SWITCHGRASS CULTIVATION ON RECLAIMED M INELAND W ITH SOME AMENDMENTS

Reclaimed mining rocks can be potential lands for biofuel feedstock production. Minelands are considered marginal because they often have low organic matter contents and adverse soil physical and chemical characteristics. Establishing perennial grasses such as switchgrass (Panicum virgatum L.) on these lands can be an economically viable option to produce cellulosic biomass with the addition of biological agents such as fertilizers, cinder and sewage sludge

X-ray fluorescence spectrometry and related techniques: an introduction

X-ray fluorescence spectrometry (XRF) is a well-established analytical technique for qualitative and quantitative elemental analysis of a wide variety of routine quality control and research samples. Among its many desirable features, it delivers true multi-element character analysis, acceptable speed and economy, easy of automation, and the capacity to analyze solid samples. This remarkable contribution to this field provides a comprehensive and up-to-date account of basic principles, recent developments, instrumentation, sample preparation procedures, and applications of XRF analysis. If you are a professional in materials science, analytic chemistry, or physics, you will benefit from not only the review of basics, but also the newly developed technologies with XRF. Those recent technological advances, including the design of low-power micro- focus tubes and novel X-ray optics and detectors, have made it possible to extend XRF to the analysis of low-Z elements and to obtain 2D or 3D information on a micrometer-scale. And, the recent development and commercialization of bench top and portable instrumentation, offering extreme simplicity of operation in a low-cost design, have extended the applications of XRF to many more analytical problems

Ligandless surfactant-assisted emulsification microextraction and total reflection x-ray fluorescence analysis for Ionic gold traces quantification in aqueous samples and extracts containing gold nanoparticles

WOS: 000452693600035PubMed: 30398842Due to the current use of gold nanoparticles (AuNPs) in many fields and their potential dissolution/transformation into ionic gold (Au3+), there is an increasing interest in methods enabling the discrimination of Au3+ from AuNPs in environmental samples. In this contribution, the combination of a novel ligandless surfactant-assisted emulsification microextraction procedure (LL-SAEME) with total reflection X-ray fluorescence spectrometry (TXRF) is proposed for the isolation and preconcentration of Au3+ in aqueous extracts containing AuNPs. The method is fast, simple, and involves low operating costs and low consumption of reagents in comparison with other spectroscopic methods. It is based on the formation of a gold hydrophobic compound with the cationic surfactant cetyltrimethylammonium bromide (CTAB) which is extracted in a few microliters of 1,2-dichloroethane. After shaking the solution by hand for 5 s, the mixture is centrifuged for 3 min at 2000 rpm and 5 mu L of the organic phase containing the gold ions are deposited on a quartz reflector to carry out the TXRF analysis. Using this approach, the limit of detection for gold was 0.05 mu g/L and a good linearity (R-2 > 0.99) was assessed in the range of 1-500 mu g/L. Moreover, no matrix effects were observed when ionic gold was extracted from different types of water such as river, mineral, and tap waters as well as in synthetic aqueous solutions containing other ions, AuNPs, and dissolved organic matter. As a study case, the developed LL-SAEME TXRF method was applied to monitor AuNPs stability in soils in laboratory-controlled experiments by means of Au3+ monitoring over time.Spanish Ministry of Economy and Competitiveness [CGL2013-48802-C3-2-R]; TUBITAK (Turkey)Turkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [2016/1, 1059B191600371]This work was funded by the Spanish Ministry of Economy and Competitiveness (project CGL2013-48802-C3-2-R). Z.B. acknowledges the financial support from the TUBITAK (Turkey) for the International Postdoctoral Research Grant (2016/1, 1059B191600371)

Cellulose mini-membranes modified with TiO2 for separation, determination, and speciation of arsenates and selenites

Sorptive and selective mini-membranes based on TiO2 directly synthesized onto cellulose filters (TiO2@cellulose) have been developed. The in situ synthesis of TiO2@cellulose applied is simple and economically advantageous. The obtained membranes can be useful for (1) separating arsenic(V) and selenium(IV) from other ions and organic matter, (2) speciation of arsenic and selenium, and (3) determining ulratraces of these ions in water samples. The membranes exhibit good stability and high maximum adsorption capacities for Se(IV) (71 mg g−1) and As(V) (41 mg g−1). A monolayer chemical adsorption of analytes on the membranes was confirmed. The structure of membranes was examined with scanning electron microscopy, x-ray diffractometry, and micro energy-dispersive x-ray fluorescence spectrometry (μ-EDXRF). The membranes were characterized by homogenous distribution of TiO2 onto cellulose. The TiO2@cellulose was used as a new sorbent in micro-solid phase extraction for determination of Se(IV) and As(V) by EDXRF. Using direct analysis of mini-membranes after sorption of analytes avoids the elution step. Thus, the proposed procedure is an attractive and solvent-free option for quantitative monitoring of Se(IV) and As(V) in different materials. Both analytes were quantitatively and simultaneously separated/determined from samples at pH 2 with very good recovery (close to 100%), precision (4.5%), and detection limits (0.4 ng mL−1 Se and 0.25 ng mL−1 As). TiO2@cellulose membranes were applied to water analysis.Peer reviewe

Bromine and bromide content in soils: analytical approach from total reflection X-ray fluorescence spectrometry

Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired. In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils were evaluated. The direct analysis of a solid suspension using 20 mg of fine ground soil (<63 µm) gave a 3.7 mg kg-1 limit of detection for bromine which, in most cases, was suitable for monitoring total bromine content in soils (Br content range in soils = 5-40 mg kg-1). Information about bromide determination in soils is also possible by analyzing the Br content in water soil extracts. In this case, the TXRF analysis can be directly performed by depositing 10 µL of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 µg L-1. Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide). As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water.Peer ReviewedPostprint (published version

Bromine and bromide content in soils: analytical approach from total reflection X-ray fluorescence spectrometry

Monitoring total bromine and bromide concentrations in soils is significant in many environmental studies. Thus fast analytical methodologies that entail simple sample preparation and low-cost analyses are desired. In the present work, the possibilities and drawbacks of low-power total reflection X-ray fluorescence spectrometry (TXRF) for the determination of total bromine and bromide contents in soils were evaluated. The direct analysis of a solid suspension using 20 mg of fine ground soil (<63 µm) gave a 3.7 mg kg-1 limit of detection for bromine which, in most cases, was suitable for monitoring total bromine content in soils (Br content range in soils = 5-40 mg kg-1). Information about bromide determination in soils is also possible by analyzing the Br content in water soil extracts. In this case, the TXRF analysis can be directly performed by depositing 10 µL of the internal standardized soil extract sample on a quartz glass reflector in a measuring time of 1500 s. The bromide limit of detection by this approach was 10 µg L-1. Good agreement was obtained between the TXRF results for the total bromine and bromide determinations in soils and those obtained by other popular analytical techniques, e.g. energy dispersive X-ray fluorescence spectrometry (total bromine) and ionic chromatography (bromide). As a study case, the TXRF method was applied to study bromine accumulation in two agricultural soils fumigated with a methyl bromide pesticide and irrigated with regenerated waste water.Peer Reviewe

Study of selenium sorption processes in volcanic ash using Total Reflection X-ray Fluorescence (TXRF)

International audienceSelenium (Se) cycling around volcanoes has implications for human health given the high population density close to volcanoes and the narrow range between essential and toxic Se intake. To study the Se mobility during interaction between volcanic derived acid rain and volcanic ash, new analytical approaches are required. This paper explores the Total Reflection X-Ray Fluorescence (TXRF) for Se determination using sorption processes on volcanic ash as a geochemical application. Our experiments reveal the importance of the anion content of the rainwater for Se mobility in volcanic ash samples. Desorption studies of a weathered volcanic soil using the application of a dispersive liquid-liquid microextraction procedure (DLLME) to isolate Se prior to TXRF analysis (LOD 0.7 mu g/L) revealed much higher level of released Se in sulfuric acid rain compared to hydrochloric acid rain. Additionally, the dominance of selenate in the leaching solution suggests adsorption competition with sulfate as a Se release mechanism. Kinetic adsorption experiments using direct TXRF with as little as 10 mu L. solution (LOD 0.4-8 mu g/L depending on the sample characteristics) showed that the anions present play a key role in the selenite adsorption on volcanic ash by competitive behavior and/or changes in the pH conditions promoted by glass dissolution processes. Our experiments show the high potential of TXRF in such applications. Similarly, TXRF can be used as an analytical tool to study the mobility of trace elements in other geochemical studies

Ultratrace determination of metal ions using graphene oxide/carbon nanotubes loaded cellulose membranes and total-reflection X-ray fluorescence spectrometry: A green chemistry approach

In this paper, the determination of ultratrace heavy metal ions was developed by combining a preconcentration method using graphene oxide/carbon nanotubes membranes (GO/CNTs) and total-reflection X-ray fluorescence spectrometry (TXRF). Due to the excellent adsorptive properties of the GO, the foregoing membranes are suitable for effective simultaneous sorption of Co(II), Ni(II), Cu(II), Zn(II), Cd(II), and Pb(II) from aqueous solutions. In this method, the aqueous solution is passed through the GO/CNTs membrane. The analytes are eluted from the GO and afterward transferred onto a siliconized quartz reflector for further TXRF analysis using W and Mo target X-ray tubes. The maximum recoveries for all the elements were obtained at pH 5; thus it was chosen for all further experiments. The face centered central composite design was performed to study the influence of the flow-rate and volume of the solution on the recovery of the determined metal ions. Recovery values higher than 96% for all studied metals allow performing efficient preconcentration with an enrichment factor of 133, achieving the limits of detection (LODs) in the range of 0.08–0.21 ng mL−1 for W target X-ray tube with a measurement time of 2000 s, and much lower LODs for Mo target X-ray tube: 0.001–0.002 ng mL−1 with the exception for Cd (0.11 ng mL−1) with a very short measurement time of 600 s. Certified reference materials of spring water and seawater were examined to verify the reliability of the method. The evaluated procedure does not require toxic reagents or organic solvents, thus minimizes the portion of the sample for TXRF measurement, and stands in good accordance with green analytical chemistry basic principles.The project was supported by the National Science Centre (Poland) by the Grants No. 2018/31/B/ST4/00041 and No. 2015/17/B/ST4/03870. This work was also supported by the Spanish Ministry of Science and Innovation (Project CEX2018-000794-S). Marcin Musielak thanks the Program for new interdisciplinary elements of education at the doctoral level for a field of chemistry project (POWR.03.02.00-00-I010/17) for the support.Peer reviewe