Hybrid photocatalytic materials for contaminants of emerging concern degradation

228 p.Contaminants of emerging concern (CECs) such as pharmaceuticals represent a new global problem for water quality because these compounds are very resistant to conventional wastewater treatments and can get into environment, causing severe threats to aquatic organisms and human health. In the last decades, semiconductor photocatalysis has become a promising technology to degrade these contaminants. However, poor efficiency of photocatalysts under sunlight and time-consuming and expensive processes for photocatalyst recovery/reuse are two main limitations for photocatalysis application in water remediation. This doctoral thesis focuses on surpassing these obstacles. Firstly, the importance of the interaction between pollutants and photocatalysts, the generation of reactive oxygen species (ROS) for photocatalytic performance is considered. Then, the development of Au-functionalised plasmonic photocatalysts is carried out. Later, novel and more efficient photocatalysts using Au nanostar functionalising TiO2 are developed and tested for photocatalytic application. Finally, the novel photocatalysts are immobilised into polymer matrix through different techniques for their reusability and recovery in photocatalytic application. The results obtained show the prepared hybrid photocatalytic materials opening the door to cost-effectively degrade a high variety of CECs under sunlight for water remediation.BCMATERIALS: Basque Center for Materials, Applications & Nanostructure

Efecto de la concentración de NaOH en la desilicación de la zeolita HY en catalizadores Pt/HY para hidrocraqueo de poliestireno en disolución

Estudia el dfecto de la concentración de NaOH en el tratamiento de desilicación de la zeolita HY en catalizadores jerárquicos Pt/HY para hidrocraqueo de poliestireno en disolució

Upcycling discarded cellulosic surgical masks into catalytically active freestanding materials

[EN] The COVID-19 pandemic outbreak has resulted in the massive fabrication of disposable surgical masks. As the accumulation of discarded face masks represents a booming threat to the environment, here we propose a solution to reuse and upcycle surgical masks according to one of the cornerstones of the circular economy. Specifically, the non-woven cellulosic layer of the masks is used as an environmentally sustainable and highly porous solid support for the controlled deposition of catalytically active metal-oxide nanoparticles. The native cellulosic fibers from the surgical masks are decorated by titanium dioxide (TiO2), iron oxide (FexOy), and cobalt oxide (CoOx) nanoparticles following a simple and scalable approach. The abundant surface -OH groups of cellulose enable the controlled deposition of metal-oxide nanoparticles that are photocatalytically active or shown enzyme-mimetic activities. Importantly, the hydrophilic highly porous character of the cellulosic non-woven offers higher accessibility of the pollutant to the catalytically active surfaces and high retention in its interior. As a result, good catalytic activities with long-term stability and reusability are achieved. Additionally, developed free-standing hybrids avoid undesired media contamination effects originating from the release of nanoscale particles. The upcycling of discarded cellulosic materials, such as the ones of masks, into high-added-value catalytic materials, results an efficient approach to lessen the waste's hazards of plastics while enhancing their functionality. Interestingly, this procedure can be extended to the upcycling of other systems (cellulosic or not), opening the path to greener manufacturing approaches of catalytic materials.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature

Island biogeography theory and the habitat heterogeneity jointly explain global patterns of Rhododendron diversity

Mountain biodiversity is of great importance to biogeography and ecology. However, it is unclear what ecological and evolutionary processes best explain the generation and maintenance of its high levels of species diversity. In this study, we determined which of six common hypotheses (e.g., climate hypotheses, habitat heterogeneity hypothesis and island biogeography theory) best explain global patterns of species diversity in Rhododendron. We found that Rhododendron diversity patterns were most strongly explained by proxies of island biogeography theory (i.e., mountain area) and habitat heterogeneity (i.e., elevation range). When we examined other relationships important to island biogeography theory, we found that the planimetric area and the volume of mountains were positively correlated with the Rhododendron diversity, whereas the ‘mountains-to-mainland’ distance was negatively correlated with Rhododendron diversity and shared species. Our findings demonstrate that Rhododendron diversity can be explained by island biogeography theory and habitat heterogeneity, and mountains can be regarded as islands which supported island biogeography theory

Tree plantations displacing native forests: The nature and drivers of apparent forest recovery on former croplands in Southwestern China from 2000 to 2015

China is credited with undertaking some of the world's most ambitious policies to protect and restore forests, which could serve as a role model for other countries. However, the actual environmental consequences of these policies are poorly known. Here, we combine remote-sensing analysis with household interviews to assess the nature and drivers of land-cover change in southwestern China between 2000–2015, after China's major forest protection and reforestation policies came into effect. We found that while the region's gross tree cover grew by 32%, this increase was entirely due to the conversion of croplands to tree plantations, particularly monocultures. Native forests, in turn, suffered a net loss of 6.6%. Thus, instead of truly recovering forested landscapes and generating concomitant environmental benefits, the region's apparent forest recovery has effectively displaced native forests, including those that could have naturally regenerated on land freed up from agriculture. The pursuit of profit from agricultural or forestry production along with governmental encouragement and mobilization for certain land uses – including tree planting – were the dominant drivers of the observed land-cover change. An additional driver was the desire of many households to conform with the land-use decisions of their neighbors. We also found that households' lack of labor or financial resources, rather than any policy safeguards, was the primary constraint on further conversion of native forests. We conclude that to achieve genuine forest recovery along with the resulting environmental benefits, China's policies must more strongly protect existing native forests and facilitate native forest restoration. Natural regeneration, which thus far has been grossly neglected in China's forest policies, should be recognized as a legitimate means of forest restoration. In addition, social factors operating at the household level, notably the pursuit of profit and conformation to social norms, should be harnessed to promote better land-cover, biodiversity, and environmental outcomes. More generally, for China and other countries to succeed in recovering forests, policies must clearly distinguish between native forests and tree plantations

Size Effect in Hybrid TiO2:Au Nanostars for Photocatalytic Water Remediation Applications

TiO2:Au-based photocatalysis represents a promising alternative to remove contaminants of emerging concern (CECs) from wastewater under sunlight irradiation. However, spherical Au nanoparticles, generally used to sensitize TiO2, still limit the photocatalytic spectral band to the 520 nm region, neglecting a high part of sun radiation. Here, a ligand-free synthesis of TiO2:Au nanostars is reported, substantially expanding the light absorption spectral region. TiO2:Au nanostars with different Au component sizes and branching were generated and tested in the degradation of the antibiotic ciprofloxacin. Interestingly, nanoparticles with the smallest branching showed the highest photocatalytic degradation, 83% and 89% under UV and visible radiation, together with a threshold in photocatalytic activity in the red region. The applicability of these multicomponent nanoparticles was further explored with their incorporation into a porous matrix based on PVDF-HFP to open the way for a reusable energy cost-effective system in the photodegradation of polluted waters containing CECsThis research was funded by Spanish State Research Agency (AEI) through the project PID2019-106099RB-C43/AEI/10.13039/501100011033 and the Basque Government under the ELKARTEK program. P.M.M. thanks the FCT for contract 2020.02802.CEECIND. C.J.T. acknowledges the funding from FCT/PIDDAC through the Strategic Funds project reference UIDB/04650/2020-2023. F.Z. thanks the University of the Basque Country (UPV/EHU) for the PhD fellowship

DexPro:A Bytecode Level Code Protection System for Android Applications

Unauthorized code modification through reverse engineering is a major concern for Android application developers. Code reverse engineering is often used by adversaries to remove the copyright protection or advertisements from the app, or to inject malicious code into the program. By making the program difficult to analyze, code obfuscation is a potential solution to the problem. However, there is currently little work on applying code obfuscation to compiled Android bytecode. This paper presents DexPro, a novel bytecode level code obfuscation system for Android applications. Unlike prior approaches, our method performs on the Android Dex bytecode and does not require access to high-level program source or modification of the compiler or the VM. Our approach leverages the fact all except floating operands in Dex are stored in a 32-bit register to pack two 32-bit operands into a 64-bit operand. In this way, any attempt to decompile the bytecode will result in incorrect information. Meanwhile, our approach obfuscates the program control flow by inserting opaque predicates before the return instruction of a function call, which makes it harder for the attacker to trace calls to protected functions. Experimental results show that our approach can deter sophisticate reverse engineering and code analysis tools, and the overhead of runtime and memory footprint is comparable to existing code obfuscation methods

Exploring the causal relationship between body mass index and keratoconus: a Mendelian randomization study

BackgroundDespite reports suggesting a link between obesity and keratoconus, the causal relationship is not fully understood.MethodsWe used genome-wide association study (GWAS) data from public databases for a two-sample Mendelian randomization analysis to investigate the causal link between body mass index (BMI) and keratoconus. The primary method was inverse variance weighted (IVW), complemented by different analytical techniques and sensitivity analyses to ensure result robustness. A meta-analysis was also performed to bolster the findings’ reliability.ResultsOur study identified a significant causal relationship between BMI and keratoconus. Out of 20 Mendelian randomization (MR) analyses conducted, 9 showed heterogeneity or pleiotropy. Among the 11 analyses that met all three MR assumptions, 4 demonstrated a significant causal difference between BMI and keratoconus, while the remaining 7 showed a positive trend but were not statistically significant. Meta-analysis confirmed a significant causal relationship between BMI and keratoconus.ConclusionThere is a significant causal relationship between BMI and keratoconus, suggesting that obesity may be a risk factor for keratoconus

Chitin/Metal‐Organic Framework Composites as Wide‐Range Adsorbent

Composites based on chitin (CH) biopolymer and metal-organic framework (MOF) microporous nanoparticles have been developed as broad-scope pollutant absorbent. Detailed characterization of the CH/MOF composites revealed that the MOF nanoparticles interacted through electrostatic forces with the CH matrix, inducing compartmentalization of the CH macropores that led to an overall surface area increase in the composites. This created a micro-, meso-, and macroporous structure that efficiently retained pollutants with a broad spectrum of different chemical natures, charges, and sizes. The unique prospect of this approach is the combination of the chemical diversity of MOFs with the simple processability and biocompatibility of CH that opens application fields beyond water remediation.Fil: Tovar Jimenez, Gabriel Ibrahin. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Valverde, Ainara. Universidad del País Vasco; EspañaFil: Mendes Felipe, Cristian. Universidad del País Vasco; EspañaFil: Wuttke, Stefan. Universidad del País Vasco; EspañaFil: Fidalgo Marijuan, Arkaitz. University of the Basque Country ; EspañaFil: Larrea, Edurne S.. Loire Valley Institute for Advanced Studies, ; FranciaFil: Lezama, Luis. Universidad del País Vasco; EspañaFil: Zheng, Fangyuan. Universidad del País Vasco; EspañaFil: Reguera, Javier. Universidad del País Vasco; EspañaFil: Lanceros Méndez, Senentxu. Universidad del País Vasco; EspañaFil: Arriortua, María. Universidad del País Vasco; EspañaFil: Copello, Guillermo Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Metabolismo del Fármaco. Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Metabolismo del Fármaco; ArgentinaFil: Luis, Roberto Fernández. Universidad del País Vasco; Españ