A comparative study of alginate beads and an ion-exchange resin for the removal of heavy metals from a metal plating effluent

The capacity of dry protonated calcium alginate beads to sorb metals from an industrial effluent was studied and compared with a commercial ion-exchange resin (Lewatit TP 207). Both sorbents decreased zinc, nickel, iron and calcium concentrations in the effluent, and released sodium during treatment. Alginate beads removed lower amounts of heavy metals than the resin, but exhibited faster uptake kinetics. Zinc desorption from the sorbents was achieved in 30 minutes using 0.1 M HCl or 0.1 M H(2)SO(4). Desorption ratios with these acids varied between 90 and 100% for alginate, and 98 to 100% for the ion-exchange resin. Reusability tests with HCl showed that alginate beads can stand acid desorption and recover binding capacity. Overall, the comparison of dry protonated alginate beads with the resin supports the potential of the biosorbent for the treatment of industrial effluents.

Hydrogen production by enhanced methane reforming with membrane reactors or with CO2 capture materials

Pure hydrogen production from methane is a multi-step process run on a large scale for economic reasons. However, hydrogen can be produced in a one-pot continuous process for small scale applications, namely Low Temperature Steam Reforming. Here, Steam Reforming is carried out in a reactor whose walls are composed by a membrane selective toward hydrogen. Pd is the most used membrane material due to its high permeability and selectivity. However, Pd deteriorates at temperatures higher than 500°C, thus the operative temperature of the reaction has to be lowered. However, the employment of a membrane reactor may allow to give high yields thanks to hydrogen removal, which shifts the reaction toward the products. Moreover, pure hydrogen is produced. This work is concentrated on the synthesis of a catalytic system and the investigation of its performances in different processes, namely oxy-reforming, steam reforming and water gas shift, to find appropriate conditions for hydrogen production in a catalytic membrane reactor. The catalyst supports were CeZr and Zr oxides synthesized by microemulsion, impregnated with different noble metals. Pt, Rh and PtRh based catalysts were tested in the oxy reforming process at 500°C, where Rh on CeZr gave the most interesting results. On the opposite, the best performances in low temperature steam reforming were obtained with Rh impregnated on Zr oxide. This catalyst was selected to perform low temperature steam reforming in a Pd membrane reactor. The hydrogen removal given by the membrane allowed to increase the methane conversion over the equilibrium of a classical fixed bed reactor thanks to an equilibrium shift effect. High hydrogen production and recoveries were also obtained, and no other compound permeated through the membrane which proved to be hydrogen selective.

Development, mechanical characterization and qualification in liquid lead of stainless steels for structural applications in the future fission and fusion nuclear reactors

The research activity carried out in the Brasimone Research Center of ENEA concerns the development and mechanical characterization of steels conceived as structural materials for future fission reactors (Heavy Liquid Metal IV Generation reactors: MYRRHA and ALFRED) and for the future fusion reactor DEMO. Within this framework, two parallel lines of research have been carried out: (i) characterization in liquid lead of steels and weldings for the components of the IV Generation fission reactors (GIV) by means of creep and SSRT (Slow Strain Rate Tensile) tests; (ii) development and screening on mechanical properties of RAFM (Reduced Activation Ferritic Martensitic) steels to be employed as structural materials of the future DEMO fusion reactor. The doctoral work represents therefore a comprehensive report of the research carried out on nuclear materials both from the point of view of the qualification of existing (commercial) materials for their application in the typical environmental conditions of 4th generation fission reactors operating with lead as coolant, and from the point of view of the metallurgical study (with annexed microstructural and mechanical characterization of the selected compositions / Thermo Mechanical Treatment (TMT) options) of new compositional variants to be proposed for the “Breeding Blanket” of the future DEMO Fusion Reactor.

Development of a Whole-Genome Sequencing (WGS) approach for the characterization of Legionella environmental isolates in water systems

Legionella is a Gram-negative bacterium that represent a public health issue, with heavy social and economic impact. Therefore, it is mandatory to provide a proper environmental surveillance and risk assessment plan to perform Legionella control in water distribution systems in hospital and community buildings. The thesis joins several methodologies in a unique workflow applied for the identification of non-pneumophila Legionella species (n-pL), starting from standard methods as culture and gene sequencing (mip and rpoB), and passing through innovative approaches as MALDI-TOF MS technique and whole genome sequencing (WGS). The results obtained, were compared to identify the Legionella isolates, and lead to four presumptive novel Legionella species identification. One of these four new isolates was characterized and recognized at taxonomy level with the name of Legionella bononiensis (the 64th Legionella species). The workflow applied in this thesis, help to increase the knowledge of Legionella environmental species, improving the description of the environment itself and the events that promote the growth of Legionella in their ecological niche. The correct identification and characterization of the isolates permit to prevent their spread in man-made environment and contain the occurrence of cases, clusters, or outbreaks. Therefore, the experimental work undertaken, could support the preventive measures during environmental and clinical surveillance, improving the study of species often underestimated or still unknown.

Heavy Metals distribution in drainage canals sediments of the Ravenna province

This work, in collaboration with the Romagna Reclamation Consortium, has the aim of studying the heavy metals concentration distribution in the drainage canals of the Ravenna coastal basins, Italy. Particular attention was given to the area of the V Fosso Ghiaia and VI Bevanella basins, where water and sediment samples were collected in the field and integrated with existing databases. The hydrological regime is controlled and managed by the Consortium, which has divided the territory into several mechanical drainage basins. XRF was performed on 21 sediment samples and pH, EC, T°, Fe2+ and Fetot were measured on 15 water samples by probes and spectrophotometer, respectively. Heavy metals concentrations exceeding legal limits of the D.LGS n ° 152/2006 were found for As, Co, Cr, Pb and Zn. These results were then integrated with canal sediment analyses provided by the Consortium to perform a Principal Component Analysis. PCA results show that the main variable affecting heavy metals distribution is the use of fertilizers, followed by distance from sea, and altimetry, which are directly linked to salinity. Heavy metals concentrations increase with increasing use of fertilizers, which are mainly due to the widespread agricultural practices and industrial land use in the area. High heavy metals concentrations are also found in the canals interested by higher salinity (especially Pinetale Ramazzotti). In fact, the area is affected by salinization caused by a water table below sea level and upward seepage of salty oxygen-poor saline water from the bottom of the aquifer. According to the literature, iron and manganese oxides were found to be an important factor in controlling the heavy metals distribution.

Data analysis and hydrological modelling of rainfall and discharge extremes along the Tione River: implications for the design of water structures

There are many natural events that can negatively affect the urban ecosystem, but weather-climate variations are certainly among the most significant. The history of settlements has been characterized by extreme events like earthquakes and floods, which repeat themselves at different times, causing extensive damage to the built heritage on a structural and urban scale. Changes in climate also alter various climatic subsystems, changing rainfall regimes and hydrological cycles, increasing the frequency and intensity of extreme precipitation events (heavy rainfall).  From an hydrological risk perspective, it is crucial to understand future events that could occur and their magnitude in order to design safer infrastructures. Unfortunately, it is not easy to understand future scenarios as the complexity of climate is enormous.  For this thesis, precipitation and discharge extremes were primarily used as data sources. It is important to underline that the two data sets are not separated: changes in rainfall regime, due to climate change, could significantly affect overflows into receiving water bodies. It is imperative that we understand and model climate change effects on water structures to support the development of adaptation strategies.   The main purpose of this thesis is to search for suitable water structures for a road located along the Tione River. Therefore, through the analysis of the area from a hydrological point of view, we aim to guarantee the safety of the infrastructure over time.   The observations made have the purpose to underline how models such as a stochastic one can improve the quality of an analysis for design purposes, and influence choices.

Thermodynamic Study Of The Micellization Of Zwitterionic Surfactants And Their Interaction With Polymers In Water By Isothermal Titration Calorimetry.

The micellization of a homologous series of zwitterionic surfactants, a group of sulfobetaines, was studied using isothermal titration calorimetry (ITC) in the temperature range from 15 to 65 °C. The increase in both temperature and the alkyl chain length leads to more negative values of ΔGmic(0) , favoring the micellization. The entropic term (ΔSmic(0)) is predominant at lower temperatures, and above ca. 55-65 °C, the enthalpic term (ΔHmic(0)) becomes prevalent, figuring a jointly driven process as the temperature increases. The interaction of these sulfobetaines with different polymers was also studied by ITC. Among the polymers studied, only two induced the formation of micellar aggregates at lower surfactant concentration: poly(acrylic acid), PAA, probably due to the formation of hydrogen bonds between the carboxylic group of the polymer and the sulfonate group of the surfactant, and poly(sodium 4-styrenesulfonate), PSS, probably due to the incorporation of the hydrophobic styrene group into the micelles. The prevalence of the hydrophobic and not the electrostatic contributions to the interaction between sulfobetaine and PSS was confirmed by an increased interaction enthalpy in the presence of electrolytes (NaCl) and by the observation of a significant temperature dependence, the latter consistent with the proposed removal of hydrophobic groups from water.

Phylogenetic Analysis Of The Microbial Community In Hypersaline Petroleum Produced Water From The Campos Basin.

In this work the archaea and eubacteria community of a hypersaline produced water from the Campos Basin that had been transported and discharged to an onshore storage facility was evaluated by 16S recombinant RNA (rRNA) gene sequence analysis. The produced water had a hypersaline salt content of 10 (w/v), had a carbon oxygen demand (COD) of 4,300 mg/l and contains phenol and other aromatic compounds. The high salt and COD content and the presence of toxic phenolic compounds present a problem for conventional discharge to open seawater. In previous studies, we demonstrated that the COD and phenolic content could be largely removed under aerobic conditions, without dilution, by either addition of phenol degrading Haloarchaea or the addition of nutrients alone. In this study our goal was to characterize the microbial community to gain further insight into the persistence of reservoir community members in the produced water and the potential for bioremediation of COD and toxic contaminants. Members of the archaea community were consistent with previously identified communities from mesothermic reservoirs. All identified archaea were located within the phylum Euryarchaeota, with 98 % being identified as methanogens while 2 % could not be affiliated with any known genus. Of the identified archaea, 37 % were identified as members of the strictly carbon-dioxide-reducing genus Methanoplanus and 59 % as members of the acetoclastic genus Methanosaeta. No Haloarchaea were detected, consistent with the need to add these organisms for COD and aromatic removal. Marinobacter and Halomonas dominated the eubacterial community. The presence of these genera is consistent with the ability to stimulate COD and aromatic removal with nutrient addition. In addition, anaerobic members of the phyla Thermotogae, Firmicutes, and unclassified eubacteria were identified and may represent reservoir organisms associated with the conversion hydrocarbons to methane.

Caffeine As An Indicator Of Estrogenic Activity In Source Water.

Caffeine has already been used as an indicator of anthropogenic impacts, especially the ones related to the disposal of sewage in water bodies. In this work, the presence of caffeine has been correlated with the estrogenic activity of water samples measured using the BLYES assay. After testing 96 surface water samples, it was concluded that caffeine can be used to prioritize samples to be tested for estrogenic activity in water quality programs evaluating emerging contaminants with endocrine disruptor activity.

Culturable Bacterial Diversity From A Feed Water Of A Reverse Osmosis System, Evaluation Of Biofilm Formation And Biocontrol Using Phages.

Biofilm formation on reverse osmosis (RO) systems represents a drawback in the application of this technology by different industries, including oil refineries. In RO systems the feed water maybe a source of microbial contamination and thus contributes for the formation of biofilm and consequent biofouling. In this study the planktonic culturable bacterial community was characterized from a feed water of a RO system and their capacities were evaluated to form biofilm in vitro. Bacterial motility and biofilm control were also analysed using phages. As results, diverse Protobacteria, Actinobacteria and Bacteroidetes were identified. Alphaproteobacteria was the predominant group and Brevundimonas, Pseudomonas and Mycobacterium the most abundant genera. Among the 30 isolates, 11 showed at least one type of motility and 11 were classified as good biofilm formers. Additionally, the influence of non-specific bacteriophage in the bacterial biofilms formed in vitro was investigated by action of phages enzymes or phage infection. The vB_AspP-UFV1 (Podoviridae) interfered in biofilm formation of most tested bacteria and may represent a good alternative in biofilm control. These findings provide important information about the bacterial community from the feed water of a RO system that may be used for the development of strategies for biofilm prevention and control in such systems.

Bacterial Diversity Assessment In Soil Of An Active Brazilian Copper Mine Using High-throughput Sequencing Of 16s Rdna Amplicons.

Mining activities pose severe environmental risks worldwide, generating extreme pH conditions and high concentrations of heavy metals, which can have major impacts on the survival of organisms. In this work, pyrosequencing of the V3 region of the 16S rDNA was used to analyze the bacterial communities in soil samples from a Brazilian copper mine. For the analysis, soil samples were collected from the slopes (geotechnical structures) and the surrounding drainage of the Sossego mine (comprising the Sossego and Sequeirinho deposits). The results revealed complex bacterial diversity, and there was no influence of deposit geographic location on the composition of the communities. However, the environment type played an important role in bacterial community divergence; the composition and frequency of OTUs in the slope samples were different from those of the surrounding drainage samples, and Acidobacteria, Chloroflexi, Firmicutes, and Gammaproteobacteria were responsible for the observed difference. Chemical analysis indicated that both types of sample presented a high metal content, while the amounts of organic matter and water were higher in the surrounding drainage samples. Non-metric multidimensional scaling (N-MDS) analysis identified organic matter and water as important distinguishing factors between the bacterial communities from the two types of mine environment. Although habitat-specific OTUs were found in both environments, they were more abundant in the surrounding drainage samples (around 50 %), and contributed to the higher bacterial diversity found in this habitat. The slope samples were dominated by a smaller number of phyla, especially Firmicutes. The bacterial communities from the slope and surrounding drainage samples were different in structure and composition, and the organic matter and water present in these environments contributed to the observed differences.

Water Stress Reveals Differential Antioxidant Responses Of Tolerant And Non-tolerant Sugarcane Genotypes.

The biochemical responses of the enzymatic antioxidant system of a drought-tolerant cultivar (IACSP 94-2094) and a commercial cultivar in Brazil (IACSP 95-5000) grown under two levels of soil water restriction (70% and 30% Soil Available Water Content) were investigated. IACSP 94-2094 exhibited one additional active superoxide dismutase (Cu/Zn-SOD VI) isoenzyme in comparison to IACSP 95-5000, possibly contributing to the heightened response of IACSP 94-2094 to the induced stress. The total glutathione reductase (GR) activity increased substantially in IACSP 94-2094 under conditions of severe water stress; however, the appearance of a new GR isoenzyme and the disappearance of another isoenzyme were found not to be related to the stress response because the cultivars from both treatment groups (control and water restrictions) exhibited identical changes. Catalase (CAT) activity seems to have a more direct role in H2O2 detoxification under water stress condition and the shift in isoenzymes in the tolerant cultivar might have contributed to this response, which may be dependent upon the location where the excessive H2O2 is being produced under stress. The improved performance of IACSP 94-2094 under drought stress was associated with a more efficient antioxidant system response, particularly under conditions of mild stress.

Clustering Of Water Bodies In Unpolluted And Polluted Environments Based On Escherichia Coli Phylogroup Abundance Using A Simple Interaction Database.

Different types of water bodies, including lakes, streams, and coastal marine waters, are often susceptible to fecal contamination from a range of point and nonpoint sources, and have been evaluated using fecal indicator microorganisms. The most commonly used fecal indicator is Escherichia coli, but traditional cultivation methods do not allow discrimination of the source of pollution. The use of triplex PCR offers an approach that is fast and inexpensive, and here enabled the identification of phylogroups. The phylogenetic distribution of E. coli subgroups isolated from water samples revealed higher frequencies of subgroups A1 and B23 in rivers impacted by human pollution sources, while subgroups D1 and D2 were associated with pristine sites, and subgroup B1 with domesticated animal sources, suggesting their use as a first screening for pollution source identification. A simple classification is also proposed based on phylogenetic subgroup distribution using the w-clique metric, enabling differentiation of polluted and unpolluted sites.

Effect Of Sodium Hypochlorite And Peracetic Acid On The Surface Roughness Of Acrylic Resin Polymerized By Heated Water For Short And Long Cycles.

To evaluate the surface roughness of acrylic resin submitted to chemical disinfection via 1% sodium hypochlorite (NaClO) or 1% peracetic acid (C2H4O3). The disc-shaped resin specimens (30 mm diameter ×4 mm height) were polymerized by heated water using two cycles (short cycle: 1 h at 74°C and 30 min at 100°C; conventional long cycle: 9 h at 74°C). The release of substances by these specimens in water solution was also quantified. Specimens were fabricated, divided into four groups (n = 10) depending on the polymerization time and disinfectant. After polishing, the specimens were stored in distilled deionized water. Specimens were immersed in 1% NaClO or 1% C2H4O3 for 30 min, and then were immersed in distilled deionized water for 20 min. The release of C2H4O3 and NaClO was measured via visual colorimetric analysis. Roughness was measured before and after disinfection. Roughness data were subjected to two-way ANOVA and Tukey's test. There was no interaction between polymerization time and disinfectant in influencing the average surface roughness (Ra, P = 0.957). Considering these factors independently, there were significant differences between short and conventional long cycles (P = 0.012), but no significant difference between the disinfectants hypochlorite and C2H4O3 (P = 0.366). Visual colorimetric analysis did not detect release of substances. It was concluded that there was the difference in surface roughness between short and conventional long cycles, and disinfection at acrylic resins polymerized by heated water using a short cycle modified the properties of roughness.

A Feasibility Study Of Fricke Dosimetry As An Absorbed Dose To Water Standard For 192ir Hdr Sources.

High dose rate brachytherapy (HDR) using 192Ir sources is well accepted as an important treatment option and thus requires an accurate dosimetry standard. However, a dosimetry standard for the direct measurement of the absolute dose to water for this particular source type is currently not available. An improved standard for the absorbed dose to water based on Fricke dosimetry of HDR 192Ir brachytherapy sources is presented in this study. The main goal of this paper is to demonstrate the potential usefulness of the Fricke dosimetry technique for the standardization of the quantity absorbed dose to water for 192Ir sources. A molded, double-walled, spherical vessel for water containing the Fricke solution was constructed based on the Fricke system. The authors measured the absorbed dose to water and compared it with the doses calculated using the AAPM TG-43 report. The overall combined uncertainty associated with the measurements using Fricke dosimetry was 1.4% for k = 1, which is better than the uncertainties reported in previous studies. These results are promising; hence, the use of Fricke dosimetry to measure the absorbed dose to water as a standard for HDR 192Ir may be possible in the future.