Anna Ilnicka

The fungicidal properties of the carbon materials obtained from chitin and chitosan promoted by copper salts

Renewable raw materials chitin and chitosan (N-deacetylated derivative of chitin) were subjected to action of different copper modifiers that were carbonized in the atmosphere of the N2 inert gas. As a result of the novel manufacturing procedure, a series of carbon materials was obtained with developed surface area and containing copper derivatives of differentiated form, size, and dispersion. The copper modifier and manufacturing procedure (concentration, carbonization temperature) influence the physical-chemical and fungicide properties of the carbons. The received carbons were chemically characterized using several methods like low-temperature adsorption of nitrogen, X-ray diffraction analysis, scanning electron microscopy, cyclic voltammetry, elemental analysis, and bioassay. Besides chemical testing, some biological tests were performed and let to select carbons with the highest fungicidal activity. Such carbons were characteristic of the specific form of copper derivatives occurring in them, i.e., nanocrystallites of Cu(0) and/or Cu2O of high dispersion on the surface of carbon. The carbons may find an application as effective contact fungistatic agents in cosmetology, medicine, food industry, etc.

Discussion Remarks on the Role of Wood and Chitin Constituents during Carbonization

Nature is a source of some biomaterials like wood and chitin which can be successfully transformed into chars of advanced structural/surface parameters. The manuscript is discursive and suggests that particular components of the materials (cellulose, lignin, hemicellulose, alfa-chitin fibrils, mineral-protein matrix) play a specific role in the manufacturing of porous chars. It is proposed that some of the components (hemicellulose and mineral-protein matrixes) behave like a natural soft template during carbonization of wood and chitin. It is suggested why particular components and derivatives of wood and chitin (cellulose and chitosan) can not form porous carbonaceous matrixes when are carbonized separately.

Marine and Freshwater Feedstocks as a Precursor for Nitrogen-Containing Carbons: A Review

Marine-derived as well as freshwater feedstock offers important benefits, such as abundance, morphological and structural variety, and the presence of multiple elements, including nitrogen and carbon. Therefore, these renewal resources may be useful for obtaining N- and C-containing materials that can be manufactured by various methods, such as pyrolysis and hydrothermal processes supported by means of chemical and physical activators. However, every synthesis concept relies on an efficient transfer of nitrogen and carbon from marine/freshwater feedstock to the final product. This paper reviews the advantages of marine feedstock over synthetic and natural but non-marine resources as precursors for the manufacturing of N-doped activated carbons. The manufacturing procedure influences some crucial properties of nitrogen-doped carbon materials, such as pore structure and the chemical composition of the surface. An extensive review is given on the relationship between carbon materials manufacturing from marine feedstock and the elemental content of nitrogen, together with a description of the chemical bonding of nitrogen atoms at the surface. N-doped carbons may serve as effective adsorbents for the removal of pollutants from the gas or liquid phase. Non-recognized areas of adsorption-based applications for nitrogen-doped carbons are presented, too. The paper proves that nitrogen-doped carbon materials belong to most of the prospective electrode materials for electrochemical energy conversion and storage technologies such as fuel cells, air–metal batteries, and supercapacitors, as well as for bioimaging. The reviewed material belongs to the widely understood field of marine biotechnology in relation to marine natural products.

Salix viminalis wood as a new precursor for manufacturing of carbon molecular sieves for effective methane/nitrogen separation

Abstract Separation of a methane/nitrogen gas mixture was investigated by means of carbon molecular sieves (CMS) obtained from a newly discovered “green” resource: Salix viminalis. This plant grows quickly, yields hard wood and is frequently cultivated for energy purposes (renewable green fuel). Unconventional applications such as charcoal fabrication using this sort of wood are very rare. Carbonization of the wood (1–3 h, 600–700°C) yields carbons with a very narrow pore size distribution (determined by N2 adsorption at -196°C) resembling a perfect CMS. The diameter of most pores (ca. 0.8 nm) is comparable to the size of simple molecules, thus enabling separation. The sieving effect was proven in an industrially important process of CH4/N2 separation at 30–70°C. Despite relatively minor differences of the size of the molecules, the experiment demonstrated that separation factors are placed in the range 3.64–10.20. Additional experiments involving krypton proved that the separation mechanism is based on a geometric factor i.e. the known size and shape of the molecules under separation. Graphical Abstract