Native wood celluloses can be converted to individual nanofibers 3–4 nm wide that are at least several microns in length, i.e. with aspect ratios >100, by TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl radical)-mediated oxidation and successive mild disintegration in water. Preparation methods and fundamental characteristics of TEMPO-oxidized cellulose nanofibers (TOCN) are reviewed in this paper. Significant amounts of C6 carboxylate groups are selectively formed on each cellulose microfibril surface by TEMPO-mediated oxidation without any changes to the original crystallinity (∼74%) or crystal width of wood celluloses. Electrostatic repulsion and/or osmotic effects working between anionically-charged cellulose microfibrils, the ζ-potentials of which are approximately −75 mV in water, cause the formation of completely individualized TOCN dispersed in water by gentle mechanical disintegration treatment of TEMPO-oxidized wood cellulose fibers. Self-standing TOCN films are transparent and flexible, with high tensile strengths of 200–300 MPa and elastic moduli of 6–7 GPa. Moreover, TOCN-coated poly(lactic acid) films have extremely low oxygen permeability. The new cellulose-based nanofibers formed by size reduction process of native cellulose fibers by TEMPO-mediated oxidation have potential application as environmentally friendly and new bio-based nanomaterials in high-tech fields.

TEMPO-oxidized cellulose nanofibers

Bacterial biosorbents and biosorption

Role of organic amendments on enhanced bioremediation of heavy metal(loid) contaminated soils

Review on electrical discharge plasma technology for wastewater remediation

Several industries are using dyes as coloring agents. The effluents from these industries are increasingly becoming an environmental problem. The removal of dyes from aqueous solution has a great potential in the field of environmental engineering. This paper reviews the classification, characteristics, and problems of dyes in detail. Advantages and disadvantages of different methods used for dye removal are also analyzed. Among these methods, Fenton process-based advanced oxidation processes are an emerging prospect in the field of dye removal. Fenton processes have been classified and represented as “Fenton circle”. This paper analyzes the recent studies on Fenton processes. The studies include analyzing different configurations of reactors used for dye removal, its efficiency, and the effects of various operating parameters such as pH, catalyst concentration, H2O2 concentration, initial dye concentration, and temperature of Fenton processes. From the present study, it can be conclude that Fenton processes are very effective and environmentally friendly methods for dye removal.

Degradation of dyes from aqueous solution by Fenton processes: a review

The effects of hemicelluloses and lignin removal on water uptake behavior of hemp fibers.

Decolorization of reactive textile dyes using water falling film dielectric barrier discharge.

Quality of chemically modified hemp fibers.

Biosorption of heavy metal ions from aqueous solutions by short hemp fibers: Effect of chemical composition.

Abstract The effects of periodate oxidation on cellulose were studied by means of gel permeation chromatography (GPC) using multiple detection and carbonyl-selective fluorescence labeling according to the CCOA methodology profiling of carbonyl groups. At low degrees of oxidation, the molecular weight distribution was fully maintained. Upon more pronounced oxidation the molecular weight even increased due to cross-linking effects. More condensed structures were identified by means of light scattering. Periodate oxidation also affects crystalline regions of cellulose, as demonstrated by comparison of homogeneous and heterogeneous carbonyl labeling. Highly ordered regions in cellulose were affected by oxidation even below an oxidation degree of 2%. Two different phases for the oxidation kinetics were identified in the early stages of periodate treatments.

Mirjana Kostic

Papers

The effects of hemicelluloses and lignin removal on water uptake behavior of hemp fibers.

Decolorization of reactive textile dyes using water falling film dielectric barrier discharge.

Quality of chemically modified hemp fibers.

Biosorption of heavy metal ions from aqueous solutions by short hemp fibers: Effect of chemical composition.

Studies on oxidative modifications of cellulose in the periodate system: Molecular weight distribution and carbonyl group profiles