Photoinactivation of virus on iron-oxide coated sand: enhancing inactivation in sunlit waters

Adsorption onto iron oxides can enhance the removal of waterborne viruses in constructed wetlands and soils. If reversible adsorption is not coupled with inactivation, however, infective viruses may be released when changes in solution conditions cause desorption. The goals of this study were to investigate the release of infective bacteriophages MS2 and ΦX174 (two human viral indicators) after adsorption onto an iron oxide coated sand (IOCS), and to promote viral inactivation by exploiting the photoreactive properties of the IOCS. The iron oxide coating greatly enhanced viral adsorption (adsorption densities up to ∼10⁹ infective viruses/g IOCS) onto the sand, but had no affect on infectivity. Viruses that were adsorbed onto IOCS under control conditions (pH 7.5, 10 mM Tris, 1250 μS/cm) were released into solution in an infective state with increases in pH and humic acid concentrations. The exposure of IOCS-adsorbed MS2 to sunlight irradiation caused significant inactivation via a photocatalytic mechanism in both buffered solutions and in wastewater samples (4.9 log₁₀ and 3.3 log₁₀ inactivation after 24-h exposure, respectively). Unlike MS2, ΦX174 inactivation was not enhanced by photocatalysis. In summary, IOCS enhanced the separation of viruses from the water column, and additionally provided a photocatalytic mechanism to promote inactivation of one of the surrogates studied. These qualities make it an attractive option for improving viral control strategies in constructed wetlands.     

Removal of chromium (VI) from wastewater using bentonite-supported nanoscale zero-valent iron

Bentonite-supported nanoscale zero-valent iron (B-nZVI) was synthesized using liquid-phase reduction. The orthogonal method was used to evaluate the factors impacting Cr(VI) removal and this showed that the initial concentration of Cr(VI), pH, temperature, and B-nZVI loading were all importance factors. Characterization with scanning electron microscopy (SEM) validated the hypothesis that the presence of bentonite led to a decrease in aggregation of iron nanoparticles and a corresponding increase in the specific surface area (SSA) of the iron particles. B-nZVI with a 50% bentonite mass fraction had a SSA of 39.94 m²/g, while the SSA of nZVI and bentonite was 54.04 and 6.03 m²/g, respectively. X-ray diffraction (XRD) confirmed the existence of Fe⁰ before the reaction and the presence of Fe(II), Fe(III) and Cr(III) after the reaction. Batch experiments revealed that the removal of Cr (VI) using B-nZVI was consistent with pseudo first-order reaction kinetics. Finally, B-nZVI was used to remediate electroplating wastewater with removal efficiencies for Cr, Pb and Cu > 90%. Reuse of B-nZVI after washing with ethylenediaminetetraacetic acid (EDTA) solution was possible but the capacity of B-nZVI for Cr(VI) removal decreased by approximately 70%.     

Comparison of electrocoagulation and chemical coagulation pretreatment for enhanced virus removal using microfiltration membranes

This research studied virus removal by iron electrocoagulation (EC) followed by microfiltration (MF) in water treatment using the MS2 bacteriophage as a tracer virus. In the absence of EC, MF alone achieved less than a 0.5-log removal of MS2 virus, but, as the iron-coagulant dosage increased, the log virus removal increased dramatically. More than 4-log virus removal, as required by the Surface Water Treatment Rule, was achieved with 6-9 mg/L Fe³⁺. The experimental data indicated that at lower iron dosages and pH (<∼8 mg Fe/L and pH 6.3 and 7.3) negatively charged MS2 viruses first adsorbed onto the positively charged iron hydroxide floc particles before being removed by MF. At higher iron dosages and pH (>∼9 mg Fe/L and pH 8.3), virus removal was attributed predominantly to enmeshment and subsequent removal by MF. Additionally, the experimental data showed no obvious influence of ionic strength in the natural water range of 10⁻⁷-10⁻² M on MS2 virus removal by EC-MF. Finally, EC pretreatment significantly outperformed chemical coagulation pretreatment for virus removal. The proposed mechanism for this improved performance by EC is that locally higher iron and virus concentrations and locally lower pH near the anode improved MS2 enmeshment by iron flocs as well as adsorption of MS2 viruses onto the iron floc particles.     

Biological oxidation of arsenite in synthetic groundwater using immobilised bacteria

Biological oxidation of arsenite (As(III)) in synthetic groundwater was examined by using arsenite oxidising bacteria (AOB) isolated from an activated sludge. The phylogenetic analysis indicated that the isolated AOB was closely related to Ensifer adhaerens. Batch experiments showed that for an As(III) oxidation with the isolated AOB the optimum ratio of nitrogen source (NH₄-N) concentration to As(III) concentration was 0.5 (52 mg/L-110 mg/L) and the isolated AOB preferred pH values ranging from 6 to 8, and water temperatures greater than 20 °C. Further continuous experiments were conducted using a bioreactor with immobilised AOB. With an initial As(III) concentration of 1 mg/L at a hydraulic retention time (HRT) of 1 h, an As(III) oxidation rate was around 1 × 10⁻⁹ μg/cell/min and an As(III) oxidation efficiency of 92% was achieved. Although the maximum oxidation rate measured at an HRT of 0.5 h was 2.1 × 10⁻⁹ μg/cell/min, the oxidation efficiency decreased to 87%.These results advocate that a biological process involving immobilised AOB may be useful as an economical and environmentally friendly pre-treatment step for As removal from groundwater.     

pH-dependent effect of zinc on arsenic adsorption to magnetite nanoparticles

The effect of Zn²⁺ on both the kinetic and equilibrium aspects of arsenic adsorption to magnetite nanoparticles was investigated at pH 4.5-8.0. At pH 8.0, adsorption of both arsenate and arsenite to magnetite nanoparticles was significantly enhanced by the presence of small amount of Zn²⁺ in the solution. With less than 3 mg/L of Zn²⁺ added to the arsenic solution prior to the addition of magnetite nanoparticles, the percentage of arsenic removal by magnetite nanoparticles increased from 66% to over 99% for arsenate, and from 80% to 95% for arsenite from an initial concentration of ∼100 μg/L As at pH 8.0. Adsorption rate also increased significantly in the presence of Zn²⁺. The adsorption-enhancement effect of Zn²⁺ was not observed at pH 4.5-6.0, nor with ZnO nanoparticles, nor with surface-coated Zn-magnetite nanoparticles. The enhanced arsenic adsorption in the presence of Zn²⁺ cannot be due to reduced negative charge of the magnetite nanoparticles surface by zinc adsorption. Other cations, such as Ca²⁺ and Ag⁺, failed to enhance arsenic adsorption. Several potential mechanisms that could have caused the enhanced adsorption of arsenic have been tested and ruled out. Formation of a ternary surface complex by zinc, arsenic and magnetite nanoparticles is a possible mechanism controlling the observed zinc effect. Zinc-facilitated adsorption provides further advantage for magnetite nanoparticle-enhanced arsenic removal over conventional treatment approaches.

Synopsis

Arsenic adsorption to magnetite nanoparticles at neutral or slightly basic pH can be significantly enhanced with trace amount of Zn²⁺ due to the formation of a ternary complex.     

A photoelectrocatalytic process that disinfects water contaminated with Mycobacterium kansasii and Mycobacterium avium

Nontuberculous mycobacteria are resistant to conventional water treatment; indeed, they have been recovered from a wide variety of environmental sources. Here, we applied the photoelectrocatalytic technique using a Ti/TiO₂–Ag photoanode to inactivate mycobacteria. For a mycobacteria population of 5 × 10⁸ CFU mL⁻¹, we achieved 99.9 and 99.8% inactivation of Mycobacterium kansasii and Mycobacterium avium with rate constant of 6.2 × 10⁻³ and 4.2 × 10⁻³ min⁻¹, respectively, after 240 min. We compared the proposed method with the photolytic and photocatalytic methods. Using a mycobacteria population of 7.5 × 10⁴ CFU mL⁻¹, the proposed Ti/TiO₂–Ag photoanode elicited total mycobacteria inactivation within 3 min of treatment; the presence of Ag nanoparticles in the electrode provided 1.5 larger degradation rate constant as compared with the Ti/TiO₂ anode (1.75 × 10⁻² for M. kansassi and 1.98 × 10⁻² for M. avium). We monitored the degradation of the metabolites released during cellular lysis by TOC removal, sugar release, chromatography, and mass spectrometry measurements; photoelectrocatalysis and Ti/TiO₂–Ag photoanodes furnished the best results.     

Organic arsenic removal from drinking water

Arsenic occurs in both inorganic and organic forms in water. Although various methods have been adopted to remove inorganic species of arsenic from drinking water, not much emphasis has been given to the removal of organic species of arsenic. In the present study column studies were conducted using manganese greensand (MGS), iron oxide-coated sand (IOCS-1 and IOCS-2) and ion exchange resin in Fe³⁺ form, to examine the removal of organic arsenic (dimethylarsinate) spiked to required concentrations in tap water. Batch studies were conducted with IOCS-2, and the results showed that the organic arsenic adsorption capacity was 8 μg/g IOCS-2. Higher bed volumes (585 BV) and high arsenic removal capacity (5.7 μg/cm³) were achieved by the ion exchange resin among all the media studied. Poor performance was observed with MGS and IOCS-1.     

Microorganisms and particles in AHU systems: Measurement and analysis

In this study, for better understanding the practical removal effect of air handling unit (AHU) system on airborne microorganisms (including bacteria and fungus) and particles and microbial growth, the samples of microorganisms and particles in 10 air handling unit (AHU) systems including fan coils and indoor air were collected and analyzed in air and component surfaces of such systems in two large public buildings. It is found that the removal efficiency is of the highest for bacteria 73.9% and the lowest for particles (0.5–2 μm) 24.4%. The surface concentration of equipment bacteria is 29 CFU/cm² and fungi 137 CFU/cm². Five of 10 systems have higher fungi concentrations on air intake than that on diffuser. The results also show that the central air supply system with common components (e.g., pre-filter and bag filter) has difficulty to achieve/maintain good performance once microorganisms and particles exist, especially for particle size D ≤ 3.3 μm. The size distribution has large influence on removal efficiency. The microbial growth on surfaces of duct and equipment was noticed and may be transferred into indoor air. This will decrease the indoor air quality and lead to adverse health effect.     

Release of antibiotic resistant bacteria and genes in the effluent and biosolids of five wastewater utilities in Michigan

The purpose of this study was to quantify the occurrence and release of antibiotic resistant genes (ARGs) and antibiotic resistant bacteria (ARB) into the environment through the effluent and biosolids of different wastewater treatment utilities including an MBR (Membrane Biological Reactor) utility, conventional utilities (Activated Sludge, Oxidative Ditch and Rotatory Biological Contactors-RBCs) and multiple sludge treatment processes (Dewatering, Gravity Thickening, Anaerobic Digestion and Lime Stabilization). Samples of raw wastewater, pre- and post-disinfected effluents, and biosolids were monitored for tetracycline resistant genes (tetW and tetO) and sulfonamide resistant gene (Sul-I) and tetracycline and sulfonamide resistant bacteria. ARGs and ARB concentrations in the final effluent were found to be in the range of ND(non-detectable)-2.33 × 10⁶ copies/100 mL and 5.00 × 10²-6.10 × 10⁵ CFU/100 mL respectively. Concentrations of ARGs (tetW and tetO) and 16s rRNA gene in the MBR effluent were observed to be 1-3 log less, compared to conventional treatment utilities. Significantly higher removals of ARGs and ARB were observed in the MBR facility (range of removal: 2.57-7.06 logs) compared to that in conventional treatment plants (range of removal: 2.37-4.56 logs) (p < 0.05). Disinfection (Chlorination and UV) processes did not contribute in significant reduction of ARGs and ARB (p > 0.05). In biosolids, ARGs and ARB concentrations were found to be in the range of 5.61 × 10⁶-4.32 × 10⁹ copies/g and 3.17 × 10⁴-1.85 × 10⁹ CFU/g, respectively. Significant differences (p < 0.05) were observed in concentrations of ARGs (except tetW) and ARB between the advanced biosolid treatment methods (i.e., anaerobic digestion and lime stabilization) and the conventional dewatering and gravity thickening methods.     

Degradation of phthalate esters in an activated sludge wastewater treatment plant

Efficient removal of phthalate esters (PE) in wastewater treatment plants (WWTP) is becoming an increasing priority in many countries. In this study, we examined the fate of dimethyl phthalate (DMP), dibutyl phthalate (DBP), butylbenzyl phthalate (BBP), and di-(2-ethylhexyl) phthalate (DEHP) in a full scale activated sludge WWTP with biological removal of nitrogen and phosphorus. The mean concentrations of DMP, DBP, BBP, and DEHP at the WWTP inlet were 1.9, 20.5, 37.9, and 71.9 μg/L, respectively. Less than 0.1%, 42%, 35%, and 96% of DMP, DBP, BBP, and DEHP was associated with suspended solids, respectively. The overall microbial degradation of DMP, DBP, BBP, and DEHP in the WWTP was estimated to be 93%, 91%, 90%, and 81%, respectively. Seven to nine percent of the incoming PE were recovered in the WWTP effluent. Factors affecting microbial degradation of DEHP in activated sludge were studied using [U-¹⁴C-ring] DEHP as tracer. First order rate coefficients for aerobic DEHP degradation were 1.0×10⁻², 1.4×10⁻², and 1.3×10⁻³ at 20, 32, and 43 °C, respectively. Aerobic degradation rates decreased dramatically under aerobic thermophilic conditions (<0.1×10⁻² h⁻¹ at 60 °C). The degradation rate under anoxic denitrifying conditions was 0.3×10⁻² h⁻¹, whereas the rate under alternating conditions (aerobic-anoxic) was 0.8×10⁻² h⁻¹. Aerobic DEHP degradation in activated sludge samples was stimulated 5-9 times by addition of a phthalate degrading bacterium. The phthalate degrading bacterium was isolated from activated sludge, and maintained a capacity for DEHP degradation while growing on vegetable oil. Collectively, the results of the study identified several controls of microbial PE degradation in activated sludge. These controls may be considered to enhance PE degradation in activated sludge WWTP with biological removal of nitrogen and phosphorus.     

Norovirus and FRNA bacteriophage determined by RT-qPCR and infectious FRNA bacteriophage in wastewater and oysters

Norovirus (NoV), the leading cause of adult non-bacterial gastroenteritis can be commonly detected in wastewater but the extent of NoV removal provided by wastewater treatment plants (WWTPs) is unclear. We monitored a newly commissioned WWTP with UV disinfection on a weekly basis over a six month period for NoV using RT-qPCR and for FRNA bacteriophage GA using both RT-qPCR (total concentration) and a plaque assay (infectious concentration). Mean concentrations of NoV GI and GII in influent wastewater were reduced by 0.25 and 0.41 log₁₀ genome copies 100 ml⁻¹, respectively by the WWTP. The mean concentration of total FRNA bacteriophage GA was reduced by 0.35 log genome copies 100 ml⁻¹ compared to a reduction of infectious FRNA bacteriophage GA of 2.13 log PFU 100 ml⁻¹. A significant difference between concentrations of infectious and total FRNA bacteriophage GA was observed in treated, but not in untreated wastewaters. We conclude that RT-qPCR in isolation underestimates the reduction of infectious virus during wastewater treatment. We further compared the concentrations of infectious virus in combined sewer overflow (CSO) and UV treated effluents using FRNA bacteriophage GA. A greater percentage (98%) of infectious virus is released in CSO discharges than UV treated effluent (44%). Following a CSO discharge, concentrations of NoV GII and infectious FRNA bacteriophage GA in oysters from less than the limit of detection to 3150 genome copies 100 g⁻¹ and 1050 PFU 100 g⁻¹ respectively.     

As(III) removal by hydrous titanium dioxide prepared from one-step hydrolysis of aqueous TiCl4 solution

Hydrous titanium dioxide (TiO₂·xH₂O) nanoparticles were synthesized by a low-cost one-step hydrolysis process with aqueous TiCl₄ solution. These TiO₂·xH₂O nanoparticles ranged from 3 to 8 nm and formed aggregates with a highly porous structure, resulting in a large surface area and easy removal capability from aqueous environment after the treatment. Their effectiveness on the removal of As(III) (arsenite) from water was investigated in both laboratory and natural water samples. The adsorption capacity on As(III) of these TiO₂·xH₂O nanoparticles reached over 83 mg/g at near neutral pH environment, and over 96 mg/g at pH 9.0. Testing with a As(III) contaminated natural lake water sample confirmed the effectiveness of these TiO₂·xH₂O nanoparticles in removing As(III) from natural water. The high adsorption capacity of the TiO₂·xH₂O nanoparticles is related to the high surface area, large pore volume, and the presence of high affinity surface hydroxyl groups.     

An introductory TEM study of Fe-nanominerals within coal fly ash

The investigation presented here was conducted during a wider experiment on the technical feasibility and environmental impacts of tire combustion in a Brazilian coal-fired power station. Nanometric-sized crystalline phases in fly ash were characterised using energy-dispersive X-ray spectrometer (EDS) and high-resolution transmission electron microscopy (HR-TEM) images. The nanoparticles, which register abundance peaks at 10 nm and 100 nm, include iron-rich oxide (e.g. hematite), Fe-sulphate (e.g., yavapaiite: KFe(SO₄)₂), and Fe-aluminumsilicate glass. Individual metalliferous nanoparticles have a heterogeneous microstructure in which elements such as iron, aluminum and silicon are not uniformly distributed. HR-TEM offers a powerful analytical technique in the study of fly ash nanoparticles, providing a better understanding of the detailed chemistry of this potentially strongly bioreactive component of atmospheric particulate matter.     

Effect of geosynthetic component characteristics on the potential for GCL internal erosion

Experiments quantifying GCL permittivity and the ultimate water head the GCLs can sustain before the initiation of internal erosion when underlain by a 50 mm angular to subangular gravel subgrade are conducted. The influence of different geotextiles over the subgrade, water heads, hydration periods before testing, masses per unit area of bentonite within the GCL, and ionic strengths of the solution (cation exchange) are considered. Test results show that GCL with the scrim-reinforced nonwoven geotextile over the subgrade has the best hydraulic performance against internal erosion, followed by the woven geotextile coated with a 110 g/m² polypropylene film. A woven or nonwoven is the least useful for preventing internal erosion, with the corresponding threshold water head initiating internal erosion >39 m for scrim-reinforced nonwoven, 21 m for lightly coated woven, 4–5 m for woven and nonwoven alone, respectively. Cation exchange, length of hydration, and mass per unit area of bentonite do not notably affect the threshold water head for the subgrade examined. Once internal erosion occurs, there is a 3-order of magnitude increase in permittivity. The practical implications are discussed.     

Assessing granular media filtration for the removal of chemical contaminants from wastewater

Granular media filtration was evaluated for the removal of a suite of chemical contaminants that can be found in wastewater. Laboratory- and pilot-scale sand and granular activated carbon (GAC) filters were trialled for their ability to remove atrazine, estrone (E1), 17α-ethynylestradiol (EE2), N-nitrosodimethylamine (NDMA), N-nitrosomorpholine (NMOR) and N-nitrosodiethylamine (NDEA). In general, sand filtration was ineffective in removing the contaminants from a tertiary treated wastewater, with the exception of E1 and EE2, where efficient removals were observed after approximately 150 d. Batch degradation experiments confirmed that the removal of E1 was through biological activity, with a pseudo-first-order degradation rate constant of 7.4 × 10⁻³ h⁻¹. GAC filtration was initially able to effectively remove all contaminants; although removals decreased over time due to competition with other organics present in the water. The only exception was atrazine where removal remained consistently high throughout the experiment. Previously unreported differences were observed in the adsorption of the three nitrosamines, with the ease of removal following the trend, NDEA > NMOR > NDMA, consistent with their hydrophobic character. In most instances the removals from the pilot-scale filters were generally in agreement with the laboratory-scale filter, suggesting that there is potential in using laboratory-scale filters as monitoring tools to evaluate the performance of pilot- and possibly full-scale sand and GAC filters at wastewater treatment plants.     

Efficiency of phenol biodegradation by planktonic Pseudomonas pseudoalcaligenes (a constructed wetland isolate) vs. root and gravel biofilm

In the last two decades, constructed wetland systems gained increasing interest in wastewater treatment and as such have been intensively studied around the world. While most of the studies showed excellent removal of various pollutants, the exact contribution, in kinetic terms, of its particular components (such as: root, gravel and water) combined with bacteria is almost nonexistent.In the present study, a phenol degrader bacterium identified as Pseudomonas pseudoalcaligenes was isolated from a constructed wetland, and used in an experimental set-up containing: plants and gravel. Phenol removal rate by planktonic and biofilm bacteria (on sterile Zea mays roots and gravel surfaces) was studied. Specific phenol removal rates revealed significant advantage of planktonic cells (1.04 × 10⁻⁹ mg phenol/CFU/h) compared to root and gravel biofilms: 4.59 × 10⁻¹¹-2.04 × 10⁻¹⁰ and 8.04 × 10⁻¹¹-4.39 × 10⁻¹⁰ (mg phenol/CFU/h), respectively.In batch cultures, phenol biodegradation kinetic parameters were determined by biomass growth rates and phenol removal as a function of time. Based on Haldane equation, kinetic constants such as μ_max = 1.15/h, K_s = 35.4 mg/L and K_i = 198.6 mg/L fit well phenol removal by P. pseudoalcaligenes.Although P. pseudoalcaligenes planktonic cells showed the highest phenol removal rate, in constructed wetland systems and especially in those with sub-surface flow, it is expected that surface associated microorganisms (biofilms) will provide a much higher contribution in phenol and other organics removal, due to greater bacterial biomass.Factors affecting the performance of planktonic vs. biofilm bacteria in sub-surface flow constructed wetlands are further discussed.     

Impact of natural organic matter and divalent cations on the stability of aqueous nanoparticles

The stability of nanoparticles in aquatic environment plays an important role in determining their environmental implication and potential risk to human health. This research studied the impact of natural organic matter (NOM) and divalent cations (Ca²⁺) on the stability of engineered metal oxide nanoparticles (e.g. ZnO, NiO, TiO₂, Fe₂O₃ and SiO₂). When nanoparticles were present in neutral water, a relatively weak electrolyte concentration (0.01 M KCl) could result in their aggregation; however, with the addition of 1 mg/L NOM, the negative surface charge of nanoparticles increased significantly and therefore their propensity to aggregate is reduced. 4 mg/L NOM stabilized most nanoparticles by producing −30 mV or higher zeta potentials. On the other hand, the negative charge that NOM imparted to nanoparticles could be neutralized by divalent cations (calcium ions). 0.04 M-0.06 M Ca²⁺ induced the aggregation of NOM-coated nanoparticles. It should be noted that among all the studied nanoparticles, SiO₂ exhibited the unique stability due to its low NOM adsorption capacity and small Hamaker constant. SiO₂ remained stable no matter whether the solution contained NOM or Ca²⁺.     

Magnetite and zero-valent iron nanoparticles for the remediation of uranium contaminated environmental water

The current work presents a comparative and site specific study for the application of zero-valent iron nanoparticles (nano-Fe⁰) and magnetite nanoparticles (nano-Fe₃O₄) for the removal of U from carbonate-rich environmental water taken from the Li?ava valley, Banat, Romania.Nanoparticles were introduced to the Li?ava water under surface and deep aquifer oxygen conditions, with a U^VI-only solution studied as a simple system comparator. Thebatch systems were analysed over an 84 day reaction period, during which the liquid and nanoparticulate solids were periodically sampled to determine chemical evolution of the solutions and particulates.Results indicated that U was removed by all nano-Fe⁰ systems to <10 μg L⁻¹ (>98% removal) within 2 h of reaction, below EPA and WHO specified drinking water regulations. Similar U concentrations were maintained until approximately 48 h. X-ray photoelectron spectroscopy analysis of the nanoparticulate solids confirmed partial chemical reduction of U^VI to U^IV concurrent with Fe oxidation. In contrast, nano-Fe₃O₄ failed to achieve >20% U removal from the Li?ava water. Whilst the outer surface of both the nano-Fe⁰ and nano-Fe₃O₄ was initially near-stoichiometric magnetite, the greater performance exhibited by nano-Fe⁰ is attributed to the presence of a Fe⁰ core for enhanced aqueous reactivity, sufficient to achieve near-total removal of aqueous U despite any competing reactions within the carbonate-rich Li?ava water.Over extended reaction periods (>1 week) the chemically simple U^VI-only solution treated using nano-Fe⁰ exhibited near-complete and maintained U removal. In contrast, appreciable U re-release was recorded for the Li?ava water solutions treated using nano-Fe⁰. This behaviour is attributed to the high stability of U in the presence of ligands (predominantly carbonate) within the Li?ava water, inducing preferential re-release to the aqueous phase during nano-Fe⁰ corrosion.The current study therefore provides clear evidence for the removal and immobilisation of U from environmental waters using Fe-based nanoparticles. As a contrast to previous experimental studies reporting impressive figures for U removal and retention from simple aqueous systems, the present work demonstrates both nanomaterials as ineffective on timescales >1 week. Consequently further research is required to develop nanomaterials that exhibit greater reactivity and extended retention of inorganic contaminants in chemically complex environmental waters.