Edible oil bleaching with a bentonite activated by micro wave irradiation

A clay impregnated with an ammonium chloride solution was activated in a micro-wave oven. Optimal conditions of activation were determined by bleaching tests of a degummed and neutralized crude edible oil. Optimum values (concentration of NH₄Cl solution: 3M, heating time: 15 minutes) led to a material as effective as a commercial virgin bleaching earth in the treatment of an edible oil. The percent bleaching values calculated at 410 nm and 465 nm are 86% and 92%, respectively, for an oil processed by the micro-wave activated clay, against 77% and 93% for the same crude oil processed by a commercial virgin bleaching earth.     

Activated peroxide bleaching of regenerated bamboo fiber using a butyrolactam-based cationic bleach activator

Regenerated bamboo fibers are potentially a valuable source of renewable fibers for use in a wide variety of applications. As with almost all natural fibers, inherent yellowness must be reduced or eliminated in order for the fibers to be used effectively in processes such as dyeing. Oxidative bleaching in the form of hot alkaline hydrogen peroxide is the most common method for bleaching cellulosic fibers. However, significant fiber damage results, especially in the case of regenerated bamboo. Recently, more benign oxidative bleaching methods have been developed using so-called bleach activators. Reported is an effective bleaching method using a novel bleach activator, N-[4-(triethylammoniomethyl)benzoyl]butyrolactam chloride (TBBC). The ratio of TBBC to hydrogen peroxide and pH were found to be critical to achieving effective bleaching at low temperature. Using equimolar amounts of TBBC and hydrogen peroxide at pH 7 and 50 °C, comparable whiteness and less fiber damage compared with conventional peroxide bleaching was obtained. However, at pH 11.5, TBBC had no effect on whiteness.     

Analysis of the effects of catalytic bleaching on cotton

Hydrogen peroxide can be catalyzed to bleach cotton fibers at temperatures as low as 30°C by incorporating dinuclear tri-μ-oxo bridged manganese(IV) complex of the ligand 1,4,7-trimethyl-1,4,7-triazacyclononane (MnTACN) as the catalyst in the bleaching solution. The catalytic system was found to be more selective under the conditions applied than the non-catalytic H₂O₂ system, showing better bleaching performance while causing slightly lower decrease in degree of polymerization (DP) of cellulose. In order to gain fundamental knowledge of the bleach effect on cotton fibers and cellulose as its main component, especially after catalytic bleaching, X-ray Photoelectron Spectroscopy (XPS) was used to study surface chemical effects. The Washburn method was applied to investigate wetting properties, and liquid porosity was used to obtain pore volume distribution (PVD) plots. Parallel analyzes performed on model cotton fabric, i.e. “clean” cotton fabric stained with morin - a pigment regularly found in native cotton fiber, helped to differentiate between pigment oxidation and other bleaching effects produced on the (regular) industrially scoured cotton fabric. Bleaching was not limited to the chemical action but also affected cotton fiber capillary parameters most likely due to the removal of non-cellulosic materials as well as chain-shortened cellulose.     

Ultrasound assisted biobleaching of cotton

In this study, the effect of ultrasound on the activity of the glucose oxidase (GOx) enzyme for bleaching of the cotton fabrics was investigated. Hydrogen peroxide generation with the GOx enzyme from glucose was carried out under ultrasonic homogenizer (UH) and ultrasonic bath support. The aim of using ultrasonic support was to increase the yield of the enzyme reactions. The enzymatically generated hydrogen peroxide was used for bleaching of cotton fabrics. The bleaching process was performed at 90 °C and pH 11 (with NaOH) for 60 min, followed by rinsing at 70 and 50 °C then cold washing. The whiteness degrees of the cotton samples that were bleached by the generated peroxide were compared to the whiteness degrees of the conventionally bleached cotton fabrics. Sufficient whiteness degrees in cotton fabrics could be obtained by enzymatically generated hydrogen peroxide by UH support. The initial whiteness degree of the cotton fabric was 59.9 Stensby degrees; the whiteness was increased to 75.6 Stensby degrees by the GOx enzyme under UH support where the conventional bleaching process yielded a whiteness value of 76.7 Stensby degrees. For efficient cotton bleaching by the GOx enzyme, UH support contributed to the concentration of enzymatically generated hydrogen peroxide by the GOx enzyme. Bleaching of cotton by the GOx enzyme was approved as a more environmentally friendly process compared to the conventional bleaching method in respect of the results of chemical oxygen demand tests.     

Bleacing of olive mill wastewater by clay in the presence of hydrogen peroxide

Treatment of olive mill wastewater (OMW) with clayey soils in the presence of hydrogen peroxide (H₂O₂) allows the elimination of phenolic compounds responsible for the black-brownish color of this industrial effluent. The aim of this research was to define optimal physicochemical parameters for the bleaching of OMW with clay in the presence of hydrogen peroxide. Two clayey soil powders were tested (A and B) and the results obtained indicate that high bleaching could be reached after 24 hours exposure of OMW to 7 % (W/V) clay material A in the presence of 0.5 % (V/V) hydrogen peroxide. Under these conditions, the bleaching led to about 87 % decrease of polyphenols (PF) and a 66 % decrease of the Chemical Oxygen Demand (COD). The structure of clay and its concentration in iron salts have an effective adsorbent and catalytic effect on the removal of the majority of polyphenols.     

Bleaching cellulosic fibers via pre-sorption of N-[4-(triethylammoniomethyl)-benzoyl]-butyrolactam chloride

The sorption of a novel cationic bleach activator, N-[4-(Triethylammoniomethyl)benzoyl]-butyrolactam Chloride (TBBC), was measured on regenerated bamboo fiber. At 25 °C near neutral pH, the sorption rate of TBBC onto the fiber was initially rapid and equilibrium was reached within 20 min. Adsorption equilibria experiments followed a Freundlich isotherm. At the sorption equilibrium, bleaching was initiated by addition of sodium perborate to liberate hydrogen peroxide, which reacted with TBBC to generate a peracid that is a more kinetically active oxidant than peroxide. A sorption–activation model was developed that supports the enhanced bleaching of cellulosic fibers using cationic bleach activators under neutral to alkaline conditions.     

Efficient total halogen-free photochemical bleaching of kraft pulps using alkaline hydrogen peroxide

Total halogen-free bleaching of kraft pulps was conducted by an oxidative photochemical process at room temperature using alkaline hydrogen peroxide. Selection of an appropriate wavelength of light was crucial for effective bleaching and avoiding degradation of cellulose. The wavelength of the light has to be selected so that the light is absorbed only by the colored compounds in the pulps and not by the bleaching reagents or the pulp itself. When a long-wavelength black-light fluorescent lamp was used in combination with aqueous hydrogen peroxide solution at pH 11, the bleaching efficiency for hardwood and softwood kraft pulps reached the same level as that obtained by conventional two-stage elemental chlorine-free processes.     

Préparation d'une argile activée pour la décoloration de l'huile d'olive

The optimum conditions for acid activation of a clay were determined in order to bleach olive oil. The methodology of experimental research, with an orthogonal central composite design, has been used in this study and the selected variables were temperature, reaction time, initial acid concentration and liquid/solid weight ratio. The last is the most significant factor in the activation process followed in decreasing order of importance, by time, temperature and initial acid concentration. Good agreement between theoretical analysis and experimental results was obtained. The quality of the bleached oil is similar to that of commercial oil. Finally, the low cost of the activated clay makes it economically very attractive.     

Applications of transition-metal catalysts to textile and wood-pulp bleaching

From an economic perspective, textile and paper bleaching are amongst the most important oxidation processes. The removal of unwanted chromophores, be it stains on cloths or residual lignin in wood pulp, consumes more than 60 % of the world production of hydrogen peroxide. However, existing technologies have their limitations. At ambient temperature, hydrogen peroxide gives little stain bleaching and is used inefficiently. Hence the high product dosages and washing temperatures required limit its application to predominantly European markets, to the exclusion of the majority of the world's population. In paper manufacture, the use of chlorine-based oxidants results in the formation of chlorinated waste products, which show poor biodegradability. On the other hand, hydrogen peroxide requires higher temperatures, longer reaction times and is more expensive. Transition-metal catalysts offer an alternative. This review discusses the main classes of known bleach catalysts and their possible modes of action.     

Applications of Transition‐Metal Catalysts to Textile and Wood‐Pulp Bleaching

From an economic perspective, textile and paper bleaching are amongst the most important oxidation processes. The removal of unwanted chromophores, be it stains on cloths or residual lignin in wood pulp, consumes more than 60 % of the world production of hydrogen peroxide. However, existing technologies have their limitations. At ambient temperature, hydrogen peroxide gives little stain bleaching and is used inefficiently. Hence the high product dosages and washing temperatures required limit its application to predominantly European markets, to the exclusion of the majority of the world's population. In paper manufacture, the use of chlorine‐based oxidants results in the formation of chlorinated waste products, which show poor biodegradability. On the other hand, hydrogen peroxide requires higher temperatures, longer reaction times and is more expensive. Transition‐metal catalysts offer an alternative. This review discusses the main classes of known bleach catalysts and their possible modes of action.     

Thermal degradation of rice husks on a pilot plant

This study is an attempt to establish the possibilities to obtain black rice husk ash (BRHA) and white rice husk ash (WRHA) via pyrolysis of wasted raw rice husks in a pilot plant fluidized-bed reactor at different conditions. The process course auto thermally, without outer fuel. The released heat may be used for steam obtaining or drying. The solid products obtained (BRHA or WRHA) are characterized using X-ray diffraction patterns, thermal analysis, and low temperature nitrogen adsorption. Using batch adsorption technique, the kinetics was studied and the adsorption capacities of crude oil and diesel fuel at different temperatures as well as some hydrocarbons at 298?K onto BRHA and WRHA are determined. It was established that BRHA have been higher adsorption capacity than WRHA. At a given temperature, BRHA sorbed more crude oil than diesel fuel. The results obtained showed that the material studied has high adsorption capacity and low cost and may successfully be used as an effective adsorbent to cleanup of bilge water and spills of oil and oil products in water basins. Because the saturated BRHA with crude oil, diesel fuel or different hydrocarbons are characterized with high calorific, they can be burnt in incinerators, industrial ovens or steam generators. By this way, we attain not only ecological but also economical effect.     

The role of stilbenes in bleaching and colour stability of mechanical pulps. I. The reaction of lignin model stilbenes with alkali and oxygen

The reactions of lignin model hydroxystilbenes and TMP with alkaline hydrogen peroxide and with alkali and oxygen have been studied to determine the susceptibility of stilbenes, to oxidative degradation. Oxygen in the presence of alkali readily destroys lignin model stilbenes via cleavage of the olefinic double bond. The stilbene must contain a ring hydroxyl substituent for the reaction to occur. The reaction is fastest if the stilbenes havep,p′-dihydroxyl substituents. Stilbenes of the type likely to be attached to the lignin in pulps have only one hydroxyl group and are more stable. Hydrogen peroxide, by itself, is unreactive with stilbenes but the presence of oxygen as a peroxide decomposition product should limit the accumulation of stilbenes during alkaline peroxide bleaching of mechanical pulps. Alkaline peroxide bleaching of mechanical pulps under a pressurised atmosphere of oxygen gas leads to a slight increase in brightness and brightness stability. Guaiacyl-substituted stilbenes are more stable to alkali and oxygen than are syringyl-substituted stilbenes. This may partially explain why it is easier to bleach hardwood than softwood mechanical pulps.     

Investigation of the properties of oil at the bleaching unit of an oil refinery

Color removal from neutralized sunflower oil was studied with different kinds of commercial bleaching earths. The effect of changes in time (25 and 35 min), temperature (80-125 degrees C), and bleaching earth dosage (0.1-0.9% by weight) on color, chlorophyll and carotene concentrations, and oxidation degree were investigated. To obtain adsorption curves from coloring compounds adsorbed onto activated bleaching earths, the Langmuir and Freundlich equations was used, the constant parameters and correlation coefficient R were calculated for each type of bleaching earth, and color changes were explained by both adsorption isotherms. It was observed that an increase in bleaching earth dosage decreases color. Its effect on oxidation state, however, is complex and related to both primary and secondary oxidation products. In addition, an increase in temperature seems to decrease chlorophyll and carotene adsorptions. Generally, time beyond equilibrium is considered useless for the removal of unwanted components. This study also confirms this claim and reveals that the peroxide value does not indicate the oxidation state of the oil completely.     

Bleach Enhancement of Mixed Wood Pulp by Xylanase–Laccase Concoction Derived Through Co-culture Strategy

Mixed enzyme preparation having both xylanase and laccase activity was evaluated for its bleach enhancing ability of mixed wood pulp. The enzyme was produced through co-cultivation of mutant Penicillium oxalicum SAU_E-3.510 and Pleurotus ostreatus MTCC 1804 under solid-state fermentation. Bleaching of pulp with mixed enzyme had resulted into a notable decrease in kappa number and increased brightness as compared to xylanase alone. Analysis of bleaching conditions had denoted that 8 IU g⁻¹ of mixed enzyme preparation (xylanase/laccase, 22:1) had led into maximal removal of lignin from pulp when bleaching was performed at 10% pulp consistency (55 °C, pH 9.0) for 3 h. An overall improvement of 21%, 8%, 3%, and 5% respectively in kappa number, brightness, yellowness, and viscosity of pulp was achieved under derived bleaching conditions. Process of enzymatic bleaching was further ascertained by analyzing the changes occurring in polysaccharide and lignin by HPLC and FTIR. The UV absorption spectrum of the compounds released during enzymatic treatment had denoted a characteristic peak at 280 nm, indicating the presence of lignin in released coloring matter. The changes in fiber morphology following enzymatic delignification were studied by scanning electron microscopy.     

Evaluation of the Effect of Elite Jojoba Lines on the Chemical Properties of their Seed Oil

Jojoba oil (JO) extracted from seeds has outstanding properties, including anti-inflammatory, antioxidant, and antibacterial activities, and can be stored forlong periodsof time. The unique properties of jojoba oil depend on its chemical composition; therefore, the effect of the jojoba genotype on the chemical properties and active components of the seed oil was evaluated in this study. Oil samples were collected from 15 elite Egyptian jojoba lines. The chemical composition, such as moisture, crude fiber, crude oil, ash, and crude protein of elite lines’ seeds was determined to investigate the variation among them based on the jojoba genotype. In addition, the iodine value was obtained to measure the degree of jojoba oil unsaturation, whereas the peroxide number was determined as an indicator of the damage level in jojoba oil. Fatty acid composition was studied to compare elite jojoba lines. Fatty acid profiles varied significantly depending on the jojoba genotype. Gadoleic acid exhibited the highest percentage value (67.85–75.50%) in the extracted jojoba oil, followed by erucic acid (12.60–14.81%) and oleic acid (7.86–10.99%). The iodine value, peroxide number, and fatty acid composition of the tested elite jojoba lines were compared withthose reported by the International Jojoba Export Council (IJEC). The results showed that the chemical properties of jojoba oils varied significantly, depending on the jojoba genotype.     

漂白过程的电化学研究 Ⅲ.利用旋转圆盘电极模拟照相漂白过程

将银旋转圆盘电极在给定时间内浸在漂白液中进行氧化。在氧化过程中,来自漂白液中的卤化物在银电极表面与氧化生成的银离子形成卤化银。氧化反应生成的卤化银量可以用电化学还原方法进行定量测定。利用这种简单的方法可以研究漂白动力学,研究漂白液的组份、浓度和pH对漂白速度的影响。通过记录在银电极上氧化还原对的电流。电位曲线可以定量描述漂白过程。     

Effect of different clay concentrations on crude oil combustion kinetics by thermogravimetry

The objective of this research was to investigate the effect of different clay composition and concentrations on the thermal behaviour and kinetics of heavy crude oil in limestone matrix by thermogravimetry (TG/DTG). In TG/DTG experiments, three distinct reaction regions were identified in all of the crude oil + limestone mixture known as low temperature oxidation (LTO), fuel deposition (FD) and high temperature oxidation (HTO) respectively. Addition of clay to porous matrix significantly affected the reaction regions. Significant reduction of activation energy due to addition of clay to crude oil indicates the catalytic effect of clay on crude oil combustion.     

Alkaline peroxide mechanical pulping of wheat straw with enzyme treatment

Alkaline peroxide mechanical pulping (APMP) of wheat straw with enzyme treatment was studied. Instead of direct enzyme pretreatment on wheat straw, an alternative treatment method was used, in which coarse pulps from refiner defibrated wheat straw rather than wheat straw were pretreated with a crude enzyme containing mainly xylanase, then impregnated with alkaline H₂O₂ solution and further refined. The optimum conditions of enzyme treatment were xylanase dosage of 10–15 IU/g of oven-dried wheat straw, 90 min, 50–60°C, pulp consistency of 5–10%, and initial pH of 5.0, and those for chemical impregnation were 6% NaOH, 70–80°C, 60–90 min, and 4 to 5% H₂O₂. Enzyme treatment improved pulpability of wheat straw by the APMP process, and final pulp quality such as brightness, breaking length, and burst index of pulp. Pulp from the APMP process with enzyme treatment could be bleached to a brightness of 70.5% ISO by two-stage H₂O₂ bleaching sequence with only 4% H₂O₂, and breaking length of the bleach pulp reached 4470 m.     

The effect of repetitive frying on physicochemical properties of refined,bleached and deodorized Malaysian tenera palm olein during deep-fat frying

Refined, bleached and deodorized tenera palm olein is widely used for domestic and commercial food frying. However, repeated heating and frying might lead to oil spoilage. This study focuses on the effect of deep-frying on physicochemical properties of repeatedly heated palm olein. Recycled palm olein was prepared by frying potato strips up to 5 cycles with potato-to-oil (g/ml) ratio of 3:20 prior to colour, density, viscosity, moisture content, contact angle, peroxide value and iodine value analyses. The fluctuation in the temperature of the oil was insignificant for every cycle (p > 0.05). The increase in red colour of the oil was significant (p < 0.05) after two cycles of frying from 3.6 to 5.0 Lovibond unit. After 5 frying cycles, there was no change in the density of RBDPO-2 and RBDPO-3. The viscosity of the oil after 5 frying cycles was higher as compared to after 5 heating cycles (67.7 ± 0.6 and 58.2 ± 0.9 cP respectively). Besides, the viscosity of RBDPO-3 was lower than RBDPO-2 only. The moisture content of the oil increased from 3.7 ± 0.1% to 30.4% (w/w) for RBDPO-2, whereas for RBDPO-3, the viscosity increased from 3.7 ± 0.1% to 30.4 ± 0.1% (w/w) due to the presence of the moisture from the potato. The change in the contact angle of the RBDPO-1 (control) was significant (p < 0.05) between the 1st cycle and the 5th cycle from 19.16 ± 0.45° to 12.03 ± 0.45° respectively. Besides, there was a significant change (p < 0.05) of contact angle for RBDPO-2 between the 1st cycle and the 5th cycle from 32.53 ± 0.5° to 18.06 ± 0.15° respectively. The peroxide value of the fresh oil was 2.8 ± 0.2 meq/kg and the value after the 1st cycle for all RBDPO(s) treatment increased, indicating that primary oxidation had occurred after the 1st cycle of heating and frying. A decreasing trend was observed from the 2nd until the 5th frying cycle because the instability of peroxide at a high temperature, causes rapid degradation and produced a dimer and volatile compound. Frying also decreased the unsaturated value of the oil as indicated by a decrease in the iodine value. Based on Pearson’s correlation test, there was a positive correlation between the colour, density and viscosity of the oil. The higher the peroxide value, the higher the density of the oil. There was also a positive correlation between the contact angle, moisture content and peroxide value of the oil. Whereas, a negative correlation was found between the iodine values, colour, density and viscosity of the oil. In conclusion, the potato repetitive deep-frying darkened the colour of the oil, increased its density, viscosity, contact angle, and peroxide value and decreased the degree of unsaturation of the oil as it shows a prominent sign of oxidative rancidity.     

Functional zinc(II) phthalocyanines bearing Schiff base complexes as oxidation catalysts for bleaching systems

Oxidation catalysis is used to increase the performance of hydrogen peroxide in laundry bleach applications. Bleach catalysts provide cost‐effective, energy‐saving and environmentally friendly bleach systems yielding perfect stain removal at lower temperatures. This comparative study is based on the synthesis of bis[bis(salicylhydrazonephenoxy)manganese(III)] phthalocyaninatozinc(II) ( 2 ), bis[bis(salicylhydrazonephenoxy)cobalt(III)] phthalocyaninatozinc(II) ( 3 ) and bis[bis(salicylhydrazonephenoxy)iron(III)] phthalocyaninatozinc(II) ( 4 ) as tri‐nuclear complexes consisting of two Schiff base complexes substituting a zinc phthalocyanine. Complexion on the periphery to obtain complexes 2 , 3 , 4 was performed through the reaction of a Schiff base‐substituted phthalocyanine using MnCl₂?4H₂O, CoCl₂?6H₂O or FeCl₃?6H₂O salts in basic condition in dimethylformamide. Fourier transform infrared, ¹H NMR, ¹³C NMR, UV–visible, inductively coupled plasma optical emission and mass spectra were applied to characterize the prepared compounds. The bleach performances of the three phthalocyanine compounds 2 , 3 , 4 were examined by the degradation of morin as hydrophilic dye. The degradation progress in the presence of catalysts 2 , 3 , 4 /H₂O₂ combination in aqueous solution was investigated using an online spectrophotometric method. It was found that the catalysts 2 , 3 , 4 exhibited better bleaching performance at 25 °C than tetraactylethylethylenediamine as bleach activator used in powder detergent formulations for stain removal. Copyright © 2015 John Wiley & Sons, Ltd.