The invention pertains to methods of reducing dissolved elements such as arsenic, selenium and mercury in aqueous solutions using, for example, various barium compounds to partition said elements to a solid phase. Such methods are particularly useful for reducing such elements at various points in coal and oil-fired power plants prior to final waste water treatment.

Provided herein are processes for the removal and/or recovery of a target metal from a liquid sample, said process comprising: [1] applying acoustic cavitation to the liquid; and [2] adding an iron (II) salt, or a precursor form thereof, to the liquid sample and allowing Fenton oxidation reaction to occur between the iron and hydrogen peroxide in the liquid, thereby producing hydroxyl radicals; thereby producing a target metal salt or metal oxide having a reduced solubility in the liquid sample, leading to removal of the target metal from the liquid sample. The use of metal ligands in such processes is also described, as well as systems for performing such processes. Methods, processes, and systems for removing organic contaminants from a liquid sample are also described.

The present disclosure provides an adsorbent which is produced using a low environmental load material as a raw material and adsorbs selenious acid selectively and efficiently. A selenious acid adsorbent according to the present disclosure includes a cellulose derivative (I) having a repeating unit represented by Formula (I). In Formula (I), each R.sup.a represents a hydrogen atom, a group represented by Formula (a-1), or a group represented by Formula (a-2), and at least one of all the R.sup.as included in the cellulose derivative is a group represented by Formula (a-1) or a group represented by Formula (a-2):

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Systems for algae-based water filtration and algae harvesting are described herein. A flow-way comprises a channel and a divider positioned within the channel that separates the channel into sub-channels. The flow-way further includes an algal growth that grows on a sidewall of the channel and/or the divider. The algal growth can be established in the flow-way by positioning a pre-seeded mesh element within the channel, the pre-seeded mesh element having an algae culture growing thereon prior to positioning the pre-seeded mesh within the channel. A harvesting system comprises a hinged container that includes a straining screen. The hinged container is positioned downstream from a flow-way and receives water from the flow-way. Biomass in the water is strained by and accumulates on the screen. Weight of the accumulated biomass causes the hinged container to tip and deposit the accumulated biomass in a second container.

The present application provides a method for recycling selenium sources in a selenium-enriched yeast fermentation process, and a treatment system for selenium-containing wastewater. The method includes: step S1, performing separation and concentration treatments on selenium-containing wastewater produced in a selenium-enriched yeast fermentation process, so as to obtain a selenium-containing concentrated solution; step S2, adjusting a selenium content of the selenium-containing concentrated solution to a predetermined selenium content, so as to obtain a selenium-containing nutrient solution; and step S3, adding the selenium-containing nutrient solution into a selenium-enriched yeast fermentation reaction, so as to realize the recycling of the selenium source.

An adsorbent for a target compound can include porous carbon particles having pores with a predominant pore size less than 10 nm, and magnetic nanoparticles (MNP) nucleated on the carbon surface and within the pores of carbon particles to provide a carbon magnetic nanoparticle adsorbent (C-MNA). A method for removing target compounds with an adsorbent, a system for removing contaminants from a liquid, and a method for adsorbing target compounds from a fluid are also disclosed.

The present invention is directed to a ligated metal-organic framework (MOF) for use in removing both anionic and cationic species from a liquid or liquid stream. The present invention also provides methods for placing the MOF on a substrate to form a MOF-containing product that can be used in the removal of certain species from a given fluid. The MOF may be a Zr-based MOF, such as NU-1000, for removal of certain anions, such as oxy-anions, or having an attached thiosulfonyl-thiol (—SO.sub.2—S—R.sub.2—SH, where R.sub.2 is an alkyl group) ligand for complexation with certain cationic species in addition to the anions. The substrate may be any substrate to which a given MOF may be attached, including inert polypropylene polymer resin beads, a macroscopic fabric such as a mesh material or mesh filter, and a molecular fabric.

Methods and systems for removal of ions from aqueous fluids are provided. In certain embodiments, the present disclosure provides a method of removing one or more oxyanions from an aqueous fluid, including the steps of contacting an aqueous fluid containing oxyanions with an aluminum metal whereby aluminum ions are released from the aluminum metal into the aqueous fluid, wherein the one or more oxyanions in the aqueous fluid react with the aluminum ions to form one or more ettringites; controlling a rate of release of the aluminum ions from the aluminum metal; and removing at least a portion of precipitated ettringites from the aqueous fluid.

A variety of compositions and materials are provided for water purification and remediation. The compositions including multiple functionalities for treating a variety of pollutants or contaminants. The compositions can include a porous organic polymer with one or more of a variety of functional groups for binding the contaminants and with a hierarchical pore size distribution over a range of pore sizes to facilitate enhanced removal of the contaminants. Functional groups can include one, two, or more different functional groups such as amines, halides, ammoniums, pyridiuiums, thiols, imidazoliums, salts thereof, or others. The range of pore sizes can be about 1 nm to 10 nm or more. Contaminants can include antimony, arsenic, barium, beryllium, cadmium, chromium, copper, lead, mercury, selenium, technetium, thallium, uranium, radium, urea, and phosphate. Methods of removing the contaminants from water using the compositions are also provided.

The present disclosure relates to methods of treating water to remove contaminants, including harmful metal ions, and water treatment plants for practicing such methods. In an embodiment, the process includes adding a sulfur-containing, metal-decreasing agent; an iron (III)-containing, metalloid-decreasing agent; forming a solid precipitate from the contaminated water, wherein the solid precipitate includes a solid metal sulfide, a solid iron metalloid, a solid calcium metalloid, or a combination thereof; and separating the contaminated water from the solid precipitate to form purified water.