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Abstract This study investigates the biofouling resistance of modified reverse osmosis (RO) feed spacers. Control spacers (made of polypropylene) were functionalized with a biocidal coating (silver), hydrophilic (SiO 2 nanoparticles) or superhydrophobic (TMPSi-TiO 2 nanoparticles) anti-adhesive coatings, or a hybrid hydrophilic-biocidal coating (graphene oxide). Performance was measured by adhesion assays, viability tests, and permeate flow decline in a bench scale RO system. The control spacers proved to be one of the better performing materials based on bacterial deposition and dynamic RO fouling experiments. The good anti-adhesive properties of the control can be explained by its near ideal surface free energy (SFE). The only surface modification that significantly reduced biofouling compared to the control was the biocidal silver coating, which outperformed the other spacers by all measured indicators. Therefore, future efforts to improve spacer materials for biofouling control should focus on engineering biocidal coatings, rather than anti-adhesive ones. Graphical abstract Image 1 Highlights • Control spacers exhibit strong anti-adhesive characteristics. • Surface free energy highly influences whether a material is anti-adhesive. • Biocidal coatings are a promising way to improve feed spacer performance. [ABSTRACT FROM AUTHOR]

Zinc oxide nanoparticles (ZnO NPs) have a wide range of applications in cosmetics, electrical, and optical industries. The wide range of applications of ZnO NPs, especially in personal care products, suggest they can reach major environmental matrices causing unforeseen effects. Recent literature has shown conflicting findings regarding the beneficial or detrimental effects of ZnO NPs towards terrestrial biota. In this review we carried out a comprehensive survey about beneficial, as well as detrimental aspects, of the ZnO NPs exposure toward various terrestrial plants. A careful scrutiny of the literature indicates that at low concentrations (about 50 mg/kg), ZnO NPs have beneficial effects on plants. Conversely, at concentrations above 500 mg/kg they may have detrimental effects, unless there is a deficiency of Zn in the growing medium. This review also remarks the critical role of the biotic and abiotic factors that may elevate or ameliorate the impact of ZnO NPs in terrestrial plants. [ABSTRACT FROM AUTHOR]

Bean ( Phaseolus vulgaris ) plants were grown for 45 days in soil amended with either uncoated (Z-COTE ® ) and coated (Z-COTE HP1 ® ) ZnO nanomaterials (NMs), bulk ZnO and ZnCl 2 , at 0–500 mg/kg. At harvest, growth parameters, chlorophyll, and essential elements were determined. None of the treatments affected germination and pod production, and only ZnCl 2 at 250 and 500 mg/kg reduced relative chlorophyll content by 34% and 46%, respectively. While Z-COTE ® did not produce phenotypic changes, Z-COTE HP1 ® , at all concentrations, increased root length (∼44%) and leaf length (∼13%) compared with control. Bulk ZnO reduced root length (53%) at 62.5 mg/kg and ZnCl 2 reduced leaf length (16%) at 125 mg/kg. Z-COTE ® , at 125 mg/kg, increased Zn by 203%, 139%, and 76% in nodules, stems, and leaves, respectively; while at the same concentration, Z-COTE HP1 ® increased Zn by 89%, 97%, and 103% in roots, stems, and leaves, respectively. At 125 mg/kg, Z-COTE HP1 ® increased root S (65%) and Mg (65%), while Z-COTE ® increased stem B (122%) and Mn (73%). Bulk ZnO and ZnCl 2 imposed more toxicity to kidney bean than the NMs, since they reduced root and leaf elongation, respectively, and the concentration of several essential elements in tissues. [ABSTRACT FROM AUTHOR]

Little is known about the effects of surface coating on the interaction of engineered nanoparticles (ENPs) with plants. In this study, basil ( Ocimum basilicum ) was cultivated for 65 days in soil amended with unmodified, hydrophobic (coated with aluminum oxide and dimethicone), and hydrophilic (coated with aluminum oxide and glycerol) titanium dioxide nanoparticles (nano-TiO 2 ) at 125, 250, 500, and 750 mg nano-TiO 2 kg −1 soil. ICP-OES/MS, SPAD meter, and UV/Vis spectrometry were used to determine Ti and essential elements in tissues, relative chlorophyll content, carbohydrates, and antioxidant response, respectively. Compared with control, hydrophobic and hydrophilic nano-TiO 2 significantly reduced seed germination by 41% and 59%, respectively, while unmodified and hydrophobic nano-TiO 2 significantly decreased shoot biomass by 31% and 37%, respectively ( p ≤ 0.05). Roots exposed to hydrophobic particles at 750 mg kg −1 had 87% and 40% more Ti than the pristine and hydrophilic nano-TiO 2 ; however, no differences were found in shoots. The three types of particles affected the homeostasis of essential elements: at 500 mg kg − 1 , unmodified particles increased Cu (104%) and Fe (90%); hydrophilic increased Fe (90%); while hydrophobic increased Mn (339%) but reduced Ca (71%), Cu (58%), and P (40%). However, only hydrophobic particles significantly reduced root elongation by 53%. Unmodified, hydrophobic, and hydrophilic particles significantly reduced total sugar by 39%, 38%, and 66%, respectively, compared with control. Moreover, unmodified particles significantly decreased reducing sugar (34%), while hydrophobic particles significantly reduced starch (35%). Although the three particles affected basil plants, coated particles impacted the most its nutritional quality, since they altered more essential elements, starch, and reducing sugars. [ABSTRACT FROM AUTHOR]

Little is known about the effects of surface modification on the interaction of nanoparticles (NPs) with plants. Tomato ( Solanum lycopersicum L.) plants were cultivated in potting soil amended with bare and citric acid coated nanoceria (nCeO 2, nCeO 2 +CA), cerium acetate (CeAc), bulk cerium oxide (bCeO 2 ) and citric acid (CA) at 0–500 mg kg −1 . Fruits were collected year-round until the harvesting time (210 days). Results showed that nCeO 2 +CA at 62.5, 250 and 500 mg kg −1 reduced dry weight by 54, 57, and 64% and total sugar by 84, 78, and 81%. At 62.5, 125, and 500 mg kg −1 nCeO 2 +CA decreased reducing sugar by 63, 75, and 52%, respectively and at 125 mg kg −1 reduced starch by 78%, compared to control. The bCeO 2 at 250 and 500 mg kg −1 , increased reducing sugar by 67 and 58%. In addition, when compared to controls, nCeO 2 at 500 mg kg −1 reduced B (28%), Fe (78%), Mn (33%), and Ca (59%). At 125 mg kg −1 decreased Al by 24%; while nCeO 2 +CA at 125 and 500 mg kg −1 increased B by 33%. On the other hand, bCeO 2 at 62.5 mg kg −1 increased Ca (267%), but at 250 mg kg −1 reduced Cu (52%), Mn (33%), and Mg (58%). Fruit macromolecules were mainly affected by nCeO 2 +CA, while nutritional elements by nCeO 2 ; however, all Ce treatments altered, in some way, the nutritional quality of tomato fruit. To our knowledge, this is the first study comparing effects of uncoated and coated nanoceria on tomato fruit quality. [ABSTRACT FROM AUTHOR]

[Display omitted] Bioaccumulation is a key factor in understanding the potential ecotoxicity of substances. While there are well-developed models and methods to evaluate bioaccumulation of dissolved organic and inorganic substances, it is substantially more challenging to assess bioaccumulation of particulate contaminants such as engineered carbon nanomaterials (CNMs; carbon nanotubes (CNTs), graphene family nanomaterials (GFNs), and fullerenes) and nanoplastics. In this study, the methods used to evaluate bioaccumulation of different CNMs and nanoplastics are critically reviewed. In plant studies, uptake of CNMs and nanoplastics into the roots and stems was observed. For multicellular organisms other than plants, absorbance across epithelial surfaces was typically limited. Biomagnification was not observed for CNTs and GFNs but were observed for nanoplastics in some studies. However, the reported absorption in many nanoplastic studies may be a consequence of an experimental artifact, namely release of the fluorescent probe from the plastic particles and subsequent uptake. We identify that additional work is needed to develop analytical methods to provide robust, orthogonal methods that can measure unlabeled (e.g., without isotopic or fluorescent labels) CNMs and nanoplastics. [ABSTRACT FROM AUTHOR]

Little is known about the physiological and biochemical responses of plants exposed to surface modified nanomaterials. In this study, tomato ( Solanum lycopersicum L.) plants were cultivated for 210 days in potting soil amended with uncoated and citric acid coated cerium oxide nanoparticles (nCeO 2 , CA + nCeO 2 ) bulk cerium oxide (bCeO 2 ), and cerium acetate (CeAc). Millipore water (MPW), and citric acid (CA) were used as controls. Physiological and biochemical parameters were measured. At 500 mg/kg, both the uncoated and CA + nCeO 2 increased shoot length by ~ 9 and ~ 13%, respectively, while bCeO 2 and CeAc decreased shoot length by ~ 48 and ~ 26%, respectively, compared with MPW ( p ≤ 0.05). Total chlorophyll, chlo- a , and chlo- b were significantly increased by CA + nCeO 2 at 250 mg/kg, but reduced by bCeO 2 at 62.5 mg/kg, compared with MPW. At 250 and 500 mg/kg, nCeO 2 increased Ce in roots by 10 and 7 times, compared to CA + nCeO 2 , but none of the treatments affected the Ce concentration in above ground tissues. Neither nCeO 2 nor CA + nCeO 2 affected the homeostasis of nutrient elements in roots, stems, and leaves or catalase and ascorbate peroxidase in leaves. CeAc at 62.5 and 125 mg/kg increased B (81%) and Fe (174%) in roots, while at 250 and 500 mg/kg, increased Ca in stems (84% and 86%, respectively). On the other hand, bCeO 2 at 62.5 increased Zn (152%) but reduced P (80%) in stems. Only nCeO 2 at 62.5 mg/kg produced higher total number of tomatoes, compared with control and the rest of the treatments. The surface coating reduced Ce uptake by roots but did not affect its translocation to the aboveground organs. In addition, there was no clear effect of surface coating on fruit production. To our knowledge, this is the first study comparing the effects of coated and uncoated nCeO 2 on tomato plants. [ABSTRACT FROM AUTHOR]

When released in the environment, microplastics undergo surface weathering due to mechanical abrasion and ultraviolet exposure. In this study, the adsorption of two model contaminants, phenanthrene and methylene blue, by weathered high density polyethylene (HDPE) and polypropylene (PPE) was evaluated to understand how the microplastics' aging influences contaminant adsorption. Microplastics were aged through an accelerated weathering process using ultraviolet exposure with or without hydrogen peroxide. Adsorption isotherms were conducted for both contaminants on pristine and aged microplastics. The adsorption of organic contaminants was higher on aged microplastics than on pristine ones, with methylene blue having the highest affinity increase with aging at 4.7-fold and phenanthrene having a 1.9-fold increase compared to the pristine particles. To understand the mechanisms involved with higher adsorption of contaminants by aged microplastics, changes in the specific surface area and surface chemistry of aged microplastics were characterized by Fourier Transform Infrared Spectroscopy, X-ray Photoelectron Spectroscopy, zeta potential, X-ray tomography, and Brunauer–Emmett–Teller krypton adsorption analyses. The results of this study show that oxidation of microplastics can enhance the adsorption of organic contaminants, which may increase their role as vectors of contaminants in the aquatic food chain. [Display omitted] • An experimental approach to mimic environmental microplastics was developed. • Microplastics were aged with ultraviolet light with or without hydrogen peroxide. • Aging was expressed quantitatively through carbonyl indices and percentage oxygen. • Adsorption of phenanthrene and methylene blue was higher on aged microplastics. • Methylene blue showed greatest increase in adsorption after microplastics aging. [ABSTRACT FROM AUTHOR]

In photosynthetic microorganisms, the toxicity of carbon nanomaterials (CNMs) is typically characterized by a decrease in growth, viability, photosynthesis, as well as the induction of oxidative stress. However, it is currently unclear how the shape of the carbon structure in CNMs, such as in the 1-dimensional carbon nanotubes (CNTs) compared to the two-dimensional graphene oxide (GO), affects the way they interact with cells. In this study, the effects of GO and oxidized multi-walled CNTs were compared in the cyanobacterium Microcystis aeruginosa to determine the similarities or differences in how the two CNMs interact with and induce toxicity to cyanobacteria. Using change in Chlorophyll a concentrations, the effective concentrations inducing 50% inhibition (EC 50) at 96 h are found to be 11.1 μg/mL and 7.38 μg/mL for GO and CNTs, respectively. The EC 50 of the two CNMs were not found to be statistically different. Changes in fluorescein diacetate and 2′,7′-dichlorodihydrofluorescein diacetate fluorescence, measured at the EC 50 concentrations, suggest a decrease in esterase enzyme activity but no oxidative stress. Scanning and transmission electron microscopy imaging did not show extensive membrane damage in cells exposed to GO or CNTs. Altogether, the decrease in metabolic activity and photosynthetic activity without oxidative stress or membrane damage support the hypothesis that both GO and CNTs induced indirect toxicity through physical mechanisms associated with light shading and cell aggregation. This indirect toxicity explains why the intrinsic differences in shape, size, and surface properties between CNTs and GO did not result in differences in how they induce toxicity to cyanobacteria. Image 1 • Carbon nanotubes and graphene oxide interact differently with cyanobacterial cells. • Both carbon nanomaterials inhibit growth, photosynthesis, and esterase activity. • No oxidative stress or membrane damage was observed for both carbon nanomaterials. • Both carbon nanomaterials induced similar toxicity to Microcystis aeruginosa. [ABSTRACT FROM AUTHOR]

Reverse Osmosis (RO) desalination is an important step of wastewater reuse as it can remove salts and trace contaminants. However, RO also generates high salinity brines that need to be dealt with. Membrane distillation (MD), a process largely unaffected by salinity, provides a way to treat desalination brines up to high water recovery and has been proposed as a solution for RO brine management. However, pore wetting of membranes in MD is one of the major hurdles that prevents its implementation in wastewater treatment systems, as amphiphilic organic compounds present in wastewater can lead to pore wetting and loss of selectivity over time. The objective of this study was to identify a pre-treatment strategy to prevent wetting in MD treatment of municipal wastewater RO brines. We compared three pre-treatments with different separation or removal mechanisms: foam fractionation, advanced oxidation, and ultrafiltration. We evaluated membrane wetting by measuring the change in conductivity in the distillate and identified the most effective pre-treatment to prevent wetting in MD. The results show that wetting is prevented by pre-treating the brine with foam fractionation. The effectiveness of foam fractionation as a wetting control strategy was confirmed for a high wetting propensity synthetic water using sodium dodecyl sulfate as a model wetting compound. Finally, the effect of the pre-treatments on the desalination brine was evaluated to understand the nature of the compounds removed by each treatment. The results of this study will help implement MD as a treatment process for desalination brines in municipal wastewater reuse systems. Image 1 • Desalination brine from wastewater reuse causes wetting in membrane distillation. • Foam fractionation is an effective pre-treatment to mitigate wetting. • Pre-treatment of the RO brine increases water recovery and distillate quality. [ABSTRACT FROM AUTHOR]

Portable water purification devices are needed to provide safe drinking water in rural communities, developing communities with low quality centralized water distribution, and military or recreational applications. Filtration, ultraviolet light, or chemical additives provide a spectrum of alternatives to remove pathogens from water. For the first time, we design, fabricate and demonstrate the performance of a small portable photoelectric point-of-use device, and document its performance on pathogen inactivation. The device utilizes a commercial teacup from which TiO 2 nanotube photoanodes were produced in-situ and, with a small rechargeable battery powered 365 nm light emitting diode, was able to achieve 5-log inactivation of Escherichia coli in 10 s and 2.6-log of Legionella in 60 s of treatment in model water samples. Treatment of natural water achieved a 1-log bacteria inactivation after 30 s due to matrix effects. The e lectro-photocatalytic d isinfection r eactor i n a k up (e-DRINK) can provide a feasible and affordable solution to ensure access to clean water. More broadly, this work demonstrates the potential for illumination to improve the efficiency of electrocatalytic surfaces. Unlabelled Image • The e-DRINK was designed as a point-of-use device for water disinfection. • Photoelectrocatalytic treatment provides a 5-log removal of E. coli in 10 s. • Photoelectrocatalytic treatment provides a 2.6-log removal of Legionella in 60 s. • Photoelectrocatalysis overperforms photolysis, photocatalysis and electrocatalysis. • Photoelectrocatalytic treatment provides a 1-log removal of E. coli in 30 s in natural waters. [ABSTRACT FROM AUTHOR]

The response of plants to copper oxide nanoparticles (nano-CuO) in presence of exogenous phytohormones is unknown. In this study, green pea ( Pisum sativum ) plants were cultivated to full maturity in soil amended with nano-CuO (10–100 nm, 74.3% Cu), bulk-CuO (bCuO, 100–10,000 nm, 79.7% Cu), and CuCl 2 at 50 and 100 mg/kg and indole-3-acetic acid (IAA) at 10 and 100 μM. Results showed that IAA at 10 and 100 μM, averaged over all Cu treatments, reduced the number of plants by ~ 23% and ~ 34%, respectively. IAA at 10 μM, nano-CuO at 50 mg/kg, b-CuO at 50 mg/kg, and CuCl 2 at 100 mg/kg reduced pod biomass by about 50%. Although some combinations of IAA, mainly at 100 μM, with the Cu compounds altered nutrient accumulation in tissues, none of them affected pod elements. Conversely, without IAA, nano-CuO at 50 mg/kg, increased pod Fe and Ni by 258% and 325%, respectively, while bCuO at 100 mg/kg increased pod Ni by 275%, compared with control. With IAA at 10 μM, nano-CuO (100 mg/kg) and bCuO (50 mg/kg) increased stem Cu by ~ 84% and ~ 78%. When IAA increased to 100 μM, nano-CuO and bCuO reduced stem Ca by 32% and 37%, and Mg by ~ 35%. Results suggest that both the nano-CuO and bCuO could improve the nutritional quality of pea pods, while exogenous IAA combined with Cu-based compounds could impact green pea production since these treatments reduced the number of plants and pod biomass. [ABSTRACT FROM AUTHOR]

Soil organic matter plays a major role in determining the fate of the engineered nanomaterials (ENMs) in the soil matrix and effects on the residing plants. In this study, kidney bean plants were grown in soils varying in organic matter content and amended with 0–500 mg/kg cerium oxide nanoparticles (nano-CeO 2 ) under greenhouse condition. After 52 days of exposure, cerium accumulation in tissues, plant growth and physiological parameters including photosynthetic pigments (chlorophylls and carotenoids), net photosynthesis rate, transpiration rate, and stomatal conductance were recorded. Additionally, catalase and ascorbate peroxidase activities were measured to evaluate oxidative stress in the tissues. The translocation factor of cerium in the nano-CeO 2 exposed plants grown in organic matter enriched soil (OMES) was twice as the plants grown in low organic matter soil (LOMS). Although the leaf cover area increased by 65–111% with increasing nano-CeO 2 concentration in LOMS, the effect on the physiological processes were inconsequential. In OMES leaves, exposure to 62.5–250 mg/kg nano-CeO 2 led to an enhancement in the transpiration rate and stomatal conductance, but to a simultaneous decrease in carotenoid contents by 25–28%. Chlorophyll a in the OMES leaves also decreased by 27 and 18% on exposure to 125 and 250 mg/kg nano-CeO 2 . In addition, catalase activity increased in LOMS stems, and ascorbate peroxidase increased in OMES leaves of nano-CeO 2 exposed plants, with respect to control. Thus, this study provides clear evidence that the properties of the complex soil matrix play decisive roles in determining the fate, bioavailability, and biological transport of ENMs in the environment. [ABSTRACT FROM AUTHOR]

Abstract: Background: Although much has been written about bacteremia, evidence of the clinical diagnostic accuracy of bacteremia sources in the absence of microbiological results and the impact of diagnostic accuracy on mortality is scarce. Methods: This is a retrospective study of bacteremia episodes over a 2-year period at a general hospital in Madrid. Congruence analyses between clinically presumed and definite sources, acquisition, causative organism, empirical treatment and progression to death were performed. Results: The study included 323 bacteremia episodes. Clinicians' diagnostic accuracy was higher for gastrointestinal (88.8%; 95% CI: 79%–84%), respiratory (93.9%; 95% CI: 79%–99%) and urinary tract sources (83.6%; 95% CI: 75%–89%) and lower for skin and soft tissues (77.2%; 95% CI: 54%–92%) and, notably, intravascular sources (56%; 95% CI: 39%–71%). Overall, a non-significant (3.45%; 95% CI: −0.6%–13.5%, p=0.47) increase in mortality was observed in the incorrectly suspected bacteremia source group. Mortality related to a definitive source was significantly higher when an intravascular origin was not suspected, resulting in a 26% increase in mortality (95% CI: 1%–52%, p=0.03). Differences in mortality related to inaccurate source assumptions were non-significant when the definitive bacteremia sources were gastrointestinal, urinary, respiratory, skin and soft tissues or unknown. Mortality in the group receiving appropriate empirical antimicrobial treatment was 10.6% compared with 19.7% mortality in the group receiving inappropriate empirical antimicrobial treatment (OR 2; 95% CI: 1.01–4.25). Conclusions: The diagnostic accuracy of bacteremia sources is high in all but intravascular sources. A non-suspected intravascular source and inappropriate empirical treatment are related to a higher mortality. [Copyright &y& Elsevier]

• Graphene nanofillers improve the durability of thermoplastic polyurethane (TPU). • An order of magnitude less UV weathering (dry and wet) of TPU occurs with graphene. • Humid UV conditions lead to removal of more polymer matrix in the nanocomposites. • Graphene particles accumulate at the degraded nanocomposite surface. • Graphene release occurs under humid UV conditions with small mechanical forces. The ultraviolet (UV)-induced degradation of graphene/polymer nanocomposites was investigated in this study. Specifically, the effect of few-layer graphene nanofillers on the degradation of a thermoplastic polyurethane (TPU) and the release potential of graphene from the degraded nanocomposite surfaces were assessed. Graphene/TPU (G/TPU) nanocomposites and neat TPU were UV-exposed under both dry and humid conditions in the NIST SPHERE, a precisely controlled, high intensity UV-weathering device. Neat TPU and G/TPU were characterized over the time course of UV exposure using color measurements and infrared spectroscopy, for appearance and chemical changes, respectively. Changes in thickness and surface morphology were obtained with scanning electron microscopy. A new fluorescence quenching measurement approach was developed to identify graphene sheets at the nanocomposite surface, which was supported by contact angle measurements. The potential for graphene release from the nanocomposite surface was evaluated using a tape-lift method followed by microscopy of any particles present on the tape. The findings suggest that graphene improves the service life of TPU with respect to UV exposure, but that graphene becomes exposed at the nanocomposite surface over time, which may potentially lead to its release when exposed to small mechanical forces or upon contact with other materials. Image, graphical abstract [ABSTRACT FROM AUTHOR]