Microbiological Investigations of Surface Film Oil Across a Sea Water Discontinuity

Traditional technologies of gold mining are exhausted due to the depletion of stocks of conditioned raw materials at functioning gold mining enterprises, in addition, the preservation or disposal of large-scale waste of these technologies requires significant financial costs for environmental protection measures. Recently, the search for alternative methods of gold leaching, which involve the use of non-toxic factors, but which in their physicochemical properties can compete with traditional levels, and especially with cyanides. The authors of this work investigated the mechanism and kinetics of the process of dissolving metallic gold in chloride-hypochlorite solutions and believe that alkali metal hypochlorites (first of all, sodium hypochlorite NaOCl, which is easily obtained by electrolysis from a solution of food’s salt NaCl, or from sea water) are a very promising replacement for cyanide-containing leachates. Two series of experiments were carried out to study sodium hypochlorite as a gold leaching agent using a traditional gold disk and finely dispersed native gold as dissolution objects. Found fundamental differences in methodological techniques when working with a traditional model object and native gold. The dependences of the dissolution rate on the solution pH, sodium hypochlorite concentration, and temperature are determined. Conditions of the gold surface passivation during its dissolution are discussed. The first-order rate constant of the gold dissolution 1 0,079 - 0,4030  ki  h at temperatures from 277 K to 304 K and others are calculated. The activation energy from the temperature dependence of the rate constants (40,3 kJ/mol) evidences a diffusion-kinetic control of the gold dissolution. Electron microscopy (using electron probe scanning on an energy dispersive spectrometer) of native gold particles revealed foreign inclusions - adsorbed mineral particles of calcite (CaCO3) and, presumably, a surface film consisting of aluminum oxide (Al2O3), which create a significant obstacle to the contact of leaching agents with the surface of the target gold grains. Quantitative data on the composition of surface adsorption films, formed by model gold electrode dissolution products, are obtained using atomic adsorption spectroscopy.

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Biofouling and Microbially Influenced Corrosion of Stainless Steels

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.794.539 ◽

2013 ◽

Vol 794 ◽

pp. 539-551 ◽

Cited By ~ 1

Author(s):

K.A. Natarajan

Keyword(s):

Stainless Steels ◽

Corrosion Potential ◽

Sea Water ◽

Surface Film ◽

Microbial Corrosion ◽

Delta Ferrite ◽

Corrosion Resistant ◽

Anaerobic Microorganisms ◽

Microbially Influenced Corrosion ◽

Aerobic And Anaerobic

Stainless steels are among the most investigated materials on biofouling and microbially-influenced corrosion (MIC). Although, generally corrosion-resistant owing to tenacious and passive surface film due to chromium, stainless steels are susceptible to extensive biofouling in sub-soil, fresh water and sea water and chemical process environments. Biofilms influence their corrosion behavior due to corrosion potential ennoblement and sub-surface pitting. Both aerobic and anaerobic microorganisms catalyse microbial corrosion of stainless steels through biotic and abiotic mechanisms. MIC of stainless steels is common adjacent to welds at the heat-affected zone. Both austenite and delta ferrite phases may be susceptible. Even super stainless steels are found to be amenable to biofouling and MIC. Microbiological, electrochemical as well as physicochemical aspects of MIC pertaining to stainless steels in different environments are analyzed.

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Characterization of the Surface Film Growth During the Electrochemical Process; Part 1: Nickel - Sea Water System

10.21236/ada380232 ◽

1999 ◽

Author(s):

Srinivasa Rao

Keyword(s):

Film Growth ◽

Sea Water ◽

Surface Film ◽

Water System ◽

Electrochemical Process

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A MICRO INJECTION STUDY ON THE PERMEABILITY OF THE STARFISH EGG

The Journal of General Physiology ◽

10.1085/jgp.5.2.189 ◽

1922 ◽

Vol 5 (2) ◽

pp. 189-193 ◽

Cited By ~ 35

Author(s):

Robert Chambers

Keyword(s):

Aqueous Solution ◽

Living Cell ◽

Sea Water ◽

Surface Film ◽

Acid Group ◽

The Other ◽

Mustard Gas ◽

Cut Surface ◽

Concentration Limits ◽

Injection Study

The experiments with the NH4Cl are similar to, and corroborate micro injection experiments performed in connection with some work on mustard gas in which the writer collaborated. Eggs immersed in sea water containing decomposed mustard gas, at a certain low concentration are not affected. If, however, the solution be injected, the egg quickly cytolyzes owing to the free HCl present. A similar impermeability of the protoplasmic surface film to certain substances was also encountered in injection work on Amœba. Amœbœ immersed in an aqueous solution of eosin will not take the stain till after death. On the other hand, the eosin, when injected into the Amœba, quickly permeates the protoplasm, to be arrested only at the surface. The semipermeability of a living cell appears primarily to be a function of its surface film. It is immaterial whether this film be that of the original cortex of the cell, a film newly formed over a cut surface, or a film that surrounds an artificially induced vacuole within the cell. As long as such a surface film exists neither the acid group of the NH4Cl nor the alkaline group of the NaHCO3 can, within certain concentration limits, penetrate the protoplasm. These solutions, if injected beneath the surface film, however, will produce their characteristic effects upon the protoplasm.

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Net environmental benefit analysis — a tool of decision-making at oil spill response

Arctic Ecology and Economy ◽

10.25283/2223-4594-2017-1-47-58 ◽

2017 ◽

pp. 47-58

Author(s):

G.N. Semanov ◽

◽

A.N. Gutnik ◽

S.N. Zatsepa ◽

A.A. Ivchenko ◽

...

Keyword(s):

Oil Spill ◽

Oil Spills ◽

Sea Water ◽

Surface Film ◽

Economic Damage ◽

Benefit Analysis ◽

Environmental Benefit ◽

Dispersed Oil ◽

The Impact ◽

Mechanical Recovery

Development of oilfields started in Arctic requires adequate response preparedness to potential oil spills. Mechanical recovery due to specific conditions of Arctic has a lot of limitation in application and cannot prevent pollution of Special protected areas (SPA). It is necessary to consider application of dispersants and in situ burning (ISB). Oil spill dispersants are mixtures of nontoxic surface active agents in organic solvent, specifically formulated to enhance the natural dispersion of oil into the sea water column thus enhancing the biodegradation processes. Dispersed oil is practically non adhesive to feather of birds and hair of mammals. The treatment of oil with dispersants requires a cautious strategy in making decisions. It can be achieved by usage of special tool –Net Environmental Benefit Analysis (NEBA) procedures. The decision of dispersants application should be based on the following comparison: “What would be the impact of the pollution when treated with dispersant and when non treated with dispersant?” The NEBA should consider the behaviour of the treated non-treated oil, assess consequently the different resources which will be concerned either by the treated oil or by the surface film oil, assess the sensitivity of the different resources at concern towards the dispersed oil and toward the floating oil film. These analyses assist decision makers when considering whether or not the use of dispersants is appropriate to minimize the environmental/economic damage. This article describes the experience of NEBA application to substantiate decisions how to respond to potential oil spills at the sites on Aniva bay of Sakhalin-2 project at different oil spills scenarios. It was used incremental approach to choose them. Based on sensitivity maps, information about level of impact dispersed and floating oil on bioresources and results of mathematical modelling efficacy of different response methods application: monitoring (no actions to recover spilt oil), mechanical recovery and mechanical recovery together with dispersants application it was shown that SPA can be protected from pollution in most scenarios only in case of dispersants application. Amount of oil stranded on shore in case of application of response method was used as criteria of efficacy of method application level of damage.

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Observation of Concanavalin-A receptors on hydrated planar erythrocyte membrane film by in situ electron microscopy

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100076640 ◽

1983 ◽

Vol 41 ◽

pp. 608-609

Author(s):

Neng-Bo He ◽

S.W. Hui

Keyword(s):

Lipid Bilayers ◽

Erythrocyte Membrane ◽

Lipid Membranes ◽

Surface Film ◽

Biological Membranes ◽

Electron Microscopic Observation ◽

Electron Microscopic ◽

Black Lipid Membranes ◽

Fine Mesh ◽

Planar Films

Monolayers and planar "black" lipid membranes have been widely used as models for studying the structure and properties of biological membranes. Because of the lack of a suitable method to prepare these membranes for electron microscopic observation, their ultrastructure is so far not well understood. A method of forming molecular bilayers over the holes of fine mesh grids was developed by Hui et al. to study hydrated and unsupported lipid bilayers by electron diffraction, and to image phase separated domains by diffraction contrast. We now adapted the method of Pattus et al. of spreading biological membranes vesicles on the air-water interfaces to reconstitute biological membranes into unsupported planar films for electron microscopic study. hemoglobin-free human erythrocyte membrane stroma was prepared by hemolysis. The membranes were spreaded at 20°C on balanced salt solution in a Langmuir trough until a surface pressure of 20 dyne/cm was reached. The surface film was repeatedly washed by passing to adjacent troughs over shallow partitions (fig. 1).

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Surface Films on Zircaloy-2 Samples Cracked in Neutral Aqueous NaCl by Stress Corrosion

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100070679 ◽

1973 ◽

Vol 31 ◽

pp. 46-47

Author(s):

R.A. Ploc

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

Film Thickness ◽

Stress Corrosion ◽

Zirconium Dioxide ◽

Surface Film ◽

Surface Films ◽

Continuous Layer ◽

Transmission Electron ◽

Product Film

Samples of low-nickel Zircaloy-2 (material MLI-788-see(1)), when anodically polarized in neutral 5 wt% NaCl solutions, were found to be susceptible to pitting and stress corrosion cracking. The SEM revealed that pitting of stressed samples was occurring below a 2000Å thick surface film which behaved differently from normal zirconium dioxide in that it did not display interference colours. Since the initial film thickness was approximately 65Å, attempts were made to examine the product film by transmission electron microscopy to deduce composition and how the corrosion environment could penetrate the continuous layer.

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