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Poly-,Per-fluorinated alkyl substances (PFAS) are versatile chemicals that were incorporated in a wide range of products. One of their most important use was in aqueous film-forming foams for fighting liquid fuel fires. PFAS compounds have recently been identified as potential environmental contaminants. In the United States there are hundreds of potential military sites with PFAS contamination. The ERDC designed and constructed a mobile treatment system to address small sites (250,000 gallons or less) and as a platform to field test new adsorptive media. The PFAS Effluent Treatment System (PETS) has cartridge filters to remove sediments and a granular activated carbon (GAC) media filter to remove organic compounds that might compete with PFAS in the ion exchange process, although it may also remove PFAS too. The last process is an ion exchange resin specifically designed to remove PFAS to a target level of 70 ng/L or less (equivalent to the US Environmental Protection Agency (EPA) Drinking Water Health Advisory). The system was tested at Hurlburt Field, a US Air Force facility in Florida and at Naval Support Activity (NSA) Mid-South in Millington, TN.

Department of defense (DoD) hand grenade training ranges have implemented alkaline hydrolysis, which is the practice of applying hydrated lime [Ca(OH)2] to range soil, to manage the deposi...

Magnetic calcium (Ca) and magnesium (Mg)-modified iron oxide adsorbents were synthesized using CaCl 2 , CaCO 3 , MgCl 2 , or MgCO 3 by a simple combustion method for the remediation of phosphate. Modification with Ca and Mg significantly improved the phosphate adsorption capacity of the magnetic iron oxide adsorbents. Additionally, polyvinyl alcohol (PVA) was incorporated during synthesis to aid in the magnetism of the samples, making the adsorbents easy to separate from solutions. Physicochemical properties of the adsorbents were determined by characterization with X-ray diffraction (XRD), particle analyzer, scanning electron microscopy (SEM), transmission electron microscopy (TEM), and high resolution TEM (HR-TEM). Batch adsorption experiments were carried out to gain insight on the materials' ability to remove phosphate from water supplies. Samples without the addition of PVA had higher phosphate capacities (ranging from 16.92 to 16.97 mg g −1 ) compared to PVA-containing samples (ranging from 12.39 to 16.74 mg g −1 ), yet the PVA-containing samples were magnetic and thus, easily separable.

The field of water disinfection has gained much interest since waterborne diseases caused by pathogenic microorganisms directly endanger human health. Antibacterial surfaces offer a new, ecofriendly technique to reduce the harmful disinfection byproducts that form in medical and food processing industries. Titanium dioxide (TiO2) photocatalysts have been extensively studied to prepare antibacterial surfaces due to their environmentally favorable properties. The studies demonstrate TiO2 improves the efficiency of disinfection by the effective inactivation of pathogenic microorganisms (i.e., Escherichia coli, Enterococcus faecalis, Staphylococcus aureus, Pseudomonas putida, and Listeria innocua). TiO2 photocatalysts decompose natural algal toxins such as microcystin-LR and cylindrospermopsin under solar light irradiation. On the basis of literature review, these antibacterial surfaces may be applied to hospital, food, ceramic, and building industries or to environmental remediation where bacteria inactivation is required to ensure the safety of human health and the environment.

Phosphorus is an essential and limited nutrient that is supplied by a depleting resource, mineral phosphate rock. Eutrophication is occurring in many water bodies which provides an opportunity to recover this nutrient from the water. One method of recovery is through adsorption; this study focused on fabricating a porous and granular adsorptive material for the removal and recovery of phosphate. Magnesium carbonate was combined with cellulose in varying weight ratios (0, 5, 10, 15, 20%) to synthesize pellets, which were then calcined to increase internal surface area. Physiochemical properties such as surface area, surface morphology, elemental composition, and crystal structure of the materials were characterized using Brunauer, Emmett, and Teller (BET) surface area analysis, X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). The pellet proved to be uniform in composition and an increase in BET surface area correlated with an increase in cellulose content until pellet stability was lost. Phosphate adsorption using the pellets was studied via batch kinetics and sorption isotherms. The pseudo-second-order kinetics model fits best suggesting that the adsorption occurring was chemisorption. The isotherm model that fit best was the Langmuir isotherm, which showed that the maximum equilibrium adsorption capacity increased with an increase in cellulose content between 10% and 20%. The average adsorption capacity achieved in the triplicate isotherm study was 96.4 mg g(−1) for pellets synthesized with 15% cellulose. Overall, using cellulose and subsequent calcination created an additional internal surface area for adsorption of phosphate and suggested that granular materials can be modified for efficient removal and recovery of phosphate from water.

Adsorption behavior of Bayoxide® E33 (E33) and three E33-modified sorbents for the removal of phosphate from lake water was investigated in this study. E33-modified sorbents were synthesized by coating with manganese (E33/Mn) and silver (E33/AgI and E33/AgII) nanoparticles. Adsorbent characterization was done by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), surface area analyzer (BET), transmission electron microscopy (TEM), and high resolution TEM (HR-TEM) analysis. Batch, equilibrium, and column experiments were conducted to determine various adsorption parameters. Equilibrium data were fitted to different adsorption isotherms and the Langmuir isotherm provided the best fit. Based on the Langmuir model, it was found that E33/AgII had a slightly higher maximum monolayer adsorption capacity (38.8 mg g−1) when compared to unmodified E33 (37.7 mg g−1). Data for adsorption kinetics were found to best fit with the pseudo-second-order model, suggesting chemisorption is the mechanism of sorption. Intra-particle diffusion studies indicated that the rate-limiting step for phosphate sorption onto E33 and modified E33 was intra-particle diffusion. Although limited improvements were seen, the results of this study suggest that the surface of E33 can be modified with nanoparticles to enhance the adsorption of phosphate from aqueous solutions and may give other advantages such as limiting biofouling over an extended lifetime of numerous recovery/regeneration steps.

The adsorption of phosphate onto modified Bayoxide® E33 (E33) and underlying mechanisms were comparatively investigated by batch kinetics, sorption isotherms, rapid small-scale column tests, and material characterization. Synthesis of modified E33 was conducted by the addition of manganese and silver nanoparticles on the surface of the goethite (α-FeOOH)-based E33. Upon successful adsorbent synthesis, the materials were characterized using SEM, TEM, XRD, EDX, HR-TEM, and BET surface area analysis. The adsorption kinetics is described by a fast initial adsorption stage followed by a slow adsorption stage, complying with pseudo second-order kinetics and Elovich kinetics. Sorption isotherms revealed that the equilibrium capacity of one of the modified adsorbents (E33/AgII) exceeded that of unmodified E33 likely due to its increased BET surface area. Column experiments confirmed the results for adsorption kinetics and equilibrium of phosphate sorption onto E33 and modified E33. This suggests that media modification has the potential to improve phosphate removal properties.

The overall objective of this research was to determine the effects of oxidative coupling (oligomerization) phenomenon on the adsorption kinetics of dissolved natural organic matter (DOM) on novel tailored activated carbons. A comparison of adsorption kinetics data collected in the presence and absence of phenolic compounds under both oxic (presence of molecular oxygen) and anoxic (absence of molecular oxygen) conditions showed that the adsorption rate of DOM was strongly affected by the oligomerization phenomenon. The diffusion rate of DOM is in inverse proportion to the critical oxidation potential of the phenolic compound. In addition, the roles of carbon physicochemical characteristics and DOM molecular weight distribution were also investigated. Tailored activated carbon impregnated with manganese oxide was found to play an important role in promoting complexation reactions between DOM and phenolic compounds. Meanwhile, Fulvic acid molecules (component of DOM) with molecular weight below 2000 Da appeared to have more potential to get influenced from oligomerization effects.

Greener synthesis of Ag and Au nanoparticles is described using antioxidants from blackberry, blueberry, pomegranate, and turmeric extracts. The synthesized particles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), high-resolution TEM (HR-TEM), particle size analysis, UV–vis spectroscopy, and thermogravimetric analysis. The XRD patterns indicated the formation of Ag and Au nanoparticles, and the results are in line with UV plasma resonance peaks.

Risks associated with current disinfection techniques, including the formation of disinfection by-products and multi-drug resistant bacterial species, have prompted the exploration of advanced disinfection methods. One such technique employs silver nanoparticle incorporation on various surfaces (e.g. metals, plastics, polymers). While silver's bactericidal impact has been known since ancient times, advancements in nanotechnology have improved the efficiency of silver disinfection and have enabled the use of silver as a viable disinfection option. Yet silver particles in drinking water can pose serious health risks. Consequently, before the immobilization of these bactericidal particles onto a surface could be considered a safe and efficient method of bacterial disinfection, various parameters including disinfection efficiency, silver leaching, and substrate reuse must be evaluated.

The use of silver nanoparticles (AgNPs) is gaining in popularity due to silver’s antibacterial properties. Conventional methods for AgNP synthesis require dangerous chemicals and large quantities of energy (heat) and can result in formation of hazardous byproducts. This article summarizes recent activity in this general area where environmentally friendly synthetic techniques are currently being explored for the synthesis of “greener” AgNPs including the use of plant extracts, biodegradable polymers, and enzymes/bacteria and alternative energy input systems, such as microwave irradiation. Microwave heating enables efficient formation of nanostructures of uniform small sizes in shorter reaction times with reduced energy consumption; preventing agglomeration of ensuing nanoparticles is an additional attribute.