Development of technological process of cotton cellulose production and evaluation of experimental results

In the course of this study, the technology of bleaching of cotton pulp for various purposes has been improved, which can be used in the production of cotton pulp by "Khlopoprom-Cellulose" LLP and other enterprises to increase the production efficiency and competitiveness of the products obtained. The proposed development makes it possible to obtain cellulose with a high degree of polymerization and whiteness, as well as to solve the problem of stabilization and high decomposition rate of hydrogen peroxide in the technological cycle. The bleached cellulose meets the requirements of GOST (State Standard) 595-79 "Cotton cellulose" and has an average degree of whiteness of 90%, which is 5-6% higher than the samples of cotton cellulose bleached without the use of a hydrogen peroxide stabilizer.

Extraction and Characterization of Microfibrillated Cellulose from Discarded Cotton Fibers through Catalyst Preloaded Fenton Oxidation

With rapid developments in science and technology, mankind is faced with the dual severe challenges of obtaining needed resources and protecting the environment. The need for sustainable development strategies has become a global consensus. As the most abundant biological resource on Earth, cellulose is an inexhaustible, natural, and renewable polymer. Microfibrillated cellulose (MFC) offers the advantages of abundant raw materials, high strength, and good degradability. Simultaneously, MFC prepared from natural materials has high practical significance due to its potential application in nanocomposites. In this study, we reported the preparation of MFCs from discarded cotton with short fibers by a combination of Fe2+ catalyst-preloading Fenton oxidation and a high-pressure homogenization cycle method. Lignin was removed from the discarded cotton with an acetic acid and sodium chlorite mixed solution. Then, the cotton was treated with NaOH solution to obtain cotton cellulose and oxidized using Fenton oxidation to obtain Fenton-oxidized cotton cellulose. The carboxylic acid content of the oxidized cotton cellulose was 126.87 μmol/g, and the zeta potential was −43.42 mV. Then, the Fenton-oxidized cotton cellulose was treated in a high-speed blender under a high-pressure homogenization cycle to obtain the MFC with a yield of 91.58%. Fourier transform infrared spectroscopy (FTIR) indicated that cotton cellulose was effectively oxidized by Fe2+ catalyst-preloading Fenton oxidation. The diameter of the MFC ranged from several nanometers to a few micrometers as determined by scanning electron microscopy (SEM), the crystallinity index (CrI) of the MFC was 83.52% according to X-ray diffraction (XRD), and the thermal stability of the MFC was slightly reduced compared to cotton cellulose, as seen through thermogravimetric analysis (TGA). The use of catalyst-preloading Fenton oxidation technology, based on the principles of microreactors, along with high-pressure homogenization, was a promising technique to prepare MFCs from discarded cotton.

Sorption And Physicochemical Properties of A Phosphorylated Mercerised Cotton Cellulose

A process of a mercerised cotton cellulose sample phosphorylation has been investigated. After oxidation a phosphorus content was determined by spectrophotometric analysis and it was in a range of 0.179 to 0.950 mmol g–1. A significant decrease in the tensile strength of the sample was found upon an increase of phosphoric acid concentration in a phosphorylating solution. Phosphorylated mercerized fabric contents more phosphorous as unmercerized fabric in 3 times. The sorption properties of phosphorylated cotton cellulose in aqueous solution containing Cu2+ were characterized. The maximum of static exchange capacity was found to be 1.48 ± 0.11 mmol g–1 for phosphorylated cotton with content 0.898 ± 0.090 mmol g–1 of phosphorus. The sorption of Cu2+ by single phosphorus-containing group occurs for samples with not exceeding 0.80 mmol g–1 of phosphorus. The preliminary studies of uranium(VI) micro quantities of radionuclides 241Am, 233U and 239Pu sorption from aqueous solution with phosphorylated textile demonstrated the high efficiency.