Cross-sectional imaging after pancreatic surgery: The dialogue between the radiologist and the surgeon.

Pancreatic surgery is nowadays considered one of the most complex surgical approaches and not unscathed from complications. After the surgical procedure, cross-sectional imaging is considered the non-invasive reference standard to detect early and late compilations, and consequently to address patients to the best management possible. Contras-enhanced computed tomography (CECT) should be considered the most important and useful imaging technique to evaluate the surgical site. Thanks to its speed, contrast, and spatial resolution, it can help reach the final diagnosis with high accuracy. On the other hand, magnetic resonance imaging (MRI) should be considered as a second-line imaging approach, especially for the evaluation of biliary findings and late complications. In both cases, the radiologist should be aware of protocols and what to look at, to create a robust dialogue with the surgeon and outline a fitted treatment for each patient.

Health needs and perception of health care quality among Asylum Seekers and Refugees in an Italian local health authority: A qualitative study.

Background: Migrants, Asylum Seekers and Refugees (ASRs) represent a vulnerable diversified population with increased risks of developing health problems, and in the hosting countries several barriers often hamper their access to the health services. Gathering information about ASRs' experiences and perceptions of host country health care systems may contribute to improve the quality of health care provided. The aim of this study was to explore the health needs in their bio-psycho-social meaning, and the quality of health care as perceived from the ASRs' perspective. Methods: The qualitative descriptive study was conducted as part of the Project "G-START - testing a governance model of receiving and taking care of the Asylum Seekers and Refugees." Through purposeful and snowball sampling, four Focus Groups conducted in English, Italian and French were carried out between July and August 2019, involving 50 ASRs hosted by four reception centers located on the territory pertaining to an Italian Local Health Authority covering a general population of 500.000 people. The analysis of data was categorical, and was performed using N-Vivo software. Results: The macro-categories emerged were the ASRs' bio-psycho-social health needs, including mental health, sexual and reproductive health, food and nutrition, knowledge of the health care system, need for inclusion; healthcare services access, including barriers before and after the access and the ability of the local health system to respond to existing and evolving demands; strengths of the healthcare and reception systems, and suggestions for improving them in the future. Discussion and conclusions: ASRs present vulnerabilities and specific health needs, and the health care system is not always able to guarantee access or to respond to these needs. Several obstacles have been highlighted, such as linguistic barriers and lack of cultural mediation, bureaucratic and administrative barriers, lack of knowledge of the Italian health care system. An effective reorganization of services driven by a more detailed output analysis of the target population needs, together with the use of cultural mediation, peer to peer education and support, and the training of health professionals are recommended to ensure a more accessible, equitable and effective health care system at local level.

The rs599839 A>G Variant Disentangles Cardiovascular Risk and Hepatocellular Carcinoma in NAFLD Patients.

BACKGROUND AND AIMS: Dyslipidemia and cardiovascular diseases (CVD) are comorbidities of nonalcoholic fatty liver disease (NAFLD), which ranges from steatosis to hepatocellular carcinoma (HCC). The rs599839 A>G variant, in the CELSR2-PSRC1-SORT1 gene cluster, has been associated CVD, but its impact on metabolic traits and on the severity liver damage in NAFLD has not been investigated yet. METHODS: We evaluated the effect of the rs599839 variant in 1426 NAFLD patients (Overall cohort) of whom 131 had HCC (NAFLD-HCC), in 500,000 individuals from the UK Biobank Cohort (UKBBC), and in 366 HCC samples from The Cancer Genome Atlas (TCGA). Hepatic PSRC1, SORT1 and CELSR2 expressions were evaluated by RNAseq (n = 125). RESULTS: The rs599839 variant was associated with reduced circulating LDL, carotid intima-media thickness, carotid plaques and hypertension (p < 0.05) in NAFLD patients and with protection against dyslipidemia in UKBBC. The minor G allele was associated with higher risk of HCC, independently of fibrosis severity (odds ratio (OR): 5.62; 95% c.i. 1.77-17.84, p = 0.003), poor prognosis and advanced tumor stage (p < 0.05) in the overall cohort. Hepatic PSRC1, SORT1 and CELSR2 expressions were increased in NAFLD patients carrying the rs599839 variant (p < 0.0001). SORT1 mRNA levels negatively correlated with circulating lipids and with those of genes involved in lipoprotein turnover (p < 0.0001). Conversely, PSRC1 expression was positively related to that of genes implicated in cell proliferation (p < 0.0001). In TCGA, PSRC1 over-expression promoted more aggressive HCC development (p < 0.05). CONCLUSIONS: In sum, the rs599839 A>G variant is associated with protection against dyslipidemia and CVD in NAFLD patients, but as one it might promote HCC development by modulating SORT1 and PSRC1 expressions which impact on lipid metabolism and cell proliferation, respectively.

Ceruloplasmin gene variants are associated with hyperferritinemia and increased liver iron in patients with NAFLD.

BACKGROUND & AIMS: Non-alcoholic fatty liver disease (NAFLD) is a multifactorial disorder resulting from genetic and environmental factors. Hyperferritinemia has been associated with increased hepatic iron stores and worse outcomes in patients with NAFLD. The aim of this study was to evaluate the prevalence of variants of iron-related genes and their association with hyperferritinemia, hepatic iron stores and liver disease severity in patients with NAFLD. METHODS: From a cohort of 328 individuals with histological NAFLD, 23 patients with ferritin >750 ng/ml and positive iron staining, and 25 controls with normal ferritin and negative iron staining, were selected. Patients with increased transferrin saturation, anemia, inflammation, ß-thalassemia trait, HFE genotype at risk of iron overload and ferroportin mutations were excluded. A panel of 32 iron genes was re-sequenced. Literature and in silico predictions were employed for prioritization of pathogenic mutations. RESULTS: Patients with hyperferritinemia had a higher prevalence of potentially pathogenic rare variants (73.9% vs. 20%, p = 0.0002) associated with higher iron stores and more severe liver fibrosis (p <0.05). Ceruloplasmin was the most mutated gene and its variants were independently associated with hyperferritinemia, hepatic siderosis, and more severe liver fibrosis (p <0.05). In the overall cohort, ceruloplasmin variants were independently associated with hyperferritinemia (adjusted odds ratio 5.99; 95% CI 1.83-19.60; p = 0.0009). CONCLUSIONS: Variants in non-HFE iron genes, particularly ceruloplasmin, are associated with hyperferritinemia and increased hepatic iron stores in patients with NAFLD. Carriers of such variants have more severe liver fibrosis, suggesting that genetic predisposition to hepatic iron deposition may translate into liver disease. LAY SUMMARY: Non-alcoholic fatty liver disease (NAFLD) is a common disease which can progress to cirrhosis and liver cancer. Increased levels of serum ferritin are often detected in patients with NAFLD and have been associated with altered iron metabolism and worse patient outcomes. We found that variants of genes related to iron metabolism, particularly ceruloplasmin, are associated with high ferritin levels, hepatic iron deposition and more severe liver disease in an Italian cohort of patients with NAFLD.

New insights into the radiolytic stability of metal(iv) phosphonate hybrid adsorbent materials.

Stable metal(iv) phosphonate hybrids are a promising class of materials for the critical issue of nuclear waste cleanup. However, to be of practical use, adsorbent materials must demonstrate radiolytic stability and this property remains poorly understood. Therefore, the radiolytic stabilities of post-functionalised mesoporous zirconium titanate and zirconium phosphonate coordination polymers were compared. For the first time, solid-state 31P MAS-NMR was used to probe the radiolytic degradation of metal(iv) phosphonates and provide mechanistic insight. Polyphosphonate-functionalized hybrids were more stable than monophosphonate hybrids, as the monophosphonate readily detached from the oxide surface. The zirconium phosphonate coordination polymer (Zr-ATMP) demonstrated the greatest radiolytic stability, attributed to its high ligand loading and intimately mixed structure. Zr-ATMP maintained highly efficient sorption from strongly acidic solutions even after receiving doses of gamma radiation up to 2.9 MGy.

Actinide and Lanthanide Adsorption onto Hierarchically Porous Carbons Beads: A High Surface Affinity for Pu.

Structured carbon adsorbents were prepared by carbonizing macroporous polyacrylonitrile beads whose pores were lined with a mesoporous phenolic resin. After activation, the beads were tested for minor actinide (Np and Am), major actinide (Pu and U) and lanthanide (Gd) adsorption in varying acidic media. The activation of the carbon with ammonium persulfate increased the surface adsorption of the actinides, while decreasing lanthanide adsorption. These beads had a pH region where Pu could be selectively extracted. Pu is one of the longest lived, abundant and most radiotoxic components of spent nuclear fuel and thus, there is an urgent need to increase its security of storage. As carbon has a low neutron absorption cross-section, these beads present an affordable, efficient and safe means for Pu separation from nuclear waste.

Rare Pathogenic Variants Predispose to Hepatocellular Carcinoma in Nonalcoholic Fatty Liver Disease.

Nonalcoholic fatty liver disease (NAFLD) is a rising cause of hepatocellular carcinoma (HCC). We examined whether inherited pathogenic variants in candidate genes (n = 181) were enriched in patients with NAFLD-HCC. To this end, we resequenced peripheral blood DNA of 142 NAFLD-HCC, 59 NAFLD with advanced fibrosis, and 50 controls, and considered 404 healthy individuals from 1000 G. Pathogenic variants were defined according to ClinVar, likely pathogenic as rare variants predicted to alter protein activity. In NAFLD-HCC patients, we detected an enrichment in pathogenic (p = 0.024), and likely pathogenic variants (p = 1.9*10-6), particularly in APOB (p = 0.047). APOB variants were associated with lower circulating triglycerides and higher HDL cholesterol (p < 0.01). A genetic risk score predicted NAFLD-HCC (OR 4.96, 3.29-7.55; p = 5.1*10-16), outperforming the diagnostic accuracy of common genetic risk variants, and of clinical risk factors (p < 0.05). In conclusion, rare pathogenic variants in genes involved in liver disease and cancer predisposition are associated with NAFLD-HCC development.

Study of plasma off-gas treatment from spent ion exchange resin pyrolysis.

Polystyrene divinylbenzene-based ion exchange resins are employed extensively within nuclear power plants (NPPs) and research reactors for purification and chemical control of the cooling water system. To maintain the highest possible water quality, the resins are regularly replaced as they become contaminated with a range of isotopes derived from compromised fuel elements as well as corrosion and activation products including 14C, 60Co, 90Sr, 129I, and 137Cs. Such spent resins constitute a major proportion (in volume terms) of the solid radioactive waste generated by the nuclear industry. Several treatment and conditioning techniques have been developed with a view toward reducing the spent resin volume and generating a stable waste product suitable for long-term storage and disposal. Between them, pyrolysis emerges as an attractive option. Previous work of our group suggests that the pyrolysis treatment of the resins at low temperatures between 300 and 350 °C resulted in a stable waste product with a significant volume reduction (>50%) and characteristics suitable for long-term storage and/or disposal. However, another important issue to take into account is the complexity of the off-gas generated during the process and the different technical alternatives for its conditioning. Ongoing work addresses the characterization of the ion exchange resin treatment's off-gas. Additionally, the application of plasma technology for the treatment of the off-gas current was studied as an alternative to more conventional processes utilizing oil- or gas-fired post-combustion chambers operating at temperatures in excess of 1000 °C. A laboratory-scale flow reactor, using inductively coupled plasma, operating under sub-atmospheric conditions was developed. Fundamental experiments using model compounds have been performed, demonstrating a high destruction and removal ratio (>99.99%) for different reaction media, at low reactor temperatures and moderate power consumption. The role of H2O as an important participant of the oxidation mechanisms in plasma conditions was established. The combination of both processes could represent a simple, safe, and effective alternative for treating spent ion exchange resins with a large reduction of generated gaseous byproducts in fuel cycle facilities where processes that utilize open flames are undesirable.

In-column immobilization of Cs-saturated crystalline silicotitanates using phenolic resins.

The in situ immobilization of granulated Cs-saturated crystalline silicotitanates (Cs-CST) in fixed-bed columns has been investigated using commercially available phenol formaldehyde (PF) resin as a binding agent. Two types of PF resin were investigated as part of this study both being prepared from resol polymer having a formaldehyde:phenol ratio of 3:1. However, one of the resol polymers had water as the primary solvent and the other ethanol. Both resol polymers were observed to completely infiltrate the space between the Cs-CST beads and also the pores within the beads themselves. PF resin monoliths prepared after curing the water-based resol at 180 °C were considerably less porous than the ethanol-based counterparts cured under the same conditions. The enhanced macroporosity of the resin prepared from the ethanol-based resol was presumably the result from enhanced gas bubble generation. Little or no micro- or mesoporosity was measured using nitrogen porosimetry. For both resins cured at 180 °C, intimate contacts with the Cs-CST beads were observed that were not modified even after complete immersion in water over long time frames. Little or no migration of Cs from Cs-CST to the resin binder was observed. The compressive strength of the Cs-CST-PF resin monoliths was measured and benchmarked against cement monoliths and was found to be two to three times higher than cement in the case of the water-based resin. Leaching of the monoliths was conducted in demineralized water at 90 °C. Normalized Cs mass losses of the order of 1.0 g/m2 were measured after 30 days for the ethanol-based resin monoliths. For the less porous water-based monoliths, the normalized mass loss was one order of magnitude lower. The leaching of monoliths irradiated with a 2-MGy dose of γ radiation showed no difference in Cs mass loss suggesting that the ability to retain Cs of either the CST or PF resin was not affected. PF resins are capable of acting as a mechanically robust, radiation-resistant, and impermeable active secondary barrier reducing the likelihood of Cs entry into the biosphere.

Zirconium(IV)-Benzene Phosphonate Coordination Polymers: Lanthanide and Actinide Extraction and Thermal Properties.

Coordination polymers with different P/(Zr + P) molar ratios were prepared by combining aqueous solutions of Zr(IV) and benzenephosphonate derivatives. 1,3,5-Benzenetrisphosphonic acid (BTP) as well as phosphonocarboxylate derivatives in which carboxylate substitutes one or two of the phosphonate groups were chosen as the building blocks. The precipitates obtained on combining the two solutions were not X-ray amorphous but rather were indicative of poorly ordered materials. Hydrothermal treatment did not alter the structure of the materials produced but did result in improved crystalline order. The use of HF as a mineralizing agent during hydrothermal synthesis resulted in the crystallization of at least three relatively crystalline phases whose structure could not be determined owing to the complexity of the diffraction patterns. Gauging from the similarity of the diffraction patterns of all the phases, the poorly ordered precipitates and crystalline materials appeared to have similar underlying structures. The BTP-based zirconium phosphonates all showed a higher selectivity for lanthanides and thorium compared with cations such as Cs(+), Sr(2+), and Co(2+). Substitution of phosphonate groups by carboxylate groups did little to alter the pattern of selectivity implying that selectivity in the system was entirely determined by the -POH group with little influence from the -COOH groups. Samples with the highest phosphorus content showed the highest extraction efficiencies for lanthanide elements, especially the heavy lanthanides such as Dy(3+) and Ho(3+) with separation factors of around four with respect to La(3+). In highly acid solutions (4 M HNO3) there was a pronounced variation in extraction efficiency across the lanthanide series. In situ, nonambient diffraction was performed on ZrBTP-0.8 loaded with Th, Ce, and a complex mixture of lanthanides. In all cases the crystalline Zr2P2O7 pyrophosphate phase was formed at ∼800 °C demonstrating the versatility of this structure.

Gold nanoparticles supported in zirconia-ceria mesoporous thin films: a highly active reusable heterogeneous nanocatalyst.

Gold nanoparticles (NP) trapped in the mesopores of mixed zirconia-ceria thin films are prepared in a straightforward and reproducible way. The films exhibit enhanced stability and excellent catalytic activity in nitro-group reduction by borohydride and electrocatalytic activity in CO and ethanol oxidation and oxygen reduction.

One-pot preparation and CO2 adsorption modeling of porous carbon, metal oxide, and hybrid beads.

Hierarchically porous carbon (C), metal oxide (ZrTi), or carbon-metal oxide (CZrTi) hybrid beads are synthesized in one pot through the in situ self-assembly of Pluronic F127, titanium and zirconium propoxides, and polyacrylonitrile (PAN). Upon contact with water, a precipitation of PAN from the liquid phase occurs concurrently with polymerization and phase separation of the inorganic precursors. The C, ZrTi, and CZrTi materials have similar morphologies but different surface chemistries. The adsorption of carbon dioxide by each material has been studied and modeled using the Langmuir-Freundlich equation, generating parameters that are used to calculate the surface affinity distributions. The Langmuir, Freundlich, Tóth, and Temkin models were also applied but gave inferior fits, indicating that the adsorption occurred on an inhomogeneous surface reaching a maximum capacity as available surface sites became saturated. The carbon beads have higher surface affinity for CO2 than the hybrid and metal oxide materials.

Hydrolytic stability of mesoporous zirconium titanate frameworks containing coordinating organic functionalities.

The hydrolytic stability of lanthanide and actinide selective mono- and polyphosphonate-functionalized mesoporous zirconium titanium oxide adsorbents has been investigated in nitric acid solutions. Hydrolytic degradation of the surfaces, as measured through the fractional loss of phosphorus and elements of the oxide framework, increased by more than an order of magnitude as the nitric acid concentration was increased from 0 to 2 mol/L. The unfunctionalized parent oxide suffered considerable dissolution in 2 mol/L acid over a period of 72 h. Under identical conditions, the fractional Zr and Ti release was reduced to 1 × 10(-2) for monophosphonate functionalized hybrids and reached as low as 1 × 10(-6) for trisphosphonate functionalized variants. The bisphosphonates showed intermediate values. The leaching of P, Zr and Ti was found to be incongruent with the Zr leaching to a lesser extent implying enhanced stability of the Zr-O-P bond. Quantitative analysis of the dissolution kinetics indicated a parabolic dissolution model with a rate constant in the range of 0.5-1.5 mg g(-1) min(-1/2) for the elemental leaching of P, Ti, and Zr. The leaching of Zr from the mesoporous matrix was relatively more complex than for the other elements with evidence of a leaching mechanism involving two processes. ToF-SIMS and DRIFT analysis demonstrated that after leaching in 2 M HNO3 for 24 h, a significant proportion of grafted ligands remained on the surface. The oxide functionalized with amino trismethylenephosphonic acid, which had previously shown excellent (153)Gd(3+) selectivity, was demonstrated to have outstanding stability, with low fractional elemental losses and preservation of mesoporous texture even after leaching for 24 h in 2 M HNO3. This suggests this particular hybrid to be worthy of additional study.

Monitoring bisphosphonate surface functionalization and acid stability of hierarchically porous titanium zirconium oxides.

To take advantage of the full potential of functionalized transition metal oxides, a well-understood nonsilane based grafting technique is required. The functionalization of mixed titanium zirconium oxides was studied in detail using a bisphosphonic acid, featuring two phosphonic acid groups with high surface affinity. The bisphosphonic acid employed was coupled to a UV active benzamide moiety in order to track the progress of the surface functionalization in situ. Using different material compositions, altering the pH environment, and looking at various annealing conditions, key features of the functionalization process were identified that consequently will allow for intelligent material design. Loading with bisphosphonic acid was highest on supports calcined at 650 °C compared to lower calcination temperatures: A maximum capacity of 0.13 mmol g(-1) was obtained and the adsorption process could be modeled with a pseudo-second-order rate relationship. Heating at 650 °C resulted in a phase transition of the mixed binary oxide to a ternary oxide, titanium zirconium oxide in the srilankite phase. This phase transition was crucial in order to achieve high loading of the bisphosphonic acid and enhanced chemical stability in highly acidic solutions. Due to the inert nature of phosphorus-oxygen-metal bonds, materials functionalized by bisphosphonic acids showed increased chemical stability compared to their nonfunctionalized counterparts in harshly acidic solutions. Leaching studies showed that the acid stability of the functionalized material was improved with a partially crystalline srilankite phase. The materials were characterized using nitrogen sorption, X-ray powder diffraction, and UV-vis spectroscopy; X-ray photoelectron spectroscopy was used to study surface coverage with the bisphosphonic acid molecules.

Hybrid inorganic-organic adsorbents Part 1: Synthesis and characterization of mesoporous zirconium titanate frameworks containing coordinating organic functionalities.

A series of functional hybrid inorganic-organic adsorbent materials have been prepared through postsynthetic grafting of mesoporous zirconium titanate xerogel powders using a range of synthesized and commercial mono-, bis-, and tris-phosphonic acids, many of which have never before been investigated for the preparation of hybrid phases. The hybrid materials have been characterized using thermogravimetric analysis, diffuse reflectance infrared (DRIFT) and 31P MAS NMR spectroscopic techniques and their adsorption properties studied using a 153Gd radiotracer. The highest level of surface functionalization (molecules/nm2) was observed for methylphosphonic acid (∼3 molecules/nm2). The level of functionalization decreased with an increase in the number of potential surface coordinating groups of the phosphonic acids. Spectral decomposition of the DRIFT and 31P MAS NMR spectra showed that each of the phosphonic acid molecules coordinated strongly to the metal oxide surface but that for the 1,1-bis-phosphonic acids and tris-phosphonic acids the coordination was highly variable resulting in a proportion of free or loosely coordinated phosphonic acid groups. Functionalization of a porous mixed metal oxide framework with the tris-methylenephosphonic acid (ATMP-ZrTi-0.33) resulted in a hybrid with the highest affinity for 153Gd3+ in nitric acid solutions across a wide range of acid concentrations. The ATMP-ZrTi-0.33 hybrid material extracted 153Gd3+ with a Kd value of 1×10(4) in 0.01 M HNO3 far exceeding that of the other hybrid phases. The unfunctionalized mesoporous mixed metal oxide had negligible affinity for Gd3+ (Kd<100) under identical experimental conditions. It has been shown that the presence of free or loosely coordinated phosphonic acid groups does not necessarily translate to affinity for 153Gd3+. The theoretical cation exchange capacity of the ATMP-ZrTi-0.33 hybrid phase for Gd3+ has been determined to be about 0.005 mmol/g in 0.01 M HNO3. This behavior and that of the other hybrid phases suggests that the surface-bound ATMP ligand functions as a chelating ligand toward 153Gd3+ under these acidic conditions.

One-pot preparation and uranyl adsorption properties of hierarchically porous zirconium titanium oxide beads using phase separation processes to vary macropore morphology.

A simple and engineering friendly one-step process has been used to prepare zirconium titanium mixed oxide beads with porosity on multiple length scales. In this facile synthesis, the bead diameter and the macroporosity can be conveniently controlled through minor alterations in the synthesis conditions. The precursor solution consisted of poly(acrylonitrile) dissolved in dimethyl sulfoxide to which was added block copolymer Pluronic F127 and metal alkoxides. The millimeter-sized spheres were fabricated with differing macropore dimensions and morphology through dropwise addition of the precursor solution into a gelation bath consisting of water (H(2)O beads) or liquid nitrogen (LN(2) beads). The inorganic beads obtained after calcination (550 °C in air) had surface areas of 140 and 128 m(2) g(-1), respectively, and had varied pore architectures. The H(2)O-derived beads had much larger macropores (5.7 µm) and smaller mesopores (6.3 nm) compared with the LN(2)-derived beads (0.8 µm and 24 nm, respectively). Pluronic F127 was an important addition to the precursor solution, as it resulted in increased surface area, pore volume, and compressive yield point. From nonambient XRD analysis, it was concluded that the zirconium and titanium were homogeneously mixed within the oxide. The beads were analyzed for surface accessibility and adsorption rate by monitoring the uptake of uranyl species from solution. The macropore diameter and morphology greatly impacted surface accessibility. Beads with larger macropores reached adsorption equilibrium much faster than the beads with a more tortuous macropore network.

Size matters: incorporation of poly(acrylic acid) and small molecules into hierarchically porous metal oxides prepared with and without templates.

Template synthesis of metal oxides can create materials with highly controlled and reproducible pore structures that can be optimized for particular applications. Zirconium titanium oxides (25:75 mol %) with three different pore structures were synthesized in order to relate polymer loading capacity to macropore architecture. Sol-gel chemistry was used to prepare the materials in conjunction with (i) agarose gel templating, (ii) no template, and (iii) stearic acid templating. The three materials possessed high surface areas (212-316 m(2) g(-1)). Surface modification was performed postsynthetically using propionic acid (a monomer), glutaric acid (a dimer), and three molecular weights of poly(acrylic acid) (2000, 100,000, and 250,000 g mol(-1)). Higher loading (mg g(-1)) was observed for the polymers than for the small molecules. Following surface modification, a perceptible decrease in surface area and mesopore volume was noted, but both mesoporosity and macroporosity were retained. The pore architecture had a strong bearing on the quantity and rate of polymer incorporation into metal oxides. The templated pellet with hierarchical porosity outperformed the nontemplated powder and the mesoporous monolith (in both loading capacity and surface coverage). The materials were subjected to irradiation with (60)Co gamma-rays to determine the radiolytic stability of the inorganic support and the hybrid material containing the monomer, dimer, and polymer. The polymer and the metal oxide substrate demonstrated notable radiolytic stability.

Aerosol-assisted production of mesoporous titania microspheres with enhanced photocatalytic activity: the basis of an improved process.

An aerosol-based process was used to prepare mesoporous TiO(2) microspheres (MTM) with an average diameter in the range of 0.5-1 microm. The structural characteristics and photocatalytic properties of the synthesized materials were determined. As-prepared MTM materials and those heated in air from 400 to 600 degrees C exhibited mesoporous texture with a narrow size distribution and an inorganic framework that consisted of 4-13 nm anatase crystallites. Pore volumes for the MTM materials were in the range of 0.17-0.34 cm(3) g(-1). Microspheres heated to 400 degrees C presented a locally ordered mesopore structure and possessed X-ray diffraction d spacings between 9.8 and 17.3 nm. Heating above 400 degrees C resulted in a loss of the mesoscopic order, a decrease of the surface area, retention of the porosity, and an increase of the anatase nanoparticle size to 13 nm. The accessibility of the pore volume was measured by monitoring the uptake of gallic acid (GA) using Fourier transform IR. The MTM materials made excellent catalysts for the photodegradation of GA, with the performance being higher than that of an equivalent sample of Degussa P25. The present MTM materials are advantageous in terms of their ease of separation from the aqueous phase, and hence a novel photocatalytic process is proposed based on separate adsorption and photocatalytic decomposition steps with an improved and more rational use of both catalyst and sunlight.

Mesoporous zirconium titanium oxides. Part 3. Synthesis and adsorption properties of unfunctionalized and phosphonate-functionalized hierarchical polyacrylonitrile-F-127-templated beads.

A method is presented for the preparation of zirconium titanate mixed oxides in bead form having hierarchical pore structure. This method entailed the use of both preformed polyacrylonitrile (PAN) polymer beads and surfactants as templates. The templates were removed by calcination at temperatures below about 500 degrees C, resulting in mixed oxide beads with trimodal pore size distributions and interconnected pores. The pore size distributions as determined using nitrogen adsorption-desorption showed clear maxima at 4.5 and 45 nm length scales and also clear evidence of microporosity. The macroporous framework morphology was a replica of the PAN beads with radial structure. The mesoporous framework possessed wormhole-like pores with pore size of about 6 nm that was consistent with the F-127 triblock copolymer template used. The mixed oxide beads exhibited surface areas of 215 and 185 m2/g after calcination at 500 and 600 degrees C. Thermal stability up to 650 degrees C is unprecedented for bulk systems. The adsorption properties were characterized using uranyl as the target cation and the mass transport in the beads with the present hierarchical architectures has been shown to be exceptional. The beads were functionalized with 4-amino,1-hydroxy,1,1-bis-phosphonic acid (HABDP) and amino-tris-methylene phosphonic acid (ATMP) and the adsorption properties for the extraction of uranyl sulfate complexes from acidic solution examined. Of the two molecules investigated, ATMP functionalization resulted in the best extraction efficiency with equilibrium uptake of about 90% of uranium available in solution between pH 1 and 2. The beads could potentially be utilized as catalysts, catalyst supports, adsorbents, and separation materials.