Application of Photoactive Nanomaterials in Degradation of Pollutants

Photoactive nanomaterials have been receiving increasing attention due to their potential application in the light-driven degradation of water and gas-phase pollutants. However, to exploit the great potential of photoactive materials and access their properties requires fine-tuning of their size/shape-dependent chemical–physical properties, and on the ability to integrate them in photoreactors or to deposit them onto large surfaces. Therefore, the synthetic approach as well as post-synthesis manipulation could strongly affect the final photocatalytic properties of the nanomaterial. The aim of the present Special Issue is to report on the most recent progress towards the application of photoactive nanomaterials and nanomaterial-based coatings in pollutant degradation, paying particular attention to cases close to real application: scalable synthetic approaches to nanocatalysts, preparation of nanocatalyst-based coatings, degradation of real pollutants and bacterial inactivation, and application in building materials

High-order harmonic generation in a chip fabricated through femtosecond laser irradiation followed by chemical etching techniques

LAUREA MAGISTRALELa generazione di armoniche di ordine elevato (high-order harmonic generation, HHG) è un processo fortemente non lineare successivo all'interazione di una radiazione laser, molto intensa e di breve durata, con la materia. Il processo fisico consiste nell'emissione di elettroni da parte degli atomi o molecole che costituiscono il bersaglio, solitamente in forma gassosa; questi elettroni sono quindi riaccelerati dal campo elettrico dell'impulso fino ad impattare contro i rispettivi ioni parenti, causando così l'emissione di radiazione nell'estremo ultravioletto (XUV) sotto forma di armoniche di ordine elevato della fondamentale. Questo processo è un utile strumento per ottenere impulsi isolati ad attosecondi (10^-18 s) e una radiazione coerente con lunghezza d'onda centrale molto corta, necessaria a studiare dinamiche molecolari ultraveloci e a sondare target in una nuova regione spettrale. Grandi strutture o interi laboratori sono necessari per ottenere questi output. Al contempo, l'ottica sta dirigendo attenzioni verso il mondo dei dispositivi fotonici integrati, con l'avvento della cosiddetta optofluidica. Lo scopo di questa tesi magistrale è quello di unire per la prima volta la fisica degli attosecondi all'optofluidica. Un chip di vetro con all'interno un canale cavo, fabbricato tramite irraggiamento con laser a femtosecondi seguito da etching chimico (femtosecond laser irradiation followed by chemical etching, FLICE), ospita il target fluido nel quale il processo di HHG ha luogo. I risultati sperimentali sono raccolti per differenti condizioni di lavoro, come la pressione e l'intensità incidente, e interpretati considerando le diverse condizioni di phase matching instauratesi all'interno del capillare, dimostrando la compatibilità tra l'HHG e l'optofluidica. Gli spettri sono ottenuti in vari gas nobili, utilizzando una lunghezza d'onda incidente di 800 nm; l'accordo tra le misure osservate e simulate è una chiara evidenza della generazione di armoniche all'interno del canale. Per di più, un confronto sistematico tra le tecniche solitamente impiegate per l'HHG e il chip cavo mostra uno scaling favorevole e promettente per quanto riguarda l'efficienza del processo. Questi risultati lastricano la strada ad una serie di nuovi dispositivi fabbricati con le stesse tecniche e che permetteranno una complessiva riduzione dell'ingombro del setup di pari passo con una maggiore complessità dell'apparato sperimentale.High-order harmonic generation (HHG) is a strongly nonlinear process which follows with the interaction of a very intense and short laser radiation with matter. The physical process consists in the emission of electrons from the atoms or molecules constituting the target, usually in the gaseous form; these electrons are accelerated back from the pulse electric field and the impact with their respective parent ions causes the emission of extreme ultraviolet radiation (XUV), under the form of high-order harmonics of the fundamental. This process is a useful tool to obtain isolated attosecond (10^-18 s) pulses and a coherent radiation with very short central wavelength, necessary to study ultrafast molecular dynamics and to probe targets in an unprecedented spectral region. Big facilities or room-sized laboratories are needed to generate these outputs. At the same time, optics is pushing towards the world of integrated photonic devices, with the advent of optofluidic. The aim of this master thesis work is to join for the first time attosecond physics with optofluidics. A fused silica chip with a hollow-core channel, fabricated with the femtosecond laser micromachining followed by chemical etching technique (FLICE), hosts the flowing fluid target in which the HHG process can take place. Results are gathered for different working conditions, like pressure and incoming laser intensity, and then interpreted considering the different phase matching conditions established inside the capillary, demonstrating the compatibility of HHG and optofluidics. Spectra are obtained in different noble gases using an 800 nm driver and the accordance between simulated and observed measurements serves as clear evidence of an in-channel harmonic generation. Moreover, a systematic comparison between the usually employed techniques to obtain HHG and the hollow-core chip shows a promising favorable scaling of the efficiency of the process. These results paved the way to a series of new devices fabricated with the same technique and which will allow an overall reduction of the setup encumbrance along with an increased complexity of the experimental apparatus

Colloidal inorganic nanocrystal based nanocomposites: Functional materials for micro and nanofabrication

The unique size- and shape-dependent electronic properties of nanocrystals (NCs) make them extremely attractive as novel structural building blocks for constructing a new generation of innovative materials and solid-state devices. Recent advances in material chemistry has allowed the synthesis of colloidal NCs with a wide range of compositions, with a precise control on size, shape and uniformity as well as specific surface chemistry. By incorporating such nanostructures in polymers, mesoscopic materials can be achieved and their properties engineered by choosing NCs differing in size and/or composition, properly tuning the interaction between NCs and surrounding environment. In this contribution, different approaches will be presented as effective opportunities for conveying colloidal NC properties to nanocomposite materials for micro and nanofabrication. Patterning of such nanocomposites either by conventional lithographic techniques and emerging patterning tools, such as ink jet printing and nanoimprint lithography, will be illustrated, pointing out their technological impact on developing new optoelectronic and sensing devices. © 2010 by the authors

Lifestyle interventions and prevention of suicide

Over the past years, there has been a growing interest in the association between lifestyle psychosocial interventions, severe mental illness, and suicide risk. Patients with severe mental disorders have higher mortality rates, poor health states, and higher suicide risk compared to the general population. Lifestyle behaviors are amenable to change through the adoption of specific psychosocial interventions, and several approaches have been promoted. The current article provides a comprehensive review of the literature on lifestyle interventions, mental health, and suicide risk in the general population and in patients with psychiatric disorders. For this purpose, we investigated lifestyle behaviors and lifestyle interventions in three different age groups: adolescents, young adults, and the elderly. Several lifestyle behaviors including cigarette smoking, alcohol use, and sedentary lifestyle are associated with suicide risk in all age groups. In adolescents, growing attention has emerged on the association between suicide risk and internet addiction, cyberbullying and scholastic and family difficulties. In adults, psychiatric symptoms, substance and alcohol abuse, weight, and occupational difficulties seems to have a significant role in suicide risk. Finally, in the elderly, the presence of an organic disease and poor social support are associated with an increased risk of suicide attempt. Several factors may explain the association between lifestyle behaviors and suicide. First, many studies have reported that some lifestyle behaviors and its consequences (sedentary lifestyle, cigarette smoking underweight, obesity) are associated with cardiometabolic risk factors and with poor mental health. Second, several lifestyle behaviors may encourage social isolation, limiting the development of social networks, and remove individuals from social interactions; increasing their risk of mental health problems and suicide

Photocatalytic degradation of methyl-red by immobilised nanoparticles of TiO2 and ZnO

none6noIn this work, we report on the degradation of methyl-red (2-(4-Dimethylamino-phenylazo)-benzoic acid - C.I. 13020) under UV irradiation in the presence of nanosized ZnO and TiO2. Oxide nanocrystals with controlled size were synthesised by using non-hydrolytic approaches and tested for the photocatalysed degradation. The performances of the immobilised nanoparticles were compared with their commercial counterparts after immobilization onto a solid support. The influence of some experimental conditions, namely pH and dye concentration, were investigated by monitoring the dye decoloration spectrophotometrically. Several intermediate by-products were identified by HPLC-MS, showing that two different mechanisms were operative during the photocatalytic oxidationsee at: http://www.iwaponline.com/wst/04904/wst049040183.htmopenR. COMPARELLI; P. D. COZZOLI; M. L. CURRI; A. AGOSTIANO; G. MASCOLO; G. LOVECCHIOR., Comparelli; Cozzoli, Pantaleo Davide; M. L., Curri; A., Agostiano; G., Mascolo; G., Lovecchi

Opto‐Electronic Characterization of Photocatalysts Based on p,n‐Junction Ternary and Quaternary Mixed Oxides Semiconductors (Cu2O‐In2O3 and Cu2O‐In2O3‐TiO2)

Semiconductor materials are the basis of electronic devices employed in the communication and media industry. In the present work, we report the synthesis and characterization of mixed metal oxides (MOs) as p,n‐junction photocatalysts, and demonstrate the correlation between the preparation technique and the properties of the materials. Solid‐state UV-visible diffuse reflectance spectroscopy (UV‐VIS DRS) allowed for the determination of the light absorption properties and the optical energy gap. X‐ray photoelectron spectroscopy (XPS) allowed for the determination of the surface speciation and composition and for the determination of the valence band edge. The opto‐electronic behavior was evaluated measuring the photocurrent generated after absorption of chopped visible light in a 3‐electrode cell. Scanning electron microscopy (SEM) measurements allowed for auxiliary characterization of size and morphology, showing the formation of composites for the ternary Cu2O‐In2O3 p,n‐mixed oxide, and even more for the quaternary Cu2O‐In2O3‐TiO2 MO. Light absorption spectra and photocurrent‐time curves mainly depend upon the composition of MOs, while the optical energy gap and defective absorption tail are closely related to the preparation methodology, time and thermal treatment. Qualitative electronic band structures of semiconductors are also presented

UV and solar-based photocatalytic degradation of organic pollutants by nano-sized TiO2 grown on carbon nanotubes

Anew photocatalyst based on nano-sized TiO2 supported on single wall carbon nanotubes (SWCNTs) with tailored photocatalytic properties upon irradiation by both UV and solar simulated light was successfully employed for the degradation of a mixture of 22 organic pollutants in both ultrapure water and real secondary wastewater effluent. First-order degradation rates showed that under UV irradiation nanosized TiO2 supported on SWCNTs is much more effective than conventional Degussa P25 for degradation of iopamidol, iopromide, diatrizoic acid, diclofenac, triclosan and sulfamethoxazole in ultrapure water. For the remaining organics the degradation rates were comparable being in most of the cases Degussa P25 slightly more effective than nano-sized TiO2 supported on SWCNTs. Reactions performed in real secondary wastewater effluent showed a general reduction of degradation rates. Specifically, such a reduction was in the range 9-87% and 9-96% for the Degussa P25 and the nano-sized TiO2 supported on SWCNTs, respectively. Overall, the nano-sized TiO2 supported on SWCNTs under UV irradiation displayed comparable degradation rates with respect to convention Degussa P25. Under simulated solar irradiation the new prepared photocatalyst showed lower efficiency than Degussa P25 in ultrapure water. Such a gap was greatly reduced when the reactions were carried out in real secondary wastewater effluent. The nano-sized TiO2 supported on SWCNTs demonstrated to have the addition benefit to be easily removed from the aqueous solution by a mild centrifugation or a filtration step and, consequently, can be reused for a further photocatalytic treatment batch. Therefore, the obtained results showed that new photocatalyst based on nano-sized TiO2 supported on SWCNTs has proved to be a promising candidate to be used in a photocatalytic based-AOP and to be integrated with a biological step for the effective removal of emerging organic pollutants

Photocatalytic TiO2-Based Nanostructured Materials for Microbial Inactivation

Pathogenic microorganisms can spread throughout the world population, as the currentCOVID-19 pandemic has dramatically demonstrated. In this scenario, a protection against pathogensand other microorganisms can come from the use of photoactive materials as antimicrobial agents ableto hinder, or at least limit, their spreading by means of photocatalytically assisted processes activatedby light—possibly sunlight—promoting the formation of reactive oxygen species (ROS) that can killmicroorganisms in different matrices such as water or different surfaces without affecting humanhealth. In this review, we focus the attention on TiO2nanoparticle-based antimicrobial materials,intending to provide an overview of the most promising synthetic techniques, toward possiblelarge-scale production, critically review the capability of such materials to promote pathogen (i.e.,bacteria, virus, and fungi) inactivation, and, finally, take a look at selected technological applications

Social cognition in people with schizophrenia: A cluster-analytic approach

Background The study aimed to subtype patients with schizophrenia on the basis of social cognition (SC), and to identify cut-offs that best discriminate among subtypes in 809 out-patients recruited in the context of the Italian Network for Research on Psychoses. Method A two-step cluster analysis of The Awareness of Social Inference Test (TASIT), the Facial Emotion Identification Test and Mayer-Salovey-Caruso Emotional Intelligence Test scores was performed. Classification and regression tree analysis was used to identify the cut-offs of variables that best discriminated among clusters. Results We identified three clusters, characterized by unimpaired (42%), impaired (50.4%) and very impaired (7.5%) SC. Three theory-of-mind domains were more important for the cluster definition as compared with emotion perception and emotional intelligence. Patients more able to understand simple sarcasm (14 for TASIT-SS) were very likely to belong to the unimpaired SC cluster. Compared with patients in the impaired SC cluster, those in the very impaired SC cluster performed significantly worse in lie scenes (TASIT-LI <10), but not in simple sarcasm. Moreover, functioning, neurocognition, disorganization and SC had a linear relationship across the three clusters, while positive symptoms were significantly lower in patients with unimpaired SC as compared with patients with impaired and very impaired SC. On the other hand, negative symptoms were highest in patients with impaired levels of SC. Conclusions If replicated, the identification of such subtypes in clinical practice may help in tailoring rehabilitation efforts to the person's strengths to gain more benefit to the person

Eudragit s100 entrapped liposome for curcumin delivery: Anti-oxidative effect in Caco-2 cells

Curcumin is a natural polyphenol with strong antioxidant activity. However, this molecule shows a very poor bioavailability, instability, and rapid metabolism in vivo. In this work curcumin was loaded in Eudragit-coated liposomes to create a gastroresistant carrier, able to protect its load from degradation and free it at the site of absorption in the colon region. Small unilamellar vesicles were prepared and coated with Eudragit by a pH-driven method. The physico-chemical properties of the prepared systems were assessed by light scattering, transmission electron microscopy, infrared spectroscopy, and differential scanning calorimetry. The uptake of vesicles by Caco-2 cells and the anti-oxidant activity in cells were evaluated. The produced vesicles showed dimensions of about forty nanometers that after covering with Eudragit resulted to have micrometric dimensions at acid pH. The experiments showed that at pH > 7.0 the polymeric coating dissolves, releasing the nanometric liposomes and allowing them to enter Caco-2 cells. Delivered curcumin loaded vesicles were then able to decrease significantly ROS levels as induced by H2O2 in Caco-2 cells. The proposed work showed the possibility of realizing effective gastroresistant curcumin liposome formulations for the delivery of antioxidant molecules to Caco-2 cells, potentially applicable to the treatment of pathological conditions related to intestinal oxidative stress. View Full-Tex