Typical Defects of Natural Phospholipid Fatliquors in Leather Industry and Their Solutions

2021 ◽  
Vol 116 (11) ◽  
Author(s):  
Zhikun Chen ◽  
Tao Luo ◽  
Xu Zhang ◽  
Biyu Peng ◽  
Chunxiao Zhang
Keyword(s):  
Hexavalent Chromium ◽  
Chromium Content ◽  
Addition Reaction ◽  
Primary Source ◽  
Purification Process ◽  
Oxidative Rancidity ◽  
Leather Industry ◽  
Main Components ◽  
Volatile Aldehydes ◽  
Soybean Phospholipid

Leather made with soybean phospholipid fatliquors is prone to problems such as yellowing, elevated hexavalent chromium content, and undesirable odor. In this study, the aforementioned typical defects of soybean phospholipid fatliquors were investigated in respect to the main components, the antioxidants and the unsaturation degree of the natural soybean phospholipid. The results showed that the oxidation of soybean phospholipid is the primary source for its yellowing, elevated hexavalent chromium content, and undesirable odor. The volatile aldehydes produced by lipid oxidative rancidity are the main components of the undesirable odor. The purification of natural soybean phospholipid through removing the non-phospholipid components cannot solve the problems caused by oxidation of phospholipid. Furthermore, as a typical natural antioxidant existing in natural soybean phospholipid, tocopherols can restrain the oxidation of phospholipid to a certain degree, however, the dissolving out and destruction of tocopherols at high temperature in the phospholipid purification process can lead to more obviously oxidation of phospholipids. Additionally, the oxidation defects of phospholipid cannot be completely resolved by adding extra tocopherols, even at high dosages. The research finds that the defects of soybean phospholipid fatliquors can be thoroughly solved by increasing the saturation degree of lipid through addition reaction, the suggested iodine value of phospholipid products is lower than 20 g I2/100 g.

Study on leaching kinetics of hexavalent chromium from aged calcium-free chromium slag

2021 ◽  
pp. 1-13
Author(s):  
Quan Qi ◽  
Liang Li ◽  
Liangyu Wei ◽  
Baoming Hu ◽  
Zheng Liu ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Resource Utilization ◽  
Scientific Basis ◽  
Diffusion Reaction ◽  
Leaching Kinetics ◽  
Leaching Rate ◽  
Chromium Slag ◽  
Leaching Solution ◽  
Main Components ◽  
Kinetics Of

To provide a scientific basis for the resource utilization of chromium slag, this article studies the release law of hexavalent chromium in the aged calcium-free chromium slag. XRD (X-ray diffractometer) and MLA (Mineral Liberation Analyzer) were used to analyze the composition of the chromium slag; using sulfuric acid-nitric acid as the leaching solution, the release law of hexavalent chromium in chromium slag and the leaching kinetics were studied. The results show that main components of the chromium slag are magnesioferrite, chromite, hematite, hydrargillite, and spinel; chromium is mainly present in chromite and magnesioferrite; the leaching rate of hexavalent chromium increases with the increase of temperature or the decrease of pH. The analysis of leaching kinetics shows the leaching rate is controlled by the internal diffusion reaction, and the apparent activation energy is 11.93 kJ·mol–1. The chromium slag is aged in high temperature seasons, which is conducive to the precipitation of hexavalent chromium in the chromium slag, can increase the yield of chromate in the roasting kiln, and is conducive to resource utilization; chromium slag should be stored in order to prevent acid rain erosion which leads to environmental pollution risk (e.g. drinking water).

Total control of chromium in tanneries – thermal decomposition of filtration cake from enzymatic hydrolysis of chrome shavings

2016 ◽  
Vol 35 (4) ◽  
pp. 444-449 ◽  
Author(s):  
P Kocurek ◽  
K Kolomazník ◽  
M Bařinová ◽  
J Hendrych
Keyword(s):  
Thermal Decomposition ◽  
Enzymatic Hydrolysis ◽  
Chromium Content ◽  
Leather Industry ◽  
Collagen Hydrolysate ◽  
Decomposition Products ◽  
Thermal Decomposition Products ◽  
Total Control ◽  
Magnesium Removal ◽  
Hydrolysis Of

This paper deals with the problem of chromium recovery from chrome-tanned waste and thus with reducing the environmental impact of the leather industry. Chrome-tanned waste was transformed by alkaline enzymatic hydrolysis promoted by magnesium oxide into practically chromium-free, commercially applicable collagen hydrolysate and filtration cake containing a high portion of chromium. The crude and magnesium-deprived chromium cakes were subjected to a process of thermal decomposition at 650°C under oxygen-free conditions to reduce the amount of this waste and to study the effect of magnesium removal on the resulting products. Oxygen-free conditions were applied in order to prevent the oxidation of trivalent chromium into the hazardous hexavalent form. Thermal decomposition products from both crude and magnesium-deprived chrome cakes were characterized by high chromium content over 50%, which occurred as eskolaite (Cr2O3) and magnesiochromite (MgCr2O4) crystal phases, respectively. Thermal decomposition decreased the amount of chrome cake dry feed by 90%. Based on the performed experiments, a scheme for the total control of chromium in the leather industry was designed.

Hexavalent chromium content in stainless steel welding fumes is dependent on the welding process and shield gas type

2009 ◽  
Vol 11 (2) ◽  
pp. 418-424 ◽  
Author(s):  
Michael Keane ◽  
Samuel Stone ◽  
Bean Chen ◽  
James Slaven ◽  
Diane Schwegler-Berry ◽  
...  
Keyword(s):  
Stainless Steel ◽  
Hexavalent Chromium ◽  
Chromium Content ◽  
Welding Process ◽  
Welding Fumes ◽  
Stainless Steel Welding

scholarly journals Chemical Composition of Lipophilic Bark Extracts from Pinus pinaster and Pinus pinea Cultivated in Portugal

2018 ◽  
Vol 8 (12) ◽  
pp. 2575 ◽  
Author(s):  
Joana L. C. Sousa ◽  
Patrícia A. B. Ramos ◽  
Carmen S. R. Freire ◽  
Artur M. S. Silva ◽  
Armando J. D. Silvestre
Keyword(s):  
Chemical Composition ◽  
Pinus Pinaster ◽  
Primary Source ◽  
Dehydroabietic Acid ◽  
Resin Acids ◽  
Pinus Pinea ◽  
Gas Chromatography Mass Spectrometry ◽  
Major Constituent ◽  
Main Components ◽  
Micro Organisms

The chemical composition of lipophilic bark extracts from Pinus pinaster and Pinus pinea cultivated in Portugal was evaluated using gas chromatography-mass spectrometry. Diterpenic resin acids were found to be the main components of these lipophilic extracts, ranging from 0.96 g kg−1 dw in P. pinea bark to 2.35 g kg−1 dw in P. pinaster bark. In particular, dehydroabietic acid (DHAA) is the major constituent of both P. pinea and P. pinaster lipophilic fractions, accounting for 0.45 g kg−1 dw and 0.95 g kg−1 dw, respectively. Interestingly, many oxidized compounds were identified in the studied lipophilic extracts, including DHAA-oxidized derivatives (7-oxo-DHAA, 7α/β-hydroxy-DHAA, and 15-hydroxy-DHAA, among others) and also terpin (an oxidized monoterpene). These compounds are not naturally occurring compounds, and their formation might occur by the exposure of the bark to light and oxygen from the air, and the action of micro-organisms. Some of these compounds have not been previously reported as lipophilic constituents of the bark of the referred pine species. Other constituents, such as aromatic compounds, fatty acids, fatty alcohols, and sterols, are also present in the studied extracts. These results can represent an opportunity to valorize P. pinaster and P. pinea by-products as a primary source of the bioactive resin acids that are integrated into the current uses of these species.

scholarly journals Assessing the Contribution of Agriculture for Boosting Nepalese Economy

2021 ◽  
Vol 4 (1) ◽  
pp. 31-41
Author(s):  
Omkar Poudel ◽  
Khom Raj Kharel ◽  
Yadav Mani Upadhyay
Keyword(s):  
Economic Development ◽  
Positive Impact ◽  
Primary Source ◽  
High Growth ◽  
Agriculture Sector ◽  
Real Gdp ◽  
Using Data ◽  
Main Components ◽  
Growth Economic

Agriculture sector is the main components of economic development of developing countries likeNepal. This sector contributes boosting economy in terms of GDP, employment and food security,as more than 60% of Nepalese residents chose agriculture as their primary source of income. Theincrease in output and productivity in this sector is crucial for reducing poverty through long-term,high-growth economic growth. Increased agricultural production and output are important contrib-utors to the country's overall economic development. This study aims to look at how the agriculturesector contributes to the Nepalese economy's growth. Using data collected over a 20-year period,a simple linear regression model has applied to determine the economic impact of farm sector pro-duction on real GDP. The study finds a positive impact of agriculture sector on real GDP and othersectors. Though, agriculture sector has been facing diversified challenges improving its productionin Nepal.

Quantification of the toxic hexavalent chromium content in an organic matrix by X-ray photoelectron spectroscopy (XPS) and ultra-low-angle microtomy (ULAM)

2017 ◽  
Vol 396 ◽  
pp. 665-671 ◽  
Author(s):  
Theresia Greunz ◽  
Hubert Duchaczek ◽  
Raffaela Sagl ◽  
Jiri Duchoslav ◽  
Roland Steinberger ◽  
...  
Keyword(s):  
Hexavalent Chromium ◽  
Photoelectron Spectroscopy ◽  
Chromium Content ◽  
Organic Matrix ◽  
X Ray

scholarly journals Purification of Industrial Copper Electrolyte from Bismuth Impurity

Minerals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 36
Author(s):  
Patrycja Kowalik ◽  
Dorota Kopyto ◽  
Mateusz Ciszewski ◽  
Michał Drzazga ◽  
Katarzyna Leszczyńska-Sejda
Keyword(s):  
Barium Sulfate ◽  
Barium Carbonate ◽  
Lead Sulfate ◽  
Strontium Carbonate ◽  
Barium Hydroxide ◽  
Process Time ◽  
Purification Process ◽  
Copper Electrolyte ◽  
Bismuth Concentration ◽  
Main Components

This work focused on purifying copper electrolytes from a bismuth impurity on a laboratory scale. The electrolyte came from Polish copper electrorefineries with the content of main components, g/dm3: 49.6 Cu, 160 H2SO4. The electrolyte was enriched in bismuth by Bi2O3 addition. Purification of bismuth contamination was carried out using selected agents with adsorbing effects, such as barium hydroxide octahydrate, strontium carbonate, barium carbonate, barium and lead sulfates. The trials were performed until achieving the Bi level—below 0.1 g/dm3. During the experiments, it was noticed that electrolyte purification degree depends on initial Bi concentration in electrolyte, time and temperature, as well as on the type and amount of the bismuth-lowering agent. The most satisfactory results of Bi impurity removal were with additions of barium hydroxide octahydrate, strontium carbonate and barium carbonate to electrolyte at 60 °C for 1 h. These parameters revealed the highest electrolyte purification degree. Bismuth is not removed effectively from electrolytes by barium sulfate or lead sulfate addition. The efficiency of the purification process is much higher when the agents are added to the solution in the form of carbonates or hydroxides. Extending the electrolyte purification process time may cause dissolution of bismuth from the resulting precipitate and increase of bismuth concentration in electrolytes.

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