Waste materials and adsorbents for water treatment: from material characterization to applications in continuous operation systems

Wastewater treatment is a crucial activity that prevents soils and water bodies pollution avoiding the decrease of freshwater availability. Industrial and agricultural sectors are the main responsible for the generation of contaminated water and standard primary or secondary treatments are usually not enough to deal with such effluents. As a matter of fact, a specific tertiary treatment is often required for the removal of recalcitrant compounds that are harmful even at very low concentrations. Among all the technologies used to face such issue (e.g. Advanced Oxidation processes, Membrane processes), Adsorption constitutes a valid alternative for its ease of operation. However, the most commonly adopted solid adsorbents such as Active Carbons or Zeolites have to sustain high activation and synthesis costs respectively. In order to reduce such costs as well as to promote circular economy principles, in this thesis three different waste materials were proposed as bio-adsorbents: Yerba Mate (Ilex paraguarensis, YM) tea, Aloe vera (AV) rind and Pteris Vittata (PV) fern roots. Yerba Mate was used for the removal of anionic and cationic compounds from wastewater. Chromium hexavalent Cr(VI), Remazol brilliant blue (RBB) and methylene blue (MB) were selected as pollutants. A calcination step was performed after the washing and drying steps to evaluate its effectiveness at increasing the adsorption capacity of the solid. Both YM and calcinated YM (CYM) were characterized by means of scanning electron microscopy (FE SEM), Fourier transform infrared spectroscopy (FT-IR) and Brunauer–Emmett–Teller (BET) analysis. Adsorption batch tests revealed that YM was ineffective for the removal of Cr(VI) and RBB, while good results were obtained for MB (up to 80%) without pH dependency of the adsorption process, and CYM was able to remove Cr(VI) (up to 77%) and RBB (up to 65%) but not MB. The adsorption isotherm of MB on YM at 298 K was obtained experimentally and it is well represented by the Langmuir isotherm. YM’s adsorption capacity for MB was estimated to be 59.6 mg/g. Kinetic batch tests were conducted and the experimental results were fitted with a mathematical model. The low influence of temperature compared to the influence of the YM concentration on the adsorption rate was explained. The adsorption properties of Aloe vera (Aloe barbadensis Miller) for the uptake of Methylene Blue (MB) from water were investigated after pre-treating the material with water–ethanol solutions at different ethanol concentrations: 0% v/v (AV0), 25% v/v (AV25), and 50% v/v (AV50). The pretreated materials were characterized as follows: the pH of zero charge was evaluated to be 6, 5.7, and 7.2 for AV0, AV25, and AV50, respectively; from BET-BJH analysis the mesoporous nature of the material and an increase from 108.2 (AV0) to 331.7 (AV50) m2/kg of its solid surface area was observed; TG analysis revealed a significant increase in volatile compounds from the untreated (5.4%) to the treated materials (8.9%, 10.3%, and 11.3% for AV0, AV25, and AV50, respectively). Adsorption batch tests were then 10 performed to investigate the equilibrium, the kinetics, and the thermodynamics of the process. Results suggested that the Langmuir model was in agreement with the experimental results, and the values for the adsorption capacity were evaluated to be 199 mg/g, 311 mg/g, and 346 mg/g for AV0, AV25, and AV50, respectively. The kinetic results were used to develop a mathematical model to estimate the effective diffusion coefficient for each type of Aloe adopted. Effective diffusion coefficients of 5.43·10−7 cm2 /min, 3.89·10−7 cm2 /min, and 5.78·10−7 cm2 /min were calculated for AV0, AV25, and AV50, respectively. It was found that pre-treatment, on the one hand, enhances the adsorption capacity of the material and on the other, reduces its affinity toward MB uptake. The perennial fern Pteris vittata is an Arsenic-hyperaccumulator plant able to grow in hydroponic cultures and hence used for phytoremediation of contaminated water. In order to abate the costs linked to the disposal of As-contaminated biomass, in this work Pteris vittata waste roots were tested for the removal of Methylene Blue (MB). The pH of zero charge was evaluated to be 6.2, hence all the adsorption tests were performed at a neutral pH. Isotherms at 20 °C and 40 °C showed a typical Langmuir trend with a maximum adsorption capacity of 112 mg/g and 154 mg/g respectively. Kinetic tests were also carried out for different solid-liquid ratios and fitted by a mathematical model. The effective diffusivity of MB in the solid was estimated using the maximum likelihood method and the values of 5.99·10−8 ± 9 .6·10−9 cm2/s and 9.56·10−8 ± 4.5·10−9 cm2/s were obtained at 20 °C and 40 °C respectively. After calculating the Biot number it was found out that both the intra particle resistance and the external mass transfer resistance are important for the description of the rate of the dye uptake. Among all the three materials, Pteris vittata roots were selected to perform fixed bed column tests for the removal of Methylene Blue from water. As a matter of fact, swelling phenomena for Aloe vera induced to an excessive packing of the bed, while Yerba Mate tea showed a smaller adsorption capacity than Pteris vittata. Breakthrough curves were obtained experimentally at 20°C and the Linear Driving Force (LDF) model was used to predict their behavior. An empirical expression for the evaluation of the LDF mass transfer coefficient was then derived and validated for Reynolds number less than 0.025. In conclusion, this thesis provides all the steps (from characterization to fixed bed applications) that are required to evaluate the feasibility of adopting an agro-waste material as an adsorbent for real industrial applications. In this sense this work constitutes a guide from both an experimental and modeling point of view setting the basis for further studies in this research field

Polyphenols Extraction from Hazelnut Skin Using Water as Solvent: Equilibrium Studies and Quantification of the Total Extractable Polyphenols

In this work, a system for the extraction of antioxidant agents from waste vegetal matrices was studied. To this end, the extraction of polyphenols from food waste hazelnut skins was taken into consideration as a case study and a continuous set-up using distilled water at 70 °C as a solvent has been developed. Various extraction cycles were performed at different solid/liquid ratios (ranging from 2 to 5.7 g/l) in order to study the effect of this parameter on extraction efficiency. Through a mass balance, data obtained from the various cycles were used to calculate the total extractable polyphenols, and a value of 0.114 g of polyphenols per g of hazelnut skin was evaluated. Moreover, for two selected cycles the polyphenols concentration in the aqueous solution was measured at different time intervals in order to determine the extraction time, and in both tests it reached a plateau within the first hour. Finally, equilibrium concentrations of polyphenols in liquid and solid phases of the six tests were correlated by a linear isotherm equation, and a partition coefficient of 0.0368 l/g was evaluated through a fitting of experimental data

"Delirium Day": A nationwide point prevalence study of delirium in older hospitalized patients using an easy standardized diagnostic tool

Background: To date, delirium prevalence in adult acute hospital populations has been estimated generally from pooled findings of single-center studies and/or among specific patient populations. Furthermore, the number of participants in these studies has not exceeded a few hundred. To overcome these limitations, we have determined, in a multicenter study, the prevalence of delirium over a single day among a large population of patients admitted to acute and rehabilitation hospital wards in Italy. Methods: This is a point prevalence study (called "Delirium Day") including 1867 older patients (aged 65 years or more) across 108 acute and 12 rehabilitation wards in Italian hospitals. Delirium was assessed on the same day in all patients using the 4AT, a validated and briefly administered tool which does not require training. We also collected data regarding motoric subtypes of delirium, functional and nutritional status, dementia, comorbidity, medications, feeding tubes, peripheral venous and urinary catheters, and physical restraints. Results: The mean sample age was 82.0 \ub1 7.5 years (58 % female). Overall, 429 patients (22.9 %) had delirium. Hypoactive was the commonest subtype (132/344 patients, 38.5 %), followed by mixed, hyperactive, and nonmotoric delirium. The prevalence was highest in Neurology (28.5 %) and Geriatrics (24.7 %), lowest in Rehabilitation (14.0 %), and intermediate in Orthopedic (20.6 %) and Internal Medicine wards (21.4 %). In a multivariable logistic regression, age (odds ratio [OR] 1.03, 95 % confidence interval [CI] 1.01-1.05), Activities of Daily Living dependence (OR 1.19, 95 % CI 1.12-1.27), dementia (OR 3.25, 95 % CI 2.41-4.38), malnutrition (OR 2.01, 95 % CI 1.29-3.14), and use of antipsychotics (OR 2.03, 95 % CI 1.45-2.82), feeding tubes (OR 2.51, 95 % CI 1.11-5.66), peripheral venous catheters (OR 1.41, 95 % CI 1.06-1.87), urinary catheters (OR 1.73, 95 % CI 1.30-2.29), and physical restraints (OR 1.84, 95 % CI 1.40-2.40) were associated with delirium. Admission to Neurology wards was also associated with delirium (OR 2.00, 95 % CI 1.29-3.14), while admission to other settings was not. Conclusions: Delirium occurred in more than one out of five patients in acute and rehabilitation hospital wards. Prevalence was highest in Neurology and lowest in Rehabilitation divisions. The "Delirium Day" project might become a useful method to assess delirium across hospital settings and a benchmarking platform for future surveys

Measurement and interpretation of same-sign W boson pair production in association with two jets in pp collisions at s = 13 TeV with the ATLAS detector

This paper presents the measurement of fducial and diferential cross sections for both the inclusive and electroweak production of a same-sign W-boson pair in association with two jets (W±W±jj) using 139 fb−1 of proton-proton collision data recorded at a centre-of-mass energy of √s = 13 TeV by the ATLAS detector at the Large Hadron Collider. The analysis is performed by selecting two same-charge leptons, electron or muon, and at least two jets with large invariant mass and a large rapidity diference. The measured fducial cross sections for electroweak and inclusive W±W±jj production are 2.92 ± 0.22 (stat.) ± 0.19 (syst.)fb and 3.38±0.22 (stat.)±0.19 (syst.)fb, respectively, in agreement with Standard Model predictions. The measurements are used to constrain anomalous quartic gauge couplings by extracting 95% confdence level intervals on dimension-8 operators. A search for doubly charged Higgs bosons H±± that are produced in vector-boson fusion processes and decay into a same-sign W boson pair is performed. The largest deviation from the Standard Model occurs for an H±± mass near 450 GeV, with a global signifcance of 2.5 standard deviations

Studies of new Higgs boson interactions through nonresonant HH production in the b¯bγγ fnal state in pp collisions at √s = 13 TeV with the ATLAS detector

A search for nonresonant Higgs boson pair production in the b ¯bγγ fnal state is performed using 140 fb−1 of proton-proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. This analysis supersedes and expands upon the previous nonresonant ATLAS results in this fnal state based on the same data sample. The analysis strategy is optimised to probe anomalous values not only of the Higgs (H) boson self-coupling modifer κλ but also of the quartic HHV V (V = W, Z) coupling modifer κ2V . No signifcant excess above the expected background from Standard Model processes is observed. An observed upper limit µHH < 4.0 is set at 95% confdence level on the Higgs boson pair production cross-section normalised to its Standard Model prediction. The 95% confdence intervals for the coupling modifers are −1.4 < κλ < 6.9 and −0.5 < κ2V < 2.7, assuming all other Higgs boson couplings except the one under study are fxed to the Standard Model predictions. The results are interpreted in the Standard Model efective feld theory and Higgs efective feld theory frameworks in terms of constraints on the couplings of anomalous Higgs boson (self-)interactions

Comparison of inclusive and photon-tagged jet suppression in 5.02 TeV Pb+Pb collisions with ATLAS

Parton energy loss in the quark–gluon plasma (QGP) is studied with a measurement of photon-tagged jet production in 1.7 nb−1 of Pb+Pb data and 260 pb−1 of pp data, both at sNN=5.02 TeV, with the ATLAS detector. The process pp →γ+jet+X and its analogue in Pb+Pb collisions is measured in events containing an isolated photon with transverse momentum (pT) above 50 GeV and reported as a function of jet pT. This selection results in a sample of jets with a steeply falling pT distribution that are mostly initiated by the showering of quarks. The pp and Pb+Pb measurements are used to report the nuclear modification factor, RAA, and the fractional energy loss, Sloss, for photon-tagged jets. In addition, the results are compared with the analogous ones for inclusive jets, which have a significantly smaller quark-initiated fraction. The RAA and Sloss values are found to be significantly different between those for photon-tagged jets and inclusive jets, demonstrating that energy loss in the QGP is sensitive to the colour-charge of the initiating parton. The results are also compared with a variety of theoretical models of colour-charge-dependent energy loss

Combination of searches for heavy spin-1 resonances using 139 fb−1 of proton-proton collision data at s = 13 TeV with the ATLAS detector

A combination of searches for new heavy spin-1 resonances decaying into different pairings of W, Z, or Higgs bosons, as well as directly into leptons or quarks, is presented. The data sample used corresponds to 139 fb−1 of proton-proton collisions at = 13 TeV collected during 2015–2018 with the ATLAS detector at the CERN Large Hadron Collider. Analyses selecting quark pairs (qq, bb, , and tb) or third-generation leptons (τν and ττ) are included in this kind of combination for the first time. A simplified model predicting a spin-1 heavy vector-boson triplet is used. Cross-section limits are set at the 95% confidence level and are compared with predictions for the benchmark model. These limits are also expressed in terms of constraints on couplings of the heavy vector-boson triplet to quarks, leptons, and the Higgs boson. The complementarity of the various analyses increases the sensitivity to new physics, and the resulting constraints are stronger than those from any individual analysis considered. The data exclude a heavy vector-boson triplet with mass below 5.8 TeV in a weakly coupled scenario, below 4.4 TeV in a strongly coupled scenario, and up to 1.5 TeV in the case of production via vector-boson fusion