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Moringa oleifera (MO) seed is a natural plant with active bio-coagulate compounds that can be used for water clarification since it reduces the use of chemical-based coagulants. This study aims to evaluate the impact of Moringa oleifera (MO) seeds and MO seeds with a reduced amount of oil as coagulants in conventional water treatment to remove cyanobacteria from different natural surface waters. Tests were performed for waters with low (5–10 NTU) and high (30–60 NTU) initial turbidity with and without Microcystis aeruginosa cells and for MO integral powder, MO oil-extracted with ethanol and with a pressurized technique, and MO extracted with NaCl. The results show that MO oil-extraction is not necessary when using MO seeds as a coagulant in coagulation/flocculation/sedimentation (CF/S). Chlorophyll a and turbidity removals were up to 85% for high-turbidity waters, with 50 mg·L −1 MO obtained, for MO integral powder and for all of the MO extraction methods used. Therefore, for these waters, integral powder (without any extraction) can be used. For low-turbidity waters and using a 1 M saline extraction of the active coagulant compound, chlorophyll a and turbidity removals were approximately 60%. It was also demonstrated that MO is capable of removing some of the organic matter present in water, namely, aromatic organic matter, between 40 and 50% when using MO extracted with NaCl. However, dissolved organic matter results showed an increase independent of the type of MO extraction used. [ABSTRACT FROM AUTHOR]

Nanoparticles, namely titanium dioxide (TiO 2 ), are emerging contaminants widely used to commercial and industrial applications, are a potential hazard and can cause damage to environment and human health due to their toxicity. Therefore, their removal from the water is urgent to minimize or eliminate the adverse environmental and human effects. This work, investigates the efficiency of conventional coagulation/flocculation/sedimentation (C/F/S) from drinking water treatment to remove TiO 2 nanoparticles (NPs) from surface waters, and pretends to understand if the removal of TiO 2 NPs affects the ability of C/F/S to remove natural organic matter (NOM) and turbidity, and consequently affects the quality of the treated water. Results show that TiO 2 NPs removal is high (>90%) for all the waters studied (hydrophobic and hydrophilic waters) and the treated water quality is not compromised (turbidity, Ti and Al concentrations, pH and conductivity are below the national and international guidelines). In addition, TiO 2 initial concentrations, ranging between 0.2 and 10 mg/L, have not a significant impact on NPs removal by C/F/S. Therefore, the widely used polyaluminium based coagulants are effective in the removal of TiO 2 NPs by conventional C/F/S treatment, but removal is strongly influenced by the water characteristics. Hydrophobic waters need a higher coagulant dose than hydrophilic waters to achieve the same TiO 2 NPs removals, as well as water with higher UV 254nm values. The principal mechanism involved in TiO 2 NPs removal is charge neutralisation. [ABSTRACT FROM AUTHOR]

A new [O 2 N 2 N′ 2 ] 1,4,8,11-tetraazacyclotetradecane-based bis(phenol) chelate, H 2 ( Me2 ArO) 2 Me 2 -cyclam ( 2 ), containing methyl groups in the phenolate rings, has been synthesized and fully characterized. The studies of the coordination chemistry of the hexadentate dianionic ligands, ( R2 ArO) 2 Me 2 -cyclam 2− (R = t Bu, Me), with [YbI 2 (thf) 2.5 ] are reported. The reaction of K 2 ( tBu2 ArO) 2 Me 2 -cyclam with [YbI 2 (thf) 2.5 ] in 1:1 ratio in thf led to the formation of a divalent ytterbium complex that is highly unstable and propitious to the formation of Yb(III) species, while the metathesis reaction of the less bulky ligand ( Me2 ArO) 2 Me 2 -cyclam 2− with [YbI 2 (thf) 2.5 ] showed a preference for the stabilization of polynuclear divalent ytterbium complexes. The reaction of the potassium salt of this ligand, K 2 ( Me2 ArO)Me 2 -cyclam, with 1.5 and 2 equiv. of [YbI 2 (thf) 2.5 ] in thf led to formation of [Yb 3 (μ-{( Me2 ArO) 2 Me 2 -cyclam}) 2 I]I ( 4 ) and [Yb 2 (μ-{( Me2 ArO) 2 Me 2 -cyclam})I 2 (thf) 2 ] ( 5 ), respectively. The trimer ( 4 ) and dimer ( 5 ) were characterized by elemental analysis, UV–Vis and NMR spectroscopy and single-crystal X-ray diffraction. These are the first examples of ytterbium(II) complexes incorporating bis(phenolate) cyclam ligands. [ABSTRACT FROM AUTHOR]

Environmental health hazards of Quantum Dots (QDs) are of emergent concern, but limited data is available about their toxicokinetics (TK) and tissue distribution in marine bivalves. This study investigated the QDs behavior in seawater, their TK and tissue distribution in Mytilus galloprovincialis, in comparison with soluble Cd. Mussels were exposed to CdTe QDs and soluble Cd for 21 days at 10 μgCd L −1 followed by a 50 days depuration. TK of QDs in mussels is related to the homo-aggregate uptake, surface charge, aggregation and precipitation as key factors. There were tissue- and time-dependent differences in the TK of both Cd forms, and soluble Cd is the most bioavailable form. Digestive gland is a preferential site for QDs storage and both Cd forms are not eliminated by mussels (t 1/2 >50 days). Results indicate that the TK model of CdTe QDs in marine mussels is distinct from their soluble counterparts. [ABSTRACT FROM AUTHOR]

Abstract: Toxic cyanotoxins such as microcystins represent a human health risk in water bodies. Nanofiltration is an effective technology to remove these micro-contaminants from drinking water. However, long-term operational sustainability is necessary because of decreases in membrane fluxes over time and increasing operation costs. The rejection of natural organic matter (NOM) is a key issue regarding membrane fouling and flux decline, and is also of great importance in the water industry due to its relationship with public health. Therefore, this study aimed to analyse the effect of microcystins and NOM properties on membrane fouling and to understand the fouling mechanisms, using a series of experiments with different water types. Results showed that nanofiltration was capable of reducing low molecular weight NOM fractions from water and that these fractions were responsible for flux decline and membrane fouling. The adsorption of NOM onto the membrane surface was reduced in the presence of microcystins due to the hydrophobic character of microcystins, which are the first to be adsorbed on the membrane surface. Microcystins contributed to the rejection of smaller natural organic fractions by blocking the membrane pores and reducing NOM adsorption onto the membrane pores. [Copyright &y& Elsevier]

The influence of the fuel (glycine, urea, citric acid and sucrose) and calcination temperature used to obtain calcium aluminate in the mayenite phase assisted by solution combustion synthesis (SCS) is the central point of this work. Thermal gravimetric analysis helps to establish the calcination temperatures used (1100, 1200 and 1300 °C). Using the X-ray diffraction technique (XRD) and complementary analyses, such as Raman spectroscopy, the specific surface area and laser granulometry, it was possible to elucidate the behavior and relationship of the fuel and heat treatment on the phase formation, crystallite size and powder crystallinity. Glycine showed better performance than other fuels, with the lowest calcination temperature, obtaining pure mayenite with nanometric crystallite size in all calcination ranges. Thus, it was observed that the type of fuel has an influence on obtaining pure mayenite, as well as the calcination temperature, and glycine reveals the best performance. [ABSTRACT FROM AUTHOR]

Abstract: Dissolved air flotation (DAF) performance with two different naturally occurring cyanobacterial morphologies was investigated with respect to the biomass removal efficiency, the toxin release to water and the coagulant demand by different water background natural organic matter (NOM). Coagulation (C)/Flocculation (F)/DAF bench-scale experiments (2 min coagulation at 380 s−1 with polyaluminium chloride (0.5–4 mg/L Al2O3, the dose depending on the water NOM content); 8 min flocculation at 70 s−1; 8 min DAF with 5 bar relative pressure and 8% pressurised recycle) were performed with single cells of Microcystis aeruginosa and Planktothrix rubescens filaments spiked in synthetic waters with different NOM contents (hydrophobic vs. hydrophilic NOM; moderate (2–3 mgC/L) vs. moderate-high concentration (ca. 6 mgC/L)). For both morphologies, the results show no apparent cyanobacterial damage (since the water quality did not degrade in dissolved microcystins and the removal of intracellular microcystins matched the removal of chlorophyll a) and high biomass removal efficiencies (93–99% for cells and 92–98% for filaments) provided optimal coagulant dose for chlorophyll a removal was ensured. Charge neutralisation by the polyaluminium chloride was the main coagulation mechanism of the M. aeruginosa cells and most likely also of the P. rubescens filaments. The specific coagulant demand was severely affected by NOM hydrophobicity, hydrophobic NOM (with a specific UV254nm absorbance, SUVA, above 4 L/(m mgC)) requiring ca. the triple of hydrophilic NOM (SUVA below 3 L/(m mgC)), i.e. 0.7 vs. 0.2–0.3 mg Al2O3/mg DOC. [Copyright &y& Elsevier]

Nanoplastics (NP) (1–100 nm) are a growing global concern, and their adverse effects in marine organisms are still scarce. This study evaluated the effects of polystyrene nanoplastics (10 μg/L; 50 nm nPS) in the marine mussel Mytilus galloprovincialis after a 21 – day exposure. The hydrodynamic diameter and zeta potential of nPS were analysed, over time, in seawater and ultrapure water. A multibiomarker approach (genotoxicity (the comet assay) was assessed in mussel haemocytes, and the antioxidant enzymes (superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx)), biotransformation enzyme (glutathione – S – transferase (GST)), and oxidative damage (LPO)) was assessed in gills and digestive glands to evaluate the toxicity of nPS towards mussels. In seawater, aggregation of nPS is favoured and consequently the hydrodynamic diameter increases. Genotoxicity was highly noticeable in mussels exposed to nPS, presenting a higher % tail DNA when compared to controls. Antioxidant enzymes are overwhelmed after nPS exposure, leading to oxidative damage in both tissues. Results showed that mussel tissues are incapable of dealing with the effects that this emerging stressor pursues towards the organism. The Integrated Biomarker Response index, used to summarise the biomarkers analysed into one index, shows that nPS toxicity towards mussels are both tissue and time dependent, being that gills are the tissue most compromised. [Display omitted] • Polystyrene nanoplastics aggregation/agglomeration is favoured in seawater. • Genotoxicity occurs in mussel haemolymph after NPs exposure. • NPs toxicity is tissue and time dependent. • Gills are the predominate tissue affected by nanoplastic toxicity. [ABSTRACT FROM AUTHOR]

The emergence of nanotechnologically-enabled materials, compounds or products inevitably leads to engineered nanoparticles (ENPs) released into surface waters. ENPs have already been detected in wastewater streams, drinking water sources and even in tap water at concentrations in the ng/L and μg/L range, making the latter a potential route for humans. The presence of ENPs in raw waters raises concerns over the possibility that ENPs might pose a hazard to the quality and security of drinking water and whether drinking water treatment plants (DWTPs) are prepared to handle this problem. Therefore, it is essential to critically evaluate if ENPs can be effectively removed through water treatment processes to control environmental and human health risks associated with their release. This review includes a summary of the available information on production, presence, potential hazards to human health and environment, and release and behaviour of metal-based ENPs in surface waters and drinking water. In addition, the most extensively studied water treatment processes to remove metal-based ENPs, specifically conventional and advanced processes, are discussed and highlighted in detail. Furthermore, this work identifies the research gaps regarding ENPs removal in DWTPs and discusses future aspects of ENPs in water treatment. Unlabelled Image • Engineered nanoparticles (ENP) have been detected in drinking water sources. • The unique ENP properties represent a potential threat to human health. • ENP properties hamper their effective removal increasing the risk to human health. • Conventional/advanced water treatments must be adjusted to effectively remove ENP. • Optimised drinking water treatments are a barrier for ENP. [ABSTRACT FROM AUTHOR]

Green technologies are environmentally friendly operations that limit the negative impacts of traditional industrial activities and can contribute to solving the challenge of sustainable water management. This work aims to develop a green water treatment sequence using a natural coagulant ( Moringa oleifera ) and a natural activated carbon (vegetable coconut palm) to remove Microcystis aeruginosa and natural organic matter in an integrated process. The proposed sequence, coagulation/flocculation/dissolved air flotation and activated carbon, is an eco-friendly and innovative option for water treatment managers, since it includes environmentally friendly products for the contaminant removal from water, replacing the traditional inorganic/synthetic coagulants and adsorbents. Results demonstrated that waters with concentrations as high as 150–200 μg/L of chlorophyll a and natural organic matter between 5 and 16 mg C/L presented removals higher than 80% for turbidity and chlorophyll a , 70–80% for dissolved organic matter and 80–90% for UV 254nm . Moringa oleifera natural coagulant removed almost 80% of Microcystis aeruginosa cells in coagulation/flocculation/dissolved air flotation processes. The coconut palm activated carbon showed a high capacity to adsorb DOC from water with a maximum adsorbed capacity of 51.8 mg/g at equilibrium. The values obtained in treated water for the parameters measured are very encouraging, so this innovative integrated sequence may be used for improving water quality, benefiting human health and wellbeing. [ABSTRACT FROM AUTHOR]

The increasing production and application of engineered nanomaterials (ENMs) in consumer products over the past decade will inevitably lead to their release into aquatic systems and thereby cause the exposure to aquatic organisms, resulting in growing environmental and human health concern. Since bivalves are widely used in the monitoring of aquatic pollution, the aim of this review was to compile and analyse data concerning the ecotoxicity of ENMs using bivalve molluscs. The state of the art regarding the experimental approach, characterization, behaviour, fate, bioaccumulation, tissue and subcellular distribution and mechanisms of toxicity of ENMs in marine and freshwater bivalve molluscs is summarized to achieve a new insight into the mode of action of these nanoparticles in invertebrate organisms. This review shows that the studies about the toxic effects of ENMs in bivalves were conducted mainly with seawater species compared to freshwater ones and that the genus Mytilus is the main taxa used as a model system. There is no standardization of experimental approaches for toxicity testing and reviewed data indicate the need to develop standard protocols for ENMs ecotoxicological testing. In general, the main organ for ENM accumulation is the digestive gland and their cellular fate differs according to nano-specific properties, experimental conditions and bivalve species. Endosomal-lysosomal system and mitochondria are the major cellular targets of ENMs. Metal based ENMs mode of action is related mainly to the dissolution and/or release of the chemical component of the particle inducing immunotoxicity, oxidative stress and cellular injury to proteins, membrane and DNA damage. This review indicates that the aquatic environment is the potential ultimate fate for ENMs and confirms that bivalve molluscs are key model species for monitoring aquatic pollution by ENMs. [ABSTRACT FROM AUTHOR]

The generation of energy by thermoelectric plants powered by biomass in Brazil has grown by ∼3% in the last three years. In 2016, 8.8% of the electric energy in Brazil was generated using biomass as an input. However, the generation of residues and the possibility of reapproaching have motivated the planning and uses of electrochemical processes to evaluate the obtained gases (mainly hydrogen and carbon monoxide) as clean energy sources. Although thermochemical processes using biomass as an energy source already exist, few reports regarding the study of this process through electrolysis are available. Herein, we describe a water electrolysis process using sugarcane bagasse, rice husk, and malt bagasse as biomass residues to obtain gases with potential uses as clean energy sources and analyze the mass concentration influences on the behavior of the electrochemical solution. Tafel and cyclic voltammetry analyzes showed a tendency to decrease the kinetics and current of the system with the increase of the biomass residue concentration in the solution. In contrast, sugarcane bagasse concentrations of 0.1%–1% increase the current. The faradaic efficiency and partial current density analysis confirm the results obtained from cyclic voltammetry for hydrogen production, with less faradaic efficiency for hydrogen and reduced current values in the system when the biomass residue concentration is higher. The production efficiency of carbon monoxide formed at the anode increases with the concentration for sugarcane bagasse (2.01–5.21 μA/cm2) with 1% of the biomass in solution. [Display omitted] [ABSTRACT FROM AUTHOR]

This study presents a low-cost method for obtaining nanometric zinc oxide (ZnO) using a cassava starch (Tapioca)-assisted by sol-gel route. In this procedure, ZnO nanopowders (~20 nm and 59 nm according to XRD) were obtained after 2 h of calcination at 500oC. The cassava starch played a fundamental role during the sol-gel synthesis allowing the obtention of ZnO nanopowders (ZnO T) with crystallite size three times smaller than the ones without cassava starch (ZnO). SEM and TEM images corroborate the idea that Tapioca inhibited crystal growth in ZnO T when compared to the ZnO obtained from the same methodology. The synthesis of the obtained ZnO T was studied by FTIR and the results point to a possible interaction between zinc cations and C–O groups of glucose molecule that arises from the starch hydrolysis; thus, showing that Tapioca works as a good chelating agent, as well as presenting a very low cost. [ABSTRACT FROM AUTHOR]

To make SOFC high efficiency energy generation devices, thin ceramic films are proposed as their main components. The rate of the oxygen reduction reaction is relevant for the overall performance of the SOFC, hence a lot of attention is given to the cathodes and their interfaces. The airbrushed solution combustion (ASC) method was used to fabricate an LSM thin film on a dense YSZ substrate. A single phase LSM perovskite was obtained with very thin and interconnected porosity, and a small average grain size (55 nm). The nanostructured LSM thin film electrode showed a low total activation energy (1.27 eV) at high temperatures, but a high area specific resistance at 850°C (55 Ω.cm2). The activation energy for the dissociative adsorption and diffusion of oxygen was significantly low (1.27 eV), while the charge transfer and oxygen ion migration activation energy at the LSM/YSZ interface (1.28 eV) was closer to those usually reported. • The novel Airbrushed Solution Combustion (ASC) deposition method was tested. • A thin LSM film with average grain size of 55 nm and 10 μm thick was obtained. • A very thin and interconnected porosity was observed in the nanostructured film. • Electrochemical phenomena were separately related with microstructural features. • O 2 reduction steps had low activation energies but high area specific resistance. [ABSTRACT FROM AUTHOR]

Electrospun La x Sr 1−x Co 1−y Fe y O 3 (LSCF) fibers with y=0.2 – 1.0 have been investigated as the cathode of intermediate solid oxide fuel cells (IT-SOFC). The electrochemical performances of LSCF (y=0.2–1.0) fibers were studied by impedance spectroscopy in symmetrical cells containing gadolinium doped ceria (CGO) electrolyte and LSCF electrode infiltrated with CGO. Impedance measurements showed that the impedance spectra have two or three semicircles, depending on the measurement temperature. The LSCF electrodes with higher cobalt content exhibit lower polarization resistance (R p ) and the La 0.6 Sr 0.4 Co 0.8 Fe 0.2 O 3 electrode displayed the lowest polarization resistance between 500 and 900 °C, classifying this composite cathode as a promising material for intermediate temperature SOFC based on CGO electrolyte. [ABSTRACT FROM AUTHOR]

The aim of this work was to evaluate the efficiency of the new GreenDune photobioreactors for tertiary wastewater treatment, treated wastewater reuse and biomass application, using naturally occurring microalgae consortia. The study was conducted on a pilot installation in a wastewater treatment plant in Portugal and different operational conditions were tested. The system was capable to remove up to 95% of NH 4 +, the main pollutant in wastewater after secondary treatment using hydraulic retention times as low as 24 h. The application of a non-conservative scenario allowed the reuse of treated wastewater for seed production, and irrigation of naturally restricted use areas. The produced biomass was rich in proteins and carbohydrates with potential for biofuel production such as biogas or use as biofertilizers, closing the energy and nutrients cycle. Finally, the life cycle assessment of both the GreenDune and existing nitrification/denitrification systems were compared revealing that the operation of the GreenDune are more environmentally favourable than the existing system. [Display omitted] • Up to 95% of ammonia was removed using an HRT of 24h in the GreenDune PBRs • In a non-conservative scenario treated water could be reused for irrigation • Produced biomass showed high protein and carbohydrates content • Decreased areal footprint with the GreenDune PBRs • GreenDune system has less environmental impact than bacterial tertiary WWT [ABSTRACT FROM AUTHOR]

Silver nanoparticles (Ag NPs) have emerged as one of the most commonly used NPs in a wide range of industrial and commercial applications. This has caused increasing concern about their fate in the environment as well as uptake and potential toxicity towards aquatic organisms. Accordingly, mussels Mytilus galloprovincialis were exposed to 10 μg L −1 of Ag NPs and ionic silver (Ag + ) for 15 days, and biomarkers of oxidative stress and metal accumulation were determined. Accumulation results show that both Ag NPs and Ag + accumulated in both gills and digestive glands. Antioxidant enzymes (superoxide dismutase, catalase and glutathione peroxidase) were activated by Ag NPs and Ag + , showing different antioxidant patterns in both gills and digestive glands. Moreover, metallothionein was inducted in gills, directly related to Ag accumulation, while in the digestive glands only a small fraction of Ag seems to be associated with this protein. Lipid peroxidation was higher in gills exposed to Ag NPs, whereas in the digestive glands only Ag + induced lipid peroxidation. Ag NPs and Ag + cause oxidative stress with distinct modes of action and it's not clear if for Ag NPs the observed effects are attributed to free Ag + ions associated with the nanoparticle effect. [ABSTRACT FROM AUTHOR]

There is an increased use of Quantum Dot (QDs) in biological and biomedical applications, but little is known about their marine ecotoxicology. So, the aim of this study was to investigate the possible immunocytotoxic, cytogenotoxic and genotoxic effects of cadmium telluride QDs (CdTe QDs) on the marine mussel Mytilus galloprovincialis . Mussels were exposed to 10 μg L −1 of CdTe QDs or to soluble Cd [Cd(NO 3 ) 2 ] for 14 days and Cd accumulation, immunocytotoxicity [hemocyte density, cell viability, lysosomal membrane stability (LMS), differential cell counts (DCC)], cytogenotoxicity (micronucleus test and nuclear abnormalities assay) and genotoxicity (comet assay) were analyzed. Results show that in vivo exposure to QDs, Cd is accumulated in mussel soft tissues and hemolymph and induce immunotoxic effects mediated by a decrease in LMS, changes in DCC, as well as genotoxicity (DNA damage). However, QDs do not induce significant changes in hemocytes density, cell viability and cytogenetic parameters in opposition to Cd 2+ . Soluble Cd is the most cytotoxic and cytogenotoxic form on Mytilus hemocytes due to a higher accumulation of Cd in tissues. Results indicate that immunotoxicity and genotoxicity of CdTe QDs and Cd 2+ are mediated by different modes of action and show that Mytilus hemocytes are important targets for in vivo QDs toxicity. [ABSTRACT FROM AUTHOR]

ZnO nanoparticles were successfully synthesized using cassava starch (tapioca) as a chelating agent. X-ray diffraction (XRD) and Fourier transform infrared (FTIR) analyses revealed that the synthesized nanoparticles were in the form of ZnO with no impurities present. The estimated average crystallite size, determined from Rietveld refined XRD patterns, increased from 20 to 41 nm as calcination temperature increased from 500 to 700 °C. Transmission electron microscopy (TEM) images showed ZnO nanoparticles with an average size ranging from 30 nm (500 °C) to 100 nm (700 °C). The optical band gap was affected by heat treatment, and the lowest value was found at 500 °C (3.16 eV). Photoluminescence spectroscopy (PL) results show that all synthesized ZnO nanoparticles presented emission in the blue region, which was attributed to oxygen vacancies and optimized by calcination at 700 °C. Image 1 • ZnO nanoparticles were synthesized by a tapioca-assisted sol–gel route. • A heat treatment of 500–800 °C was applied to the synthesized ZnO. • TEM confirmed the formation of ZnO nanoparticles. • The calcination affected particle size and optical properties. • The smallest band gap was obtained in the calcined ZnO at 500 °C. [ABSTRACT FROM AUTHOR]