Green Degumming Technology of Hemp and a Comparison between Chemical and Biological Degumming

Abstract

This paper provides an efficient and environmentally friendly biochemical degumming method for hemp fiber, which can address the problems of high temperature, high pressure, and extreme pollution of the traditional chemical method and the harsh reaction conditions of biological degumming, such as a long reaction time and pH. In the biochemical method, dilute solutions of alkali pectinase lyase and chemical additives were used to process the hemp fiber and then the fiber composition and structure were investigated. A comparison of the chemical, biological, and biochemical degumming methods shows that the biochemical method can replace the chemical one causing a similar degumming effect, both being better than the biological method. The best proportion of the biochemical solution was found to be 1.5% alkali pectinase lyase, and for chemical auxiliaries the total amount of alkali was ≤0.4% and the total amount of salt was ≤0.8%. The best conditions of the biochemical degumming process were determined to be a bath ratio of 1:10, reaction temperature of 60 °C, and the time of 60 min. After degumming, the composition of the fiber was as follows: lignin 3.69%, pectin 4.09%, hemicellulose 13.34%, and cellulose 78.87%. The fiber quality index of fibers dealt by the biochemical method shows that the linear density was 4.66 dtex, length was 35.6 mm, and fracture strength was 64.5 cN/dtex, which were higher than those treated by the chemical method. This shows that the biological degumming method can be a green degumming method with higher efficiency, lower consumption, and pollution, as well as has a broad application scope.

A cleaning and reusable biochemical degumming method for hemp fibers through immobilized pectinase lyase on calcium alginate microspheres

“…The chemical auxiliaries provided by the patent acted on the fiber surface to cause the fibers to swell so that the released pectinase lyase could act on the pectin layer of the fibers more quickly to achieve the pectin removal effect rapidly. 20 The alkali content of the biochemical degumming solutions was 0.4% and the total content of salt was 0.8%, which is much less than that of reported chemical solutions with an alkali content of 10%. 21 2.2.3.…”

Eco-Friendly Preparation of Hydrophobic and Flexible Nanocellulose Fibers without Further Modification

“…It showed that pectin was greatly removed after the third alternating boiling cycle. By comparison, the obvious characteristic peak at 1740 cm –1 is shown in Figure e,f, after fourth and fifth alternating boiling cycle due to the hydroxyl group of cellulose formed carboxyl group during the esterification reaction in the fourth and fifth alternating boiling cycle, which made CNFs with hydrophobicity in the preparing process. , …”

“…By comparison, the obvious character-istic peak at 1740 cm −1 is shown in Figure 6e,f, after fourth and fifth alternating boiling cycle due to the hydroxyl group of cellulose formed carboxyl group during the esterification reaction in the fourth and fifth alternating boiling cycle, which made CNFs with hydrophobicity in the preparing process. 48,49 Figure 6 also showed that characteristic peak ranges from 1508 to 1243 cm −1 correspond to the benzene ring, which illustrated the removal effect of acid-insoluble lignin and cellulose extraction. The tensile vibration at 1250 cm −1 corresponds to the acetyl group which is cross-linked between lignin and hemicelluloses shown in Figure 6a.…”

Preparation of nanocellulose by a biological method from hemp stalk in contrast to the chemical method and its application on the electrospun composite film

“…Biological solution preparation: 58 the following samples were prepared; 1.5% pectin lyase, 0.4% sodium hydroxide, 0.13% sodium carbonate, 0.17% sodium chloride, 0.13% calcium chloride, 0.03% sodium phosphate, 0.02% sodium formate, 0.2% sodium silicate, 0.13% sodium sulfite, 0.15% ethylene glycol, as well as distilled water of 97.0%. The solution was prepared in proportion; weak acid solution preparation: 59 5% sodium chlorite, 0.8% acetic acid, and 94.2% water in proportion; chemical solution preparation: 60 dilute 98% concentrated sulfuric acid to 54% H 2 SO 4 and cooled to ambient temperature.…”