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Recent studies have shown the widespread occurrence of microplastics in multiple environmental compartments. When discharged into the aquatic environment, microplastics interact with other chemicals acting as vectors of organic and inorganic micropollutants. In the present study, we examined the sorption of two commonly used antihypertensive drugs, valsartan (VAL) and losartan (LOS), onto polystyrene (PS) microplastics and we studied the effects of water matrix, solution's pH, salinity, and microplastics' aging on their sorption. According to the results, the sorption of VAL and LOS onto PS is a slow process that reaches equilibrium after 12 days. The sorption of both target micropollutants was pH-dependent and significantly decreased under alkaline conditions. The removal of VAL was enhanced in the presence of 100 mM of Ca2+ while no statistical significant effects were observed when Na+ was added. The increase of salinity either did not affect or decreased the removal of LOS. Lower sorption of both drugs was observed when aged PS was used despite that the specific surface area for aged PS was 39% higher than pristine. Calculation of the sorption distribution coefficient (Kd) for different water matrices showed that the increase of matrix complexity inhibited target compounds' removal and the sorption rate decreased from bottled water > river water ≈ treated wastewater for the two compounds. For VAL, the Kd values ranged between 795 ± 63 L/kg (bottled water) and 384 ± 88 L/kg (river water), while for LOS between 4453 ± 417 L/kg (bottled water) and 3078 ± 716 L/kg (treated wastewater). Both VAL and LOS sorption onto PS microplastics can be described by hydrophobic and electrostatic interactions. The current results indicate that PS particles could affect the transportation of antihypertensive drugs in the aquatic environment causing potential adverse effects on the environment and public health. © 2022 Elsevier B.V.

In this study, the oxidative degradation of losartan (LOS), a widely administered medicine for high blood pressure by heat-activated persulfate was investigated. Increased temperature and persulfate concentration, as well as acidic conditions enhance the degradation efficiency of LOS, whose rate follows pseudo-first order kinetics. From the respective apparent rate constants in the range 40–60 °C, an apparent activation energy of 112.70 kJ/mol was computed. Radical scavenging tests demonstrated that both HO• and SO4•− contribute towards LOS degradation. LOS degradation was suppressed in real water matrices including bottled water (BW) and secondary wastewater effluent (WW), while other experiments indicated that the presence of bicarbonates and humic acid negatively affected its oxidation. Instead, the addition of chloride ions at 250 mg/L resulted in a positive effect on LOS removal. The combination of heat-activated PS with low-frequency ultrasound exhibited a synergistic effect, with the ratio S being 2.29 in BW and 1.52 in WW. Five transformation products of LOS were identified through HRMS suspect and non-target screening approaches, among which two are reported for the first time. Using the in-house risk assessment program, ToxTrAMs was revealed that most of the identified TPs present higher toxicity than LOS against Daphnia magna. © 2021

The sonochemical degradation of trimethoprim (TMP), a widely used antibiotic, in various water matrices was investigated. The effect of several parameters, such as initial TMP concentration (0.5–3 mg/L), actual power density (20–60 W/L), initial solution pH (3–10), inorganic ions, humic acid and water matrix on degradation kinetics was examined. The pseudo-first order degradation rate of TMP was found to increase with increasing power density and decreasing pH, water complexity (ultrapure water > bottled water > secondary wastewater) and initial TMP concentration. TMP degradation is accompanied by the formation of several transformation products (TPs) as evidenced by LC-QToF-MS analysis. Nine such TPs were successfully identified and their time-trend profiles during degradation were followed. An in silico toxicity evaluation was performed showing that several TPs could potentially be more toxic than the parent compound towards Daphnia magna, Pimephales promelas and Pseudokirchneriella subcapitata. © 2020 Elsevier B.V.

Towards supercritical extraction of valuable compounds from waste: Phase equilibrium measurements of CO2 with diethyl succinate

Nut Shells as Absorbents of Pollutants: Perspectives and Obstacles

Valorisation of residual biomass from the cultivation of olive trees in mountainous areas

An innovative process battery comprising coagulation–flocculation, extraction of phenolic compounds and photo-Fenton post-oxidation has been developed for the valorization and treatment of olive mill effluents (OMEs). Pre-conditioning by coagulation–flocculation using FeSO4⋅7H2O as the coagulant, and an anionic polyelectrolyte (FLOCAN 23) as the flocculant was performed to remove the solid content of the effluent. The addition of 6.67 g/L of FeSO4⋅7H2O and 0.287 g/L of FLOCAN 23 led to the optimal removal of total suspended solids (TSS) (97 ± 1.3%), of Chemical Oxygen Demand (COD) (72 ± 1.5%), and of Total Phenols (TPs) (40 ± 1.3%). Solvent extraction was then applied to recover a fraction of the remaining phenolic compounds; for instance, extraction for 15 min with ethyl acetate at a solvent to sample ratio of 2:1 (v/v) led to 36% TP recovery post-coagulation–flocculation. Finally, photo-Fenton was applied as a post-treatment method; oxidation for 240 min at 0.2 g/L Fe2+, 5 g/L H2O2 and pH = 3 reduced the remaining COD and TP by 73 ± 2.3% and 87 ± 3.1%, respectively. Toxicity assays to Daphnia magna as well as phytotoxicity tests to three plant species to untreated OME and oxidized samples were also performed, indicating the evolution of more biologically potent products during the oxidation.

The efficiency of TiO2 photocatalysis to degrade three estrogen hormones, that is, 17α-ethynylestradiol (EE2), estrone (E1), and 17β-estradiol (E2), in environmentally relevant samples was investigated. Radiation at a photon flux of 1.7 × 10–7 einstein/s was provided by a solar simulator and experiments were conducted at various TiO2 loadings (25–1500 mg/L), estrogen concentrations (85–300 μg/L in individual solutions and 400 μg/L in mixture), and water matrices (ultrapure water, drinking water, and secondary treated wastewater). Changes in estrogen concentration were followed by high performance liquid chromatography and estrogenicity by the yeast estrogen screening assay. Aeroxide P25, a commercially available mixture of 75:25 anatase/rutile, was considerably more active than carbon-doped and undoped anatase titania, with degradation increasing with increasing catalyst loading and treatment time. The organic and inorganic constituents typically found in wastewater and drinking water impeded degradation ...

The efficiency of heterogeneous photocatalysis to degrade 17α-ethynylestradiol (EE2), a synthetic estrogen hormone, in environmentally relevant samples was investigated. In most cases, UV-A radiation at a photon flux of 2.81 × 10 −4 einstein/min was provided by a 9 W lamp and experiments were conducted at various concentrations of Aeroxide P25 TiO 2 (50–1000 mg/L), EE2 concentrations (50–900 μg/L) and water matrices (from ultrapure water to secondary treated wastewater). Some runs were performed at photon fluxes between 6.4 × 10 −7 and 3.7 × 10 −4 einstein/min to study the effect of intensity on degradation. Changes in estrogen concentration were followed by high performance liquid chromatography. EE2 degradation, which follows first order kinetics, increases with (i) increasing catalyst loading up to a threshold value beyond which it remains unaffected; (ii) increasing photon flux and (iii) decreasing matrix complexity, i.e. the organic and inorganic constituents of wastewater retard degradation. This may be overcome coupling photocatalysis with ultrasound radiation at 80 kHz and 41 W/L power density; the combined sonophotocatalytic process acts synergistically toward EE2 degradation. Several transformation products were identified by means of UPLC–MS/MS and a reaction network for the photocatalytic degradation of EE2 is suggested. An artificial neural network comprising five input variables (reaction time, TiO 2 and EE2 concentration, organic content and conductivity of the water matrix), thirteen neurons and an output variable (EE2 conversion) was optimized, tested and validated for EE2 degradation. The network, based on tangent sigmoid and linear transfer functions for the hidden and input/output layers, respectively, and the Levenberg–Marquardt back propagation training algorithm, can successfully predict EE2 degradation.

BACKGROUND: Recently, the fate of emerging micro-contaminants in environmentally relevant samples has attracted considerable attention. Semiconductor photocatalysis may offer an appealing methodology to treat such contaminants in this respect, the degradation of synthetic estrogen 17α-ethynylestradiol (EE2) employing simulated solar radiation and ZnO as the photocatalyst was investigated. RESULTS: A factorial design approach was adopted to evaluate the effect of estrogen concentration (100–500 µg L−1), ZnO concentration (50-500 mg L−1 in suspension), treatment time (2-10 min), photon flux (4.93 × 10−7–5.8 × 10−7 einstein L−1 s−1) and the water matrix (ultrapure water and treated wastewater) on EE2 removal. The first four variables had a statistically important, positive effect on degradation, while the water matrix introduced a negative effect presumably due to the competition between EE2 and the effluent organic and inorganic matter for hydroxyl radicals and other oxidizing species. Moreover, second-order interactions of estrogen concentration with time and the water matrix were also significant. EE2 degradation follows first-order kinetics with the respective rate constants in wastewater and water being 9.2 ± 0.7 × 10−2 and 41 ± 8 × 10−2 min−1 at the maximum ZnO concentration and photon flux. On the other hand, the removal rate of effluent's overall estrogenicity (as assessed by the yeast estrogen screening bioassay) was an order of magnitude lower than that of EE2, implying the presence of persistent estrogenic compounds in the photocatalyzed effluent. CONCLUSIONS: An effective treatment process is demonstrated which benefits from the use of renewable energy and a stable and highly active photocatalyst. Copyright © 2012 Society of Chemical Industry 87 8 1051 1058

Summarization: The use of low frequency (20 kHz), high energy ultrasound for the degradation of the antibiotic ofloxacin in water was investigated. Experiments were performed with a horn-type ultrasound generator at varying applied power densities (130–640 W/L), drug concentrations (5–20 mg/L), hydrogen peroxide concentrations (0–100 mM) and sparging gases (air, oxygen, nitrogen and argon). In general, conversion (which was assessed following sample absorbance at 288 nm) increased with increasing ultrasound energy and peroxide concentration and decreasing initial drug concentration. Moreover, reactions under an argon atmosphere were faster than with diatomic gases, possibly due to argon's physical properties (e.g. solubility, thermal conductivity and specific heat ratio) favoring sonochemical activity. Overall, low to moderate levels of ofloxacin degradation were achieved (i.e. it never exceeded 50%), thus indicating that radical reactions in the liquid bulk rather than thermal reactions in the vicinity of the cavitation bubble are responsible for ofloxacin degradation. Presented on: Water Science and Technology

The photocatalytic mineralization of the antibiotic erythromycin (ERM) in aqueous TiO 2 suspensions was investigated. UV-A irradiation was provided by a 9 W lamp at a photon flux of 4.69 × 10 −6 einstein/s and runs were performed at ERM initial concentrations between 2.5 and 30 mg/L, 10 commercially available TiO 2 catalysts at loadings between 100 and 750 mg/L and at acidic or near neutral conditions. The extent to which the aforementioned factors influence ERM mineralization was assessed measuring the total organic carbon (TOC) content of the solution. Of the various catalysts tested, Degussa P25 (75:25, anatase:rutile) was highly active yielding 90% TOC reduction after 90 min of reaction with 10 mg/L ERM and 250 mg/L TiO 2 ; the second best catalyst consisting of pure anatase (Hombikat UV 100) yielded only 65% reduction. TOC removal decreased with decreasing titania loading and increasing ERM concentration and solution pH. For the range of the ERM concentrations studied, mineralization kinetics appears to follow the Langmuir–Hinshelwood model. Short (i.e. 15 min) photocatalytic treatment of 30 mg/L ERM was capable of abolishing completely the antimicrobial properties of ERM to E. coli but this was accompanied by insignificant levels (i.e. 10%) of total oxidation.

Winery wastewaters contain high concentrations of organic compounds including phytotoxic and recalcitrant compounds like phenols. Its treatment by conventional processes is difficult due to the variability of the characteristics of the liquid waste. The main objectives of this work were to (1) monitor onsite the quality of winery wastes prior to and following sequential physical and biological treatment and (2) assess the efficiency of coupling physical and biological treatment to photo-Fenton oxidation serving as the final polishing step. A partially treated effluent with chemical oxygen demand (COD) and biochemical oxygen demand (BOD5) values of 1060 and 210 mg/L respectively was subject to photo-Fenton oxidation at H2O2 and Fe2+ concentrations between 34–175 and 0.5–2 mM respectively, solution pH0 = 2.5, under continuous UV-A irradiation provided by a 125 W lamp. In general, organic matter degradation increased with increasing treatment time reaching values of COD or BOD removal as high as 80% after 4 h of reaction. Regarding the effect of initial iron and hydrogen peroxide concentrations, there appears to be an optimum dosage for both, above which treatment performance deteriorated. Hence, the combined biological + photo-Fenton oxidation resulted in 95% COD removal.

•EE2 degradation in wastewater under UVC or simulated solar light was studied.•The effect of several operating parameters on process efficiency was investigated.•Estrogenicity in wastewater matrices is not completely removed upon EE2 elimination.•The formation of transformation products (TPs) was followed by UPLC–MS/MS.•EE2 degradation pathways during UVC/H2O2 or solar/Fe2+ treatment were proposed. The extensive use of estrogens and their release, through various pathways, into the environment, constitutes an emerging environmental problem that poses serious threats onto public health. In this work the efficiency of UVC/H2O2 and solar/Fe2+ treatment to degrade 17α-ethynylestradiol (EE2) in environmentally relevant concentrations of 100μg/L in secondary-treated wastewater matrices was investigated. Also, photolytic treatment was performed under different irradiation sources, namely UVC, UVA and simulated solar light. The effect of H2O2 (0–20mg/L) and Fe2+ (0–15mg/L) concentration was investigated and, at optimal operating parameters, EE2 removal was 100% after 15min of UVC/H2O2 treatment, while EE2 removal reached 86% after 60min of solar/Fe2+ treatment. In addition, the effect of water matrix and pH was studied. Total organic carbon (TOC) and yeast estrogen screening (YES) measurements showed the formation of stable intermediate products during EE2 treatment and an attempt to elucidate the reaction pathways and mechanisms through the identification of transformation products (TPs) by means of UPLC–MS/MS was made. Several TPs, including quinone methide and 1,2-quinone derivatives, were identified and competing pathways were suggested, in which hydroxylation, alkylation, dealkylation, demethylation and dehydroxylation, amongst others were described as major transformation mechanisms. 252 8 84 92

In this work, the degradation of the azo dye methyl orange in model aqueous solutions by UVC light-induced persulfate oxidation was studied. Five operating parameters that may influence the decolorization kinetics were evaluated, namely, methyl orange (MO) (5-50 mg L(-1)) and sodium persulfate (SPS) (50-150 mg L(-1)) concentration, reaction time (up to 60 min), (un-buffered) solution pH (3-9) and the addition of NaCl (0-500 mg L(-1)). The process was simulated, applying and comparing two methodologies, namely two-level factorial design and an artificial neural network (ANN). It was found that MO concentration is the most influential parameter, followed by the reaction time and SPS concentration, while the effects of solution pH and the addition of sodium chloride are statistically less significant; this order of significance was predicted by both methodologies. The ANN can simulate the process more accurately (i.e. in terms of R(2), mean square error (MSE) and residuals) than factorial design, although it needs significantly larger sets of data and longer computational time.

Recently, the fate of emerging compounds in environmentally relevant samples has attracted considerable attention. Solar semiconductor photocatalysis may offer an appealing methodology to treat such contaminants. At the same time the use of solar photocatalysis for water and wastewater disinfection is a topic well-documented in the literature. In this respect, the simultaneous degradation of synthetic estrogen 17 alpha-ethynylestradiol (EE2) and Escherichia coli removal employing simulated solar radiation and TiO2 as the photocatalyst was investigated. In general, the more complex the water matrix is the slower E. coli removal becomes, while the presence of E. coli in the reaction mixture did not obstruct EE2 removal.Although EE2 removal occurred relatively fast, overall estrogenic activity was only partially removed. This implies that other species inherently present in the effluent and/or some photocatalytic transformation by-products may be proportionately more estrogenic than EE2. Overall, the use of solar radiation can constitute an advantageous treatment strategy for the simultaneous removal of micro-pollutants and pathogens from secondary treated effluent.

It is well known that chlorine and its compounds, traditionally utilized for water and wastewater disinfection, react with some organic matter to form undesirable by-products, hazardous to human health, known as Disinfection By-Products (DBPs). In many countries very stringent limits for chlorination by-products such as trihalomethanes were set for wastewater reuse. Accordingly, the use of different oxidation/disinfection systems should be evaluated as possible alternative to chlorine. Ultrasound (US) was recently found to be effective for this purpose. Aim of this work is to review main US disinfection studies, pointing out ultrasound mechanisms as well as its effects in terms of different bacteria inactivation (Total coliform, Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Saccharomyces cerevisiae, Klebsiella pneumonia) at both laboratory scale and pilot-scale. To this end, several experimental results were discussed and both focal interest points and encountered problems were summarized. Moreover the intensification of cavitation phenomena by combined oxidation processes was overviewed and main advantages and disadvantages were pointed out, in order to address future research and promote efficient large scale operations.

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