Methods for synthesizing macroscale 3D heteroatom-doped carbon nanotube materials (such as boron doped carbon nanotube materials) and compositions thereof. Macroscopic quantities of three-dimensionally networked heteroatom-doped carbon nanotube materials are directly grown using an aerosol-assisted chemical vapor deposition method. The porous heteroatom-doped carbon nanotube material is created by doping of heteroatoms (such as boron) in the nanotube lattice during growth, which influences the creation of elbow joints and branching of nanotubes leading to the three dimensional super-structure. The super-hydrophobic heteroatom-doped carbon nanotube sponge is strongly oleophilic and can soak up large quantities of organic solvents and oil. The trapped oil can be burnt off and the heteroatom-doped carbon nanotube material can be used repeatedly as an oil removal scaffold. Optionally, the heteroatom-doped carbon nanotubes in the heteroatom-doped carbon nanotube materials can be welded to form one or more macroscale 3D carbon nanotubes.

Methods for synthesizing macroscale 3D heteroatom-doped carbon nanotube materials (such as boron doped carbon nanotube materials) and compositions thereof. Macroscopic quantities of three-dimensionally networked heteroatom-doped carbon nanotube materials are directly grown using an aerosol-assisted chemical vapor deposition method. The porous heteroatom-doped carbon nanotube material is created by doping of heteroatoms (such as boron) in the nanotube lattice during growth, which influences the creation of elbow joints and branching of nanotubes leading to the three dimensional super-structure. The super-hydrophobic heteroatom-doped carbon nanotube sponge is strongly oleophilic and an soak up large quantities of organic solvents and oil. The trapped oil can be burnt off and the heteroatom-doped carbon nanotube material can be used repeatedly as an oil removal scaffold. Optionally, the heteroatom-doped carbon nanotubes in the heteroatom-doped carbon nanotube materials can be welded to form one or more macroscale 3D carbon nanotubes.

A composition for capturing, removing, and in some cases recovering a pollutant or raw material wherein the composition includes a polymeric material, one or more metal or nonmetal materials in granular form, and preferably a small amount of a salt material.

Removing heavy metal ions from an aqueous composition includes contacting an aqueous composition including a heavy metal with nanoflakes comprising MoS.sub.2 for a length of time sufficient to form nanoclusters of the heavy metal on the nanoflakes. A composite may include a porous polymeric matrix and MoS.sub.2 nanoflakes coupled to the porous polymeric matrix. Making a porous MoS.sub.2-polymer composite may include combining a solution phase dispersion of MoS.sub.2 with a polymer precursor solution to yield a mixture, treating the polymer precursor solution to yield a composite precursor, and drying the composite precursor to yield a porous MoS.sub.2-polymer composite.

The present disclosure discloses an application of cuprous sulfide in a recovery of Au (III) from aqueous solutions, which relates to the fields of hydrometallurgy and precious metal recovery. The method of the present disclosure uses cuprous sulfide nanoparticles to recover Au (III) from aquesous solution, and undergoes gold adsorption under mechanical stirring. The method described in the present disclosure can efficiently recover Au (III) from aqueous solutions, has good recovery effects on Au (III) from acidic waste liquid, and has the advantages of energy conservation, environmental protection, and low cost.

The invention relates to a corrosion-resistant, reactive adsorbent which is made up of element iron on a carbon carrier plus sulfur and additional phosphorus as well as a method for producing this reactive adsorbent and use thereof for removal of reductively degradable pollutants in contaminated groundwater and wastewater.

A system and method for cleaning, conditioning, and/or rejuvenating carbon-based sorbents is disclosed where a chemical cleaning process is used to separate contaminants from the sorbent. The contaminants can be disposed of or recycled for industrial uses. The cleaned and/or rejuvenated carbon-based sorbent is recycled back into a reverse venturi shaped fluidized bed apparatus for later use. Spent carbon-based sorbent can be routed for appropriate disposal. The carbon-based sorbents include, but are not limited to, activated carbon sorbent and biochar sorbent. Optionally, the sorbents can be processed through the system prior to exposure to contaminated emissions to enhance and increase the porosity of the outer surface of the sorbents.

Methods of preparing a mercury sorbent material are provided. The methods comprise making a copper/clay mixture by admixing a dry clay and a dry copper source; making a sulfur/clay mixture by admixing a dry clay and a dry sulfur source; admixing the copper/clay mixture and the sulfur/clay mixture, to form a mercury sorbent pre-mixture; and shearing the mercury sorbent pre-mixture to form the mercury sorbent material. Various substrates may be used with or instead of the clay, and various additives may be added to the copper, sulfur, clay, or mixture thereof.

A method for preparing the ferrous sulfide-containing passivator includes: dissolving a sulfide in an alkaline solution to form a mixed solution with a pH of 12-13; adding sodium silicate to the mixed solution and stirring for 0.5-1 hour at 20-40? C.; adding an aqueous solution of ferrous salt to the mixed solution containing sodium silicate, and allowing to react at 40-60? C. for 2-3 hours; where, with decrease of the pH of the mixed solution, sodium silicate is converted into silica nanoparticles, and the ferrous salt reacts with the sulfide to form ferrous sulfide; and further adding an aqueous solution of an organic modifier, and allowing to react at 40-60? C. for 1-2 hours to form a passivator slurry including surface-modified ferrous sulfide doped with silicon dioxide; filtering the passivator slurry to form a passivator.

A dolomite-based adsorbent for heavy metal, halogen and metalloid is half-fired dolomite, and a content of a residual CaMg(CO.sub.3).sub.2 phase in the half-fired dolomite, which is analyzed using a Rietveld method by means of powder X-ray diffraction, is 0.4x35.4 (wt %), and preferably, the dolomite-based absorbent for heavy metal, halogen and metalloid further comprises ferrous sulfate.