1. A method for treating contaminants in water, comprising:
(A) contacting the water with a methylmorpholine-N-oxide solution while in a presence of iron oxide, wherein the contaminants comprise hydrogen sulfide, iron sulfides, or any combinations thereof;
(B) treating the water by allowing the methylmorpholine-N-oxide to react with the contaminants in the presence of the iron oxide to produce elemental sulfur and thiosulfate reaction products; and
(C) removing the elemental sulfur and thiosulfate reaction products from the water.
2. The method of claim 1, wherein the methylmorpholine-N-oxide solution comprises between about 1 weight volume % and about 60 weight volume % methylmorpholine-N-oxide.
3. The method of claim 1, wherein the water is in a vessel, and wherein the methylmorpholine-N-oxide solution is introduced to the vessel to contact the water.
4. The method of claim 3, wherein the vessel is a tank.
5. The method of claim 3, wherein the methylmorpholine-N-oxide solution is introduced to the vessel by a drum pump, a tank truck, or any combinations thereof.
6. The method of claim 3 wherein the methylmorpholine-N-oxide solution is not heated before introduction to the vessel.
7. The method of claim 1, wherein the molar ratio of methylmorpholine-N-oxide solution to contaminant is about 1.0 mole methylmorpholine-N-oxide:1.0 mole contaminant to about 3.0 moles methylmorpholine-N-oxide:1.0 mole contaminant.
8. The method of claim 1, further comprising introducing steam to contact the water.
9. The method of claim 8, wherein the steam comprises 150 psig steam or less.
10. The method of claim 8, further comprising introducing the steam to contact the water to increase temperature of the water to a temperature from about 75\xb0 F. to about 212\xb0 F.
11. The method of claim 1, wherein the iron oxide comprises ferrous or ferric oxides that are hydrated.
12. The method of claim 1, wherein the iron oxide comprises Fe2O3.7H2O, Fe2O3.10H2O, or any combinations thereof.
13. The method of claim 1, wherein the iron oxide is present in the water in an amount from about 100 ppm to about 1,000 ppm iron oxide.
14. The method of claim 1, wherein the methylmorpholine-N-oxide solution reacts with the contaminants from about one hour to about fifty hours.
15. The method of claim 1, wherein treating the water provides a treated water, and wherein the treated water comprises about 0 ppm hydrogen sulfide.
16. The method of claim 1, further comprising re-circulating the water and the methylmorpholine-N-oxide solution.
17. The method of claim 16, wherein re-circulating comprises re-circulating between about one volume of the total amount of water and methylmorpholine-N-oxide solution to about two volumes of the total amount of water and methylmorpholine-N-oxide solution.
18. The method of claim 16, wherein re-circulating further comprises heating the water and methylmorpholine-N-oxide solution.
19. The method of claim 18, wherein the heating comprises a heat exchanger providing heat to the water and methylmorpholine-N-oxide solution.
20. The method of claim 1, wherein the elemental sulfur and thiosulfate reaction products are removed from the water by centrifugation.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. An optical fiber extending along a longitudinal fiber axis and comprising: at least one cladding centered along the fiber axis; and a monolithic elongated multimode (MM) core concentric with and surrounded by the one cladding, the monolithic MM core being configured with a double bottleneck-shaped cross section having an input region which receives a single mode SM input beam that excites a fundamental mode distortionlessly propagating along the MM core, the single and fundamental modes having respective Gaussian intensity profiles with respective mode field diameters which substantially match one another in the input region, the MM core being configured with a refractive step index profile having a centrally located dip which is centered on an axis of symmetry of the MM core and gradually enlarges between the input and central regions of the core so as to transform the Gaussian intensity profile of the fundamental mode into a two-peak shaped profile of the fundamental mode in a central region of the MM core, and further narrows towards an output region of the MM core so as to transform the two-peak shaped intensity profile of the fundamental mode into substantially Gaussian intensity profile thereof.
2. The optical fiber of claim 1, wherein the double bottleneck-shaped cross section of the MM core, extending along a longitudinal axis, includes: input and output mode transformer regions space axially from one another and each having a frustoconically-shaped cross section so that the transformer regions have respective relatively small ends next to the respective input and output regions and respective relatively large ends; and a uniformly dimensioned central region bridging the large ends of the respective input and output transformer regions; the input and out end each being uniformly dimensioned.
3. The fiber of claim 2, wherein the input and output end regions each have a length varying between about 1\u03bb and about 5\u03bb, where \u03bb is a given wavelength at which the MM core supports substantially only the fundamental mode.
4. The fiber of claim 1, wherein the dip, extending along the central region, is configured with a uniform width larger than a uniform width of the dip along the input region.
5. The Fiber of claim 4, wherein the two-peak shaped intensity profile of the fundamental mode is shaped with two power peak regions spaced equidistantly from the axis of symmetry of the refractive step index of the core and a valley which is centered on the axis of symmetry and has a bottom configured with a refractive index greater than a refractive index of the cladding, and is centered on the symmetry axis and bridges the peak power regions.
6. The fiber of claim 5, wherein the core is configured with a doped ring-shaped region spaced from the axis of symmetry and terminating at a distance from a periphery of the refractive step index, the doped region providing a gain to the peak power regions of the fundamental mode without amplification of central and peripheral HOMs.
7. The fiber of claim 1, wherein the MM core is configured with a dopant concentration area or without the dopant concentration area.
8. A fiber comprising a MM core capable of supporting substantially a single fundamental mode at a give wavelength, the core being configured with a refractive index profile provided with a dip, the dip having a configuration varying along a length of the MM core so as to transform an intensity profile of the fundamental mode between Gaussian and two-speak shaped intensity profile as the fundamental mode propagates along the core, wherein the two-peak shaped intensity profile has a valley, centered on an axis of symmetry and bridging two power peak regions of the intensity profile, and overlaps an area of a central region of the core larger than an area of the central region that would be covered by the Gaussian profile, the MM core having input and output uniformly dimensioned end regions, each of which is provided with a uniform width, and transformer regions gradually expanding and narrowing from and to respective input and output ends, the input end region of the MM core being configured so that the mode field diameters of respective SM, which is coupled into the input end, and fundamental mode substantially match one another.
9. The fiber of claim 8, wherein the MM core is configured with:
an input end region receiving a single-mode input and configured to support the fundamental mode excited in response to a received SM input;
an output end region spaced from the input end region and configured to output a radiation in the fundamental mode, respectively,
input and output transformer regions running inwardly from respective input and output end regions, the transformer regions each having spaced small-diameter and large-diameter ends, and
a central region extending between the large-diameter ends of respective input and output transformer regions, wherein the end, transformer and central regions of the MM core are configured to guide the fundamental mode without distortion along the MM core.
10. The fiber of claim 9, wherein the MM core has a dopant concentration profile provided with a ring shape which is configured to provide a gain substantially only to two peak power regions of the intensity two peak intensity profile of the fundamental mode along the central region of the core.