Functionalization of polymers and nanomaterials for water treatment, food packaging, textile and biomedical applications: a review

AbstractThe inert nature of most commercial polymers and nanomaterials results in limitations of applications in various industrial fields. This can be solved by surface modifications to improve physicochemical and biological properties, such as adhesion, printability, wetting and biocompatibility. Polymer functionalization allows to graft specific moieties and conjugate molecules that improve material performances. In the last decades, several approaches have been designed in the industry and academia to graft functional groups on surfaces. Here, we review surface decoration of polymers and nanomaterials, with focus on major industrial applications in the medical field, textile industry, water treatment and food packaging. We discuss the advantages and challenges of polymer functionalization. More knowledge is needed on the biology behind cell–polymer interactions, nanosafety and manufacturing at the industrial scale

Materials and processes for 3D printed electronics

Dissertação de mestrado integrado em Engenharia de MateriaisThe traditional manufacturing of electronic components consists of complex and with high environmental impact methods. Those materials are potentially dangerous for both environmental and public health, during the manufacturing process and at the end of the product lifetime when not correctly handled. Thus, the goal consists of producing in a simpler/cheaper way and with lower environmental impact, materials to be used into electronic components. In this work inks based of a natural polymer (carrageenan) and ultrapure water (a “green” solvent) were used to produce more environmentally friendly printable electronic components. To achieve magnetic, conductive and dielectric properties CoFe2O4 (CFO), multiwalled carbon nanotubes (MWCNTs) and BaTiO3 (BTO) nanoparticles were added, respectively. To promote a better dispersion and, therefore, to improve the properties of the final product, Triton X-100 was used as a surfactant. Trition X-100 was selected among other surfactants, since it has shown better results on initial selection tests. For the printing process, the most suitable parameters were selected according to the ink viscosity to improve the process as well as to optimize the method to introduce the ink into the syringe. Morphological, thermal, and mechanical tests were performed in order to evaluate the effects of fillers addition and concentration. Dielectric tests were carried out to the samples with BTO. The higher dielectric constant has been obtained for the sample with 20 wt.% BTO content, reaching 1.3 x 104 at 10 kHz. The electrical conductivity evaluation in the samples with MWCNTs shows that a DC conductivity of 0.026 S.m-1 is achieved for the sample with 5 wt.% MWCTNs content. Vibrating sample magnetometer (VSM) test was performed to analyse the magnetic behaviour of the composite samples with CFO, a saturation magnetization of 11 emu.g-1 being obtained for the samples with 20 wt.% CFO content. The inks developed on this work highlights the relevance of the implementation of natural materials as a base for the development of functional and multifunctional materials. Adding to that, this work can also act as an incentive to the study of materials and manufacturing procedures with lower environmental risks with the capacity of still answering society’s needs.A manufatura tradicional de componentes eletrónicos consiste em métodos complexos, com elevado impacto ambiental, quer por gasto energético quer pelos materiais usados que são potencialmente nocivos para o ambiente e para a saúde pública, durante o processo de fabrico e no final de vida do produto, quando não corretamente processados. Visto isto, o objetivo deste projeto consiste em produzir de um modo simples, com baixo custo e com menor impacto ambiental materiais que possam ser usados em componentes eletrónicos. Assim, neste trabalho foram desenvolvidas tintas à base de um polímero natural (carragenina) e água ultrapura (usada como solvente “verde”) para produzir componentes eletrónicos impressos mais amigos do ambiente. De modo a fornecer propriedades magnéticas, condutivas e dielétricas foram adicionadas nanopartículas de CoFe2O4 (CFO), Multicamadas de Nanotubos de Carbono (MWCNTs) e BaTiO3 (BTO), respetivamente. Para promover uma melhor dispersão foi usado Triton X-100 como surfactante. No processo de impressão foram estudados os parâmetros mais adequados de acordo com a viscosidade da tinta para tornar o processo mais rentável assim como tentar encontrar o melhor método para introduzir a tinta dentro da seringa com a menor formação de bolhas possível. Os testes morfológicos, térmicos e mecânicos foram feitos para todas as amostras para comparar as propriedades fornecidas pela adição das partículas, avaliando a sua interferência com o aumento da concentração de filler. Os testes dielétricos foram realizados para as amostras de BTO. A constante dielétrica com valor mais elevado foi obtido para a amostra com concentração de 20 wt.% BTO, atingindo 1.3 x 104 a 10 kHz. A avaliação dos testes de condutividade elétrica nas amostras de MWCNTs, mostraram uma condutividade DC de 0.026 S.m-1 foi obtida para a mostra com concentração de 5 wt.% MWCTNs. O teste de mapeamento de fluxo de valor (VSM) foi realizado para analisar o comportamento magnético do compósito com partículas de CFO, a magnetização de saturação de 11 emu.g-1 foi obtida para a amostra com concentração de 20 wt.% CFO . As tintas desenvolvidas neste trabalho veem dar relevância à implementação de materiais naturais como base para o desenvolvimento de materiais funcionais e multifuncionais. Vem também promover o estudo de materiais e métodos de produção com menos impacto ambiental e que consigam manter a resposta às necessidades da sociedade

Highlighting the gaps in hazard and risk assessment of unregulated Endocrine Active Substances in surface waters: retinoids as a European case study

Regulatory hazard and risk assessment of endocrine-active substances currently specifies four modes of action: interference with sex hormone (oestrogen, androgen) pathways, steroidogenesis, and thyroid hormone signalling. This does not encompass the full complexity of the endocrine system and its extended interfaces with environmental pollutants that can potentially disrupt the carefully maintained balance. Here we take the retinoid signalling pathway as a European case study for both, under- and unregulated endocrine pathways and outline the different levels of interference, discuss their adversity, and indicate crosstalk to other signalling pathways. Retinoid compounds already exist in drinking water sources, occur naturally in cyanobacterial blooms and/or enter surface waters via wastewater discharge, where they pose a potential hazard to the environment and human health - a situation that can be expected to worsen due to water shortages induced by climate-change and population growth. We briefly review relevant aspects of current endocrine disruptor (ED) testing for regulatory purposes and then expand upon the needs for inclusion of disruption of retinoid signalling in (ED) regulatory safety assessment contributing to adverse health outcomes that include cognitive function and neurological disease. An overview of developmental effects of retinoid signalling disruption across species highlights critical processes and potential crosstalk with other signalling pathways. A focused weight of evidence-based evaluation of the biologically plausible associations between neurological disorders and altered retinoid signalling highlights the evidence gaps. We show that monitoring only a limited number of anthropogenic priority chemicals in water is insufficient to address the environmental risks of retinoid signalling disruption. To comprehensively assess impacts on the endpoints, processes, and pathways of the endocrine system that are most vulnerable to chemical interference we need further investigation of the true mixture composition in environmental matrices. On a weight of evidence-basis this information can then be integrated into a reliable, inclusive, quantitative approach that ultimately accommodates all the critical pathways. By focusing on the retinoid signalling pathway, we intend to improve the scope and relevance of an integrated approach for the risk assessment of endocrine disruptors

ASSESSING THE FATE AND BIOACCUMULATION BEHAVIOR OF LEGACY POPS AND EMERGING CONTAMINANTS IN SINGAPORE'S COASTAL MARINE ECOSYSTEMS

Ph.DDOCTOR OF PHILOSOPH

Sample Preparation-Quo Vadis

Sample preparation is and will always be the most important step in chemical analysis. Numerous techniques, methods, methodologies, and approaches are published in the literature offering a wide range of analytical tools to the lab practitioner. Analytical scientists all over the world are trying to develop protocols for a plethora of analytes in various sample matrices. In the last decade, sample pre-treatment advances have followed green chemistry and green analytical chemistry demands, focusing on miniaturization and automation, using the least possible amount of organic solvents. The question is how far we have been till now, and what the future perspectives are. To answer this question, analytical chemists were invited to share their experience in the field and report on the recent advances in sample-preparation approaches. The outcome of our invitation was eleven excellent manuscripts, including four review articles and seven original research articles in the first edition of the Special Issue “Sample Preparation-Quo Vadis: Current Status of Sample Preparation Approaches”.The second edition is a collection of ten significant contributions to the field of sample preparation. It includes two highly interesting and comprehensive review articles and eight innovative research articles

Development of advanced analytical methods for the determination of emerging pollutants in environmental waters

This thesis work was focused on the analytical determination of emerging pollutants in environmental water matrix, concerning preparative step and analysis using Gas Chromatography coupled with Mass Spectrometry (GCMS). The emerging pollutants are so defined because they have been recognized only recently as pollutants and regulatory and monitoring plans are not yet implemented at Italian and European level. Pharmaceuticals and Personal Care Products (PPCPs) are considered emerging contaminants, they describe a large class of chemical contaminants that can originate from human usage and excretions and veterinary applications. There are a large number of different substances used as medicines, during and after treatment, humans and animals excrete a combination of intact and metabolised pharmaceuticals, many of which are generally soluble in water and have been discharged to the aquatic environment with little evaluation of possible risks or consequences to humans and environment. In addition, the chemicals that are components of personal care products (PCPs) number in the thousands, the world’s people consume enormous quantities of skin care products, dental care products, soaps, sunscreen agents, and hair styling products. PCPs continuously enter the wastewater after their regular use during showering or bathing. Recent studies indicate the potential widespread occurrence on low-level concentrations (ng-μg/L) of PPCPs in the aquatic environment. Therefore, there’s critical need for efficient and reliable analytical methods to address the occurrence concentrations, and fate of the PPCPs in environment. GC-MS has been the basic tool for environmental analyses of various organic pollutants and it has been the approach of this study choice because of its superior separation and identification capabilities. The activity has been concentrated on the development of sample preparation procedures that could be fast, cost-effective and environmentfriendly for the analysis of PPCPs. It’s known that sample pre-treatment causes an analysis bottleneck that typically accounts for over 60% of the total analysis time. The work was focused on evaluation and optimization of different extraction techniques for treatment of water matrix. There are fundamentally two kinds of approach for parameters optimization. One Factor At Time (OFAT) method involves the testing of factors, or causes, one at a time instead of all factors are changed at once. Even more people, prominent text books and academic papers currently favour design of experiments (DOE) approach; it’s a statistically multivariate method for screening and/or optimization of different factors at the same time (multiple factors are changed at once). It shows several relevant advantages over OFAT approach: it requires less runs for the same (sometimes more) precision in effect estimation, it can estimate interactions and it provides a knowledge (and optimal settings of factors) in the whole experimental domain, where OFAT can miss them. For these reasons this approach was chosen for several published works, using in particular Central Composite Design (CCD) or Box-Behnken Design (BBD). Two different extraction procedure have been studied: Solid Phase Extraction (SPE) and Solid Phase Micro Extraction (SPME). The first technique was evaluated in order to optimize extraction step of 25 PCPs, including fragrances, PAHs, antioxidants, UV-filters, plasticizers, and pesticides, from water, using OFAT approach. The optimized parameters were different: SPE sorbent, type and volume of eluent, elution rate, and evaporation procedure. The better recovery yield considering the totality of PCPs were found extracting with a Strata-X SPE cartridge, using a volume of 15 mL of Ethyl Acetate as solvent, operating with slow flow rate, and evaporating at 40°C of temperature. Under these con ditions the procedure achieves a recovery higher than 70% for most PCPs investigated (with LOD ranged from 5 to 10 pg injected on GC), this result makes the developed method suitable for comprehensive chemical profiling of PCPs in various aqueous matrices. It is clear that higher recovery values can be achieved only for selected PCPs using specific target-compound methods. That it was done for method optimization for determination of two synthetic phenolic antioxidants and their five main metabolites in water. This is the first published method dedicated solely to the determination of this chemical class in water samples. The methodology was developed using SPE approach with derivatization before GC-MS analysis. Extraction on 10 mg Oasis HLB cartridges provides a satisfactory enrichment factor for environmental samples avoiding the need of solvent evaporation and reducing SPE costs and organic solvent wastes. After extraction, polar metabolites are derivatized with MTBSTFA to produce stable, less polar analytes that are determined by GC-MS at low levels. The usage of two surrogate internal standards results in a method providing good accuracy, with relative recoveries between 80 and 110%, and limits of detection (2-44 ng/L). The application of the method to wastewater and river samples showed BHT and BHT-Q as the compounds in higher concentrations in wastewater (up to 800 ng/L) and the metabolites BHT-CHO and BHTCOOH as the most resistant to water treatment, being at the 10-100 ng/L in sewage and river samples. In this work the optimization was done with an experimental design approach, using a Box-Behnken design (BBD). This work was developed in collaboration with University of Santiago de Compostela (E). SPME technique was investigated in order to extract a mixture of several PCPs, evaluating extraction time and temperature and desorption time and temperature. A simple SPME method has been developed for the simultaneous GC-MS determination of 23 PCPs (i.e. antioxidants, PAHs, UV-filters, pesticides, fragrances, plasticizers, that display log Kow values > 3.2) at trace levels in water. An Inscribed Central Composite (CCI) design approach was employed for investigate extraction temperature and time, and desorption temperature and time. A direct immersion mode was used for extraction from a fixed sample volume. The optimum SPME operating conditions have been defined as: extraction time of 90 min at a temperature of 80°C, desorption time of 11 min at 260°C. Under these conditions the procedure provides low detection limits (<= ppb) and satisfactory reproducibility (RSD%<=1%) for most of the PCPs investigated. The analysis was then extended to more polar compounds, for a total of 21 PPCPs that display a range of log Kow between 1.2 and 6.4 (i.e. antiseptic, antinflammatory drugs, estrogens, UV-filters) with the necessity of derivatize the compounds before GC analysis. A on-fiber after extraction approach was chosen for SPME derivatization, using silylation agent. The derivatization can be performed in only 30.5 minutes with a very small consumption of silylation reagent and without need of high temperature. Under the optimized conditions of extraction, derivatization and desorption, the procedure provides low detection limits (<= 1 ppb for the non polar analytes and <=35 ppb for the derivatized ones) and satisfactory reproducibility (RSD% <=10% or 20%) for most of the PPCPs investigated. The PhD project, in his totality, was a logic progressive work, expanding the study in term of kind of analytes studied, extraction techniques and optimization approach. A preliminary and careful study was carried out in order to properly understand the current situation and the possible research developments of interest. The study was initially focused on less polar analytes (PCPs), then extending to more polar ones (PPCPs). It was firstly took in consideration the SPE technique, going to more innovative and preferable on several points of view SPME. The expanded range (in particular polarity range) of analytes makes necessary a derivatization step before GC-MS analysis, for these reason the subsequent step was the optimization of a method that includes SPME-derivatization. Also considering the optimization approach, the work started using OFAT optimization, this approach was left after the first work for the more accurate and precise DOE. These works led to development of multiresidual analytical method suitable for the comprehensive analysis of this kind of pollutants in water matrix. These methodologies may be the basis of water monitoring for temporal and spatial changes

Investigation of androgen receptor antagonist compounds present in influent and effluent from a wastewater works

A wide range of synthetic chemicals and their metabolites present in the environment can antagonise the receptor activity of androgen hormones present in wildlife and humans. With increasing global production of new synthetic chemicals, little is known about their environmental fate, health consequences and end-points. This study was conducted to identify and characterise chemicals with anti-androgenic activity present in wastewater influent and effluent. This study was undertaken by applying a combination of biological and analytical chemistry techniques involving Solid Phase Extraction (SPE), High Performance Liquid Chromatography (HPLC) and an in vitro steroid receptor assay for profiling and characterising extracts of grab influent and effluent wastewater samples using a toxicity identification and evaluation (TIE) procedure. Initial work revealed variable recoveries of anti-androgenic activity from SPE of wastewaters. Therefore SPE methodology to screen wastewater samples was developed using a mixture of selected compounds which possess a range of polarities (log Kow). Their recoveries from SPE were measured by HPLC protocol and ranged from 95- 100%. The mean±SD and % RSD values of the analysed wastewater replicates were 3.20±0.03 mgFeq/L and 0.78% for influent and 0.22±0.01 mgFeq/L and 3.80% for effluent samples. The recoveries of wastewater extracts after fractionation were between 78.6% and 99.6%. Fractions containing anti-androgenic activity were analysed by Gas Chromatography Mass Spectrometry (GC-MS). A number of household chemicals were detected in both influent and effluent wastewater fractions that contained antiandrogenic activity. These included the anti-bacterial agents- triclosan, chlorophene, dichlorophene, chloroxylenol, the musk fragrance galaxolide, the flame retardantstris( 1-chloro-2-propyl)phosphate (TCPP) and tris(2-butoxyethyl)phosphate (TBEP), polymer plasticizer n-butylbenzenesulfonamide (NBBSA) and bisphenol A (BPA) which is a chemical associated with the polycarbonate usage. The anti-androgenic potency of pure contaminants compared with that of flutamide ranged from 0.04 (TCPP) to 13.40 (chlorophene). Anti-androgenic activity of 1.69 and 2.00% was recovered from the fractions of the effluent and influent samples respectively indicating that AA of about 98% are yet to be recovered. This work reveals for the first time that over 12 contaminants contribute to the total anti-androgenic activity present in wastewater effluent and that a number of compounds commonly used in household products (such as chlorophene, triclosan and NBBSA) are predominant anti-androgens in wastewater effluents

Persistente organiske miljøgifter : deres påvirkning på adferd og utvikling av tykktarmskreft

Persistent organic pollutants (POPs) are a class of chemicals formerly widely used by the production industry and as pesticides in agriculture. Some of them are suspected endocrine disruptors and may interfere with hormone homeostasis, while others are carcinogenic. In order to study the effect of a mixture of these chemicals on cognition, stress responses, and the development of cancer, a Scandinavian diet-based mixture of 29 POPs was designed to add to an experimental diet. Before the exposure studies, a small-scale study was done, to assess the performance of two different mouse strains in the different behavior tests going to be used in the behavior project. Then, two exposure studies were conducted. Firstly, a behavior project, where we investigated if early-life exposure to POPs affected anxiety, using an open field (OF) test, stress responses, using a restraint stress test, as well as spatial learning and memory, using a Barnes maze (BM) test and by analyzing hippocampal gene expression. The aim of the second project was to see if POP exposure affects the development of intestinal cancer, by exposing a different strain of mice, prone to intestinal cancer, to the same experimental diet and analyzing their intestines for cancer lesions. The results from the behavior tests show that exposure to POPs had no effect on anxiety, but the restraint stress test indicated dysregulation of the hypothalamic-pituitary-adrenal axis and corticosterone secretion by exposure to the highest dose of the POP mixture. Minor group differences in BM performance were probably due to differences in stress susceptibility, rather than a true effect on learning. However, changes in the expression of genes connected to learning and memory were observed. These changes could interfere with behavioral outcomes, either directly or as compensation for POP-induced learning deficits. In addition, the results from the cancer project show that exposure to the mixture of POPs moderately increased the intestinal tumorigenesis in a mouse model of spontaneous intestinal neoplasia. In conclusion, exposure to this human-relevant mixture of POPs did alter the stress response in mice and changed the expression of genes connected to learning and memory. In addition, exposure to the mixture of POPs increased the risk of colorectal cancer in mice.Tungt nedbrytbare, organiske miljøgifter (persistent organic pollutants) er en gruppe kjemikalier som tidligere var i utstrakt bruk i industri og som plantevernmidler i landbruket. Noen av dem er mistenkt for å ha hormonforstyrrende effekter som kan endre kroppens hormonbalanse, mens noen også har vist seg å være kreftfremkallende. For å undersøke effekten av en blanding av disse kjemikaliene på kognisjon, kroppens respons på stress og utvikling av kreft, laget vi en mikstur med 29 miljøgifter, basert på kjente nivåer i den skandinaviske dietten. Før eksponeringsstudiene ble gjennomført, gjorde vi et småskalaforsøk, uten miljøgifteksponering, for å sammenlikne hvordan to ulike muse-typer gjorde det i de forskjellige testene i adferds-forsøket. Dermed ble to eksponeringsstudier gjennomført. Først, et adferds-forsøk hvor vi undersøkte om miljøgifteksponering tidlig i livet påvirket musenes fryktreaksjon, med en open field (OF) test, stressrespons, med en fengslings-stress test, læring og hukommelse, med en Barnes maze (BM) test og genuttrykket i hippocampus, et hjerneavsnitt viktig for læring, ble også målt. I det andre eksponeringsforsøket undersøkte vi om miljøgifter påvirket utviklingen av tarmkreft hos en muse-type som er utsatt for å få tarmkreft, ved å eksponere dem for den samme miksturen og analyserte tarmene deres for kreft-lesjoner. Resultatene viste at eksponering for denne miksturen av miljøgifter har ingen effekt på angst, men fengslings-stresstesten viste at eksponering for høy dose av POP miksturen førte til dysregulering av HPA-aksen og kortikosteron-sekresjonen. Den lille effekten på læring og hukommelse som ble observert i BM, var trolig et resultat av forskjeller i stressfølsomhet mellom gruppene, heller enn en direkte kognitiv effekt. Videre viste genekspresjonsanalysen at uttrykket av enkelte gener som kan knyttes til læring og hukommelse var endret, noe som kan påvirke atferd direkte eller kompensere for POP-induserte læringsdefekter. I tillegg viste resultatet fra kreftforsøket at eksponering for denne miksturen av miljøgifter kan bidra til en moderat utvikling av tarmkreft. Konklusjonen er derfor at eksponering for denne blandingen av miljøgifter påvirker stressresponsen i mus og genekspresjon av gener som kan knyttes til læring og hukommelse. I tillegg kan eksponering for den samme blandingen øke risikoen for tarmkreft hos mus.Norges forskningsrå