OXYCELLULOSE – MATERIAL FOR NEW APPLICATION AREAS

In this paper, the principles of the action of the selective (NaIO4 and 2,2,6,6-tetramethylpiperidine-1-oxyl-TEMPO radical) and non-selective (H2O2 and KMnO4) oxidation agents on cellulose are presented. Their importance in modifying the existing properties or giving new properties to cellulosic materials, as well as examples of their applications are also given. The oxidation product - oxycellulose presents the base for obtaining a wide range of materials for special applications. Particularly, the influence of TEMPO-mediated oxidation on natural and man-made cellulosic fibers is presented, with a detailed overview on the type and quantity of introduced functional groups, changes in structure, sorption and mechanical properties. Also, we described the use of TEMPOmediated oxidation for the production of cellulosic nano-materials in the form of dispersions, particles and films, as well as the potential application of these nano-structural materials.

Effect of pre-strain and KMnO4 oxidation of carbon nanotubes embedded in polyurethane on strain dependent electrical resistance of the composite

Purpose The synergistic effect of functionalization of multi-walled carbon nanotubes (CNT) using KMnO4 oxidation and initial tensile deformation on the electrical resistance of nanotube network/polyurethane composite subjected to elongation was studied. Design/methodology/approach Though the initial deformation irreversibly changed the arrangement of carbon nanotube network, subsequent cyclic elongation confirmed stable resistance values. The increased strain-dependent resistance of stimulated nanotube network/polyurethane composite was demonstrated by monitoring vibration of tambour leather after a bead impact and finger flexion. Findings The results showed a tenfold composite resistance increase for the composite prepared from KMnO4 oxidized nanotubes, quantified by a so-called gauge factor, from a value of about 20 in comparison to the network prepared from pristine nanotubes. This is a substantial increase, which ranks the stimulated composite among materials with the highest electromechanical response. Originality/value The results in this paper are new and have not been published yet. The paper combines different ideas which are developed together. It presents a new concept of synergistic effect of CNT oxidation and application of pre-strain simulation. Oxidation and pre-strain increases by several times the sensitivity of the tested composites which are predetermined for use as strain sensors of various sizes and shapes.

High-yield synthesis of a unique Mn(iii) siloxide complex through KMnO4 oxidation of a Mn(ii) precursor

A unique trivalent manganese siloxide complex, blue-violet MnIIILi2Cl[(Ph2SiO)2O]2(THF)4·2THF (3) has been prepared by a straightforward two-step synthetic protocol.

Sulphide Removal from Sewage Wastewater by Oxidation Technique

In this study sewage wastewater samples were collected from different areas of Lahore, Pakistanfrom the WASA sewer system and then different chemical oxidizers: O2, KMNO4, H2O2 were used toremove the sulphides from these samples for selection of suitable oxidizer for treatment. From these results,it was observed that H2O2 was found effective and suitable for treatment and it can be used for this purpose.Theoretical and experimental doses required for treatment were similar. The KMNO4 oxidation reactionswere completed in five minutes time while H2O2 required more time and removed sulphide completelywith slow chemical reaction. Different doses of oxidizer such as 1 to 6 g of oxygen, 1 to 14 g of KMNO4,1to 11 g of H2O2 with different ratios were used and H2O2 was found suitable. Using 11 g of H2O2 dose,100 % sulphides were removed, H2O2 as an oxidizer was found more suitable for sulphide removal fromwastewater.

Enhanced performance and mechanism of KMnO4 pre-oxidation to coagulation on the removal of the DON and proteins

Proteins were the main category of the dissolved organic nitrogen (DON) in eutrophicate water sources and posed a threat to the water quality safety and common operation of water plants, while the KMnO4 pre-oxidation and coagulation were the two important ways to control the organics. Intracellular organic matter (IOM) and phycocyanin were chosen as the target DON to study the performance of KMnO4 pre-oxidation to the enhanced removal effects for coagulation process, and molecular weight distribution, hydrophobicity, two-dimensional electrophoresis and MnO2 adsorption experiment were used to study the mechanism. The results showed that KMnO4 pre-oxidation enhanced the IOM and phycocyanin removal performance of coagulation significantly, although poor removal was found for KMnO4 oxidation alone. KMnO4 pre-oxidation altered the molecular weight, hydrophobicity and proteins' categories insignificantly. However, the in-situ formed MnO2 showed better adsorption ability for the IOM and phycocyanin. The main enhanced removal mechanism was the adsorption of MnO2 formed from the reduction of KMnO4 and little difference existed between the IOM and phycocyanin. In addition, the KMnO4 pre-oxidation could enhance the turbidity removal of the coagulation due to a similar mechanism.