There are provided methods for treating a gas having an undesirable odor. The methods comprise contacting the gas with an acidic aqueous oxidizing composition having a pH of about 2.0 to about 3.0 and comprising at least one cation of a metal; a sequestering agent; and H.sub.2O.sub.2 and submitting the gas and the composition to UV radiation when the gas and the composition are contacting each other, wherein the treatment permits to reduce by at least 60% intensity of the undesirable odor.

The invention provides a composition of particulate materials. The composition comprises lanthanum chloride in particulate form. The composition also comprises up to about 4% by weight of amorphous silica in particulate form, based on the combined weight of the lanthanum chloride and the amorphous silica. The addition of amorphous silica to desiccated lanthanum chloride forms a fine coating or barrier on the outer surfaces of the individual lanthanum crystals, providing a composition that is significantly more stable and able to resist coalescence of particles than pure desiccated lanthanum chloride.

Described are filter materials including a polyol ligand, such as n-methylglucamine, and/or a polyphosphonic acid ligand, which are highly effective for filtering metals or metal ions from fluids. The filter materials can be particularly useful to filter basic and acidic fluid compositions, such as those used for wet etching, removing photoresist, and cleaning steps in microelectronic device manufacturing.

A method of purifying a produced water comprising contacting a produced water stream with a composition comprising a (i) a chelant; (ii) an oxidizing agent; and (iii) a surfactant under conditions suitable for the formation of a purified produced water. A composition for purifying produced water comprising (i) a biochelant in an amount of from about 1 wt. % to about 10 wt. %: (ii) an oxidizing agent in an amount of from about 3 wt. % to about 50 wt. %; (iii) a surfactant in an amount of from about 0.1 wt. % to about 70 wt. % wherein the weight percentage is based on the total weight of the composition; and (iv) a solvent.

Methods for removing cadmium (Cd) from a phosphoric acid solution produced in a wet process for manufacturing phosphoric acid, comprising treating the wet-process phosphoric acid solution with a small amount of a solid adsorbing material and a complex reagent to form a cadmium complex-contaminated solid adsorbing material, and removing the contaminated solid adsorbing material to yield a treated phosphoric acid solution having a low Cd content.

Methods for treating wastewater in conjunction with subterranean operations with a wastewater treatment additive. In some embodiments, the methods include providing wastewater recovered from at least a portion of a subterranean formation, wherein the wastewater includes water and an organic foulant material, and introducing a wastewater treatment additive that includes an alcohol ethoxylate surfactant into the recovered wastewater.

Compositions and methods and systems for treating wastewater within a wastewater treatment system of described. In an embodiment, a method for treating wastewater may include adding a magnesium compound to wastewater within a wastewater treatment system. The method may also include adding an effective amount of a dispersing agent and one or more of a free magnesium control agent and a seed material to wastewater within the wastewater treatment system to control the formation of struvite scale within the wastewater treatment system. Other compositions and methods are described.

Provided is a silica particle coated with β-cyclodextrin, wherein said cyclodextrin is attached to said silica particle via at least one crosslinking agent and/or at least one copolymer. Also provided are methods of removing contaminants from a flowing or stationary liquid phase comprising the step of contacting said liquid phase with the silica particle coated with β-cyclodextrin.

A method of treating a fluid to reduce the level of H.sub.2S therein while inhibiting the deposition of scale on surfaces in contact with the fluid, comprising introducing into the fluid a triazine scavenger compound and a terpolymer. The fluid may be liquid or gas and may be petroleum, petroleum product, natural gas, liquefied petroleum gas or other type of oil fraction or refined oil. The triazine scavenger may be e.g. 1,3,5-tri(2-hydroxyethyl)-hexahydro-1, 3, 5-triazine. The terpolymer may comprise a carboxylate/sulphonate/non-ionic terpolymer. When added to a wellbore fluid, it is effective as a scavenger of H.sub.2S and also reduces the amount of scale deposition on a surface in contact with the fluid when the fluid comes into contact with or is mixed with a brine. In some aspects, the composition increases the proportion of precipitated solids held in suspension when the fluid is contacted with or mixed with a brine.

A method for selective extraction of lithium from geothermal brines using host-guest complexes of host molecules such as calixarene, dendrimeric polymers, hyper-branched polymers, and/or acid-catalyzed resins complexed with synergists such as organic acids, condensation polymers, olefin/maleic anhydride copolymers, and/or chelants.