Chemisorption of Thiols on Metals and Metal Sulfides

Author(s):  
Ronald Woods
Keyword(s):  
Author(s):  
V.K. Berry

There are two strains of bacteria viz. Thiobacillus thiooxidansand Thiobacillus ferrooxidanswidely mentioned to play an important role in the leaching process of low-grade ores. Another strain used in this study is a thermophile and is designated Caldariella .These microorganisms are acidophilic chemosynthetic aerobic autotrophs and are capable of oxidizing many metal sulfides and elemental sulfur to sulfates and Fe2+ to Fe3+. The necessity of physical contact or attachment by bacteria to mineral surfaces during oxidation reaction has not been fairly established so far. Temple and Koehler reported that during oxidation of marcasite T. thiooxidanswere found concentrated on mineral surface. Schaeffer, et al. demonstrated that physical contact or attachment is essential for oxidation of sulfur.


TAPPI Journal ◽  
2011 ◽  
Vol 10 (1) ◽  
pp. 17-23
Author(s):  
KEVIN TAYLOR ◽  
RICH ADDERLY ◽  
GAVIN BAXTER

Over time, performance of tubular backpulse pressure filters in kraft mills deteriorates, even with regular acid washing. Unscheduled filter replacement due to filter plugging results in significant costs and may result in mill downtime. We identified acid-insoluble filter-plugging materials by scanning electron microscope/energy-dispersion X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) analysis in both polypropylene and Gore-Tex™ membrane filter socks. The major filter-plugging components were calcium sulfate (gypsum), calcium phosphate (hydroxylapatite), aluminosilicate clays, metal sulfides, and carbon. We carried out detailed sample analysis of both the standard acid-washing procedure and a modified procedure. Filter plugging by gypsum and metal sulfides appeared to occur because of the acid-washing procedure. Gypsum formation on the filter resulted from significant hydrolysis of sulfamic acid solution at temperatures greater than 130°F. Modification of the acid-washing procedure greatly reduced the amount of gypsum and addition of a surfactant to the acid reduced wash time and mobilized some of the carbon from the filter. With surfactant, acid washing was 95% complete after 40 min.


2014 ◽  
Vol 6 (3) ◽  
pp. 152-160 ◽  
Author(s):  
Xiaoshuang Zheng ◽  
Jingdong Liu ◽  
Long Chen ◽  
Jianping Gao ◽  
Yousheng Tao

2008 ◽  
Vol 73 (8-9) ◽  
pp. 945-955 ◽  
Author(s):  
Luděk Kaluža ◽  
Miroslav Zdražil

The transition metals V, Cr, Mn, Fe, Co, Ni, Mo, Ru, Rh, Pd, W, Re, Os, Ir and Pt were deposited from aqueous solutions of their salts onto conventional γ-Al2O3 and unconventional TiO2 and ZrO2 supports by vacuum impregnation and characterized in their sulfided form by a model reaction of benzothiophene hydrodesulfurization. It was found that the TiO2 and ZrO2 supports influenced predominantly positively the resulting activity of relatively low-active metals (V, Cr, Mn, Fe, Co, Ni, Mo, Ru, W and Os), whereas the highly active metals (Rh, Pd, Ir, Pt and Re) were influenced slightly negatively or not at all by those supports compared with the γ-Al2O3-supported system. A significant effect of the supports on the hydrodesulfurization-activity ranking of the transition-metal sulfides studied was ascertained.


1972 ◽  
Vol 8 (1) ◽  
pp. 82-84
Author(s):  
M. A. Ryashentseva ◽  
Kh. M. Minachev ◽  
V. V. Dorogov ◽  
N. S. Prostakov
Keyword(s):  

Nanoscale ◽  
2021 ◽  
Author(s):  
Wenjun He ◽  
Jianing Cheng ◽  
Yaohui Gao ◽  
Caichi Liu ◽  
Jianling Zhao ◽  
...  

The development of earth-abundant transition metal sulfides electrocatalysts with excellent activity and stability toward alkaline hydrogen evolution reaction (HER) is critical but challenging. Iron-based sulfides are favored due to their...


2021 ◽  
Vol 9 (2) ◽  
pp. 429
Author(s):  
Rikuan Zheng ◽  
Shimei Wu ◽  
Chaomin Sun

Sulfur cycling is primarily driven by sulfate reduction mediated by sulfate-reducing bacteria (SRB) in marine sediments. The dissimilatory sulfate reduction drives the production of enormous quantities of reduced sulfide and thereby the formation of highly insoluble metal sulfides in marine sediments. Here, a novel sulfate-reducing bacterium designated Pseudodesulfovibrio cashew SRB007 was isolated and purified from the deep-sea cold seep and proposed to represent a novel species in the genus of Pseudodesulfovibrio. A detailed description of the phenotypic traits, phylogenetic status and central metabolisms of strain SRB007 allowed the reconstruction of the metabolic potential and lifestyle of a novel member of deep-sea SRB. Notably, P. cashew SRB007 showed a strong ability to resist and remove different heavy metal ions including Co2+, Ni2+, Cd2+ and Hg2+. The dissimilatory sulfate reduction was demonstrated to contribute to the prominent removal capability of P. cashew SRB007 against different heavy metals via the formation of insoluble metal sulfides.


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