Transport of nanoscale zero-valent iron in the presence of rhamnolipid.

Nanoscale zero-valent iron (nZVI) particles have gained widespread use for in-situ treatment of various chlorinated hydrocarbons. Their non-toxic nature, affordability, and minimal maintenance requirements have made them a favored material for nanoremediation. The treatment typically involves the injection of nZVI particles into contaminated sites using direct-push well injection systems. However, their small size leads to high surface energy, causing aggregation that alters their physiochemical properties, reactivity, and transport behavior. To counteract aggregation, nZVI suspension can be stabilized with different surfactants, reducing the surface energy during subsurface soil transport. This study investigates the impact of rhamnolipid, a biosurfactant produced by Pseudomonas aeruginosa during the late growth phase, on the aggregation and mobility of nZVI particles. The retardation factor of nZVI in the model media of zeolite, ZK406H, decreased from 1.66 in the absence of rhamnolipid to 1.03, 0.98, 0.93, and 0.87, corresponding to the presence of rhamnolipid at concentrations of 20, 50, 80, and 100 mg/L. The deposition coefficient also decreased from 2.39 in the absence of rhamnolipid to 0.459, 0.279, 0.217, and 0.0966, corresponding to the presence of rhamnolipid at concentrations of 20, 50, 80, and 100 mg/L. The transport parameters of nZVI in ZK406H were linked to the interactions of nZVI particles with ZK406H by the DLVO theory.

Individuals' contribution to household energy savings: The role of big-two personality traits.

Household energy consumption (HEC) is one of the major contributors to global emissions, making it a critical area for addressing sustainability challenges. The impact of personality traits on human behaviour is significant in shaping HEC patterns, and therefore, have important implications for sustainability policies. This study aims to investigate role of biologically predicted big-two personality traits (i.e., stability and plasticity), a higher order solution to five-factor traits and orthogonal traits, on HEC. To that end, a structural equation model is developed using a national household survey in Australia. The performance of the model is benchmarked against a five-factor (i.e., agreeableness, consciousness, emotional stability, extraversion and openness) personality trait model. The performance of the models is measured using six goodness-of-fit indices, all of which show a superior performance in the big-two traits model. The results indicate that a higher score in stability poses energy-intensive behaviour, while a higher plasticity score poses energy-saving behaviours. The plasticity trait is linked to environmentally friendly behaviours, while the stability trait is associated with environmentally unfavourable behavioural practices. The effects of socioeconomic status on HEC are mediated by stability and plasticity to identify those who are more likely to change their energy consumption habits as the target group for policy intervention. This study can assist policy makers to determine energy-intensive and energy-saving behaviours from the big-two traits, and to develop more effective and targeted sustainability policies that can help in reducing HEC and promote sustainable living in societies.

Barriers and facilitators to reducing low-value care for the management of low back pain in Iran: a qualitative multi-professional study.

INTRODUCTION: Low back pain (LBP) is a prevalent musculoskeletal disorder with a wide range of etiologies, ranging from self-limiting conditions to life-threatening diseases. Various modalities are available for the diagnosis and management of patients with LBP. However, many of these health services, known as low-value care (LVC), are unnecessary and impose undue financial costs on patients and health systems. The present study aimed to explore the perceptions of service providers regarding the facilitators and barriers to reducing LVC in the management of LBP in Iran. METHODS: This qualitative descriptive study interviewed a total of 20 participants, including neurosurgeons, physiatrists, orthopedists, and physiotherapists, who were selected through purposive and snowball sampling strategies. The collected data were analyzed using the thematic content analysis approach. RESULTS: Thirty-nine sub-themes, with 183 citations, were identified as barriers, and 31 sub-themes, with 120 citations, were defined as facilitators. Facilitators and barriers to reducing LVC for LBP, according to the interviewees, were categorized into five themes, including: (1) individual provider characteristics; (2) individual patient characteristics; (3) social context; (4) organizational context; and (5) economic and political context. The ten most commonly cited barriers included unrealistic tariffs, provider-induced demand, patient distrust, insufficient time allocation, a lack of insurance coverage, a lack of a comprehensive referral system, a lack of teamwork, cultural challenges, a lack of awareness, and defensive medicine. Barriers such as adherence to clinical guidelines, improving the referral system, improving the cultural status of patients, and facilitators such as strengthening teamwork, developing an appropriate provider-patient relationship, improving the cultural status of the public, motivating the patients, considering an individualized approach, establishing a desirable payment mechanism, and raising the medical tariffs were most repeatedly stated by participants. CONCLUSION: This study has pointed out a great number of barriers and facilitators that shape the provision of LVC in the management of LBP in Iran. Therefore, it is essential for relevant stakeholders to consider these findings in order to de-implement LVC interventions in the process of LBP management.

A facile synthesis of chromeno[3,4-c]spiropyrrolidine indenoquinoxalines via 1,3-dipolar cycloadditions.

A one-pot, four-component reaction for the synthesis of novel chromeno[3,4-c]spiropyrrolidine-indenoquinoxalines is described via a 1,3-dipolar cycloaddition of 3-acetyl-coumarins with the azomethine ylides followed by deacetylation and protonation (deuteration). The products were obtained in moderate to high yields, and their structures were confirmed by 1H NMR, 13C NMR, FT-IR, and MS spectroscopy.

Photo-Fenton degradation of tetracycline antibiotic over MIL-101(Cr)/FeOOH nanocomposite as stable and efficient visible light responsive photocatalyst.

Designing an inexpensive, easily synthesized, stable and efficient photocatalyst is a major challenge in photocatalysis area, especially when photo-reaction is performed in aquatic medium to degrade organic pollutants. To this aim, nano-sized MIL-101(Cr) (MIL = Materials Institute Lavoisier), as chemically tolerant metal-organic framework (MOF), was simply prepared via HF-free hydrothermal synthesis procedure. In order to decorate amorphous FeOOH quantum dots (QDs) on the surface of this MOF, various amounts of FeOOH QDs (i.e., 5, 10, 15 and 20 wt%) were synthesized in the presence of MIL-101(Cr) to prepare MIL-101(Cr)/FeOOH(x%) nanocomposites. Decoration of such iron oxide quantum dots on the surface of MIL-101(Cr) and investigation of its activity in photo-Fenton degradation of tetracycline (TC) antibiotic is reported here for the first time. Among the synthesized nanocomposites, MIL-101(Cr)/FeOOH(15%) demonstrated superior photo-Fenton activity in degradation of TC (80%) at short reaction time under optimum reaction condition using the energy-efficient white LED lamps as visible light source. It was observed that the synergy between any component of this photo-Fenton system such as nanocomposite, hydrogen peroxide and visible light is the main reason for enhancement of TC removal over time. Also, neither MIL-101(Cr) nor FeOOH QDs exhibited poor degradation efficiency, which implies the positive role of the coupling of these materials. Furthermore, the stability and recoverability of MIL-101(Cr)/FeOOH(15%) nanocomposite was investigated in four photo-Fenton cycles, which no significant decrease in TC degradation performance was observed.

Base/Solvent Controlled Divergent Synthesis of Norbornane-Fused Dihydrophenanthrenes and Triphenylenes via Palladium Catalyst.

A base/solvent controlled divergent synthesis for the construction of polycyclic hydrocarbons has been developed. In this process, norbornene through a reagent role leads to the synthesis of norbornane-fused dihydrophenanthrenes, which are essential due to their biological activities. Amazingly, by switching solvent and base, the role of norbornene becomes limited to a mediator/catalyst; therefore, it is removed from the final scaffold, and triphenylenes are regioselectively synthesized. Additionally, by removing norbornene from the reaction conditions, a different path leading to synthesis of unsymmetrically substituted triphenylenes with exceptional regioselectivity is established. This reaction includes a rare domino decarboxylation/C-H activation/annulation in a chemo- and regioselective manner.

Towards facing uncertainties in biofuel supply chain networks: a systematic literature review.

Biofuel supply chains (BSCs) face diverse uncertainties that pose serious challenges. This has led to an expanding body of research focused on studying these challenges. Hence, there is a growing need for a comprehensive review that summarizes the current studies, identifies their limitations, and provides essential advancements to support scholars in the field. To overcome these limitations, this research aims to provide insights into managing uncertainties in BSCs. The review utilizes the Systematic Reviews and Meta-Analyses (PRISMA) method, identifying 205 papers for analysis. This study encompasses three key tasks: first, it analyses the general information of the shortlisted papers. Second, it discusses existing methodologies and their limitations in addressing uncertainties. Lastly, it identifies critical research gaps and potential future directions. One notable gap involves the underutilization of machine learning techniques, which show potential for risk identification, resilient planning, demand prediction, and parameter estimations in BSCs but have received limited attention. Another area for investigation is the potential of agent-based simulation, which can contribute to analysing resilient policies, evaluating resilience, predicting parameters, and assessing the impact of emerging technologies on BSC resilience in the twenty-first century. Additionally, the study identifies the omission of various realistic assumptions, such as backward flow, lateral transshipments, and ripple effects in BSC. This study highlights the complexity of managing uncertainties in BSCs and emphasizes the need for further research and attention. It contributes to policymakers' understanding of uncertain sources and suitable approaches while inspiring researchers to address limitations and generate breakthrough ideas in managing BSC uncertainties.

A comprehensive health effects assessment of the use of sanitizers and disinfectants during COVID-19 pandemic: a global survey.

COVID-19 has affected all aspects of human life so far. From the outset of the pandemic, preventing the spread of COVID-19 through the observance of health protocols, especially the use of sanitizers and disinfectants was given more attention. Despite the effectiveness of disinfection chemicals in controlling and preventing COVID-19, there are critical concerns about their adverse effects on human health. This study aims to assess the health effects of sanitizers and disinfectants on a global scale. A total of 91,056 participants from 154 countries participated in this cross-sectional study. Information on the use of sanitizers and disinfectants and health was collected using an electronic questionnaire, which was translated into 26 languages via web-based platforms. The findings of this study suggest that detergents, alcohol-based substances, and chlorinated compounds emerged as the most prevalent chemical agents compared to other sanitizers and disinfectants examined. Most frequently reported health issues include skin effects and respiratory effects. The Chi-square test showed a significant association between chlorinated compounds (sodium hypochlorite and per-chlorine) with all possible health effects under investigation (p-value <0.001). Examination of risk factors based on multivariate logistic regression analysis showed that alcohols and alcohols-based materials were associated with skin effects (OR, 1.98; 95%CI, 1.87-2.09), per-chlorine was associated with eye effects (OR, 1.83; 95%CI, 1.74-1.93), and highly likely with itching and throat irritation (OR, 2.00; 95%CI, 1.90-2.11). Furthermore, formaldehyde was associated with a higher prevalence of neurological effects (OR, 2.17; 95%CI, 1.92-2.44). Furthermore, formaldehyde was associated with a higher prevalence of neurological effects (OR, 2.17; 95%CI, 1.92-2.44). The use of sodium hypochlorite and per-chlorine also had a high chance of having respiratory effects. The findings of the current study suggest that health authorities need to implement more awareness programs about the side effects of using sanitizers and disinfectants during viral epidemics especially when they are used or overused.

Analysis of the Reporting Requirements of Clinical Case Reports Dedicated Journals: Towards Updating the CARE Guideline.

Background: Following personalized medicine and the development of e-publishing, a large number of case report-dedicated journals have emerged. But the lack of integrated guidelines is a major obstacle to the quality of this evidence. The purpose of this study is to analyze the reporting requirements of case report-dedicated journals to update and strengthen the CARE guidelines. Material and Methods: Quantitative and qualitative research approach has been done using the content analysis method. All case report-dedicated journals were selected from Scopus (54 out of a total of 68 journals). By referring to these journals' websites, all the contents of the authors' guideline section and two sample articles were examined as a unit of analysis. Quantitative data includes frequency and percentile; qualitative data was conducted through open coding, creating categories, and abstraction. Results: 51% of journals are related to Elsevier and Hindawi publications. 14.8% of journals have been launched in the form of companions. 52% of journals endorse the CARE guidelines. Among the CARE elements, title, consent form (100%), discussion, abstract (94.4%), and introduction (90.7%) had the most frequent elements, and timeline and patients' perspective had the least repetition in the authors' guideline. Also, 19 new reporting elements and 27 types of case reports were identified. Conclusions: Improving the reporting and content quality of case reports is very important to benefit from knowledge synthesis services. Medical journals publishing case reports should follow a more integrated process. An updated version of reporting guidelines needs to be available for publishers and editors of journals.

Face mask correlation with allergic rhinitis symptoms severity during COVID-19 pandemic: A cross-sectional study.

Background: Face mask is the first line to protect the respiratory mucosa from the coronavirus particles in aerocells and droplets and without this, the exposure of the mucosa to the virus and allergens trigger the immune and inflammatory system. These lead to Allergic Rhinitis (AR) symptoms or virus infection. Aim: This study discusses about the effects of face mask on the severity of AR symptoms using the Sino-Nasal Outcome Test (SNOT-22) in AR cases during the Corona Virus Disease 2019 (COVID-19) pandemic. Method: In this cross-sectional study, 54 cases previously diagnosed as moderate and severe AR based on Allergic Rhinitis and its Impact on Asthma and Visual Analog Scale score referred to the tertiary allergy clinic were involved, while 5 of them were excluded. AR symptoms before and during the pandemic were compared based on the SNOT-22 questionnaire. Demographics, AR severity, and comorbidities were registered. Results: The mean age was 31.4 ± 13.5 years with the male-female ratio of 1.4. The mean SNOT-22 score was 36.1 ± 20.3 before and 29.5 ± 16.8 during the pandemic. Although 36.7% (n: 18) of all participants had severe symptoms before the pandemic, 10.2% (n: 5) had severe AR symptoms during the pandemic. 53.0% (n: 26) of patients had moderate AR symptoms, and 36.7% (n: 18) had mild AR symptoms in the pandemic. There was no significant difference between each paired subgroup in AR symptom changes but the symptom improvement was significant in most of the subgroups when compared to the pre-pandemic period. Smoking had an adverse effect on AR symptoms (p: 0.034). Conclusion: Face mask affects the quality of life in AR patients and improves the severity of AR symptoms during COVID-19 pandemic. Smoking worsens this severity. Age, gender, pet ownership, underlying conditions, and previous COVID-19 infection were not associated with AR symptoms severity and alteration in the AR individuals' quality of life during the COVID-19 pandemic.

Gender gaps in Australian research publishing, citation and co-authorship.

Despite improvement in gender inequality in Australian science, the problem has not been fully addressed yet. To better understand the nature of gender inequality in Australian science, all gendered Australian first authored articles published between 2010 and 2020 and indexed in the Dimensions database were analysed. Field of Research (FoR) was used as the subject classification of articles and Field Citation Ratio (FCR) was used for citation comparison. Overall, the ratio of female to male first authored articles increased over the years, and this was true for all FoRs except for information and computing sciences. The ratio of single-authored articles by females was also improved over the study period. Females appeared to have a citation advantage, using Field Citation Ratio, over males in a few FoRs including mathematical sciences, chemical sciences, technology, built environment and design, studies in human society, law and legal studies, and studies in creative arts and writing. The average FCR for female first authored articles was greater than the average FCR for male first authored articles, including in a few fields such mathematical sciences where male authors outperformed females in terms of the number of articles.

Evaluating soil loss under land use management and extreme rainfall.

Topsoil loss is a widespread environmental concern causing adverse impacts on natural and human systems. Severe weather accompanied with human activities can exacerbate this issue degrading soil health and consequently accelerating global and regional food insecurity. Erosion impairs soil physical and chemical properties such as infiltration rate, water holding capacity, loss of nutrients including soil carbon and nitrogen. Although, temporal properties of a rainfall event have meaningful implications, spatial heterogeneity of a rainfall contributes substantially and cannot be overlooked. Therefore, in this study, we investigated soil loss using weather radar NEXRAD data. We developed extreme rainfall (ER) scenarios and land use practices (nomgt, S0, S1, S2, and S3) and evaluated the watershed response. We found that grazing can manifold soil loss, and if accompanied with extreme rainfalls, soil loss accelerates impacting different subbasins each time. Our results suggest that spatial heterogeneity of ERs can be more significant in individual extreme rainfalls, however, over a year, soil moisture and type of the management practices (grazing and farming) could contribute more to topsoil loss. We classified watershed subbasins into different classes of soil loss severity to determine the soil loss hotspots. Soil loss can go as high as 350 (ton/ha/yr) under the ERs. Land use practices can increase erosion by 3600%. Slight increase in rainfall concentration (S1) can put vulnerable subbasins in extremely severe class (>150 ton/ha/yr). Under moderate increase in the rainfall concentration (S2) more subbasins fall into extremely severe category yielding approximately 200 ton/ha/yr. Under high increase in rainfall concentration (S3) almost all the subbasins fall into the extremely severe class yielding >200 ton/ha/yr. We found that in vulnerable subbasins, up to 10% increase in (Concentration Ratio Index) CI can increase annual soil loss up to 75%. Single ER can generate up to 35% of annual soil loss. Under one ER event soil loss hotspot subbasins can lose up to 160 ton/ha/day. 32% and 80% increase in rainfall amount for an ER event can increase soil loss by 94% and 285% respectively. The results, also, reveal that grazing and farming can be responsible for up 50% of soil loss. Our findings indicate the importance of site-specific managements to mitigate soil loss and all the consequences. Our study can help in better soil loss management implementation. Insights of our study may also help in water quality control and flood mitigation planning efforts.

Maximizing projects' profitability, environmental score, and quality: a multi-project scheduling and material ordering problem.

The proper trade-off between various project costs is often disregarded when planning projects. This leads to several detrimental effects, such as inaccurate planning and higher total cost, far more significant in a multi-project environment. To overcome this limitation, this study proposes a combined approach for the multi-project scheduling and material ordering problem (MPSMOP), which maintains the proper trade-off among various costs. Moreover, the environmental impact and project quality objectives are optimized alongside the economic criterion. The proposed methodology involves three stages: (a) quantifying the environmental performance of suppliers; (b) measuring the activities' quality through the Construction Quality Assessment System approach; and (c) building and solving the mathematical model of the MPSMOP. The MPSMOP is modeled as a tri-objective optimization approach aiming to determine project scheduling and material ordering decisions so that the net present value, environmental score, and total quality of implemented projects are maximized simultaneously. As the proposed model comes into the nondeterministic polynomial optimization problem category, two powerful metaheuristics are customized and used to solve the problem. The efficiency of both algorithms was assessed on several datasets. The proposed framework is applied to railway construction projects in Iran as a case study, which presents the validity of the model and the decision-making options provided to managers.

A Novel Temporal Network-Embedding Algorithm for Link Prediction in Dynamic Networks.

Understanding the evolutionary patterns of real-world complex systems such as human interactions, biological interactions, transport networks, and computer networks is important for our daily lives. Predicting future links among the nodes in these dynamic networks has many practical implications. This research aims to enhance our understanding of the evolution of networks by formulating and solving the link-prediction problem for temporal networks using graph representation learning as an advanced machine learning approach. Learning useful representations of nodes in these networks provides greater predictive power with less computational complexity and facilitates the use of machine learning methods. Considering that existing models fail to consider the temporal dimensions of the networks, this research proposes a novel temporal network-embedding algorithm for graph representation learning. This algorithm generates low-dimensional features from large, high-dimensional networks to predict temporal patterns in dynamic networks. The proposed algorithm includes a new dynamic node-embedding algorithm that exploits the evolving nature of the networks by considering a simple three-layer graph neural network at each time step and extracting node orientation by using Given's angle method. Our proposed temporal network-embedding algorithm, TempNodeEmb, is validated by comparing it to seven state-of-the-art benchmark network-embedding models. These models are applied to eight dynamic protein-protein interaction networks and three other real-world networks, including dynamic email networks, online college text message networks, and human real contact datasets. To improve our model, we have considered time encoding and proposed another extension to our model, TempNodeEmb++. The results show that our proposed models outperform the state-of-the-art models in most cases based on two evaluation metrics.

Exploring genomic regions involved in bread wheat resistance to leaf rust at seedling/adult stages by using GWAS analysis.

BACKGROUND: Global wheat productivity is seriously challenged by a range of rust pathogens, especially leaf rust derived from Puccinia triticina. Since the most efficient approach to control leaf rust is genetic resistance, many efforts have been made to uncover resistance genes; however, it demands an ongoing exploration for effective resistance sources because of the advent of novel virulent races. Thus, the current study was focused on detecting leaf rust resistance-related genomic loci against the P. triticina prevalent races by GWAS in a set of Iranian cultivars and landraces. RESULTS: Evaluation of 320 Iranian bread wheat cultivars and landraces against four prevalent rust pathotypes of P. triticina (LR-99-2, LR-98-12, LR-98-22, and LR-97-12) indicated the diversity in wheat accessions responses to P. triticina. From GWAS results, 80 leaf rust resistance QTLs were located in the surrounding known QTLs/genes on almost chromosomes, except for 1D, 3D, 4D, and 7D. Of these, six MTAs (rs20781/rs20782 associated with resistance to LR-97-12; rs49543/rs52026 for LR-98-22; rs44885/rs44886 for LR-98-22/LR-98-1/LR-99-2) were found on genomic regions where no resistance genes previously reported, suggesting new loci conferring resistance to leaf rust. The GBLUP genomic prediction model appeared better than RR-BLUP and BRR, reflecting that GBLUP is a potent model for genomic selection in wheat accessions. CONCLUSIONS: Overall, the newly identified MTAs as well as the highly resistant accessions in the recent work provide an opportunity towards improving leaf rust resistance.

Green synthesis, characterization, and application of Fe3O4 nanoparticles for methylene blue removal: RSM optimization, kinetic, isothermal studies, and molecular simulation.

Methylene Blue (MB) is a cationic dye causing various health problems such as asthma, heartbeat, eye and skin irritation, nausea, and distress during prolonged exposure. In this regard, the green magnetite nanoparticle was synthesized using the extract of Prosopis farcta. The synthesized Fe3O4nanoparticle was characterized by X-ray powder diffraction (XRD), Field emission scanning electron microscopy (FESEM), energy-dispersive X-ray spectroscopy (EDX), transmission electron microscopy (TEM), Fourier transforms Infrared spectroscopy (FTIR), vibrating sample magnetometer (VSM), and Brunauer-Emmett-Teller (BET). The corresponding parameters, including the primary concentration of MB (5-65 mg/L), the dose of synthesized nanoparticle (0.025-0.925 g/L), solution pH (3-11), and contact time (20-60 min), were considered. Also, central composite design (CCD), as one of the response surface methodologies (RSM), was used for the related modelling and optimization. The particle size of the adsorbent was between 5 and 70 nm, and the nanoparticle has 206.75 m2/g of a specific surface, 6.1 nm of average pore size, and 0.3188 cm3/g of the total pore volume. The optimal conditions for MB removal by the nanoparticle were found to follow an initial MB concentration of 20 mg/L, 0.7 g/L of the nanoparticle dose, pH = 9, and a contact time of 50 min. The pseudo-second-order (PSO) and Freundlich models were the best kinetic and isothermal models for MB removal by the synthesized nanoparticle. Molecular modelling was used to optimize the MB molecular configuration and compute HOMO-LUMO energies, quantum-chemical descriptors, and molecular electrostatic potential to evaluate the nature reactivity of the MB molecule.

The reporting requirements of case reports and adherence of case report reporting guidelines in medical journals: an analysis of the authors' guide sections.

BACKGROUND: Owing to the growth of case reports and changes in the policy of journals in publishing this evidence, the need to standardize them is felt more than before. Therefore, in this study, the authors' guide of medical journals indexed in the Scopus database that published most of the case reports has been analyzed to identify the reporting requirements and emerging case report types. METHODS: A total of 50 journals were selected from the Scopus citation database (the world's largest knowledge base) that published most of the case reports. These and the authors' guideline section on the types and requirements of writing case reports were analyzed by inductive content analysis. RESULTS: Most of the case reports were published in the fields of dermatology and surgery and general medicine. Reporting requirements in author's guide are grouped in four categories: (1) reasons for publication or content value, (2) emphasis on the patient consent form and confidentiality, (3) emphasizing the constraints on the word count and limitation, and (4) recommendation for structure and reporting elements. In terms of adherence to the reporting guidelines, 76% of journals do not adhere to any reporting guideline. In addition, 13 types of case reports were identified in these journals, among which traditional case reports, clinical image, letters, and case series were the most widely used formats. CONCLUSIONS: Improving the publication processes of case reports has been left unattended by international organizations. The policies of journals need to become more integrated, and reporting guidelines should be modified or redeveloped to enhance the quality of publications, cover different reporting requirements, and consequently, benefit from the evidence value available in case reports.

Extending the visible light absorption of NH2-UiO-66 through diazotization reaction for photocatalytic chromium (VI) reduction.

The optical properties of NH2-UiO-66 as a visible light-active metal organic framework was further enhanced through the diazotization reaction with π-conjugated 1-naphthol reagent. Diffuse reflectance UV-Vis spectrum of diazotized MOF, named as Azo-UiO-66, exhibited a significant red shift compared to unfunctionalized NH2-UiO-66 due to the formation of diazo compound. Also, Tauc calculations indicated considerable decrease in band gap energy from 2.68 to 1.7 eV, resulting in improvement of visible light harvesting. Furthermore, other physicochemical techniques, e.g., X-ray diffraction (XRD), N2 adsorption-desorption analysis, thermogravimetric analysis (TGA), energ-dispersive X-ray (EDX), and CHN elemental analyses demonstrated the successful MOF diazotization with 1-naphthol and preservation of NH2-UiO-66 framework upon post-modification process. The reduction of hexavalent chromium, Cr(VI), as a serious contaminant in wastewater to less toxic Cr(III) was performed over prepared photocatalyst, which demonstrated the positive role of ligand functionalization and enhancement of visible light absorption on overall photocatalytic performance of Azo-UiO-66.

Ln Based Metal-organic Framework for Fluorescence "Turn Off-On" Sensing of Hg2.

A highly luminescent Ln-MOF [La3(NDC)4(DMF)3(H2O)4]n, (NDC = 2, 6 naphthalen dicarboxylic acid) was designed and synthesized. The structure was characterized by x-ray single structure determination, TGA, IR spectra and PXRD and fluorescence spectroscopy. The structure shows high fluorescence intensity based on the presence of lanthanide metal and ligand. In the presence of I-, the emission can be effectively quenched introducing turn off system. Furthermore, the synthesized Ln-MOF can recognize Hg (II) by showing fluorescence turn-on signal because of the high affinity between Hg (II) and I-. Moreover, the high selectivity and sensitivity of the synthesized Ln-MOF makes it quit qualified for determination of the low concentration of mercury (2.00 nM).