An eco-friendly degumming process of flax roving without acid pickling and NaClO2-bleaching

Degumming of pre-chlorite treated jute fiber was studied in this paper. The effects of sodium hydroxide concentration, treatment time, temperature, sodium silicate concentration, fiber-to-liquor ratio, penetrating agent TF-107B concentration, and degumming agent TF-125A concentration were the process conditions examined. With respect to gum decomposition, fineness and mechanical properties, sodium hydroxide concentration, sodium silicate concentration, and treatment time were found to be the most important parameters. An orthogonal L9(34) experiment designed to optimize the conditions for degumming resulted in the selection of the following procedure: sodium hydroxide of 12g/L, sodium silicate of 3g/L, TF-107B of 2g/L, TF-125A of 2g/L, treatment time of 105 min, temperature of 100°C and fiber to liquor ratio of 1:20. The effect of the above degumming process on the removal of impurities was also examined and the results showed that degumming was an effective method for removing impurities, especially hemicellulose.

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Aerospace series - Acid pickling of aluminium and aluminium alloys without hexavalent chromium

10.3403/30389712 ◽

2020 ◽

Keyword(s):

Hexavalent Chromium ◽

Aluminium Alloys ◽

Acid Pickling

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Characterization of Phosphate Coatings: Influence of the Acid Pickling Conditions

Materials ◽

10.3390/ma14041048 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1048

Author(s):

Belén Díaz ◽

X. Ramón Nóvoa ◽

Carmen Pérez ◽

Sheila Silva-Fernández

Keyword(s):

Citric Acid ◽

High Strength ◽

Acid Pickling ◽

Acid Cleaning ◽

Inorganic Acids ◽

Phosphate Coatings ◽

Acid Bath ◽

Coating Morphology ◽

Coating Weight

This research emphasizes the importance of the acid cleaning prior to the phosphate development on high-strength steel rods. It compares the phosphate properties achieved after different acid-pickling conditions. The most common inorganic acids were considered in this study. Additionally, taking into account the environmental and safety concerns of these acids, the assessment of a less harmful organic acid is presented. This study revealed significant differences in the coating morphology and chemical composition whereas no great changes were found in terms of the coating weight or porosity. Thus, hydrochloric and sulfuric acid promote the growth of a Fe-enriched phosphate layer with a less conductive character that is not developed after the pickling with phosphoric acid. The phosphate developed after the citric acid pickling is comparable to that developed after the inorganic acids although with a porosity slightly higher. The temperature of the citric acid bath is an important parameter that affects to the phosphate appearance, composition, and porosity.

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Preparation, Characterization, and Evaluation of Macrocrystalline and Nanocrystalline Cellulose as Potential Corrosion Inhibitors for SS316 Alloy during Acid Pickling Process: Experimental and Computational Methods

Polymers ◽

10.3390/polym13142275 ◽

2021 ◽

Vol 13 (14) ◽

pp. 2275

Author(s):

Arafat Toghan ◽

Mohamed Gouda ◽

Kamal Shalabi ◽

Hany M. Abd El-Lateef

Keyword(s):

Surface Area ◽

Density Functional ◽

Protective Efficacy ◽

Protective Layer ◽

Nanocrystalline Cellulose ◽

Bet Surface Area ◽

Natural Polymers ◽

Active Centers ◽

Acid Pickling ◽

Pickling Process

Converting low-cost bio-plant residuals into high-value reusable nanomaterials such as microcrystalline cellulose is an important technological and environmental challenge. In this report, nanocrystalline cellulose (NCC) was prepared by acid hydrolysis of macrocrystalline cellulose (CEL). The newly synthesized nanomaterials were fully characterized using spectroscopic and microscopic techniques including FE-SEM, FT-IR, TEM, Raman spectroscopy, and BET surface area. Morphological portrayal showed the rod-shaped structure for NCC with an average diameter of 10–25 nm in thickness as well as length 100–200 nm. The BET surface area of pure CEL and NCC was found to be 10.41 and 27 m2/g, respectively. The comparative protection capacity of natural polymers CEL and NCC towards improving the SS316 alloy corrosion resistance has been assessed during the acid pickling process by electrochemical (OCP, PDP, and EIS), and weight loss (WL) measurements. The outcomes attained from the various empirical methods were matched and exhibited that the protective efficacy of these polymers augmented with the upsurge in dose in this order CEL (93.1%) < NCC (96.3%). The examined polymers display mixed-corrosion inhibition type features by hindering the active centers on the metal interface, and their adsorption followed the Langmuir isotherm model. Surface morphology analyses by SEM reinforced the adsorption of polymers on the metal substrate. The Density Functional Theory (DFT) parameters were intended and exhibited the anti-corrosive characteristics of CEL and NCC polymers. A Monte Carlo (MC) simulation study revealed that CEL and NCC polymers are resolutely adsorbed on the SS316 alloy surface and forming a powerful adsorbed protective layer.

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Optimization and characterization of flavonoids extracted from Cannabis sativa fibers

Textile Research Journal ◽

10.1177/00405175211027796 ◽

2021 ◽

pp. 004051752110277

Author(s):

Qilu Cui ◽

Jiawei Li ◽

Chongwen Yu

Keyword(s):

Chemical Structure ◽

Cannabis Sativa ◽

Ethanol Concentration ◽

Extraction Process ◽

Test Results ◽

Hemp Fiber ◽

Hemp Fibers ◽

Structure Surface ◽

Degumming Process

In this paper, the extraction process of flavonoids from hemp fibers was studied. Response surface methodology (RSM) analysis of the extraction parameters indicated that optimized results would be ethanol concentration 76 vol.%, bath ratio 1:50, and reaction time 139 min; therefore, an optimal extraction rate of flavonoids of 0.2275% can be obtained. The chemical structure, surface morphology and element composition of flavonoid extracts were analyzed. The test results indicated that hemp extract contains flavonoids, which can be used to extract flavonoids from hemp fiber, so as to comprehensively develop hemp fiber and reduce the discharge of waste liquid in the traditional degumming process.

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