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Carbon xerogels (CXs) were synthesized by polycondensation of resorcinol and formaldehyde, followed by thermal annealing, and subjected to hydrothermal oxidation. Solid-phase extraction (SPE) cartridges were filled with CXs and tested for extraction of metaflumizone and other seven environmental micropollutants (acetamiprid, atrazine, isoproturon, methiocarb, carbamazepine, diclofenac, and perfluorooctanesulfonic acid) before chromatographic analysis. The recoveries obtained with the pristine CX were low for most analytes, except for metaflumizone (69 ± 5%). Moreover, it was concluded that the adsorption/desorption process of the micropollutants performed better on CXs with a less acidic surface (i.e., pristine CX). Thus, cartridges were prepared with pristine CX and multi-walled carbon nanotubes (MWCNTs) in a multi-layer configuration. This reusable cartridge was able to simultaneously extract the eight micropollutants and was used to validate an analytical methodology based on SPE followed by ultra-high performance liquid chromatography-tandem mass spectrometry. A widespread occurrence of 6/8 target compounds was observed in surface water collected in rivers supplying three drinking water treatment plants and in the resulting drinking water at the endpoint of each distribution system. Therefore, the first study employing CXs and MWCNTs as sorbent in multi-layer SPE cartridges is herein reported as a proof of concept for determination of multi-class water micropollutants. [ABSTRACT FROM AUTHOR]

Silica@polymer spheres with a core@shell structure were synthesized and thermally annealed at 800 ºC to obtain silica@carbon spheres (SiO 2 @CSs). The silica core was removed by etching with NaOH, hollow carbon spheres (CSs) being obtained. The particle size of SiO 2 @CSs and CSs increased with the ethanol/water (E/W) volumetric ratio (2, 4.5, and 7) employed in the first synthesis step (i.e. , the Stöber's method to obtain silica particles). Moreover, the average diameter of the materials prepared with E/W ratio of 2 was affected by the etching of the SiO 2 core (from 168 to 109 nm), in contrast with those synthesized at higher E/W ratios of 4.5 and 7 (251–245 and 270–284 nm, respectively). The specific surface area (S BET) of the CSs ranged from 271 to 602 m2 g−1, which are more porous than SiO 2 @CSs (S BET in the range 115–144 m2 g−1). Adsorption kinetic and equilibrium studies were carried out with diclofenac and venlafaxine as model organic micropollutants (OMPs). Despite the silica removal was not effective for all the CSs (TGA residue ranging from 3 to 46 wt%), the kinetic studies and the ATR-FTIR spectra confirmed the positive effect of having a hollow core (i.e. , removing the silica core). Equilibrium studies demonstrated that CSs prepared with an E/W ratio of 7 were the best performing material when considering both OMPs. Moreover, these CSs performed well to remove a set of 24 OMPs from wastewater effluents and thus, they are an interesting option for water or wastewater treatment. [Display omitted] • Nanostructured hollow carbon spheres (CSs) with different sizes synthesized. • First study employing CSs for the adsorption of diclofenac and venlafaxine (VFX). • Beneficial role of the hollow core within the CSs was demonstrated. • Best performance in equilibrium tests with the CSs having larger particle size. • Highest VFX adsorption capacity (61.45 mg g-1) among reported carbon materials. [ABSTRACT FROM AUTHOR]

Aquaculture is the fastest growing animal food-producing sector. Water is the central resource for aquaculture, and it is essential that its quality be preserved. Micropollutants (MPs) can reach aquaculture through anthropogenic addition or inlet water, and may cause harmful effects such as endocrine disruption and antibiotic resistance, adversely affecting the fish species being farmed. Furthermore, the discharge of aquaculture effluents into the environment may contribute to the deterioration of water courses. In this sense, the implementation of environmentally responsible measures in aquaculture farms is imperative for the protection of ecosystems and human health. The European Commission (EC) has recently launched a guiding document promoting ecological aquaculture practices; however, options for water treatment are still lacking. Conventional processes are not designed to deal with MPs; this review article consolidates relevant information on the application of advanced oxidation technologies (AOTs) and constructed wetlands (CWs) as potential strategies in this regard. Although 161 studies on the application of AOTs or CWs in aquaculture have already been published, only 34 focused on MPs (28 on AOTs and 6 on CWs), whereas the others reported the removal of contaminants such as bacteria, organic matter, solids and inorganic ions. No study coupling both treatments has been reported to date for the removal of MPs from aquaculture waters. AOTs and CWs are prospective alternatives for the treatment of aquacultural aqueous matrices. However, the type of aquaculture activity and the specifications of these available technologies should be considered while selecting the most suitable treatment option. [Display omitted] • Micropollutants in aquaculture water is a concern of the European Commission. • Chemical and biological treatments to remove these micropollutants are reviewed. • Studies with real matrices are scarce for advanced oxidation technologies (AOTs). • More studies conducted at full scale are needed for constructed wetlands (CWs). • Both AOTs and CWs can remove conventional pollutants from aquaculture waters. [ABSTRACT FROM AUTHOR]

Ozone-based water treatments were investigated to simultaneously remove organic micropollutants (OMPs) and bacteria from surface water samples collected in a river reservoir supplying a drinking water treatment plant. Among the 21 environmentally relevant OMPs selected, 15 were detected at low (< 20) ng L−1 level. Surface water samples were then spiked with these 21 OMPs (100 ng L−1) and the ozone-based treatments were tested with excess of ozone and high hydraulic retention time (HRT: 41 min). Regardless of the treatment applied (O 3 , O 3 /UVA-LEDs, and O 3 /H 2 O 2), removal efficiencies higher than 85% were always obtained for 20 out of 21 OMPs (and lower than 50% for PFOS). Thus, single ozonation was considered the best treatment solution, being afterwards investigated in terms of water disinfection at milder operating conditions (3 mg O 3 L−1 and HRT: 10 min). Under these conditions, the removals of spiked OMPs were also higher than 85% (except for PFOS), whereas bacteria (i.e. , total heterotrophs at 37 and 22 °C, E. coli and enterococci) decreased to values lower than the permissible levels for drinking water, even upon storage for 3-days. However, lower ozone doses (1.5 mg O 3 L−1) could not prevent the regrowth of total heterotrophs incubated at 37 °C, which reached levels five times higher than those recommended. Because drinking water treatments should not only consider OMPs abatement but also microbial inactivation for long periods of time, the results herein obtained point out the importance of using ozone doses capable of accomplish both targets when using single ozonation. [Display omitted] • Ozone-based treatments investigated for surface water intended for consumption. • 20 out of 21 organic micropollutants were removed (>85%) by single ozonation. • PFOS removals were lower than 50% regardless of the treatment process tested. • The treated water had sufficient microbial quality for human consumption. • Ozone doses lower than 3 mg O 3 L−1 are not recommended due to bacteria regrowth. [ABSTRACT FROM AUTHOR]