Activation of glucose with Fenton’s reagent: chemical structures of activated products and their reaction efficacy toward cellulosic material

The release of harmful volatiles, such as formaldehyde, is a major issue of the chemical modification of wood that limits the utilization of the modified wood in indoor environment. In this study, glucose (Glc) was activated with Fenton’s reagent under various conditions and the chemical structure of the activated Glc was characterized. Also, the reactivity of the activated Glc toward filter paper as a wood model was evaluated. The results show that the H2O2concentration controlled the activation ratio of Glc. Additionally, the Fe(II) concentration and activation temperature determined mainly the oxidation reaction rate. The Fenton reaction in an acidic solution resulted in higher activation efficacy of Glc and better fixation in the filter paper, compared to the reaction in an alkaline solution. The Glc cannot be fixed in the filter paper, but the activated Glc exhibited a fixation ratio of up to 48.2% due to the formation of carboxyl and aldehyde groups, as evidenced by Fourier-transform infrared (FTIR) spectroscopy and gas chromatography-mass spectrometry (GC-MS). It was demonstrated that activation of Glc with the Fenton’s reagent is a feasible and eco-friendly approach and the activated products have a high potential for wood modification.

The Adsorption Character of Kapok Fiber and Reactive Dyeing Technology on Modified Kapok Fiber

The adsorption character of kapok fiber with direct dyes and the dyeing technology of cationic modified kapok fiber with reactive dyes were studied in this article. The results indicate that the optimal dyeing technique parameters for the cationic modified kapok fiber with the reactive dye Cibacron FN-R include 0.5~1% (o.w.f) of dyes, 15~20g·L-1 of NaCl, and 2g·L-1 of JFC with bath ratio of 1:50 at a dyeing temperature of 40°C for 30min. The dyed kapok fiber was fixed with 15~20g·L-1 of Na2CO3 for 60min. As a result, the dye-uptake, fixation ratio, wash fastness, friction fastness, and K/S of cationic modified kapok fabric were enhanced by above technique.

Sorghum Red Pigment Dyeing Properties of Tencel Loose Fibre

Dyeing of tencel loose fibre with sorghum red pigment as natural dyes has been studied. The values of dye uptake and fixation ratio have been calculated and disscussed. The effect of dyeing time, dyeing temperature, dye concentration and salt concentration were studied. Dye uptake and fixation ratio were high, and the fastness of dyed fibre were good.

Hydrogen Cycling by the Unicellular Marine Diazotroph Crocosphaera watsonii Strain WH8501

ABSTRACT The hydrogen (H2) cycle associated with the dinitrogen (N2) fixation process was studied in laboratory cultures of the marine cyanobacterium Crocosphaera watsonii. The rates of H2 production and acetylene (C2H2) reduction were continuously measured over the diel cycle with simultaneous measurements of fast repetition rate fluorometry and dissolved oxygen. The maximum rate of H2 production was coincident with the maximum rates of C2H2 reduction. Theoretical stoichiometry for N2 fixation predicts an equimolar ratio of H2 produced to N2 fixed. However, the maximum rate of net H2 production observed was 0.09 nmol H2 μg chlorophyll a (chl a)−1 h−1 compared to the N2 fixation rate of 5.5 nmol N2 μg chl a −1 h−1, with an H2 production/N2 fixation ratio of 0.02. The 50-fold discrepancy between expected and observed rates of H2 production was hypothesized to be a result of H2 reassimilation by uptake hydrogenase. This was confirmed by the addition of carbon monoxide (CO), a potent inhibitor of hydrogenase, which increased net H2 production rates ∼40-fold to a maximum rate of 3.5 nmol H2 μg chl a −1 h−1. We conclude that the reassimilation of H2 by C. watsonii is highly efficient (>98%) and hypothesize that the tight coupling between H2 production and consumption is a consequence of fixing N2 at nighttime using a finite pool of respiratory carbon and electrons acquired from daytime solar energy capture. The H2 cycle provides unique insight into N2 fixation and associated metabolic processes in C. watsonii.