Methods are disclosed for treating water containing a target anion to remove the target anion. The methods can include preparing a treatment composition solution that contains a metal treatment agent, adjusting the treatment composition solution to a first pH that is alkaline and then to a second pH that is acidic, and contacting the treatment composition solution with the water that contains the target anion.

Provided is a system and a method for low-temperature treatment of heavy metals and dioxins in fly ash. In the present disclosure, the fly ash is subjected to tertiary water washing and then separation by pressure filtration with a plate and frame filter press to obtain fly ash after the tertiary water washing. A low-temperature heat treatment is conducted on the fly ash after the tertiary water washing in a stirring reactor by adding an additive combination. Chlorine salts in the fly ash can be effectively removed by the tertiary water washing, which avoids the chlorination of a precursor in the fly ash to form dioxins during the low-temperature pyrolysis, thereby improving a heat reduction efficiency of the dioxins in the fly ash. Moreover, the reduction of a chlorine content in the fly ash can also avoid deactivation of the additives and improve a solidification effect of the heavy metals.

Provided is a system and a method for low-temperature treatment of heavy metals and dioxins in fly ash. In the present disclosure, the fly ash is subjected to tertiary water washing and then separation by pressure filtration with a plate and frame filter press to obtain fly ash after the tertiary water washing. A low-temperature heat treatment is conducted on the fly ash after the tertiary water washing in a stirring reactor by adding an additive combination. Chlorine salts in the fly ash can be effectively removed by the tertiary water washing, which avoids the chlorination of a precursor in the fly ash to form dioxins during the low-temperature pyrolysis, thereby improving a heat reduction efficiency of the dioxins in the fly ash. Moreover, the reduction of a chlorine content in the fly ash can also avoid deactivation of the additives and improve a solidification effect of the heavy metals.

The process of reacting nanoscale ce-MoS.sub.2 nanosheets anchored on oxide support with lead in solution at room temperature whereby the reaction is rapid and spontaneous resulting in the formation of PbMoO.sub.4-xS.sub.x in the process of scavenging Pb.sup.2+ and Pb.sup.4+ present in the solution.

A method for selective adsorption of lead ions from heavy metal wastewater by electric field enhancement relating to a method for recovering lead ions from heavy metal wastewater. The method aims to solve the technical problems that it is difficult to recover heavy metals from a complex water environment in well-targeted manner and recovery purity is poor because of poor selectivity of the existing adsorbents. The adsorption selectivity to Pb.sup.2+ is enhanced under an electric field by applying a tannic acid@graphene oxide conductive aerogel material to water heavy metal electrochemical adsorption system as a conductive adsorbent. In the method, the conductive layer of the tannic acid@graphene oxide conductive aerogel material may be optimized through electrochemical reduction, so that the material has better conductivity, and has better selectivity to lead ions under an electric field.

Described are filtration elements for removing materials from a fluid. The filtration elements generally operate by inducing cavitation into a fluid passing through them, generating energy and removing unwanted materials from the fluid. The filtration elements can be used singularly or in combination with one another for a multiple level filtration system.

A process for treating frac flowback that contains barium, naturally occurring radioactive materials (NORM) and hardness for minimizing the amount of sludge produced that contains hazardous levels of NORM by employing a dual stage precipitation process. In the first stage a sulfate source is mixed with the frac flowback and barium sulfate and NORM is precipitated, the frac flowback is subjected to a solids-liquid separation process to produce a first effluent and a first sludge. In the second stage hardness is precipitated from the first effluent by addition of an alkali reagent, said first effluent is also subjected to solids-liquid separation producing a second effluent and a second sludge. The first sludge is recycled and mixed with the frac flowback and the sulfate source in a sufficient amount to maintain the NORM concentration in the second sludge at or below a threshold level.

A process for treating frac flowback that contains barium, naturally occurring radioactive materials (NORM) and hardness for minimizing the amount of sludge produced that contains hazardous levels of NORM by employing a dual stage precipitation process. In the first stage a sulfate source is mixed with the frac flowback and barium sulfate and NORM is precipitated, the frac flowback is subjected to a solids-liquid separation process to produce a first effluent and a first sludge. In the second stage hardness is precipitated from the first effluent by addition of an alkali reagent, said first effluent is also subjected to solids-liquid separation producing a second effluent and a second sludge. The first sludge is recycled and mixed with the frac flowback and the sulfate source in a sufficient amount to maintain the NORM concentration in the second sludge at or below a threshold level.

The article includes a porous scaffold structure comprising a plurality of supports. The article further includes a plurality of metallic or non-metallic nanomaterials disposed on at least one of the supports. Each of the plurality of metallic or non-metallic nanomaterials is directly bound to at least one of the supports.

The article includes a porous scaffold structure comprising a plurality of supports. The article further includes a plurality of metallic or non-metallic nanomaterials disposed on at least one of the supports. Each of the plurality of metallic or non-metallic nanomaterials is directly bound to at least one of the supports.