Application of a simple arsenic removal filter in a rural area of Bangladesh

2012 ◽  
Vol 12 (5) ◽  
pp. 658-665 ◽  
Author(s):  
Md Mahmudul Hasan ◽  
Md Shafiquzzaman ◽  
Jun Nakajima ◽  
Quazi Hamidul Bari
Keyword(s):  
Rural Area ◽  
Arsenic Removal ◽  
Low Cost ◽  
Ceramic Filter ◽  
Manufacturing Cost ◽  
X Ray ◽  
Sustained Use ◽  
Actual Field ◽  
Contamination Levels ◽  
X Ray Absorption

A simple and low-cost household-based arsenic (As) removal filter (ARF) was tested under actual field conditions in a rural area of Bangladesh. The ARF consisted of a ceramic filter made of clay soil and rice bran collected on-site, iron netting and iron bacterial sludge liquor. Fifteen ARFs (14 shallow and one deep tubewells) were installed in three villages (five in each area) in the Khulna region (southwestern region of Bangladesh), and their performance was evaluated. More than 60% of ARFs produced effluent with As <50 μg/L (Bangladesh standard level). The effects of Fe and P on As removal were the same as in laboratory experiments. X-ray Absorption Fine Structure (XAFS) analysis showed the adsorption of primarily As(V), with lesser amounts of As(III). Continuous As removal performance was observed over 1 year of ARF use. By introducing a double ARF system, the As removal was significantly enhanced for the region with high As contamination levels. The ARF manufacturing cost was estimated to be US$4–5, which is low and affordable to the rural households of Bangladesh. The ARF, made of locally available materials, had a low cost and minimal maintenance and showed high user acceptance, satisfaction and sustained use.

scholarly journals X-ray absorption measurements on an ultrasonic spray aerosol

2011 ◽  
Vol 19 (1) ◽  
pp. 126-128 ◽  
Author(s):  
R. Schlaf ◽  
B. Höpfner ◽  
J. Figueroa ◽  
E. Tridas ◽  
E. Welter ◽  
...  
Keyword(s):  
Spray Deposition ◽  
Mass Density ◽  
Low Cost ◽  
Buffer Layers ◽  
Solution Flow ◽  
X Ray ◽  
Simple Implementation ◽  
Good Signal ◽  
X Ray Absorption ◽  
Absorption Measurements

Spray deposition of thin films and coatings is a widely used manufacturing process owing to its low cost, versatility and simple implementation. The objective of the presented experiments was to investigate whether X-ray absorption measurements on solutes carried by aerosols are possible, and what count rates can be achieved depending on solution flow through and the resulting mass density in the interrogation volume. The investigated prototypical spray aerosol was InCl3dissolved in water or ethanol dispersedviaan ultrasonic nebulizer. InCl3spray is essential for the ion layer gas reaction process used for the deposition of In2S3buffer layers for highly efficient chalcopyrite solar cells. The discussed experiments demonstrate that measurements are possible, but that the achievement of good signal-to-noise ratios requires extended sampling times and concentrated solutions.

DXS: Differential absorption x-ray spectroscopy

1992 ◽  
Vol 50 (2) ◽  
pp. 1738-1739
Author(s):  
Robert M. Fisher
Keyword(s):  
Abrupt Change ◽  
Low Cost ◽  
X Ray ◽  
Cost System ◽  
Routine Work ◽  
Precise Adjustment ◽  
Filter Array ◽  
Filter Thickness ◽  
User Friendly ◽  
X Ray Absorption

X-ray spectrochemical analysis, with either energy-dispersive (EDS) or wavelength-dispersive (WDS) systems, is is used extensively by electron microscopists to determine the chemical composition of selected features in a wide variety of specimens. Several decades of development have yielded efficient and rugged detector crystals and goniometer hardware as well as sophisticated, but user-friendly, software for quantitative chemical and image analysis. Nevertheless an alternative system, based on differential x-ray absorption with "balanced" transmission filters (DXS™) has attractive advantages as a simple, low cost, system for qualitative x-ray microanalysis which does not require liquid nitrogen. Computer processing of intensities obviates the former need for impossibly-precise adjustment of filter thickness. However the filter array must be preset for analysis of the elements that are believed to be present for routine work.DXS analysis is based on the abrupt change in x-ray absorption that occurs between particular elements. This is illustrated by the different mass absorption coefficients for Fe and Cr K radiation for a series of filters in increasing atomic number from Ti to Co as shown in Figure 1 (1,2).

scholarly journals Simple and low cost dithizone-functionalized polymer membranes as a tool for mercury preconcentration and monitoring in aqueous bodies. Preliminary results using X-ray absorption near-edge structure (XANES).

2019 ◽  
Keyword(s):  
Large Scale ◽  
Low Cost ◽  
Membrane Surface ◽  
Active Surface Area ◽  
Edge Structure ◽  
X Ray ◽  
Mercury Analysis ◽  
Functionalized Membranes ◽  
X Ray Absorption ◽  
Selective Membranes

<p>Here the effectiveness of cation selective membranes, produced for divalent mercury (Hg2+) preconcetration from aqueous bodies, is examined. To this end, the behavior of PVC-based membranes, functionalized with dithizone for mercury complexation, is examined by means of Energy Dispersive X-ray Fluorescence (EDXRF) and total reflection - X-ray absorption near-edge structure (TXRF–XANES) techniques. In our previous works, we successfully immobilized dithizone on PVC-based thin film substrates, creating novel Hg-selective membranes, and identified the optimal experimental parameters affecting mercury sorption from water samples. Nonetheless, the question remains, to what extent dithizone is responsible for mercury complexation on the membrane surface, or it just improves the membrane’s active surface area thus simply improving the adsorptive effect. Using the EDXRF technique it appears that membranes functionalized with dithizone has a much higher efficiency (by up to threefold) in preconcetrating mercury from water matrices, compared to the non-functionalized membranes. Then, the membranes were also examined by means of TXRF–XANES and it was identified that indeed mercury-dithizone complex is produced on the membrane surface, which is responsible for the much higher mercury sorption, compared to the non-functionalized membranes. Also, the XANES mercury-dithizone spectrum is presented. Given polymer membrane simple manufacturing procedure and their low cost this study works towards establishing a new method for very low concentration mercury analysis (sub-ppb levels) as well as mercury collection from aqueous bodies, provided that the membranes are produced and used in large-scale routine works.</p>

scholarly journals Resolving the effects of compositional change on structures in Cu2ZnSnS4 nanocrystals by X-ray absorption fine structure

2018 ◽  
Vol 96 (8) ◽  
pp. 785-794
Author(s):  
Matthew J. Turnbull ◽  
Saghar Khoshmashrab ◽  
Yun Mui Yiu ◽  
Zhifeng Ding
Keyword(s):  
Fine Structure ◽  
Fossil Fuels ◽  
Low Cost ◽  
Renewable Energy Sources ◽  
Metal Center ◽  
Electronic Effects ◽  
X Ray ◽  
Absorption Fine ◽  
Crystal Alignment ◽  
X Ray Absorption

Renewable energy sources, and solar energy in particular, are a high impact research topic in the push for sustainable, long-term energy alternatives to fossil fuels. Cu2ZnSnS4 (CZTS) is one of the attractive, cost-effective materials that meets these needs. The quaternary nature makes the structure prone to defects and crystal alignment disorder. Some of these defects create advantageous electronic effects through antisite substitutions of Zn for Cu, [Formula: see text]. Others such as Sn for Zn replacements are detrimental. Synchrotron-based X-ray absorbance fine structure (XAFS) analysis was used to identify specific patterns in the antisite contributions to the structure of low-cost CZTS films that produced the highest photoresponse in each of our samples. Correlations were found between the Cu/(Zn + Sn) ratio and advantageous antisite formations, though at the cost of increased alignment disorder. Similarly, the Zn/Sn ratio showed relationships between both advantageous and disadvantageous antisite and vacancy pairs. Variations in the local surroundings for each metal center were confirmed through X-ray absorption near-edge structures (XANES). Extended X-ray absorption fine structures (EXAFS), verified through FEFF fitting of the EXAFS, confirmed the patterns in crystal alignment disorder, and the effects each antisite had on the overall crystal structure. The precision and unique nature of such synchrotron techniques offers opportunities to identify these trends at each metal center, providing guidance to balance negative and positive structural components during fabrication. Each minor change in stoichiometry has been shown to affect several interactions within the structure.

scholarly journals Interlayer-Confined Cu(II) Complex as an Efficient and Long-Lasting Catalyst for Oxidation of H2S on Montmorillonite

Minerals ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 510
Author(s):  
Elena Castellini ◽  
Fabrizio Bernini ◽  
Lorenzo Sebastianelli ◽  
Claro Ignacio Sainz-Díaz ◽  
Aida Serrano ◽  
...  
Keyword(s):  
High Efficiency ◽  
Catalytic Mechanism ◽  
Atmospheric Oxygen ◽  
Low Cost ◽  
H2s Removal ◽  
X Ray ◽  
S 100 ◽  
Long Time ◽  
Phenanthroline Complex ◽  
X Ray Absorption

Removal of highly toxic H2S for pollution control and operational safety is a pressing need. For this purpose, a montmorillonite intercalated with Cu(II)-phenanthroline complex [Cu[(Phen)(H2O)2]2+ (Mt-CuPhen) was prepared to capture gaseous H2S under mild conditions. This hybrid material was simple to obtain and demonstrated an outstanding ability to entrap H2S at room temperature, retaining high efficiency for a very long time (up to 36.8 g of S/100 g Mt-CuPhen after 3 months of exposure). Sorbent and H2S uptake were investigated by elemental analysis, X-ray powder diffraction measurements, diffuse reflectance (DR) UV–Vis and infrared spectroscopy, thermal analysis and evolved gas mass spectrometry, scanning electron microscopy equipped with energy-dispersive X-ray spectrometer, and X-ray absorption spectroscopy. The H2S capture was studied over time and a mechanism of action was proposed. The entrapping involves a catalytic mechanism in which [Cu[(Phen)(H2O)2]2+ acts as catalyst for H2S oxidation to S0 by atmospheric oxygen. The low cost and the long-lasting performance for H2S removal render Mt-CuPhen an extremely appealing trap for H2S removal and a promising material for many technological applications.

scholarly journals Fischer-Tropsch Synthesis: The Characterization and Testing of Pt-Co/SiO2 Catalysts Prepared with Alternative Cobalt Precursors

Reactions ◽  
2021 ◽  
Vol 2 (2) ◽  
pp. 129-160
Author(s):  
Mohammad Mehrbod ◽  
Michela Martinelli ◽  
Caleb D. Watson ◽  
Donald C. Cronauer ◽  
A. Jeremy Kropf ◽  
...  
Keyword(s):  
Active Sites ◽  
Cobalt Chloride ◽  
Weak Interactions ◽  
Low Cost ◽  
Cobalt Acetate ◽  
Cobalt Nitrate ◽  
Strong Interactions ◽  
X Ray ◽  
Temperature Programmed ◽  
X Ray Absorption

Different low-cost cobalt precursors (acetate, chloride) and thermal treatments (air calcination/H2 reduction versus direct H2-activation) were investigated to alter the interaction between cobalt and silica. H2-activated catalysts prepared from cobalt chloride had large Co0 particles (XRD, chemisorption) formed by weak interactions between cobalt chloride and silica (temperature programmed reduction (TPR), TPR with mass spectrometry (TPR-MS), TPR with extended X-ray absorption fine structure (EXAFS) and X-ray absorption near edge spectroscopy (XANES) techniques) and retained Cl-blocked active sites, resulting in poor activity. In contrast, unpromoted Co/SiO2 catalysts derived from cobalt acetate had strong interactions between Co species and silica (TPR/TPR-MS, TPR-EXAFS/XANES); adding Pt increased the extent of the Co reduction. For these Pt-promoted catalysts, the reduction of uncalcined catalysts was faster, resulting in larger Co0 clusters (19.5 nm) in comparison with the air-calcined/H2-activated catalyst (7.8 nm). Both catalysts had CO conversions 25% higher than that of the Pt-promoted catalyst prepared in the traditional manner (air calcination/H2 reduction using cobalt nitrate) and three times higher than that of the traditional unpromoted Co/silica catalyst. The retention of residual cobalt carbide (observed in XANES) from cobalt acetate decomposition impacted performance, resulting in a higher C1–C4 selectivity (32.2% for air-calcined and 38.7% for uncalcined) than that of traditional catalysts (17.5–18.6%). The residual carbide also lowered the α-value and olefin/paraffin ratio. Future work will focus on improving selectivity through oxidation–reduction cycles.

X-ray microanalysis of thin specimens in the transmission electron microscope at voltages up to 1000 Kv.

1978 ◽  
Vol 36 (1) ◽  
pp. 540-541
Author(s):  
G. Cliff ◽  
M.J. Nasir ◽  
G.W. Lorimer ◽  
N. Ridley
Keyword(s):  
Electron Microscope ◽  
Transmission Electron Microscope ◽  
Weight Fraction ◽  
Present Series ◽  
Constant Independent ◽  
X Ray ◽  
Transmission Electron ◽  
Series Of Experiments ◽  
Image Position ◽  
X Ray Absorption

In a specimen which is transmission thin to 100 kV electrons - a sample in which X-ray absorption is so insignificant that it can be neglected and where fluorescence effects can generally be ignored (1,2) - a ratio of characteristic X-ray intensities, I1/I2 can be converted into a weight fraction ratio, C1/C2, using the equationwhere k12 is, at a given voltage, a constant independent of composition or thickness, k12 values can be determined experimentally from thin standards (3) or calculated (4,6). Both experimental and calculated k12 values have been obtained for K(11<Z>19),kα(Z>19) and some Lα radiation (3,6) at 100 kV. The object of the present series of experiments was to experimentally determine k12 values at voltages between 200 and 1000 kV and to compare these with calculated values.The experiments were carried out on an AEI-EM7 HVEM fitted with an energy dispersive X-ray detector.

SIGMAL: A Program for Calculating L-Shell lonization Cross-Sections

1981 ◽  
Vol 39 ◽  
pp. 198-199 ◽  
Author(s):  
R.F. Egerton
Keyword(s):  
Cross Sections ◽  
Fortran Program ◽  
Absorption Data ◽  
X Ray ◽  
Atomic Electrons ◽  
Energy Dependent ◽  
Hydrogenic Model ◽  
Electron Energy Loss ◽  
X Ray Absorption ◽  
Shell Ionization

SIGMAL is a short (∼ 100-line) Fortran program designed to rapidly compute cross-sections for L-shell ionization, particularly the partial crosssections required in quantitative electron energy-loss microanalysis. The program is based on a hydrogenic model, the L1 and L23 subshells being represented by scaled Coulombic wave functions, which allows the generalized oscillator strength (GOS) to be expressed analytically. In this basic form, the model predicts too large a cross-section at energies near to the ionization edge (see Fig. 1), due mainly to the fact that the screening effect of the atomic electrons is assumed constant over the L-shell region. This can be remedied by applying an energy-dependent correction to the GOS or to the effective nuclear charge, resulting in much closer agreement with experimental X-ray absorption data and with more sophisticated calculations (see Fig. 1 ).

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