Functional Cellulose Beads: Preparation, Characterization, and Applications

The extraction of plastic microparticles, so-called microplastics, from sludge is a challenging task due to the complex, highly organic material often interspersed with other benign microparticles The current procedures for microplastic extraction from sludge are time consuming and require expensive reagents for density separation as well as large volumes of oxidizing agents for organic removal, often resulting in tiny sample sizes and thus a disproportional risk of sample bias In this work, we present an improved extraction method tested on return activated sludge (RAS) The treatment of 100 ml of RAS requires only 6% hydrogen peroxide (H2O2) for bleaching at 70 °C, followed by density separation with sodium nitrate/sodium thiosulfate (SNT) solution, and is completed within 24 h Extracted particles of all sizes were chemically analyzed with confocal Raman microscopy An extraction efficiency of 78 ± 8% for plastic particle sizes 20 µm and up was confirmed in a recovery experiment However, glass shards with a diameter of less than 20 µm remained in the sample despite the density of glass exceeding the density of the separating SNT solution by 11 g/cm3 This indicates that density separation may be unreliable for particle sizes in the lower micrometer range

Heat and Bleach: A Cost-Efficient Method for Extracting Microplastics from Return Activated Sludge

http://pubs.acs.org/doi/pdf/10.1021/bm5002944

Convenient one-pot formation of 2,3-dialdehyde cellulose beads via periodate oxidation of cellulose in water.

Arsenic removal by magnetite-loaded amino modified nano/microcellulose adsorbents: Effect of functionalization and media size

The method of electrospinning was used to create nanofibers made of cellulose acetate (CA) and essential oils (EOs). CA polymer at 15% w/v was dissolved in acetone and then 1% or 5% v/v of EOs was added to the polymer solution. The utilized essential oils were rosemary and oregano oils. Then, the CA/EOs in acetone solution were electrospun, creating micro/nanofibers, approximately 700-1500 nm in diameter. Raman spectroscopy was used to detect the attachment of the EOs in the CA electrospun fibers (ESFs). Scanning electron microscopy was used to study the morphology, topography and dimensions of the ESFs. The formed CA/EOs ESFs are found to have good antimicrobial properties against three common microbial species, frequently found in difficult to treat infections: Bacteria species Staphylococcus aureus, Escherichia coli and the yeast Candida albicans. ESFs with 5% v/v oregano oil with respect to the initial solution, showed the best antimicrobial and anti-biofilm effects due to the potency of this EO against bacteria and fungi, especially for Escherichia coli and Candida albicans. This work describes an effective and simple method to prepare CA/EOs ESFs and opens up many new applications of micro/nanofibers such as improved antimicrobial wound dressings, anti-biofilm surfaces, sensors and packaging alternatives.

Electrospun Fiber Pads of Cellulose Acetate and Essential Oils with Antimicrobial Activity.

This study reports on a new method characterizing cellulose acetates and determining the contents of acetyl groups within cellulose acetates based on FT Raman spectroscopy. Cellulose acetates exhibiting diverse degrees of substitution ascribed to acetyl groups (DSAc) were obtained after the deacetylation of highly acetylated cellulose, i.e. cellulose diacetate and cellulose triacetate (CTA), with aqueous sodium hydroxide solution or 1,6-hexamethylenediamine (HMDA). After plotting the Raman intensity ratios between the bands at 1,740 and 1,380 cm−1 against the DSAc, a calibration curve with high correlation coefficient of more than 0.99 was obtained. During the deacetylation of highly acetylated cellulose, a by-product—sodium acetate (NaOAc)—forms as the most possible salt among others. In order to determine the content of NaOAc, the mixtures of cellulose acetates and NaOAc were measured with FT Raman spectroscopy. Based on the relationship between the Raman intensity ratios as I929/I1380 and the contents of NaOAc in the mixtures, a calibration curve exhibiting high correlation coefficient of more than 0.99 was generated.

FT Raman spectroscopic investigation of cellulose acetate

The aim of this work was to synthesize and characterize cellulose microspheres with a particle size below 5 μm and narrow size distribution. After activation and functionalization with antibodies, these particles shall be applied as adsorbents in suspension-based extracorporeal blood purification systems, such as the Microspheres-Based Detoxification System. In the frame of this work such microspheres were developed and synthesized with reproducible properties. Besides using well-established methods for characterization of this kind of bead cellulose, additional procedures for the examination of its properties were developed and applied.

Preparation and characterization of cellulose microspheres

Ontogenetic tissue modification in Malus fruit peduncles: the role of sclereids

The methanation process is discussed as one way to chemically store renewable energy in a future energy system. An important criterion for its application is the availability of compact, low-cost reactor concepts with high conversion rates for decentralized use where the renewable energy is produced. Current research focuses on the maximization of the methane yield through improved temperature control of the exothermic reaction, which attempts to avoid both kinetic and thermodynamic limitations. In this context, traditional manufacturing methods limit the design options of the reactor and thus the temperature control possibilities. The use of additive manufacturing methods removes this restriction and creates new freedom in the design process. This paper formulates the requirements for a novel methanation reactor and presents their implementation to a highly innovative reactor concept called ‘ADDmeth’. By using a conical reaction channel expanding from Ø 8 to 32 mm, three twisted, expanding heat pipes (Ø 8 mm in evaporation zone, Ø 12 mm in condenser zone) and a lattice structure for feed gas preheating and mechanical stabilization of the reactor, the design explicitly exploits the advantages of additive manufacturing. The reactor is very compact with a specific mass of 0.36 kg/kW and has a high share of functional volume of 52%. The reactor development was accompanied by tensile tests of additively manufactured samples with the used material 1.4404 (316 L), strength calculations for stability verification and feasibility studies on the printability of fine structures. Ultimate tensile strengths of up to 750 N/mm2 (at room temperature) and sufficiently high safety factors of the pressure-loaded structures against yielding were determined. Finally, the paper presents the manufactured bench-scale reactor ADDmeth1 and its implementation.

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Design and Implementation of an Additively Manufactured Reactor Concept for the Catalytic Methanation

The path to European climate neutrality by 2050 will require comprehensive changes in all areas of life. For large industries such as steelworks, this results in the need for climate-friendly technologies. However, the age structure of existing steelworks makes transitional solutions such as carbon capture, utilization and storage (CCUS) necessary as short-term measures. Hence, a purposeful option is the integration of technical syntheses such as methanation into the overall process. This work summarizes hydrogen-intensified methanation experiments with synthetic steel gases in the novel additively manufactured reactor ‘ADDmeth1′. The studies include steady-state operating points at various reactor loads. Blast furnace gas (BFG), basic oxygen furnace gas (BOFG) and three mixtures of these two gases serve as carbon sources. The methanation achieved methane yields of 93.5% for BFG and 95.0% for BOFG in the one-stage once-through setup. The results suggest a kinetic limitation in the case of BFG methanation, while an equilibrium limitation is likely for BOFG. There is a smooth transition in all respects between the two extreme cases. The reaction channel inlet temperature ϑin showed a large influence on the reactor ignition behavior. By falling below the threshold value, a blow-off occurred during experimental operation. By means of a simulation model, practical operating maps were created which characterize permissible operating ranges for ϑin as a function of the gas composition and the reactor load.

/pdf/utilization-of-synthetic-steel-gases-in-an-additively-iu3mikx0.pdf

Alexander Feldner

Papers

FT Raman spectroscopic investigation of cellulose acetate

Preparation and characterization of cellulose microspheres

Ontogenetic tissue modification in Malus fruit peduncles: the role of sclereids

Design and Implementation of an Additively Manufactured Reactor Concept for the Catalytic Methanation

Utilization of Synthetic Steel Gases in an Additively Manufactured Reactor for Catalytic Methanation