An in-situ reagents injection system comprises a compressed air storage tank, a remediation reagents storage tank, an injection adjusting valve, an injection pipe, an upper sealing device and a lower sealing device. When the reagents injection is carried out, the compressed air is injected before the remediation reagents is injected, the porosity of the aquifer medium is increased by utilizing the air pressure expansion technology to form a relatively uniform dominant channel, and the remediation reagents is injected to realize uniform and efficient conveying of the reagents. The in-situ reagents injection system and method can make the homogeneous and efficient conveying of the remediation reagents, and ensure the full utilization of the remediation reagents, with low energy consumption of injection equipment, simple process, and flexible operation. The injection is performed in sections from top to bottom according to the steps to improve the in-situ reagents injection efficiency and remediation efficiency.

A magnetic soil remediation agent for soil heavy metal pollution and a preparation method and application thereof are provided. The magnetic soil remediation agent is prepared by using remediation agent framework material and magnetic core material as raw materials, and heavy metal collector as modifier; said framework material is silicon dioxide activated by strong alkali; said magnetic core material comprises magnetic materials Fe.sub.3O.sub.4 and γ-Fe.sub.2O.sub.3; said modifier comprises ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid trisodium salt (NTA), (S,S)-ethylenediamine-N,N-disuccinic acid trisodium salt (EDDS) and mercaptoethylamine. The remediation agent of the present invention can effectively passivate the heavy metals in the soil, reduce their available contents, and inhibit the absorption of heavy metals by plants.

A magnetic soil remediation agent for soil heavy metal pollution and a preparation method and application thereof are provided. The magnetic soil remediation agent is prepared by using remediation agent framework material and magnetic core material as raw materials, and heavy metal collector as modifier; said framework material is silicon dioxide activated by strong alkali; said magnetic core material comprises magnetic materials Fe.sub.3O.sub.4 and γ-Fe.sub.2O.sub.3; said modifier comprises ethylenediaminetetraacetic acid (EDTA), nitrilotriacetic acid trisodium salt (NTA), (S,S)-ethylenediamine-N,N-disuccinic acid trisodium salt (EDDS) and mercaptoethylamine. The remediation agent of the present invention can effectively passivate the heavy metals in the soil, reduce their available contents, and inhibit the absorption of heavy metals by plants.

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 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 graphene coated crushed glass particle adsorbent is provided for the removal of heavy metals and other contaminants in from solutions such as wastewaters, contaminated surface water and groundwater. The adsorbent comprises crushed (e.g. recycled) glass coated with graphene nano-sheets using a staged thermal binding process and the silicas in the glass as a catalyst. The adsorbent may be configured for use in both in-situ and ex-situ treatment systems and is capable of removing heavy metals and other inorganic and organic contaminants. The strong adsorptive bond between contaminants and the graphene coating on crushed glass particles can also lead to alternative applications of the end of life adsorbent, such as base material in road and pavement (e.g. cement-like) construction materials.

A process for PFAS decontamination comprises exposing water comprising PFAS contaminant to gas to accumulate a PFAS concentrate and separating the PFAS concentrate. PFAS separation is enhanced by the addition of a hydrofluorocarbon refrigerant, such as 1,1,1,2 tetraflouroethane, difluoromethane or pentaflouroethane to the gas wherein it is believed that with carbon-fluorine bonds of the hydrofluorocarbon refrigerant aid in attracting the carbon fluorine tail of all types of PFAS compounds to the water-gas interface and especially aids separation of smaller molecular weight PFAS molecules, including beyond what can be achieved using charged or ionised gases alone, thereby allowing a larger spectrum of PFAS molecules to be extracted from soil or water.

A process for PFAS decontamination comprises exposing water comprising PFAS contaminant to gas to accumulate a PFAS concentrate and separating the PFAS concentrate. PFAS separation is enhanced by the addition of a hydrofluorocarbon refrigerant, such as 1,1,1,2 tetraflouroethane, difluoromethane or pentaflouroethane to the gas wherein it is believed that with carbon-fluorine bonds of the hydrofluorocarbon refrigerant aid in attracting the carbon fluorine tail of all types of PFAS compounds to the water-gas interface and especially aids separation of smaller molecular weight PFAS molecules, including beyond what can be achieved using charged or ionised gases alone, thereby allowing a larger spectrum of PFAS molecules to be extracted from soil or water.

A composition for remediation of soil and groundwater containing halogenated compounds. The remediation composition includes an elemental iron-based composition, which may include activated carbon capable of absorbing the halogenated compounds with numerous pores impregnated with elemental iron. The remediation composition further includes a first bioremediation material including a blend of one-to-many organisms capable of degrading the halogenated compounds. The remediation composition includes an organic compound or polymeric substance and a second bioremediation material including a blend of one-to-many organisms capable of degrading the organic compound or polymeric substance over time (e.g., 20 to 365 or more days to provide a time release substrate-creating material or platform) into smaller molecules or compounds used by the organisms in the first bioremediation material while degrading the halogenated compounds. The organic compound may be a complex carbohydrate such as food grade starch, chitin, or other complex carbohydrate such as one with low water solubility.

Fresh water contamination by heavy metals results from a variety of sources and can be damaging to wildlife, alter landscapes, and impact human health. metals removal form water sources is desirable for improving water quality and preventing adverse effects, but also for metals collection and recycling. Adsorption is a desirable metals extraction technique due to economic feasibility. Nanoscale materials exhibit high surface-area-to-volume ratio that lends to high adsorption and reactivity, making them ideal candidates for adsorptive metals extraction processes. Despite these properties, nanomaterials have elicited safety concerns. The extraordinarily small dimensions of these materials allow them to maneuver biological systems, tissues, and even cells, and combined with high reactivity, this translocation can result in toxic effects. It is therefore imperative that safety of nanomaterials for metals extraction be evaluated in addition to adsorptive properties. The current invention describes nanoparticles composed of magnetite, coated in hydroxyapatite, and functionalized for adsorption with titanium dioxide (TiHAMNPs). This material is safe, provides significant adsorption of metals, and allows efficient collection in magnetic systems.