Mimosa Extracts Research Articles

Determinación de parámetros tecnológicos en curtición vegetal de piel de paiche (Arapaima gigas) con extracto de quebracho (Schinopsis balansae) y mimosa (Acacia dealbata) para el aprovechamiento industrial ambientalmente sostenible

La crianza de paiche en la Amazonía peruana produce suficiente materia prima para la elaboración de cuero a base de piel de pescado; sin embargo, estas pieles representan un problema de contaminación debido a su limitado aprovechamiento. En esta investigación, se resalta la relevancia de emplear procedimientos tanto mecánicos como químicos con el fin de obtener cuero de excelente calidad. Para llevar a cabo este proceso, se utilizaron diferentes concentraciones de quebracho y mimosa. El cuero de piel de paiche resultante fue resistente y moldeable, con una capacidad de resistencia a la flexión que excede las 30 000 flexiones sin deformación, mayor resistencia al desgarro en T1 (146.23 N) y T5 (143.12 N) y mayor tracción en T4 (16.62 N/mm2). Además, presentó un contenido de cenizas inferior al 1%, humedad inferior al 9% y óxido de cromo inferior al 1.5%. Se trataron además los efluentes generados durante el proceso, los cuales presentaron valores aceptables de pH, conductividad y DQO.

Comparative Study of Optical and Chemical Properties of ZnO-Ag Composites Synthesized from Mimosa Pudica and Andrographis Paniculata Extracts

In this research, a comparison was made between the optical and chemical properties of ZnO-Ag composites with different ZnO and Ag ratios synthesized using extracts obtained from mimosa and Andrographis paniculata plants. The optical properties of the synthesized ZnO-Ag composites were analyzed, focusing on parameters such as absorption and bandgap energy. Moreover, the bandgap, which indicates the energy difference between the valence and conduction bands, was calculated to assess the compounds' electronic behavior. Furthermore, the chemical properties of the ZnO-Ag composites were investigated. This involved analyzing the chemical bond, crystal structure, and crystalline size using X-ray diffraction (XRD) and Fourier Transform Infrared Spectrometer (FT-IR). The experimental findings demonstrated that the crystal sizes of ZnO and Ag in ZnO-Ag composites synthesized using Mimosa pudica extract were considerably smaller compared to those synthesized using Andrographis paniculata extract. Consequently, the energy gap of the ZnO-Ag compounds synthesized with mimosa extract was higher in comparison to those synthesized with Andrographis paniculata extract. By comparing the optical and chemical properties of the ZnO-Ag composites synthesized from mimosa and Andrographis paniculata extracts, valuable insights can be gained regarding the influence of these plant extracts on the resulting composites.

Vegetable Tannins as Chrome-Free Leather Tanning

The purpose of this study is to replace chrome tannins with ecofriendly vegetable tannins as an alternative solution to prevent the public health and the environmental pollution. Vegetable tannin was extracted from Cassia singueana bark using an aqueous extraction method and applied on sheep pickle pelt. Optimum tannin extraction parameters were identified at powder concentration of 80 g/L, extraction temperature of 100°C, and extraction time of 120 mins. Chemical functionality of Cassia singueana extracted tannins was evaluated via FT-IR spectroscopy. Hence, the FT-IR spectrum confirmed the presence of wide band of phenolic hydroxyl (OH−) and carboxyl (C-O) groups connected with the aromatic ring. Moreover, physicochemical performance of the Cassia singueana extract tanned leather sample was scientifically examined and showed comparable results to conventional Mimosa tanned leather sample. The shrinkage temperature of Cassia singueana extract tanned leather recorded 83°C which is slightly higher than that of Mimosa extract (standard), 80°C. The results of mechanical properties such as tensile strength, tear strength, and elongation at break of Cassia singueana extract tanned leather sample are 15.6 N/mm2, 24.2 N/mm, and 45.3%, respectively, which are relatively higher than those of Mimosa extract tanned leather sample. A relatively higher reduction level of pollution load (BOD, COD, and TDS) was observed in the wastewater released from Cassia singueana bark extract compared to the Mimosa extract (standard). Finally, findings from this study revealed that Cassia singueana bark extract could be considered as an alternative source of vegetable tannins to reduce the consumption of chrome tanning in the leather tanning industry.

Study on the Pyrolysis Kinetic Behaviors of Different Vegetable-Tanned Sheepskin Leathers

The pyrolysis behaviors of leathers tanned with hydrolyzable tannins (Tara and Chestnut extracts), and condensed tannins (Quebracho and Mimosa extract) were studied by Thermogravimetric (TG) analysis in the present work. The TG/derivative thermogravimetry (DTG) results showed that the thermal stability of Tara- and Chestnut-tanned samples is poorer than that of Quebracho- and Mimosa-tanned ones. In order to study pyrolysis kinetics, TG experiments at different heating rates were carried out. Two methods of Flynn-Wall-Ozawa (FWO) and Friedman (FR) were employed to calculate the pyrolysis activation energy (Eα) of the samples. It was found that the average Eα of the vegetable-tanned samples is located at the range of 191.7-206.1 kJ/mol. The thermodynamic parameters (pre-exponential factor, Gibbs free energy, enthalpy, and entropy) of the samples were subsequently calculated based on the average Eα by the FR method. The Gibbs free energies of the Chestnut-, Tara-, Quebracho-, and Mimosa-tanned leathers were 176.9 kJ/mol, 179.8 kJ/mol, 179.3 kJ/mol, and 178.2 kJ/mol, respectively. The difference between the average enthalpies and the Eα is less than 5 kJ/mol, which indicated that the pyrolysis process is conductive to the product formation. The mean entropy (ΔS) of the four vegetable-tanned samples is all positive, which suggested that the pyrolysis of the samples could easily take place. This work might provide theoretical guidance for the optimization of vegetable-tanned leather waste pyrolysis.

USE OF NATURAL LEATHER IN SHOE PRODUCTION

In the work, the formation of leather material from semi-finished cattle was carried out – medium chrome-tanned beef at the stage of filling and fattening after it is planed to thickness 0,9–1,1 mm. In this case, the product of the interaction of 2-naphtholsulfonic acid with dioxydiphenylsulfone was used – BNS synthetic tanner (ТУ 17-06-165-89), mimosa extract with a tannin content of 79.0% and an emulsion of a fattening preparation Fosfol L-1301 by company «Cromogenia Units, S.A.» (Spain). Preliminary greasing of the semi-finished product and final fixation of reagents diffused into the structure of the semi-finished product with alumokalium alum gives the leather material a complex of hygienic, physical-mechanical and technological characteristics that meet the requirements for materials for sewing products. The resulting leather material exceeds industrial samples by 13.6% and 11.0%, respectively, in terms of hygroscopicity and vapor permeability. Compared to natural leather, synthetic leather is characterized by significantly lower hygienic properties, and in terms of specific surface area and sorption capacity, they are inferior to natural leather materials by at least 32.0 and 17.0 times, respectively. Accordingly, their vapor permeability and hygroscopicity are 7.0–8.0 and 5.5–6.0 times lower than natural leather. At the same time, to a greater extent, this also applies to a complex of physical and mechanical indicators, including increased defectability and reduced formability during the operation of footwear products. At the same time, their initial aesthetics are relatively quickly lost. The natural leather material obtained by the developed technology can be considered promising due to its advantages compared to synthetic leathers and compliance (ДСТУ 2726-94) for the production of high-quality shoe uppers.

Life cycle assessment of a novel tannin-boron association for wood protection

In these studies of fix boron compounds, associations between tannins and boron (TB) in the form of boric acid appear to be of interest. These TB associations allow the use of boron at very low levels (in compliance with EU restrictions, 2008/58/EC) and limit boron leaching which maintains biological resistance and fire retardant properties. As a consequence, TB wooden products present an extended service life compared to boron compounds alone and were designed to be environmentally-friendly wood protection systems. A follow-up of tannin‑boron use identified the environmental impacts using a life cycle assessment (LCA). This LCA was performed on tannin‑boron preservative products as well as several industrial preservative-treated timbers and concrete used in the landscape. Cr-containing inorganic salt and an alkaline copper quaternary preservative formulation, as well as concrete, have been used as referential materials to compare the environmental footprint with the tannin‑boron treated system. A model was created with life cycle stages used to calculate inputs and outputs during raw material extraction, supplier transportation, manufacturing process, distribution, disposal transportation and processing. Tannin production data were based on Vieira et al. in the field of condensed tannin extraction. However, the extracted tannin in the extraction yield, the inorganic salt, and the process applied are not perfectly comparable with the extraction conditions industrially applied for the Mimosa (Acacia mearnsii) extract which is the major constituent of the TB formulations. The latter is counter-current water extracted without any chemicals or with a limited amount of NaHSO3 or Na2SO3 (at 0.5 % to 1 %) — at a temperature of 70–90 °C. Unfortunately these parameters cannot be elaborated by the LCA program because there is no data available for the production of Na bisulphite or Na bicarbonate in the LCI data used. Other input data were sourced from the ecoinvent v3.8 database. The ReCiPe midpoint method was used to assess the environmental footprint and the CED method was chosen to analyze a general view of the energy-related environmental impacts in the life cycle. Overall, the results demonstrated that tannin‑boron preservatives can be regarded as a low-environmental impact formulation. Additionally, an economic analysis of the development of a commercially-viable tannin‑boron preservative would now be timely.

The Suppressive Activity of Water Mimosa Extract on Human Gastric Cancer Cells

Epidemiological studies have evidenced that natural dietary products can prevent or manage gastric cancer. Neptunia oleracea, an aquatic vegetable and edible plant, has been reported to have anti-cancer properties. In this study, N. oleracea extract’s suppression of gastric cancer cells was investigated on an in vitro experimental model. We found that ethyl acetate (EtOAc) extract inhibited cell proliferation at IC50 value of 172 µg/mL. Moreover, the treatment of EtOAc extract at a concentration of 50 µg/mL for 24 h caused suppression of cancer cell migration. Notably, a real-time PCR assay revealed that EtOAc extract induced the process of apoptosis via upregulating the mRNA expression level of caspase-8, Bax, caspase-9, and caspase-3 in cancer cells. In conclusion, N. oleracea had potential anti-cancer activity against gastric cancer cells, suggesting its role in the prevention and management of gastric cancer.

Antibacterial Potency for Mimosa, Quebracho and Essential Oils of Origanum Species against Acinetobacter pittii, Klebsiella pneumonıae and Bacillus cereus from Diabetic Foot Patient

The diabetic patients may sometime suffer from foot lesions, foot ulcers and amputation that adversely affect their quality of life. In this respect, good footwear has a critical significance for diabetic foot patients. The aim of this study to evaluate the potential efficacy of mimosa, quebracho, and essential oils of Origanum onites, Origanum onites oleum, and Origanum minutiflorum, against Acinetobacter pittii, Bacillus cereus, and Klebsiella pneumoniae, which was isolated from diabetic foot patient. According to our results, the mimosa extracts were slightly more efficient when compared to quebracho extracts to control the bacterial growth of A. pittii (8.77±0.58-35.12±8.41% inhibition for three doses), and K. pneumoniae (21.40±0.48-47.04±0.51% inhibition) except B. cereus (71.1±0.31-23.51±1.66% inhibition). But these inhibition percentages remained at lower levels. On the other hand, essential oil samples of O. onites, O. onites oleum, and O. minutiflorum at tested doses have considerably high antibacterial effects against A. pittii, B. cereus, and K. pneumoniae. The tested essential oils almost completely inhibited B. cereus with percentages of inhibition ranging from 96.18±2.98-100±0.00. Also, the bacterial growth of K. pneumoniae and A. pittii was inhibited by 88.01±2.36 to 100±0.00% and 71.42±12.57 to 100±0.00%, respectively. Moreover, the essential oils of O. onites, O. onites oleum, and O. minutiflorum, had bactericidal activity against A. pittii, and K. pneumoniae but bacteriostatic activity against B. cereus. This potency for essential oil of Origanum species may be evaluated for diabetic footwear. More detailed technical studies are required for the application of Origanum species to leather footwear.

Exploring the feasibility of substituting mimosa tannin for pine bark powder. A LCA perspective

The use of vegetable tannins is a bio-based alternative to chrome tanning. The most used vegetable extracts are Mimosa and Quebracho. To improve the sustainability of the tanning process, a chemically unmodified pine bark could be used as a natural source of tannins. The present study was aimed to evaluate the environmental impact of the use of pine bark powder to obtain vegetable leather through a life cycle assessment. Specifically, the life cycle impact evaluation was performed for both: i) pine bark powder tannin and the atomized mimosa extract production as raw material; and ii) the production process of a tanned leather with pine bark tannin versus a tanned leather with mimosa extract. An eco-friendly and cleaner production method for obtaining pine bark powder was developed. This new production method allows to obtain a reduction in 83% in the “climate change” impact category. However, when this tannin is applied to obtain a tanned leather, the tanning process shows an increase in all studied impact categories compared with the use of the atomized mimosa extract.

Assessment of the pyrolysis kinetics and mechanism of vegetable-tanned leathers

The pyrolysis kinetics and mechanism of leathers that were tanned with mimosa extract and tannic acid were investigated in this paper. The Kissinger-Akahira-Sunose (KAS) and Friedman (FR) methods were applied to calculate the activation energy and thermodynamic parameters, including the preexponential factor, Gibbs free energy, enthalpy, and entropy. The Criado method was further employed to determine the kinetic model of the pyrolysis process. Thermogravimetric analysis in combination with Fourier-transform infrared spectroscopy (TG-FTIR) analyses revealed that the evolved gaseous products from vegetable-tanned leather (VTL) pyrolysis were carbon dioxide, water, ammonia, isocyanic acid, and pyrrole. Pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) results showed that the main components of VTL pyrolysis were nitrogen-containing compounds (such as nitriles and diketopiperazines), aromatic hydrocarbons or hydrocarbons, and phenols. The results also indicated that the kinetics, mechanism, and pyrolysis products of the vegetable-tanned leathers depended on the type of tanning agent that was used. Nitro-ketone compounds accounted for more than 65% of the pyrolysis products of leather that was tanned with mimosa extract. In the case of tannic acid-tanned leather pyrolysis, phenols accounted for the highest percentage of the pyrolysis products. This research provides further insight into the mechanism and product characteristics of VTL pyrolysis, which provides a theoretical basis and evidence for converting solid leather wastes into value-added products.

Effects of Graded Levels of Mimosa (Acacia mearnsii) Tannin Purified with Organic Solvents on Gas, Methane, and In Vitro Organic Matter Digestibility of Eragrostis curvula Hay.

Simple SummaryEnteric methane emission serves as one of the major contributors to global warming, and is responsible for the loss of an appreciable amount of dietary energy. Utilization of Mimosa tannin in reducing methane yield in ruminants is well documented. However, its supplementation in large amounts affects rumen fermentation and digestibility, attributed to the presence of a high number of hydrolysable tannins and other non-tannin substances, which poison rumen microorganisms. Purification might remove the toxic compounds, thereby decreasing the methane without affecting the digestibility of the diet. In this study, mimosa tannin was purified with organic solvents (ethyl acetate and pentanol) using the Soxhlet extraction method, and the influence of different concentrations (10, 20, 30, and 40 g/kg DM) of the purified tannins on gas, methane, and in vitro organic matter digestibility of Eragrostis curvula hay were evaluated in comparison with the same levels of unpurified tannin. The addition of lower levels of ethyl acetate and pentanol purified mimosa tannin extracts reduced in vitro gas and methane production without adverse effects on dry matter digestibility.The higher contribution of methane (CH4) to global anthropogenic potential is a cause of concern to livestock producers. Mimosa tannin gained recent acceptance as an additive for enteric CH4 mitigation. However, rumen fermentation and digestibility are compromised when large quantities of tannins are supplemented due to the presence of hydrolysable tannin and other non-tannin molecules in mimosa extract, which are toxic to animals. Purification could eliminate the toxins, and thus, reduce the CH4 yield without negative effects on rumen microbial activities and organic matter degradation. The Soxhlet extraction method was used to purify the tannin using organic solvents (ethyl acetate and pentanol). The unpurified, ethyl acetate purified, and pentanol purified tannins at the dosages of 10, 20, 30, and 40 g/kg DM of substrate (Eragrostis curvula hay) were evaluated for gas, CH4, and in vitro organic matter digestibility (IVOMD) in comparison with substrate alone. Gas kinetics were tested using a simple exponential model with lag. The results showed that compared with control, gas, CH4, IVOMD, CH4/gas, CH4/IVOMD, gas/IVOMD, asymptotic gas volume (v), and rate of gas production (k) decreased (p < 0.01) linearly with the increase in the inclusion levels of all tannin extracts. Also, ethyl acetate purified and pentanol purified tannin extracts reduced gas and CH4 at lower dosage (30 g/kg DM) compared to unpurified tannin extract at a higher level (40 g/kg). Pentanol purified tannin was more effective at lower dosage (20 g/kg DM) in terms of CH4/gas and CH4/IVOMD. It was concluded that the purification of mimosa tannin with ethyl acetate and pentanol reduced potential gas production and CH4 without much reduction in substrate digestibility when up to 30 g/kg DM of feed was used. Lower inclusion levels of ethyl acetate and pentanol purified extracts could give a similar result with a higher dosage of unpurified tannin.

A chrome-free combination tanning strategy: based on silicic acid and plant tannin

Silicic acid, commonly derived from cheap and easily available sodium silicate, has recently received great attention for application in leather industry to produce ecological leather with a cleaner approach. However, leather tanned with silicic acid alone is poor in storage stability, which limits its practical application in leather production. In this work, a new environment-friendly combination tannage based on silicic acid and plant tannin was developed to address this issue along with improving the comprehensive performances of leather. The obtained leather was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy and so on. The results showed that compared with leather tanned with silicic acid alone, the leather tanned with this combination method possessed improved thermal stability, enhanced mechanical properties, acceptable softness, appropriate hydrophilicity, and especially enhanced storage stability. More importantly, the combination tanned leather with 1:1 of the mass ratio of silicic acid to vegetable tannin (composed of valonea extract and mimosa extract with the same weight) had more prominent comprehensive performances. In addition, the results demonstrated that hydrogen bonding played an important role in the combination tanning process. Furthermore, the hydrogen bonds generated between phenolic hydroxyl groups of polyphenols with silicon hydroxyl groups of silicic acid molecules inhibited the excessive condensation of Si-OH groups between themselves. Subsequently, the assessment of environmental impact revealed the value of BOD5/COD of the wastewater produced in this combination tanning process is more than 0.3, indicating the chrome-free combination tannage based on silicic acid and plant tannin was an environment-friendly tanning technology. These findings therefore indicated that a new chrome-free tanning method with silicon and biomass materials as main tanning agents has potential practical application prospect in leather production.Graphical abstract

Therapeutical properties of Mimosa caesalpiniifolia in rat liver intoxicated with cadmium.

The aim of this study was to evaluate the therapeutic properties of Mimosa caesalpiniifolia in liver of rats exposed to cadmium under morphological, oxidative, inflammatory, and mutagenic parameters. A total of 40 Wistar rats (90days, ~ 250g) were distributed into eight groups (n= 5) as follows: (i) control; (ii) cadmium: cadmium chloride injection at 1.2mg/kg; (iii) Mimosa extract: treatment with Mimosa extract at 250mg/kg; (iv) Mimosa fraction: treatment with Mimosa acetate fraction at 62.5mg/kg; (v) cadmium and Mimosa extract 62.5: submitted to cadmium chloride at 1.2mg/kg injection and treatment with Mimosa extract at 62.5mg/kg; (vi) cadmium and Mimosa extract 125: subjected to cadmium chloride at 1.2mg/kg injection and treatment with Mimosa extract at 125mg/kg; (vii) cadmium and Mimosa 250 extract: submitted to cadmium chloride 1.2mg/kg injection and treatment with Mimosa extract at 250mg/kg; (viii) cadmium treated with fraction of Mimosa acetate: submitted to cadmium chloride 1.2mg/kg injection and treatment with acetate fraction of Mimosa extract at 62.5mg/kg. In the animals intoxicated with cadmium and treated with fraction [62.5], increased expression of SOD-Mn reduced frequency of binucleated hepatocytes, karyolysis, and karyorrhexis, besides the antimutagenic and antioxidant action. The extract [62.5] was cytoprotective, antimutagenic, and reduced karyolysis. The extract [125] was cytoprotective, antioxidant, antifibrotic, anti-inflammatory, and reduced frequency of binucleated hepatocytes, while extract [250] was cytotoxic and mutagenic. In summary, the extract of Mimosa exerts some therapeutic properties in hepatic tissue after Cd intoxication, but only when it is administrated at intermediate doses. Probably, a high content of polyphenols in the EHM [250] and Fr-EtOAc groups exert pro-oxidant activities in the liver particularly when associated with Cd.

Thermal degradation study of vegetable tannins and vegetable tanned leathers

In this study, hydrolyzable tannins (commercial chestnut, valonea and tara extracts), condensed tannins (commercial quebracho and mimosa extracts) as well as calf leathers produced using these vegetable tanning agents were characterized by thermal decomposition methods using slow and high heating rates. Calf gelatin obtained by heating calf pelt in water at 70 °C was chosen as a reference material. Thermogravimetry/mass spectrometry (TG/MS) and pyrolysis-gas chromatography/mass spectrometry (Py-GC/MS) experiments were performed on the tannin and leather samples. The evolution profiles of the decomposition products as well as the thermal stability of tannins and leathers were studied by TG/MS. A net difference was observed in the thermal behavior of hydrolyzable and condensed tannins. The condensed tannins produced the highest char yield, while the hydrolyzable tara extract released the most volatile products. The tannins of higher reactivity produced more stable leathers as it results from their higher decomposition temperature. The composition of both vegetable tanned leathers and vegetable tanning agents was characterized by the pyrolysis product distribution measured by Py-GC/MS method. Resorcinol and its methylated derivative (orcinol) were found to be a characteristic decomposition product for both condensed tannins, i.e. mimosa and quebracho. They were identified among the pyrolysis products of the mimosa and quebracho tanned leathers, as well.

Characterization of phytochemical profile and phytotoxic activity of Mimosa pigra L.

The search for new biological agents produced by plants represents an alternative strategy in sustainable agriculture. The phytochemical profile of Mimosa pigra L. was investigated and the phytotoxic potential was assessed. Phytochemical analyses revealed the presence of flavonoids, tannins, phlobatannins, alkaloids and saponins in the methanolic extract of M. pigra (mimosa extract). The contents of both total phenolic compounds and flavonoids increased in a similar manner with increases in the mimosa extract concentrations. The phytotoxicity of the extract was evaluated on seedling growth and on some physiological processes in lettuce (Lactuca sativa L.) and popping pod (Ruellia tuberosa L.). Root and shoot growths were inhibited by mimosa extract in a concentration-dependent manner. Mimosa extract significantly inhibited mitosis resulting in root growth retardation. Moreover, mimosa extract caused cell death and induced lipid peroxidation in both plants. Therefore, the primary action of mimosa extract on seedling growth inhibition was related to the alteration in mitosis, loss in cell viability and trigger lipid peroxidation in affected tissues. Phytotoxicity was due to the presence of several secondary metabolites in the extract. Consequently, the mimosa extract could be considered as a source of metabolites to be used as alternatives for biological weed control.

Formaldehyde scavengers for cleaner production: A case study focused on the leather industry

Due to its carcinogenic character, the presence of formaldehyde in leather continues to be a subject of great concern. By using formaldehyde scavengers, it is possible to reduce the formaldehyde content in leather. In this work, the potential ability of three different compounds (ethylene urea, pyrogallol and gallic acid) to reduce the formaldehyde content in splits leathers treated with formaldehyde resins (melamine-formaldehyde and dicyandiamide-formaldehyde) is assessed. This capacity is compared with that of a fourth scavenger (hydroxylamine sulphate) already used in tanneries. The evolution of the formaldehyde content with time is also considered, as well as the potential coadjuvant effect of other compounds such as mimosa extract and an acid dye (Acid Black 234). Hydroxylamine sulphate initially showed the highest ability to reduce formaldehyde content. However, after a certain time, this ability proved to be inferior to the ability of other compounds due to the reversibility of the reaction between hydroxylamine and formaldehyde. Pyrogallol showed a higher ability than gallic acid when used in the final wash of leather processing. However, the treatment with pyrogallol results in a darkening of the leather; this darkening limits its use. Gallic acid may be a good alternative to formic acid as the final fixing agent in leather processing when the presence of formaldehyde in leathers is suspected. The use of gallic acid in the final wash or as a fixing agent fulfils the formaldehyde content limit (65–75?mg/kg) of the major brands in leather goods in direct contact with the skin. The addition of 2% of gallic acid in the final wash of leather processing resulted in formaldehyde content reductions that varied from 65% to 85%. However, further experiments are required to assess the influence of gallic acid on the fastness properties and the coloration acquired by the treated leathers. The joint effect of gallic acid in the final wash or as a fixing agent and mimosa extract as a retanning agent in formaldehyde content reduction is even enhanced by subsequently using a dye with amino groups in its chemical structure. Reducing the formaldehyde content by using scavengers can contribute to the achievement of a cleaner production in those sectors (leather, textile, wood) that use formaldehyde resins.

COMPARISON LEATHER PROPERTIES OF BARKI AND ABU-DLEEK SHEEPS

The aim followed in the present paper was to evaluate physical and chemical properties of Barki and Abu-Dleek sheep leathers, tanned with different tanning materials. Fifteen sheepskins from each breed at marketing age were collected and tanned with different tanning methods; mineral with chromium salts and vegetable with quebracho or mimosa extracts. Leather properties were assessed. Abu-Dleek leathers were higher quality than Barki leathers when tanned with different tanning materials. With respect to influence of tanning method, mineral tanned leathers were higher quality than vegetable tanned leathers. Within vegetable tanned leathers, leathers tanned with quebracho extract were higher than leathers tanned with mimosa extract.

Larvicidal activities of some bark and wood extracts against wood-damaging insects

This study investigates the larvicidal activities of plant extracts and tannins against wood-damaging insects. Scots pine (Pinus sylvestris), beech (Fagus orientalis), and poplar wood (Populus tremula) were subjected to larvae of Spondylis buprestoides (Coleoptera: Cerambycidae) by impregnating them with mimosa (Acacia mollissima), quebracho (Schinopsis lorentzii) and redpine bark (Pinus brutia) extracts. At the end of the 6-month experiment, the numbers of dead and live larvae as well as the mean mass losses of woods were determined. In terms of wood species, the lowest larva resistance was observed in Scots pine wood, while the highest larva resistance was achieved by beech wood. The lowest mass losses and the highest dead termite rates in all tree species were observed when the concentration of mimosa and quebracho extracts was 12%. On the other hand, the pine bark extract showed a lower larvicide effect than the other two extracts.

Utilization of Tannins Extract of Acacia seyal Bark (Taleh) in Tannage of Leather

Leather is a durable and flexible material created by the tanning of animal raw hide and skin, primarily cattle hide and natural grain, variation in the grains, good breathability and other natural features are all signs that the material is genuine. The most commonly used tanning methods are chrome and vegetable tanning. The vegetable tannins are extracted by using a suitable solvent, usually water followed by concentration and spray drying to get powder or solid. The tanneries in the Sudan imported mimosa and synthetic (syntan) tannins material for the process of retanning and pretanning. This study was undertaken to utilize Taleh bark (Acacia seyal Bark) as a retanning material for production of upper and garment leathers. The tannins content of Taleh bark was found to be 28.9% and therefore it was promising and would successfully be used as retaining and tanning materials. In this study; the factors that affect leaching which are mainly time, solvent to solid ratio, temperature, agitator speed and time of extraction. A two - level factorial experiments were designed and the level of the above factors was determined according to the statistical analysis. It was found that a solvent solid ratio of 6:1, speed of agitation of 250 rpm, temperature of 30°C and time 2 hours were the optimum conditions. A complete design of a long tube triple-effect evaporator is made for production of 1000 tons per year which is enough for the present level of capacities in the tanneries to date. In conclusion it is clear that Sudan can produce tannins extract from Taleh bark which can be used for pretannage, tannage and retannage. It is recommended that the Taleh bark and similar Acacia seyal can be analyzed and leached to give tannins powder extract to replace imported Mimosa extract.

A comprehensive evaluation of mimosa extract as a corrosion inhibitor on AA6060 alloy in acid rain solution: part I. Electrochemical AC methods

The inhibition effect of mimosa extract on the corrosion of AA6060 aluminum alloy in acid rain solution was investigated by electrochemical impedance spectroscopy and dynamic electrochemical impedance spectroscopy (DEIS). All the studied electrochemical parameters showed good corrosion inhibitive characteristics with respect to the aluminum alloy in the tested solution. Inhibitor efficiency increased with the concentration and attained 45% at 2750 ppm. The advantage of DEIS as a tool for the investigation of corrosion inhibitor influence was discussed.