A system is provided for removing arsenic from water to safe levels at or below the EPA standards. The system is a hybrid spouted vessel/fixed bed filter system that significantly enhances/improves arsenic removal for drinking water using zero-valent iron (ZVI) particles. Movement of the circulating, iron-containing particles in a dense moving bed that forms on the spouted vessel bottom creates an abrasive “self-polishing” action among them that continuously generates colloidal iron corrosion products. This material then circulates with the water in the vessel and is removed and concentrated in a fixed bed filter. The colloidal material captured and immobilized in the filter has been shown to remove arsenic from contaminated water at very rapid rates.

A replaceable water filter includes a filter assembly having a filter structure with first, second, and third filtering elements sharing a common axis, the first filtering element for removing and/or reducing particulate contaminants in the water, the second filtering element for removing and/or reducing particulate and organic contaminants in the water and the third filtering element for removing and/or reducing at least one of fluoride and arsenic in the water. The filter further includes a housing that contains the filter assembly. The housing includes a first end adapted to removably attach the filter to a filter mount of the refrigerator where the filter communicates with the water supply of the refrigerator. The first filtering element can be fabric, the second filtering element can be a carbon block, and the third filtering element can be activated alumina.

A resin is provided for selectively binding to perchloride and related anions (e.g., TcO.sub.4.sup.−, ReO.sub.4.sup.− and I.sup.−) in aqueous solution. The resin may take the form of microparticles or beads. The beads are prepared by cross-linking macromolecules such as hyperbranched PEI, and quaternizing the amines with hydrocarbon substituents.

A biodegradable iron-crosslinked alginate is useful as a remediation agent for environmental contaminants such as phosphate. When charged with phosphate, or other nutrients, the iron-functionalized alginate can be used as an agricultural fertilizer.

Embodiments of the present disclosure are directed towards methods for preparing mixed-metal oxide particles by heating adamantane-intercalated layered double-hydroxide (LDH) particles at a reaction temperature of from 400° C. to 800° C. to form mixed-metal oxide particles. The adamantane-intercalated LDH particles have a general formula [M.sub.1-xAl.sub.x(OH).sub.2](A).sub.x.mH.sub.2O, where x is from 0.14 to 0.33, m is from 0.33 to 0.50, M is chosen from Mg, Ca, Co, Ni, Cu, or Zn, and A is adamantane carboxylate, and an aspect ratio greater than 100. The aspect ratio is defined by the width of an adamantane-intercalated LDH particle divided by the thickness of the adamantane-intercalated LDH particle. The mixed-metal oxide particles comprise a mixed-metal oxide phase containing M, Al or Fe, and carbon.

A device for collecting contaminants from water samples is provided. The device includes a solid sorbent that collects and stores the contaminants from water samples. The solid sorbent is configured to allow for the preservation of the stored contaminants. The concentrations of the contaminants in the water samples are determined via analysis of the solid sorbent or via elution of the stored contaminants from the sorbent and analysis of the eluate solution.

According to one embodiment, an electrolytic membrane separation (EMS) subsystem is configured to remove one or more impurities from a contaminated reject solution and to recycle the reusable reject solution for subsequent use in regenerating ion exchange resins. According to another embodiment of the invention, the EMS subsystem is configured to concentrate the impurities recovered from the contaminated brine solution for subsequent disposal or treatment.

Bi-metal nanoadsorbents and methods for their preparation and use are provided. Methods of using bi-metal nanoadsorbents to remove contaminants from samples, such as water, are also provided.

The present invention relates to a calcined diatomite aggregate coated with metal oxides, more specifically to a diatomite aggregate having a diameter larger than 2 mm.

The present invention provides a method of reducing and controlling a hazardous substance in a process of high-value biological conversion of an urban organic waste. The method includes: 1) mixing a sludge, a first urban organic waste and an organic acid with water for acclimation to obtain an acclimatized sludge; 2) stage 1 of biological conversion: mixing the acclimatized sludge with a second urban organic waste to perform anaerobic culture; 3) stage 2 of biological conversion: adding nitrate and bacteria to continue anaerobic culture so as to obtain an organic acid. In the present invention, sludge microbes are acclimatized and then added to high-value chemicals such as acetic acid, propanoic acid and lactic acid prepared in biological conversion of the urban organic waste and then added with bacteria. Thus, by controlling pH value, microbe addition amount and nitrate concentration, the unfavorable effect of the antibiotics and heavy metal ions.