Evaluating Diatomaceous Earth for Long-Term Use in Hydrogen Storage.

Efficient hydrogen storage is essential for its use as a sustainable energy carrier. Diatomaceous earth, a high-surface-area siliceous geomaterial, shows potential as a physisorption material for hydrogen storage. This study analyzes diatomaceous earth's long-term characteristics when subjected to high-pressure hydrogen injection. The diatomaceous earth was subjected to a hydrogen pressure of 1200 psi for a period of 80 days at room temperature. Neither notable morphological or mineralogical changes were observed. Nevertheless, there was a slight reduction in fine particles and a slight increase in larger particles. The Brunauer-Emmett-Teller (BET) surface area decreased slightly with a significant decrease in pore width. However, the hydrogen adsorption at 77 K temperature was increased significantly (45.5%) after the hydrogen storage test. Moreover, there was a delayed release of molecular water as the temperature increased. These changes suggest that a condensation reaction has occurred involving some of the opal-A silanol groups (Si-O-H), producing molecular water. Bonding through siloxane bridges (Si-O-Si) results in a significant decrease in pore width and increased hydrophobicity (i.e., the interaction between diatomaceous surface and H2 was increased), thereby enhancing hydrogen adsorption capacity. These findings indicate that diatomaceous earth holds promise as a material for hydrogen storage, with the potential for its hydrogen adsorption capacity to improve over time.

Boosting the Electrocatalytic Water Splitting Performance Using Hydrophilic Metal-Organic Framework.

In this study, we employed a rapid and efficient microwave method to synthesize Metal-Organic Framework (MOF-303), which was subsequently embedded onto Palladium/Carbon (Pd/C) electrodes. The resulting hybrid material, Pd/C@MOF-303, was thoroughly characterized, and its performance in the Hydrogen Evolution Reaction (HER) was systematically investigated. The Pd/C@MOF-303 composite exhibited remarkable improvements in HER performance compared to the unmodified Pd/C electrode. At a benchmark current density of 10 mA cm-2 , the overpotentials for Pd/C and Pd/C@MOF-303 were measured at 185 mV and 175 mV, respectively. This reduction in overpotential highlights the superior catalytic activity of the Pd/C@MOF-303 hybrid material in facilitating the HER. Furthermore, the Pd/C@MOF-303 electrode demonstrated enhanced HER activity, increased mass activity, and excellent charge transfer rates compared to its unmodified counterpart, Pd/C. The findings underscore the significance of the hydrophilic MOF-303 in tailoring the surface characteristics of electrocatalysts, thereby offering insights into the design principles for advanced materials with superior performance in electrochemical applications.

CO2 Adsorption on Biomass-Derived Carbons from Albizia procera Leaves: Effects of Synthesis Strategies.

CO2 capture is a useful strategy for controlling the risks associated with global warming. The design of an adsorbent is essential for clean and potentially energy-efficient adsorption-based carbon capture processes. This study reports a facile and moderately temperature single-stage combined pyrolysis and activation strategy for the synthesis of nitrogen-doped carbons for high-performance CO2 capture. Using nitrogen-rich Albizia procera leaves as the precursor and carrying out single-stage pyrolysis and activation at temperatures of 500, 600, and 700 °C in the presence NaHCO3 as an activating agent, carbons with different surface characteristics and ultrahigh weight percentage (22-25%) of nitrogen were obtained. The subtle differences in surface characteristics and nitrogen content had a bearing on the CO2 adsorption performance of the resultant adsorbents. Outstanding results were achieved, with a CO2 adsorption capacity of up to 2.5 mmol/g and a CO2 over N2 selectivities reaching 54. The isotherm results were utilized to determine the performance indicators for a practical vacuum swing adsorption process. This study provides a practical strategy for the efficient synthesis of nitrogen-doped carbons for various adsorption applications.

3D porous polymers for selective removal of CO2 and H2 storage: experimental and computational studies.

In this article, newly designed 3D porous polymers with tuned porosity were synthesized by the polycondensation of tetrakis (4-aminophenyl) methane with pyrrole to form M1 polymer and with phenazine to form M2 polymer. The polymerization reaction used p-formaldehyde as a linker and nitric acid as a catalyst. The newly designed 3D porous polymers showed permanent porosity with a BET surface area of 575 m2/g for M1 and 389 m2/g for M2. The structure and thermal stability were investigated by solid 13C-NMR spectroscopy, Fourier-transform infrared (FT-IR) spectroscopy, and thermogravimetric analysis (TGA). The performance of the synthesized polymers toward CO2 and H2 was evaluated, demonstrating adsorption capacities of 1.85 mmol/g and 2.10 mmol/g for CO2 by M1 and M2, respectively. The importance of the synthesized polymers lies in their selectivity for CO2 capture, with CO2/N2 selectivity of 43 and 51 for M1 and M2, respectively. M1 and M2 polymers showed their capability for hydrogen storage with a capacity of 66 cm3/g (0.6 wt%) and 87 cm3/g (0.8 wt%), respectively, at 1 bar and 77 K. Molecular dynamics (MD) simulations using the grand canonical Monte Carlo (GCMC) method revealed the presence of considerable microporosity on M2, making it highly selective to CO2. The exceptional removal capabilities, combined with the high thermal stability and microporosity, enable M2 to be a potential material for flue gas purification and hydrogen storage.

CO2 Adsorption on Pore-Engineered Carbons Derived from Jute Sticks.

CO2 capture is a practical approach to mitigating the impacts of global warming. Adsorption-based carbon capture is a clean and potentially energy-efficient method whose performance greatly depends on adsorbent design. In this study, we explored the use of jute-derived carbon as a high-performance adsorbent for CO2 capture. The carbons were produced by pyrolyzing powdered jute sticks with NaHCO3 as an activating agent at 500-700 °C. Impressive adsorption capacities of up to 2.5 mmol ⋅ g-1 and CO2 /N2 selectivities of up to 54 were achieved by adjusting the pore size distribution and surface functionalization. Based on the isotherm results, the working capacities, regenerabilities, and potentials for CO2 separation were determined for a practical vacuum swing adsorption process. The adsorbent materials were characterized by XRD, FTIR, Raman, FESEM and N2 sorption at 77 K. This study provides a general approach for designing adsorbents for various gas-separation applications.

Design and Synthesis of N-Doped Porous Carbons for the Selective Carbon Dioxide Capture under Humid Flue Gas Conditions.

The design of novel porous solid sorbents for carbon dioxide capture is critical in developing carbon capture and storage technology (CCS). We have synthesized a series of nitrogen-rich porous organic polymers (POPs) from crosslinking melamine and pyrrole monomers. The final polymer's nitrogen content was tuned by varying the melamine ratio compared to pyrrole. The resulting polymers were then pyrolyzed at 700 °C and 900 °C to produce high surface area nitrogen-doped porous carbons (NPCs) with different N/C ratios. The resulting NPCs showed good BET surface areas reaching 900 m2 g-1. Owing to the nitrogen-enriched skeleton and the micropore nature of the prepared NPCs, they exhibited CO2 uptake capacities as high as 60 cm3 g-1 at 273 K and 1 bar with significant CO2/N2 selectivity. The materials showed excellent and stable performance over five adsorption/desorption cycles in the dynamic separation of the ternary mixture of N2/CO2/H2O. The method developed in this work and the synthesized NPCs' performance towards CO2 capture highlight the unique properties of POPs as precursors for synthesizing nitrogen-doped porous carbons with a high nitrogen content and high yield.

Facile Hydrogenation of Furfural by MOF-Derived Graphitic Carbon Wrapped FeCo Bimetallic Catalysts.

A catalytic system for selective transformation of furfural into biofuel is highly desirable. However, selective hydrogenation of the C=O group over the furan ring of furfural to produce ether in one step is challenging. Here, we report the preparation of a series of magnetically recoverable FeCo@GC nano-alloys (37-40 nm). Fe3 O4 (3-5 nm) and MOF-71 (Co), used as the Co and C source, were mixed together in a range of Fe/Co ratios, and then encapsulated in a graphitic carbon (GC) shell to prepare such alloys. STEM-HAADF shows the darker core made of FeCo and the shell of graphitic carbon. Furfural is hydrogenated to produce >99% isopropyl furfuryl ether in isopropanol with >99% conversion at 170 °C under 40 bars of H2 , whereas n-chain alcohol, such as ethanol, produces corresponding ethyl levulinate in 93%. The synergistic effect due to the charge transfer from Fe to Co leads to higher reactivity of FeCo@GC. The catalyst, which can be separated from the reaction medium using a simple magnet without significant damage to the surface or composition, retained its reactivity and selectivity for up to four consecutive cycles.

Hemin-Modified Multi-Walled Carbon Nanotube-Incorporated PVDF Membranes: Computational and Experimental Studies on Oil-Water Emulsion Separations.

The separation of oil/water emulsions has attracted considerable attention for decades due to the negative environmental impacts brought by wastewater. Among the various membranes investigated for separation, polyvinylidene fluoride (PVDF) membranes have shown significant advantages of ease of fabrication, high selectivity, and fair pore distribution. However, PVDF membranes are hydrophobic and suffer from severe fouling resulting in substantial flux decline. Meanwhile, the incorporation of wettable substrates during fabrication has significantly impacted the membrane performance by lowering the fouling propensity. Herein, we report the fabrication of an iron-containing porphyrin (hemin)-modified multi-walled carbon nanotube incorporated PVDF membrane (HA-MWCNT) to enhance fouling resistance and the effective separation of oil-in-water emulsions. The fabricated membrane was thoroughly investigated using the FTIR, SEM, EDX, AFM, and contact angle (CA) analysis. The HA-MWCNT membrane exhibited a water CA of 62° ± 0.5 and excellent pure water permeance of 300.5 L/m2h at 3.0 bar (400% increment), in contrast to the pristine PVDF, which recorded a CA of 82° ± 0.8 and water permeance of 59.9 L/m2h. The hydrophilic HA-MWCNT membrane further showed an excellent oil rejection of >99% in the transmembrane pressure range of 0.5−2.5 bar and a superb flux recovery ratio (FRR) of 82%. Meanwhile, the classical molecular dynamics (MD) simulations revealed that the HA-MWCNT membrane had greater solvent-accessible pores, which enhanced water permeance while blocking the hydrocarbons. The incorporation of the hemin-modified MWCNT is thus an excellent strategy and could be adopted in the design of advanced membranes for oil/water separation.

Optimization of tannase production by Aspergillus glaucus in solid-state fermentation of black tea waste.

Tannases are valuable industrial enzymes used in food, pharmaceutical, cosmetic, leather manufacture and in environmental biotechnology. In this study, 15 fungal isolates were obtained from Egyptian cultivated soil and marine samples. The isolated fungi were qualitatively and quantitatively screened for their abilities to produce tannase. The selected fungal isolate NRC8 giving highest tannase activity was identified by molecular technique (18S rRNA) as Aspergillus glaucus. Among different tannin-containing wastes tested, the black tea waste was the best substrate for tannase production by Aspergillus glaucus in solid-state fermentation (SSF). Optimization of the different process parameters required for maximum enzyme production was carried out to design a suitable SSF process. Maximal tannase production was achieved with moisture content of 75%, an inoculums size of 6 × 108 spore/ml and sodium nitrate 0.2% (pH of 5.0) at 30 °C after 5 days of incubation. Box-Behnken experiment was designed to get a quadratic model for further optimization studies. Four-factor response-surface method with 27 runs was prepared using independent parameters including (moisture content %, initial pH, substrate concentration (g) and sodium nitrate concentration (g) for tannase model. The F- and P-values of the model were 4.30 and 0.002, respectively, which implied that the model is significant. In addition, the lack-of-fit was 1040.37 which indicates the same significance relative to the pure error. A. glaucus tannase was evaluated by the efficiency of conversion of tannic acid to gallic acid. Moreover, production of gallic acid from SSF process of A. glaucus using black tea waste was found to be 38.27 mg/ml. The best bioconversion efficiency was achieved at 40 °C with tannic acid concentration up to 200 g/L.

Trans-pedal access for endovascular revascularization in complex infra-popliteal lesions in critically ischemic limb: A cohort study.

Background: critical limb ischemia is one of the most challenging cases we face nowadays with high risk for amputation, retrograde trans-pedal angioplasty offers an alternative technique after failure of traditional ante-grade angioplasty. Patients and Methods: 96 patients underwent trans-pedal or trans-tibial retrograde angioplasty after failure of the traditional ante-grade angioplasty with the aid of US, 21-gauge needle and 0.018 wire through sheath-less approach as a last chance for revascularization. Results: clinical success or improvement in 77 cases (80.2%), and in other 19 cases (19.8%) there was no clinical success or improvement. The technical success was achieved in 81 cases with percentage of (84.4%), and not achieved in 15 cases (15.6%) only. Conclusions: Retrograde Trans-pedal angioplasty is an efficient, safe, and practical procedure with a high technical success and a relatively minimal procedural adverse effect.

Posterior component separation with transversus abdominis muscle release versus mesh-only repair in the treatment of complex ventral-wall hernia: a randomized controlled trial.

BACKGROUND: Complex ventral hernias (VHs) represent a real challenge to both general and plastic surgeons. This study aims to compare Sublay Mesh-Only Repair to Posterior Component Separation "PCS" with Transversus Abdominis Release "TAR" in the treatment of complex ventral-wall hernias (VHs). METHODS: This a randomized, controlled, intervention, including two parallel groups: A; Sublay Mesh-Only Repair and Group B; "TAR". Consecutive patients of both genders aged between 18 and 65 years old with complex VHs presented at Mansoura University Hospitals including large-sized abdominal-wall hernia ≥ 10 cm in width, loss of domain ≥ 20%, multiple hernial defects, or recurrent hernias. Immuno-compromised patients, patients with liver impairment, or severe heart failure were considered an exclusion criterion. The primary outcome is the recurrence rate after 12-months following the procedure. RESULTS: Fifty-six patients were recruited in this study. There was no significant difference between both groups regarding recurrence. However, there was significant differences between both groups regarding seroma favoring mesh-only repair. CONCLUSIONS: Although TAR may be associated with longer operative times and more blood losses, these were not found to be statistically significant. Postoperative complication, except for seroma, and recurrence rates were comparable in both groups. Trail registration The study was registered on clicaltrials.gov "NCT04516031".

Higher symptom score, larger residual rectocele, and lower rectal compliance predict failure of improvement after surgical treatment of rectocele

Background: Rectocele is a frequent finding in women and is usually asymptomatic. However, it is sometimes associated with symptoms of obstructed defecation syndrome (ODS). While most patients with ODS due to rectocele respond well to conservative treatment, some may require surgical treatment. The aim of the study was to determine the predictors of failure of symptom improvement after rectocele repair. Methods: The study included adult women with rectocele who underwent surgical treatment by transperineal repair (TPR) or transvaginal repair (TVR). The preoperative and postoperative assessment was done using the Wexner constipation score, anorectal manometry, and defecography. Results: A total of 93 female patients with a mean age of 43.7 years were included. Among them, 65.6% of patients underwent TPR and 34.4% underwent TVR; 22 (23.7%) patients reported failure of significant improvement in ODS symptoms after surgery. The independent predictors of failure of improvement were higher preoperative Wexner score (odds ratio, OR: 1.4, 95% confidence interval, CI: 1.09-1.84, p = 0.009), larger residual rectocele after repair (OR: 2.95, 95% CI: 1.43-6.08, p = 0.003), and lower postoperative maximum tolerable volume (OR: 0.949, 95% CI: 0.907-0.992, p = 0.02). The predictive cutoff point for the preoperative Wexner score was 15. Conclusions: Patients with a preoperative Wexner score higher than 15 and larger residual rectocele after surgery may experience little improvement in symptoms after rectocele repair. Although TPR was associated with a poorer relief of symptoms than did TVR; it was not an independent predictor of failure. (AU)

Azo-Linked Porous Organic Polymers for Selective Carbon Dioxide Capture and Metal Ion Removal.

The facile and environmentally friendly synthesis of porous organic polymers with designed polar functionalities decorating the interior frameworks as an excellent adsorbent for selective carbon dioxide capture and metal ion removal is a target worth pursuing for environmental applications. In this regard, two azo-linked porous organic polymers denoted man-Azo-P1 and man-Azo-P2 were synthesized in water by the azo-linking of 4,4'-diaminobiphenyl (benzidine) and 4,4'-methylenedianiline, respectively, with 1,3,5-trihydroxybenzene. The resulting polymers showed good BET surface areas of 290 and 78 m2 g-1 for man-Azo-P1 and man-Azo-P2, respectively. Due to the enriched core functionality of the azo (-N=N-) and hydroxyl groups along with the porous frameworks, man-Azo-P1 exhibited a good CO2 uptake capacity of 32 cm3 g-1 at 273 K and 1 bar, in addition to the remarkable removal of lead (Pd), chromium (Cr), arsenic (As), nickel (Ni), copper (Cu), and mercury (Hg) ions. This performance of the synthesized man-Azo-P1 and man-Azo-P2 in the dual application of CO2 capture and heavy metal ion removal highlights the unique properties of azo-linked POPs as excellent and stable sorbent materials for the current challenging environmental applications.

A pilot randomized controlled trial on ligation of intersphincteric fistula tract (LIFT) versus modified parks technique and two-stage seton in treatment of complex anal fistula.

Complex anal fistula (CAF) is a challenging condition for surgeons. This randomized trial aimed to compare ligation of the intersphincteric fistula tract (LIFT), modified Parks technique, and two-stage seton in the treatment of complex anal fistula in terms of the success of treatment and complications. This was a pilot randomized trial conducted in the period of January 2019 to December 2019 on adult patients with CAF who were allocated to one of three groups: LIFT, modified Parks technique, and two-stage seton. The main outcome measures were healing rates, time to healing, complications, operation time, and quality of life. Sixty-six patients (75.7% males) of a mean age of 45.2 years were included. Mean operation time of LIFT was significantly shorter than the other two procedures (p < 0.0001). There was a significant difference between the three groups in terms of success rate (p = 0.04) but not in regard to complications (p = 0.59). The modified Parks technique had a significantly higher success rate than LIFT (95.2% vs 68.1%, p = 0.045) whereas the success rates of two-stage seton and LIFT were not significantly different (86.9% vs 68.1%, p = 0.16). The average time to healing after LIFT was significantly shorter than the other two procedures. The quality-of-life scores were comparable among the three groups. There was a significant difference in healing rates after the three procedures as the modified Parks technique achieved the highest success rate followed by two-stage seton and then the LIFT procedure. Time to complete healing after LIFT was significantly shorter than the other two procedures. The three procedures achieved similar quality of life and complication rates.

One-anastomosis gastric bypass (OAGB) with fixed bypass of the proximal two meters versus tailored bypass of the proximal one-third of small bowel: short-term outcomes.

BACKGROUND: One-anastomosis gastric bypass (OAGB) is an effective bariatric procedure that confers satisfactory weight loss and improvement in comorbidities. The present study aimed to compare OAGB with fixed bypass of the proximal 200 cm of small bowel and tailored bypass of the proximal 1/3 of bowel. METHODS: Patients with class II/III obesity underwent OAGB with either fixed bypass of the proximal two meters or tailored bypass of the proximal 1/3 of bowel. The main outcomes of the study were weight loss, improvement in comorbidities, complications, and changes in nutritional parameters after each technique. RESULTS: The present study included 80 patients (62 female) of a mean age of 41 years and mean body mass index (BMI) of 50.9 kg/m2. The tailored bypass group was followed by a significantly lower BMI and significantly higher excess weight loss and total weight loss at 6 and 12 months postoperatively. There was no significant difference between the two groups in terms of improvement in comorbidities. The fixed bypass group was associated with a significantly higher complication rate than the tailored bypass group (22.5 vs. 5%, P = 0.04). Both groups were associated with similar changes in the nutritional parameters at 12 months postoperatively, except for the higher serum albumin levels after the tailored bypass than the fixed bypass. CONCLUSIONS: OAGB with tailored bypass of the proximal one-third of bowel was associated with greater weight loss and comparable improvement in comorbidities as compared to fixed bypass of the proximal two meters of intestine.

Advanced Strategies in Metal-Organic Frameworks for CO2 Capture and Separation.

The continuous carbon dioxide (CO2 ) gas emissions associated with fossil fuel production, valorization, and utilization are serious challenges to the global environment. Therefore, several developments of CO2 capture, separation, transportation, storage, and valorization have been explored. Consequently, we documented a comprehensive review of the most advanced strategies adopted in metal-organic frameworks (MOFs) for CO2 capture and separation. The enhancements in CO2 capture and separation are generally achieved due to the chemistry of MOFs by controlling pore window, pore size, open-metal sites, acidity, chemical doping, post or pre-synthetic modifications. The chemistry of defects engineering, breathing in MOFs, functionalization in MOFs, hydrophobicity, and topology are the salient advanced strategies, recently reported in MOFs for CO2 capture and separation. Therefore, this review summarizes MOF materials' advancement explaining different strategies and their role in the CO2 mitigations. The study also provided useful insights into key areas for further investigations.

Experimental and Theoretical Study on the Interchange between Zr and Ti within the MIL-125-NH2 Metal Cluster.

This study aims to investigate the effect of replacing Ti with Zr in the SBU of MIL-125-NH2 . We were able to replace Ti with Zr in the mixed metal synthesis of MIL-125-NH2 , for the first time. After experimentally confirming the consistency in their framework structure and comparing their morphology, we related the femtosecond light dynamics with photocatalytic CO2 visible light conversion yield of the different variants in order to establish the composition-function relation in MIL-125 vis a vis CO2 reduction. Introducing Zr to the system was found to cause structure defects due to missing linkers. The lifetime of the charge carriers for the mixed metal samples were shorter than that of the MIL-125-NH2 . The study of CO2 photocatalytic reduction under visible light indicated that the NH2 group enhances the photocatalytic activity while the Zr incorporation inside the MIL framework introduces no significant improvements. In addition, the material systems were modelled and simulated through DFT calculations which concluded that the decrease of the photocatalytic activity is not related to the system electronic structure, insinuating that defects are the culprit.

Trends and Prospects in UiO-66 Metal-Organic Framework for CO2 Capture, Separation, and Conversion.

Among thousands of known metal-organic frameworks (MOFs), the University of Oslo's MOF (UiO-66) exhibits unique structure topology, chemical and thermal stability, and intriguing tunable properties, that have gained incredible research interest. This paper summarizes the structural advancement of UiO-66 and its role in CO2 capture, separation, and transformation into chemicals. The first part of the review summarizes the fast-growing literature related to the CO2 capture reported by UiO-66 during the past ten years. The second part provides an overview of various advancements in UiO-66 membranes in CO2 purification. The third part describes the role of UiO-66 and its composites as catalysts for CO2 conversion into useful products. Despite many achievements, significant challenges associated with UiO-66 are addressed, and future perspectives are comprehensively presented to forecast how UiO-66 might be used further for CO2 management.

Sinus laser therapy versus sinus lay open in the management of sacrococcygeal pilonidal disease.

AIM: There is no standard method for the management of sacrococcygeal pilonidal disease (SPND); however, surgery remains the gold standard treatment. Wide surgical excision of the sinus is the traditional surgical treatment of SPND, yet it is associated with extended healing time and delayed recovery. This study aimed to compare the outcomes of sinus laser therapy (SiLaT) and sinus lay open in the management of SPND. METHODS: Patients with SPND who were treated with SiLaT or lay open were retrospectively reviewed. The main outcome measures were the success of surgery in terms of complete healing at 12 months postoperatively, time to complete healing, complications, operation time and quality of life (QoL). RESULTS: A total of 139 patients with a mean age of 25 years were included to the study. Sixty-two patients underwent SiLaT and 77 underwent lay open. Six patients experienced recurrence after SiLaT while there was no recorded recurrence after the lay open technique (P = 0.007). Sinus lay open had a shorter operation time than SiLaT (P < 0.0001). On the other hand, SiLaT was followed by a shorter healing time, lower incidence of delayed wound healing, better cosmetic outcome, and higher QoL scores compared to the lay open group. The complication rates were comparable between the two groups. CONCLUSION: Sinus lay open was associated with better success than SiLaT. On the other hand, SiLaT was associated with quicker healing, better cosmesis, better QoL and longer operation time. The complication rate of the two procedures was comparable.