high concentrations that may contaminate the soil upon decomposition.

Deposition of TRISO Particles With Superhard SiC Coatings and the Characterization of Anisotropy by Raman Spectroscopy

2009 ◽  
Vol 131 (4) ◽  
Author(s):  
E. López-Honorato ◽  
P. J. Meadows ◽  
J. Tan ◽  
Y. Xiang ◽  
P. Xiao
Keyword(s):  
Solid Solution ◽  
Raman Spectroscopy ◽  
Pyrolytic Carbon ◽  
X Ray Diffraction ◽  
X Ray ◽  
Flat Substrate ◽  
High Concentrations ◽  
Triso Particles ◽  
Sic Coatings

In this work we have deposited silicon carbide (SiC) at 1300°C with the addition of small amounts of propylene. The use of propylene and high concentrations of methyltrichlorosilane (9 vol %) allowed the deposition of superhard SiC coatings (42 GPa). The superhard SiC could result from the presence of a SiC–C solid solution, undetectable by X-ray diffraction but visible by Raman spectroscopy. Another sample obtained by the use of 50 vol % Argon, also showed the formation of SiC with good properties. The use of a flat substrate together with the particles showed the importance of carrying out the analysis on actual particles rather than in flat substrates. We show that it is possible to characterize the anisotropy of pyrolytic carbon by Raman spectroscopy.

scholarly journals Synthesis of Nanobentonite as Heavy Metal Adsorbent with Various Solvents

2018 ◽  
Vol 34 (4) ◽  
pp. 1854-1857
Author(s):  
Makmur Sirait ◽  
Saharman Gea ◽  
Nurdin Bukit ◽  
Nurdin Siregar ◽  
Ceria Sitorus
Keyword(s):  
Heavy Metal ◽  
Diffraction Analysis ◽  
Metal Content ◽  
Energy Analysis ◽  
Nanometer Scale ◽  
X Ray Diffraction ◽  
X Ray ◽  
Atomic Adsorption ◽  
Heavy Metal Adsorbent ◽  
Scanning Electron

The nanobentonite has been synthesized from natural bentonite taken from Tapanuli Utara, Indonesia using coprecipitation method with various solvents (HCl, H2SO4, and HNO3). Its properties as a metal adsorbent were investigated by Atomic Adsorption Spectrophotometry. X-Ray Diffraction analysis revealed that the bentonite produced is in nanometer scale. The characterization results obtained from the SiO2single phase with highest dhkl was at millier index (101) with 2 of 21.9o, 22.0o, 22.07o respectively. The results of Microscope-Scanning Electron Energy analysis of nanobentonite dispersion indicated a reduction in agglomeration and finer nanobentonite surface. The Surface Area Analyzer results showed the SBET nanobentonite for solvent variation of HCL, H2SO4, and HNO3 respectively were 731.76 m2/g, 868.11 m2/g, 493.97 m2/ g. Lastly, Atomic Adsorption Spectrophotometric test showed that the optimal absorption of the metal content possessed by variety of HCl and nanobentonites with adsorption power of 91.16% for Pb, 76.39% for Cu, and 82.74% Co.

scholarly journals Heavy Metal Contamination of Soils around a Hospital Waste Incinerator Bottom Ash Dumps Site

2016 ◽  
Vol 2016 ◽  
pp. 1-6 ◽  
Author(s):  
M. Adama ◽  
R. Esena ◽  
B. Fosu-Mensah ◽  
D. Yirenya-Tawiah
Keyword(s):  
Heavy Metal ◽  
Metal Contamination ◽  
Heavy Metal Contamination ◽  
Bottom Ash ◽  
Waste Incineration ◽  
Waste Incinerator ◽  
Hospital Waste ◽  
Dump Site ◽  
High Concentrations ◽  
Health Care Waste

Waste incineration is the main waste management strategy used in treating hospital waste in many developing countries. However, the release of dioxins, POPs, and heavy metals in fly and bottom ash poses environmental and public health concerns. To determine heavy metal (Hg, Pb, Cd, Cr, and Ag) in levels in incinerator bottom ash and soils 100 m around the incinerator bottom ash dump site, ash samples and surrounding soil samples were collected at 20 m, 40 m, 60 m, 80 m, 100 m, and 1,200 m from incinerator. These were analyzed using the absorption spectrophotometer method. The geoaccumulation (Igeo) and pollution load indices (PLI) were used to assess the level of heavy metal contamination of surrounding soils. The study revealed high concentrations in mg/kg for, Zn (16417.69), Pb (143.80), Cr (99.30), and Cd (7.54) in bottom ash and these were above allowable limits for disposal in landfill. The study also found soils within 60 m radius of the incinerator to be polluted with the metals. It is recommended that health care waste managers be educated on the implication of improper management of incinerator bottom ash and regulators monitor hospital waste incinerator sites.

scholarly journals Structural and optical study of alternating layers of In and GaAs prepared by magnetron sputtering

2019 ◽  
Vol 24 (3) ◽  
pp. 523-542 ◽  
Author(s):  
Santiago Torres-Jaramillo ◽  
Camilo Pulzara-Mora ◽  
Roberto Bernal-Correa ◽  
Miguel Venegas de la Cerda ◽  
Salvador Gallardo-Hernández ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Low Cost ◽  
Longitudinal Mode ◽  
Longitudinal Optical ◽  
X Ray Diffraction ◽  
X Ray ◽  
Mode Behavior ◽  
Optical Modes ◽  
High Concentrations ◽  
Secondary Ion

Currently, the obtention of nano-structures based on III-V materials is expensive. This calls for novel and inexpensive nanostructure manufacturing approaches. In this work we report on the manufacture of a nanostructures consisting of alternating layers of In and GaAs on a silicon substrate by magnetron sputtering. Furthermore, we characterized the produced nanostructures using secondary ion mass spectroscopy (SIMS), X-ray diffraction analysis, and Raman spectroscopy. SIMS revealed variation in the concentration of In atoms across In/GaAs/In interphases, and X-ray diffraction revealed planes corresponding to phases associated with GaAs and InAs due to In interfacial diffusion across GaAs layers. Finally, in order to study the composition and crystalquality of the manufactured nanostaructures, Raman spectra were taken using laser excitation lines of 452 nm, 532 nm, and 562 nm at different points across the nanostructures.This allowed to determine the transverse and longitudinal optical modes of GaAs and InAs,characteristic of a two-mode behavior. An acoustic longitudinal vibrational mode LA(Γ) of GaAs and an acoustic longitudinal mode activated by disorder (DALA) were observed. These resulted from the substitution of Ga atoms for In atoms in high concentrations due to the generation of Ga(VGa) and/or Arsenic(VAs) vacancies.This set of analyses show that magnetron sputtering can be aviable and relatively low-cost technique to obtain this type of semiconductors.

Otolith-Based Chronology of Brazilian Shellmounds

Radiocarbon ◽  
2019 ◽  
Vol 61 (2) ◽  
pp. 415-433 ◽  
Author(s):  
Carla Carvalho ◽  
Fabiana Oliveira ◽  
Kita Macario ◽  
Tania Lima ◽  
Ingrid Chanca ◽  
...  
Keyword(s):  
Rio De Janeiro ◽  
Brazilian Coast ◽  
X Ray Diffraction ◽  
Geochemical Composition ◽  
X Ray ◽  
Human Bones ◽  
Native Populations ◽  
Micropogonias Furnieri ◽  
Over Time ◽  
Fish Otoliths

ABSTRACTThe radiocarbon (14C) chronology of hunter-fisher-gatherers’ archaeological settlements along the Brazilian coast is usually based on mollusk shells, charcoal from hearths, and eventually human bones. However, fish otoliths are found in several archaeological contexts and may represent a reliable option as a chronological record. In this work, we compare the 14C dates of whitemouth croakers (Micropogonias furnieri) otoliths with dates obtained from other materials (shell and charcoal), collected from shellmounds on the coast of Rio de Janeiro, with the aim of improving the accuracy in the 14C dating of Brazilian shellmounds, strengthening the comprehension of the native populations’ occupational trends and the coeval palaeoceanographic context. Based on x-ray diffraction results for archaeological otoliths, their geochemical composition indicates minimal diagenesis effect over time even under burial conditions in the studied sites. The comparison between otolith dates and dates obtained from other proxies revealed similar results but with decreased deviations in otolith dates in all of the studied sites.

Abundance of halloysite neoformation in soils developed from crystalline rocks. Contribution of transmission electron microscopy

Clay Minerals ◽  
1992 ◽  
Vol 27 (1) ◽  
pp. 35-46 ◽  
Author(s):  
R. Romero ◽  
M. Robert ◽  
F. Elsass ◽  
C. Garcia
Keyword(s):  
Thermal Analyses ◽  
Crystalline Rocks ◽  
Metamorphic Rocks ◽  
X Ray Diffraction ◽  
Nw Spain ◽  
X Ray ◽  
Transmission Electron ◽  
High Concentrations ◽  
Bioclimatic Conditions ◽  
Mineralogical Phases

AbstractThe soils developed from crystalline and metamorphic rocks in Galicia (NW Spain), are characterized by high concentrations of 1 : 1 phyllosilicates and gels. Thermal analyses, X-ray diffraction after formamide treatment, and IR spectroscopy in the OH vibration range have been performed on the clay fractions, but do not discriminate clearly between the different associated mineralogical phases. HRTEM studies linked with microdiffraction and microanalyses have led to the identification of several types of gel which transform into goethite, gibbsite, clay precursors, and/ or halloysite according to their composition (Fe, Al or Si-Al). Halloysite-like minerals are the main constituents and they have a great variety of morphologies: lamellar, spheroidal, tubular, platy or poikilitic. In general, halloysite and gel formation on crystalline rocks is related to the bioclimatic conditions, involving high hydrolysis in the presence of organic matter. This halloysite seems to be a metastable mineral which would evolve into kaolinite with increasing weathering time.

scholarly journals Absorbed Pb2+ and Cd2+ Ions in Water by Cross-Linked Starch Xanthate

2017 ◽  
Vol 2017 ◽  
pp. 1-9 ◽  
Author(s):  
Kai Feng ◽  
Guohua Wen
Keyword(s):  
Heavy Metal ◽  
Metal Ions ◽  
Heavy Metal Ions ◽  
Adsorption Mechanism ◽  
Potato Starch ◽  
Sodium Acrylate ◽  
X Ray Diffraction ◽  
X Ray ◽  
Concentration Of Ions ◽  
Cross Linker

A cross-linked starch xanthate was prepared by graft copolymerization of acrylamide and sodium acrylate onto starch xanthate using potassium persulfate and sodium hydrogen sulfite initiating system and N,N′-methylenebisacrylamide as a cross-linker. As this kind of cross-linked potato starch xanthate can effectively absorb heavy metal ions, it was dispersed in aqueous solutions of divalent heavy metal ions (Pb2+ and Cd2+) to investigate their absorbency by the polymer. Factors that can influence absorbency were investigated, such as the ratio of matrix to monomers, the amount of initiator and cross-linker, pH, and the concentration of metal ions. Results were reached and conclusion was drawn that the best synthetic conditions for the polymer adsorbing Pb2+ and Cd2+ were as follows: the quality ratio of matrix to monomers was 1 : 12 and 1 : 11, the amount of initiator was 2.4% and 3.2% of matrix, and the amount of cross-linker was 12 mg and 13 mg. When the initial concentration of ions was 10 mg/L, the highest quantities of adsorption of Pb2+ and Cd2+ were 47.11 mg/g and 36.55 mg/g. Adsorption mechanism was discussed by using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscope (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) test, and adsorption kinetic simulation.

Reactive atmosphere synthesis of sol-gel heavy metal fluoride glasses

1992 ◽  
Vol 7 (6) ◽  
pp. 1534-1540 ◽  
Author(s):  
A.M. Mailhot ◽  
A. Elyamani ◽  
R.E. Riman
Keyword(s):  
Heavy Metal ◽  
Sol Gel ◽  
Fluoride Glass ◽  
Metal Fluoride ◽  
X Ray Diffraction ◽  
Combustion Analysis ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Heavy Metal Fluoride ◽  
Heavy Metal Fluoride Glasses

A glass based on ZrF4 was synthesized by a combination of sol-gel and reactive atmosphere processing. Infrared spectroscopy and combustion analysis show that the fluorination process reduces the concentration of organic and hydroxide impurities. Chemical changes have occurred during fluorination; this is indicated by different x-ray diffraction traces and crystallization characteristics for the fluorinated sample compared to the oxide gel product. Chemical analysis from x-ray fluorescence indicates that the fluorinated gel is chemically similar to a melted glass of the same composition. Differential scanning calorimetry gives a glass transition temperature of 290 °C and a crystallization temperature of 390 °C. These values are consistent with those expected for a fluoride glass prepared by conventional methods.

Sign in / Sign up

Export Citation Format

Share Document