Mineralogy and chemistry of ochre sediments from an acid mine drainage near a disused mine in Cornwall, UK

Clay Minerals ◽  
1999 ◽  
Vol 34 (2) ◽  
pp. 301-317 ◽  
Author(s):  
Balwant Singh ◽  
M. J. Wilson ◽  
W. J. McHardy ◽  
A. R. Fraser ◽  
G. Merrington
Keyword(s):  
Acid Mine Drainage ◽  
Photoelectron Spectroscopy ◽  
Mine Drainage ◽  
Close Association ◽  
Ammonium Oxalate ◽  
X Ray Diffraction ◽  
Thermal Methods ◽  
X Ray ◽  
Acid Mine ◽  
Transmission Electron

AbstractOchre sediments from acid mine drainage in Cornwall have been investigated using X-ray diffraction, thermal methods, infrared spectroscopy, X-ray photoelectron spectroscopy, transmission electron microscopy and chemical methods in order to determine their mineralogical and chemical composition. Fresh sediments consist of ferrihydrite and goethite. Large fractions of these minerals are dissolved by the ammonium oxalate treatment reflecting their poorly crystalline structure. Fresh sediments contain large amounts of surface-adsorbed SO4 (up to 9.3%) which is readily desorbed by the PO4 treatment. Goethite is the only mineral present in relatively older sediments and the mineral is well crystallized with rod-shaped morphology. Environmental conditions, such as pH and SO4 content, are not favourable for the presence of schwertmannite at the site. Iron minerals appear to be precipitating around filamentous algae and the shape of algae is preserved in the Fe oxide matrix. The ubiquitous presence of algae in close association with Fe minerals indicate their possible role in the crystallization of Fe oxides.

scholarly journals Initial pH and K+ concentrations jointly determine the types of biogenic ferric hydroxysulfate minerals and their effect on adsorption removal of Cr(VI) in simulated acid mine drainage

2018 ◽  
Vol 78 (10) ◽  
pp. 2183-2192 ◽  
Author(s):  
Yongwei Song ◽  
Jianyu Zhang ◽  
Heru Wang
Keyword(s):  
Acid Mine Drainage ◽  
Photoelectron Spectroscopy ◽  
Mine Drainage ◽  
Practical Significance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Mine ◽  
Adsorption Removal ◽  
Initial Ph ◽  
Strong Ability

Abstract It is of practical significance to promote the transformation of Fe in acid mine drainage (AMD) into ferric hydroxysulfate minerals with strong ability to remove heavy metals or metalloids. To investigate the types of biogenic ferric hydroxysulfate minerals generated in AMD by Acidithiobacillus ferrooxidans (A. ferrooxidans), different pH and K+ concentrations are tested for the formation of precipitates in media containing 160 mmol/L Fe2+. The Cr(VI) removal efficiencies of ferric hydroxysulfate minerals in AMD with different acidities are also compared. Results indicate that the mineralizing abilities of the initial pH levels (pH 3.0 > pH 2.5 > pH 2.0) and K+ concentrations (53.3 mmol/L > 3.2 mmol/L ≈ 0.8 mmol/L) differ, with cumulative Fe precipitation efficiencies of 58.7%, 58.0%, and 44.2% (K+ = 53.3 mmol/L), and 58.7%, 29.9%, and 29.6% (pH 3.0) after 96 h of A. ferrooxidans incubation, respectively. X-ray diffraction indicates that K-jarosites are formed in the treatments n(Fe)/n(K) = 0.1 and 3 at pH 2.0–3.0, while only schwertmannite is generated in a system of pH 3.0 and n(Fe)/n(K) = 200. X-ray photoelectron spectroscopy reveals that HCrO4− may be adsorbed as an inner-sphere complex on schwertmannite when the AMD pH is 3.0.

scholarly journals STUDI KARAKTERISTIK MINERAL PIRIT PADA BATUBARA BERDASARKAN HASIL ANALISIS MIKROSKOPI, PROKSIMAT, SULFUR TOTAL, DAN X-RAY DIFRACTION

2019 ◽  
Vol 5 (2) ◽  
pp. 121 ◽  
Author(s):  
Sri Widodo ◽  
Sufriadin Sufriadin ◽  
Ansyariah Ansyariah ◽  
Agus Ardianto Budiman ◽  
Nur Asmiani ◽  
...  
Keyword(s):  
Acid Mine Drainage ◽  
Iron Sulfide ◽  
Mine Drainage ◽  
Total Sulfur ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Mine

Mineral pirit merupakan salah satu mineral sulfida yang sangat sering dijumpai di dalam batubara. Kehadiran mineral pirit sangat berpotensi menimbulkan masalah pada kegiatan penambangan dan pemanfaatan batubara. Terkhusus pada kegiatan penambangan, mineral pirit berpotensi menimbulkan air asam tambang (acid mine drainage) dan pada pemanfaatannya menimbulkan dampak negatif terhadap lingkungan. Permasalahan tersebut melatarbelakangi penulis untuk melakukan kegiatan penelitian dan analisis terhadap karakteristik mineral pirit yang terkandung pada batubara di Desa Massenrengpulu, Kecamatan Lamuru, Kabupaten Bone, Provinsi Sulawesi Selatan. Metode yang digunakan dalam penelitian ini adalah analisis mikroskopi (petrografi), ultimat (total sulfur) dan X-Ray Diffraction. Hasil analisis mikroskopi menunjukkan bahwa mineral pirit pada batubara di bawah mikroskop terlihat dalam keadaan bebas (tidak terikat) dan tidak terinklusi oleh mineral lain. Kenampakan di bawah mikroskop juga memperlihatkan adanya mineral kuarsa yang diinklusi oleh mineral karbonat. Kenampakan mineral pirit (FeS2) (iron sulfide) memperlihatkan warna krem pucat, isotropik, relief tinggi, berbutir halus, tersebar tidak merata pada massa maseral. Hasil pengamatan mikroskop menunjukkan bahwa bentuk mineral pirit yang dominan adalah bentuk pirit framboidal yang terdiri dari kristal oktahedral, ukuran halus dan speroidal. Hasil analisis XRD memperlihatkan mineral pirit terdeteksi dalam difaktogram pada semua conto batubara ML-1, ML-2A, ML-3, ML-4 dan ML-F. Pada sampel ML-1 terlihat peak tertinggi dengan sudut 2θ 33.26o dan  intensitas 2.6195Å. Pada Conto ML-1 juga terlihat di sudut 2θ 57.982o dengan intensitas 1.5893Å dan peak pirit masih sangat mendominasi dan mempunyai sistem kristal isometrik. Hasil analisis ultimat (total sulfur) conto batubara yang diteliti memiliki kandungan sulfur minimum 1,54% (sampel ML-F) dan  maksimum 11,86% (sampel ML-1). Rata-rata kandungan sulfur total pada sampel batubara di daerah penelitian memperlihatkan nilai rata-rata sebesar 5,18%. Hal ini menunjukkan bahwa batubara yang dianalisis dikatagorikan sebagai batubara dengan kandungan sulfur yang tinggi. Mineral pirit merupakan mineral sulfida yang paling umum dijumpai pada batubara dan memberikan kontribusi yang besar terhadap kandungan sulfur pada batubara. Berdasarkan hasil analisis yang telah dilakukan, karakteristik pirit pada batubara yang terdapat di daerah penelitian berpotensi memicu terbentuknya air asam tambang dan dapat menimbulkan masalah dalam pemanfaatannya.Kata Kunci: batubara, mineral pirit, total sulfur, mikroskopi, XRD, air asam tambang.

scholarly journals Effective Desalination of Acid Mine Drainage Using an Advanced Oxidation Process: Sodium Ferrate (VI) Salt

Water ◽  
2021 ◽  
Vol 13 (19) ◽  
pp. 2619
Author(s):  
Alexis Munyengabe ◽  
Caliphs Zvinowanda ◽  
James Ramontja ◽  
John Ngoni Zvimba
Keyword(s):  
Acid Mine Drainage ◽  
Inductively Coupled Plasma ◽  
Advanced Oxidation Process ◽  
Mine Drainage ◽  
Optical Emission ◽  
X Ray Diffraction ◽  
X Ray ◽  
Treated Water ◽  
Inductively Coupled ◽  
Acid Mine

The screening and treatment of acid mine drainage (AMD) using Na2FeO4 was explored. Elemental composition was performed, using an Inductively Coupled Plasma-Optical Emission Spectroscopy (ICP-OES) for the raw and treated AMD. The AMD samples were collected from three different sampling sites:(Raw Tailing Water 1 (RTW1), Raw Tailing Water 2 (RTW2) and Raw Tailing Water 3 (RTW3)) in Pretoria, South Africa, with acidic pH ranging between 2.50 and 3.13. Total dissolved solids and the electrical conductivity of AMD samples ranged between 960 and 1000 mg L−1, 226 and 263 µS. cm−1, respectively. The final pH of treated water samples increased up to ≥9.5 after treatment with sodium ferrate (VI) (Na2FeO4). Liquid Na2FeO4 was quantitatively produced through a wet oxidation method and was fully characterized, using Fourier Transform Infra-Red (FTIR), X-ray Diffraction spectroscopy (XRD) and UV-Vis instruments. Na2FeO4 showed dual functions by removing metals and raising the pH of the treated water. Concentrations of most trace elements did not comply with WHO and DWAF guideline standards in raw AMD while after treatment with Na2FeO4, the concentrations were below guidelines for domestic and irrigation purposes.

Characterization of Philippine Natural Zeolite and its Application for Heavy Metal Removal from Acid Mine Drainage (AMD)

2017 ◽  
Vol 737 ◽  
pp. 407-411 ◽  
Author(s):  
Eleanor Olegario-Sanchez ◽  
Christian Mark Pelicano
Keyword(s):  
Heavy Metal ◽  
Acid Mine Drainage ◽  
Natural Zeolite ◽  
Mine Drainage ◽  
Metal Removal ◽  
Heavy Metal Removal ◽  
Metal Species ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acid Mine

In this study, the adsorption efficiency of Philippine natural zeolite for treating acid mine drainage is investigated. The metal ions considered were Cu2+, Ni2+, and Pb2+ ions. The natural zeolite was characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM) equipped with Energy Dispersive X-ray Spectroscopy (EDX). The XRD result revealed that the natural zeolite is mainly composed of heulandite (Ca,Na)2-3Al3(Al,Si)2Si13O36 • 12H2O. Plate-like structures having rough surface and micro-pores were observed. The natural zeolite exhibited adsorption efficiencies of 99.03%, 35.88% and 35.36% for Pb2+, Cu2+, and Ni2+ ions, respectively, which are higher than those of alumina adsorbent for the same ions. Based on these results, the Philippine natural zeolite has a great potential for removing cationic heavy metal species from acid mine drainage (AMD).

scholarly journals α-Cellulose Fibers of Paper-Waste Origin Surface-Modified with Fe3O4 and Thiolated-Chitosan for Efficacious Immobilization of Laccase

Polymers ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 581
Author(s):  
Gajanan S. Ghodake ◽  
Surendra K. Shinde ◽  
Ganesh D. Saratale ◽  
Rijuta G. Saratale ◽  
Min Kim ◽  
...  
Keyword(s):  
Enzyme Immobilization ◽  
Photoelectron Spectroscopy ◽  
Cellulose Fibers ◽  
Relative Activity ◽  
Significant Activity ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Laccase Immobilization ◽  
Surface Modified

The utilization of waste-paper-biomass for extraction of important α-cellulose biopolymer, and modification of extracted α-cellulose for application in enzyme immobilization can be extremely vital for green circular bio-economy. Thus, in this study, α-cellulose fibers were super-magnetized (Fe3O4), grafted with chitosan (CTNs), and thiol (-SH) modified for laccase immobilization. The developed material was characterized by high-resolution transmission electron microscopy (HR-TEM), HR-TEM energy dispersive X-ray spectroscopy (HR-TEM-EDS), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared spectroscopy (FT-IR) analyses. Laccase immobilized on α-Cellulose-Fe3O4-CTNs (α-Cellulose-Fe3O4-CTNs-Laccase) gave significant activity recovery (99.16%) and laccase loading potential (169.36 mg/g). The α-Cellulose-Fe3O4-CTNs-Laccase displayed excellent stabilities for temperature, pH, and storage time. The α-Cellulose-Fe3O4-CTNs-Laccase applied in repeated cycles shown remarkable consistency of activity retention for 10 cycles. After the 10th cycle, α-Cellulose-Fe3O4-CTNs possessed 80.65% relative activity. Furthermore, α-Cellulose-Fe3O4-CTNs-Laccase shown excellent degradation of pharmaceutical contaminant sulfamethoxazole (SMX). The SMX degradation by α-Cellulose-Fe3O4-CTNs-Laccase was found optimum at incubation time (20 h), pH (3), temperatures (30 °C), and shaking conditions (200 rpm). Finally, α-Cellulose-Fe3O4-CTNs-Laccase gave repeated degradation of SMX. Thus, this study presents a novel, waste-derived, highly capable, and super-magnetic nanocomposite for enzyme immobilization applications.

scholarly journals Surface Stoichiometry and Depth Profile of Tix-CuyNz Thin Films Deposited by Magnetron Sputtering

Materials ◽  
2021 ◽  
Vol 14 (12) ◽  
pp. 3191
Author(s):  
Arun Kumar Mukhopadhyay ◽  
Avishek Roy ◽  
Gourab Bhattacharjee ◽  
Sadhan Chandra Das ◽  
Abhijit Majumdar ◽  
...  
Keyword(s):  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Film Surface ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
X Ray ◽  
Relative Composition ◽  
Transmission Electron ◽  
Deposited Film ◽  
Deposited Films

We report the surface stoichiometry of Tix-CuyNz thin film as a function of film depth. Films are deposited by high power impulse (HiPIMS) and DC magnetron sputtering (DCMS). The composition of Ti, Cu, and N in the deposited film is investigated by X-ray photoelectron spectroscopy (XPS). At a larger depth, the relative composition of Cu and Ti in the film is increased compared to the surface. The amount of adventitious carbon which is present on the film surface strongly decreases with film depth. Deposited films also contain a significant amount of oxygen whose origin is not fully clear. Grazing incidence X-ray diffraction (GIXD) shows a Cu3N phase on the surface, while transmission electron microscopy (TEM) indicates a polycrystalline structure and the presence of a Ti3CuN phase.

scholarly journals Synthesis of Ce1−xPdxO2−δ Solid Solution in Molten Nitrate

Catalysts ◽  
2020 ◽  
Vol 10 (6) ◽  
pp. 640
Author(s):  
Hideaki Sasaki ◽  
Keisuke Sakamoto ◽  
Masami Mori ◽  
Tatsuaki Sakamoto
Keyword(s):  
Electron Microscopy ◽  
Solid Solution ◽  
Solid Solutions ◽  
Photoelectron Spectroscopy ◽  
Synthesis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Co Precipitation ◽  
Ionic States

CeO2-based solid solutions in which Pd partially substitutes for Ce attract considerable attention, owing to their high catalytic performances. In this study, the solid solution (Ce1−xPdxO2−δ) with a high Pd content (x ~ 0.2) was synthesized through co-precipitation under oxidative conditions using molten nitrate, and its structure and thermal decomposition were examined. The characteristics of the solid solution, such as the change in a lattice constant, inhibition of sintering, and ionic states, were examined using X-ray diffraction (XRD), scanning electron microscopy–energy-dispersive X-ray spectroscopy (SEM−EDS), transmission electron microscopy (TEM)−EDS, and X-ray photoelectron spectroscopy (XPS). The synthesis method proposed in this study appears suitable for the easy preparation of CeO2 solid solutions with a high Pd content.

scholarly journals Extremely Acidophilic Protists from Acid Mine Drainage Host Rickettsiales-Lineage Endosymbionts That Have Intervening Sequences in Their 16S rRNA Genes

2003 ◽  
Vol 69 (9) ◽  
pp. 5512-5518 ◽  
Author(s):  
Brett J. Baker ◽  
Philip Hugenholtz ◽  
Scott C. Dawson ◽  
Jillian F. Banfield
Keyword(s):  
Acid Mine Drainage ◽  
16S Rrna ◽  
16S Rrna Gene ◽  
Mine Drainage ◽  
Close Association ◽  
Variable Region ◽  
16S Rrna Genes ◽  
Rrna Genes ◽  
Rrna Gene ◽  
Acid Mine

ABSTRACT During a molecular phylogenetic survey of extremely acidic (pH < 1), metal-rich acid mine drainage habitats in the Richmond Mine at Iron Mountain, Calif., we detected 16S rRNA gene sequences of a novel bacterial group belonging to the order Rickettsiales in the Alphaproteobacteria. The closest known relatives of this group (92% 16S rRNA gene sequence identity) are endosymbionts of the protist Acanthamoeba. Oligonucleotide 16S rRNA probes were designed and used to observe members of this group within acidophilic protists. To improve visualization of eukaryotic populations in the acid mine drainage samples, broad-specificity probes for eukaryotes were redesigned and combined to highlight this component of the acid mine drainage community. Approximately 4% of protists in the acid mine drainage samples contained endosymbionts. Measurements of internal pH of the protists showed that their cytosol is close to neutral, indicating that the endosymbionts may be neutrophilic. The endosymbionts had a conserved 273-nucleotide intervening sequence (IVS) in variable region V1 of their 16S rRNA genes. The IVS does not match any sequence in current databases, but the predicted secondary structure forms well-defined stem loops. IVSs are uncommon in rRNA genes and appear to be confined to bacteria living in close association with eukaryotes. Based on the phylogenetic novelty of the endosymbiont sequences and initial culture-independent characterization, we propose the name “Candidatus Captivus acidiprotistae.” To our knowledge, this is the first report of an endosymbiotic relationship in an extremely acidic habitat.

scholarly journals Aluminum Nitride-Silicon Carbide Alloy Crystals Grown on SiC Substrates by Sublimation

2005 ◽  
Vol 10 ◽  
Author(s):  
Z. Gu ◽  
L. Du ◽  
J.H. Edgar ◽  
E.A. Payzant ◽  
L. Walker ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
X Ray Diffraction ◽  
Original Source ◽  
X Ray ◽  
Alloy Crystal ◽  
Transmission Electron ◽  
Crystal Substrate ◽  
Vapor Distribution ◽  
Uniform Composition

AlN-SiC alloy crystals, with a thickness greater than 500 µm, were grown on 4H- and 6H-SiC substrates from a mixture of AlN and SiC powders by the sublimation-recondensation method at 1860-1990 °C. On-axis SiC substrates produced a rough surface covered with hexagonal grains, while 6H- and 4H- off-axis SiC substrates with different miscut angles (8° or 3.68°) formed a relatively smooth surface with terraces and steps. The substrate misorientation ensured that the AlN-SiC alloy crystals grew two dimensionally as identified by scanning electron microscopy (SEM). X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that the AlN-SiC alloys had the wurtzite structure. Electron probe microanalysis (EPMA) and x-ray photoelectron spectroscopy (XPS) demonstrated that the resultant alloy crystals had non-stoichiometric ratios of Al:N and Si:C and a uniform composition throughout the alloy crystal from the interface to the surface. The composition ratio of Al:Si of the alloy crystals changed with the growth temperature, and differed from the original source composition, which was consistent with the results predicted by thermodynamic calculation of the solid-vapor distribution of each element. XPS detected the bonding between Si-C, Si-N, Si-O for the Si 2p spectra. The dislocation density decreased with the growth, which was lower than 106 cm−2 at the alloy surface, more than two orders of magnitude lower compared to regions close to the crystal/substrate interface, as determined by TEM.

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