A Comparative Review of Binder-Containing Extrusion and Alternative Shaping Techniques for Structuring of Zeolites into Different Geometrical Bodies

Zeolites are crystalline metallosilicates displaying unique physicochemical properties with widespread applications in catalysis, adsorption, and separation. They are generally obtained by a multi-step process that starts with primary mixture aging, followed by hydrothermal crystallization, washing, drying, and, finally, a calcination step. However, the zeolites obtained are in the powder form and because of generating a pressure drop in industrial fixed bed reactors, not applicable for industrial purposes. To overcome such drawbacks, zeolites are shaped into appropriate geometries and desired size (a few centimeters) using extrusion, where zeolite powders are mixed with binders (e.g., mineral clays or inorganic oxides). The presence of binders provides good mechanical strength against crushing in shaped zeolites, but binders may have adverse impacts on zeolite catalytic and sorption properties, such as active site dilution and pore blockage. The latter is more pronounced when the binder has a smaller particle size, which makes the zeolite internal active sites mainly inaccessible. In addition to the shaping requirements, a hierarchical structure with different levels of porosity (micro-, meso-, and macropores) and an interconnected network are essential to decrease the diffusion limitation inside the zeolite micropores as well as to increase the mass transfer because of the presence of larger auxiliary pores. Thus, the generation of hierarchical structure and its preservation during the shaping step is of great importance. The aim of this review is to provide a comprehensive survey and detailed overview on the binder-containing extrusion technique compared to alternative shaping technologies with improved mass transfer properties. An emphasis is allocated to those techniques that have been less discussed in detail in the literature.</p

Synergistic Catalytic Effects of Alloys of Noble Metal Nanoparticles Supported on Two Different Supports:Crystalline Zeolite Sn-Beta and Carbon Nanotubes for Glycerol Conversion to Methyl Lactate

Two multifunctional catalytic systems comprising Sn-based/doped crystalline zeolite Beta were synthesized, and they were employed as heterogeneous catalysts in the selective conversion of glycerol to methyl lactate. The first catalytic system, named Au-Pd-Sn-deAl-7.2-Beta-DP, was created through the post-synthesis dealumination of the parent zeolite Beta (Si/Al = 10) using 7.2 M HNO3. Subsequently, it was grafted with 27 mmol of SnCl4, resulting in Sn-deAl-7.2-Beta. Following this, Au and Pd nanoparticles were supported on this catalyst using the deposition–precipitation (DP) method. The second catalytic system was a physical mixture of Au and Pd nanoparticles supported on functionalized carbon nanotubes (Au-Pd-F-CNTs) and Sn-containing zeolite Beta (Sn-deAl-7.2-Beta). Both catalytic systems were employed in glycerol partial oxidation to methyl lactate under the following conditions: 140 °C for 4.5 h under an air pressure of 30 bar. The Au-Pd-Sn-deAl-7.2-Beta-DP catalytic system demonstrated 34% conversion of glycerol with a 76% selectivity for methyl lactate. In contrast, the physical mixture of Au-Pd-F-CNTs and Sn-deAl-7.2-Beta exhibited higher activity, achieving 58% glycerol conversion and a nearly identical selectivity for methyl lactate (77%). The catalytic results and catalyst structure were further analyzed using various characterization techniques, such as X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), X-ray fluorescence (XRF), transmission electron microscopy (TEM), UV-vis spectroscopy, and pyridine Fourier transform infrared (FTIR). These analyses emphasized the significance of adjusting the quantity of active sites, particle size, and active sites proximity under the chosen reaction conditions.</p

Synergistic Catalytic Effects of Alloys of Noble Metal Nanoparticles Supported on Two Different Supports:Crystalline Zeolite Sn-Beta and Carbon Nanotubes for Glycerol Conversion to Methyl Lactate

Two multifunctional catalytic systems comprising Sn-based/doped crystalline zeolite Beta were synthesized, and they were employed as heterogeneous catalysts in the selective conversion of glycerol to methyl lactate. The first catalytic system, named Au-Pd-Sn-deAl-7.2-Beta-DP, was created through the post-synthesis dealumination of the parent zeolite Beta (Si/Al = 10) using 7.2 M HNO3. Subsequently, it was grafted with 27 mmol of SnCl4, resulting in Sn-deAl-7.2-Beta. Following this, Au and Pd nanoparticles were supported on this catalyst using the deposition–precipitation (DP) method. The second catalytic system was a physical mixture of Au and Pd nanoparticles supported on functionalized carbon nanotubes (Au-Pd-F-CNTs) and Sn-containing zeolite Beta (Sn-deAl-7.2-Beta). Both catalytic systems were employed in glycerol partial oxidation to methyl lactate under the following conditions: 140 °C for 4.5 h under an air pressure of 30 bar. The Au-Pd-Sn-deAl-7.2-Beta-DP catalytic system demonstrated 34% conversion of glycerol with a 76% selectivity for methyl lactate. In contrast, the physical mixture of Au-Pd-F-CNTs and Sn-deAl-7.2-Beta exhibited higher activity, achieving 58% glycerol conversion and a nearly identical selectivity for methyl lactate (77%). The catalytic results and catalyst structure were further analyzed using various characterization techniques, such as X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), X-ray fluorescence (XRF), transmission electron microscopy (TEM), UV-vis spectroscopy, and pyridine Fourier transform infrared (FTIR). These analyses emphasized the significance of adjusting the quantity of active sites, particle size, and active sites proximity under the chosen reaction conditions.</p

Synergistic Catalytic Effects of Alloys of Noble Metal Nanoparticles Supported on Two Different Supports:Crystalline Zeolite Sn-Beta and Carbon Nanotubes for Glycerol Conversion to Methyl Lactate

Two multifunctional catalytic systems comprising Sn-based/doped crystalline zeolite Beta were synthesized, and they were employed as heterogeneous catalysts in the selective conversion of glycerol to methyl lactate. The first catalytic system, named Au-Pd-Sn-deAl-7.2-Beta-DP, was created through the post-synthesis dealumination of the parent zeolite Beta (Si/Al = 10) using 7.2 M HNO3. Subsequently, it was grafted with 27 mmol of SnCl4, resulting in Sn-deAl-7.2-Beta. Following this, Au and Pd nanoparticles were supported on this catalyst using the deposition–precipitation (DP) method. The second catalytic system was a physical mixture of Au and Pd nanoparticles supported on functionalized carbon nanotubes (Au-Pd-F-CNTs) and Sn-containing zeolite Beta (Sn-deAl-7.2-Beta). Both catalytic systems were employed in glycerol partial oxidation to methyl lactate under the following conditions: 140 °C for 4.5 h under an air pressure of 30 bar. The Au-Pd-Sn-deAl-7.2-Beta-DP catalytic system demonstrated 34% conversion of glycerol with a 76% selectivity for methyl lactate. In contrast, the physical mixture of Au-Pd-F-CNTs and Sn-deAl-7.2-Beta exhibited higher activity, achieving 58% glycerol conversion and a nearly identical selectivity for methyl lactate (77%). The catalytic results and catalyst structure were further analyzed using various characterization techniques, such as X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), X-ray fluorescence (XRF), transmission electron microscopy (TEM), UV-vis spectroscopy, and pyridine Fourier transform infrared (FTIR). These analyses emphasized the significance of adjusting the quantity of active sites, particle size, and active sites proximity under the chosen reaction conditions.</p

Synergistic Catalytic Effects of Alloys of Noble Metal Nanoparticles Supported on Two Different Supports:Crystalline Zeolite Sn-Beta and Carbon Nanotubes for Glycerol Conversion to Methyl Lactate

Two multifunctional catalytic systems comprising Sn-based/doped crystalline zeolite Beta were synthesized, and they were employed as heterogeneous catalysts in the selective conversion of glycerol to methyl lactate. The first catalytic system, named Au-Pd-Sn-deAl-7.2-Beta-DP, was created through the post-synthesis dealumination of the parent zeolite Beta (Si/Al = 10) using 7.2 M HNO3. Subsequently, it was grafted with 27 mmol of SnCl4, resulting in Sn-deAl-7.2-Beta. Following this, Au and Pd nanoparticles were supported on this catalyst using the deposition–precipitation (DP) method. The second catalytic system was a physical mixture of Au and Pd nanoparticles supported on functionalized carbon nanotubes (Au-Pd-F-CNTs) and Sn-containing zeolite Beta (Sn-deAl-7.2-Beta). Both catalytic systems were employed in glycerol partial oxidation to methyl lactate under the following conditions: 140 °C for 4.5 h under an air pressure of 30 bar. The Au-Pd-Sn-deAl-7.2-Beta-DP catalytic system demonstrated 34% conversion of glycerol with a 76% selectivity for methyl lactate. In contrast, the physical mixture of Au-Pd-F-CNTs and Sn-deAl-7.2-Beta exhibited higher activity, achieving 58% glycerol conversion and a nearly identical selectivity for methyl lactate (77%). The catalytic results and catalyst structure were further analyzed using various characterization techniques, such as X-ray diffraction (XRD), N2 physisorption, scanning electron microscopy (SEM), X-ray fluorescence (XRF), transmission electron microscopy (TEM), UV-vis spectroscopy, and pyridine Fourier transform infrared (FTIR). These analyses emphasized the significance of adjusting the quantity of active sites, particle size, and active sites proximity under the chosen reaction conditions.</p

Solid-State NMR Spectroscopy:Towards Structural Insights into Starch-Based Materials in the Food Industry

Solid-state NMR is a nondestructive and noninvasive technique used to study the chemical structure and dynamics of starch-based materials and to bridge the gap between structure–function relationships and industrial applications. The study of crystallinity, chemical modification, product blending, molecular packing, amylose–amylopectin ratio, end chain motion, and solvent–matrix interactions is essential for tailoring starch product properties to various applications. This article aims to provide a comprehensive and critical review of research characterizing starch-based materials using solid-state NMR, and to briefly introduce the most advanced and promising NMR strategies and hardware designs used to overcome the sensitivity and resolution issues involved in structure–function relationships

Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes

A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p

Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes

A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p

Surfactant-Free Peroxidase-Mediated Enzymatic Polymerization of a Biorenewable Butyrolactone Monomer via a Green Approach:Synthesis of Sustainable Biobased Latexes

A green surfactant-free one-pot horseradish peroxidase-mediated enzymatic polymerization is successfully applied to produce a sustainable and thermally stable biobased high average molar mass poly(α-methylene-γ-butyrolactone) (PMBL) at ambient conditions in water for the first time. The initiation step required only very low concentrations of hydrogen peroxide and 2,4-pentanedione water-soluble initiator to generate the keto-enoxy radicals responsible for forming the primary latex particles. The polymer nanoparticles can be seen as monodisperse, and the biobased latexes are colloidally stable and likely stabilized by the adsorption of 2,4-pentanedione moieties on the particle surfaces. Polymerizations in air produced a 98% yield of PMBL after only 3 h, highlighting the relevance of molecular oxygen. An array of characterization techniques such as dynamic light scattering (DLS), Fourier transform infrared (FTIR), 1H, 13C, and HSQC two-dimensional (2D) nuclear magnetic resonance (NMR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and size-exclusion chromatography (SEC) are used to confirm the properties of the synthesized latexes. The PMBL exhibited high thermal stability, with only a 5% weight loss at 340 °C and a glass-transition temperature of 200 °C, which is double that of polymethyl methacrylate (PMMA). This research provides an interesting pathway for the synthesis of sustainable biobased latexes via enzymes in a green environment using just water at ambient conditions and the potential use of the polymer in high-temperature applications.</p

Mortality from gastrointestinal congenital anomalies at 264 hospitals in 74 low-income, middle-income, and high-income countries: a multicentre, international, prospective cohort study

Summary Background Congenital anomalies are the fifth leading cause of mortality in children younger than 5 years globally. Many gastrointestinal congenital anomalies are fatal without timely access to neonatal surgical care, but few studies have been done on these conditions in low-income and middle-income countries (LMICs). We compared outcomes of the seven most common gastrointestinal congenital anomalies in low-income, middle-income, and high-income countries globally, and identified factors associated with mortality. Methods We did a multicentre, international prospective cohort study of patients younger than 16 years, presenting to hospital for the first time with oesophageal atresia, congenital diaphragmatic hernia, intestinal atresia, gastroschisis, exomphalos, anorectal malformation, and Hirschsprung’s disease. Recruitment was of consecutive patients for a minimum of 1 month between October, 2018, and April, 2019. We collected data on patient demographics, clinical status, interventions, and outcomes using the REDCap platform. Patients were followed up for 30 days after primary intervention, or 30 days after admission if they did not receive an intervention. The primary outcome was all-cause, in-hospital mortality for all conditions combined and each condition individually, stratified by country income status. We did a complete case analysis. Findings We included 3849 patients with 3975 study conditions (560 with oesophageal atresia, 448 with congenital diaphragmatic hernia, 681 with intestinal atresia, 453 with gastroschisis, 325 with exomphalos, 991 with anorectal malformation, and 517 with Hirschsprung’s disease) from 264 hospitals (89 in high-income countries, 166 in middleincome countries, and nine in low-income countries) in 74 countries. Of the 3849 patients, 2231 (58·0%) were male. Median gestational age at birth was 38 weeks (IQR 36–39) and median bodyweight at presentation was 2·8 kg (2·3–3·3). Mortality among all patients was 37 (39·8%) of 93 in low-income countries, 583 (20·4%) of 2860 in middle-income countries, and 50 (5·6%) of 896 in high-income countries (p<0·0001 between all country income groups). Gastroschisis had the greatest difference in mortality between country income strata (nine [90·0%] of ten in lowincome countries, 97 [31·9%] of 304 in middle-income countries, and two [1·4%] of 139 in high-income countries; p≤0·0001 between all country income groups). Factors significantly associated with higher mortality for all patients combined included country income status (low-income vs high-income countries, risk ratio 2·78 [95% CI 1·88–4·11], p<0·0001; middle-income vs high-income countries, 2·11 [1·59–2·79], p<0·0001), sepsis at presentation (1·20 [1·04–1·40], p=0·016), higher American Society of Anesthesiologists (ASA) score at primary intervention (ASA 4–5 vs ASA 1–2, 1·82 [1·40–2·35], p<0·0001; ASA 3 vs ASA 1–2, 1·58, [1·30–1·92], p<0·0001]), surgical safety checklist not used (1·39 [1·02–1·90], p=0·035), and ventilation or parenteral nutrition unavailable when needed (ventilation 1·96, [1·41–2·71], p=0·0001; parenteral nutrition 1·35, [1·05–1·74], p=0·018). Administration of parenteral nutrition (0·61, [0·47–0·79], p=0·0002) and use of a peripherally inserted central catheter (0·65 [0·50–0·86], p=0·0024) or percutaneous central line (0·69 [0·48–1·00], p=0·049) were associated with lower mortality. Interpretation Unacceptable differences in mortality exist for gastrointestinal congenital anomalies between lowincome, middle-income, and high-income countries. Improving access to quality neonatal surgical care in LMICs will be vital to achieve Sustainable Development Goal 3.2 of ending preventable deaths in neonates and children younger than 5 years by 2030