Systems for removing one or more contaminants from water are provided that can include a hydrate formation chamber assembly; a contaminated water diffusion assembly within the hydrate formation chamber assembly; a space between a wall of the hydrate formation chamber assembly and the diffusion assembly; and a guest compound conduit configured to provide a guest compound within the space and form a hydrate comprising water and the guest compound. Methods for removing one or more contaminants from water are provided that can include providing a contaminated water mixture and one or more guest compounds; forming a hydrate complex comprising water and the one or more guest compounds; and separating the water from the guest compounds to provide water with less contaminant. Mixtures are also provided that can include a liquid component comprising water and at least one contaminant, and a solid component comprising a hydrate complex. One embodiment of the system provides methods for production of excess electric power as a byproduct of the desalination process.

Metals, such as mercury, may be removed from aqueous, hydrocarbon, or mixed oilfield or refinery fluids by: applying a sulfur compound having the general formula HS—X, where X is a heteroatom substituted alkyl, cycloalkyl, aryl, and/or alkylaryl group either alone or in combination with or as a blend with at least one demulsifier, a buffering agent, a pour point depressant, and/or a water clarifier to chelate the at least one metal and form a chelate complex of the sulfur compound with the at least one metal and then separating the chelate complex from the fluid.

A method includes mixing seawater with a two-part additive system configured to precipitate sulfate from the seawater; removing the sulfate precipitates from the seawater; and delivering the seawater into an oilfield reservoir.

A small-scale system for removing hydrogen sulfide and ammonia from a wastewater stream includes a sulfur recovery stage, an ammonia recovery stage, and a separation stage. Sulfur species are oxidized and converted into solid sulfur and solid sulfur species by exposure to a combination of chelated iron and oxidizer. The solid sulfur and solid sulfur species are removed by filtration to yield a sulfur-free stream to which oxidizer is added and electromagnetic radiation is inputted to break the N—H bonds of the ammonia into amine radicals. The combination of additional oxidizer and electromagnetic radiation promotes the creation of water and nitrogen gas.

A method to reduce or eliminate N-heterocycles, the method providing one or more environmentally benign chelators (EBCs) to an aqueous cooling system, the aqueous cooling system having at least one N-heterocycle in the presence of a halogenating or non-halogenating oxidizer. A method to reduce or eliminate AOX, the method providing one or more environmentally benign chelators (EBCs) to an aqueous cooling system, the aqueous cooling system having at least one AOX-containing species in the presence of a halogenating biocide.

A method of removing a metal ion from water is disclosed. The method includes treating the water with a nanocomposite to absorb the metal ion with the nanocomposite, forming a polymer-metal ion composite and removing the polymer-metal ion composite from the water. The nanocomposite includes aluminum oxide dispersed in a matrix of an uncrosslinked graft copolymer that includes a chitosan backbone and side chains of poly(itaconic acid) grafted to the chitosan backbone. The chitosan backbone has a plurality of amino groups that are acetylated by itaconic acid.

A temperature-regenerated hydrophobic liquid composition includes an extracting molecule of a non-alkaline cationic species, a solvating molecule of a complimentary anionic species and a fluidizing agent. The extracting molecule of a non-alkaline cationic species is a macrocycle of which the ring is formed from 24-32 carbon atoms and has the following formula (I) or (II): wherein -n is an integer ranging from 5 to 8, -p is 1 or 2, -m is 3 or 4, -q and t, which may be identical or different, are 0, 1 or 2, —R is a tert-butyl, tert-octyl, O-methyl, O-ethyl, O-propyl, O-isopropyl, O-butyl, O-isobutyl, O-pentyl, O-hexyl, O-heptyl, O-octyl, or OCH.sub.2Phenyl group or a hydrogen atom, and—R′ and R″, which may be identical or different, are chosen from methyl, ethyl, propyl, isopropyl, butyl, isobutyl, heptyl and octyl groups or R′ and R″ together form a pyrrolidine, piperidine or morpholine ring.

The present disclosure provides compositions and methods of use for effectively treating aquarium water in long term. The compositions include various components functioning to improve water quality, reduce or remove inorganic nitrogen and phosphorus, stabilize buffer capacity, and provide other advantages to aquarium water. Methods of using the compositions to improve the efficiency of treating aquarium water are also provided. The compositions and methods of the present disclosure can improve prophylaxis against unfavorable aquatic plant such as algae and extend life of animals in aquarium water.

The disclosure provides a silica-based scale cleaning technology. The disclosure can provide a cleaning agent of a silica-based scale, containing a silicic acid compound. The disclosure can also provide a cleaning method of a water treatment apparatus, including: using a solution containing a silicic acid compound. Further, the disclosure can provide a cleaning method of a silica-based scale, including: using an agent containing a silicic acid compound for a water system.

A water conditioning composition includes water, at least one gluconate compound, at least one carbonate compound, a non-ionic preservative, and a citrate compound. For example, the composition can include 87-95 wt. % water, 0.5 to 1.5 wt. % gluconate compound, 3 to 8 wt. % carbonate compound, 0.5 to 1.5 wt. % non-ionic preservative, and 0.5 to 2.5 wt. % citrate compound.