Bleaching Process Research Articles

The investigation of the effect of sodium chlorite and phosphonic acid catalysts on cotton bleaching process conditions

Today's environmental and living conditions necessitate reconsideration of traditional cotton fabric bleaching processes. For this reason, it is very important for the environment and the economy to obtain higher whiteness values by using less water and chemicals in bleaching. Sodium chlorite (NaClO2), the source of chlorine dioxide (ClO2) as the most important disinfectant, which gained popularity and availability during the COVID-19 pandemic, is an appropriate oxidant for the purpose. Using NaClO2 as bleaching agent has significant advantages, such as reducing the amount of washing proses and increasing of cotton strength. Another advantage of this reagent is that it causes less fabric weight loss than other reagents. Therefore, the present work was intended to improve the process conditions (different temperatures, concentrations, and times) of bleaching of cotton fabric by using NaClO2. Optimum temperature and time were determined as 30 min at 65 °C and 30 min at 85 °C, and a high whiteness index (W.I.=88) was obtained by using phosphonic acid (HEDP). Moreover, the tensile strength, weight loss and morphologies of the samples were examined. It has been observed that sodium chlorite causes little damage to cotton fibers and requires less water for rinsing since it does not form alkaline residues.

Utilization of Recycled Egg Carton Pulp for Nitrocellulose as an Accelerant in Briquette Production.

Nitrocellulose (NC) is a conservative material that is used in a variety of applications, such as coating agents, biodegradable plastics, and propellant main charge. Nitrocellulose raw materials are easily obtained from lignocellulose sources, most notably cotton and wood pulp. The egg carton, a recycled paper waste designed for packaging and transporting eggs, is used in this study to make nitrocellulose in pulp form. The effects of different nitration durations (40, 50, and 60 min) from egg carton pulp bleached with various KOH concentrations (0.6 M, 1.0 M, and 1.5 M) on NC properties were evaluated. The accelerant properties of the NC of nitration time in 50 min were studied in a rice husk charcoal briquette. Rice husk charcoal briquettes are made in various ratios with nitrocellulose as an accelerant (97:3, 96:4, and 95:5). The NC was characterized using Fourier transform infrared (IR) spectroscopy and thermogravimetric (TG) analysis. 1.0 M of bleached egg carton pulp has the highest cellulose content (86.94%) with the presence of crystalline structure of cellulose at peak 1430 cm-1 after the bleaching process. Meanwhile, different nitration times revealed that 50 min had the highest nitrogen content (7.97%) with a 1.23 degree of substitution (DS) value. Based on its TG analysis, NC 50 has met the requirements for use as an accelerant for briquettes, with an onset temperature of 91.60 °C and a weight loss of 62.60%. Infrared at peak 1640 cm-1 confirmed the presence of NO2 groups in nitrocellulose successfully formed by nitration. After the addition of nitrocellulose, the calorific value of the briquette increased from 13.54% to 15.47%. Fixed carbon and volatile matter showed the same pattern. The combustion of nitrocellulose-briquette has also been demonstrated by Td10% of degradation, which degraded between 310 and 345 °C.

Laser-Activated Organic Bleaching Process as an Environmentally Friendly Clean Alternative to Permanganate Bleaching in Denim Washing

Laser-Activated Organic Bleaching Process as an Environmentally Friendly Clean Alternative to Permanganate Bleaching in Denim Washing

Effect of industrial bleaching on the physicochemical and nutritional quality of non-allergenic lecithin derived from rice bran oil (Oryza sativa L.)

The demand for lecithin has increased due to the need for plant-derived products, its important role in health benefits, and the wide range of industrial applications. However, most studies with lecithin use allergenic sources such as soy and egg yolk. Lecithin can be used in the crude form or modified with chemical by the bleaching process in order to quality proprieties. Therefore, we produced lecithin from a non-allergenic source (rice bran oil) by water degumming and evaluated the physicochemical and nutritional properties of natural and bleached lecithin by addition of hydrogen peroxide in an industrial scale. The physicochemical parameters indicated the quality of 12 lecithin samples. From these, 5 and 2 simples of natural and bleached lecithin, respectively, achieved FAO quality recommendations (acid value < 36 mgNaOH/g; hexane insoluble <0.3%; acetone insoluble from 50 to 60%; peroxide value < 10 meq/kg; and moisture <1%). From the multivariate analysis, it was observed that the bleaching process resulted in the improvement of physicochemical parameters, reduction of moisture and depigmentation of lecithin. Natural lecithin showed a greater tendency to accumulate phospholipids, tocopherols, tocotrienols, palmitic, stearic, and linolenic acids, while bleached lecithin stood out for accumulating γ-oryzanol, δ-tocotrienol, oleic and linoleic acids. In this paper, we suggest that the by-product of rice bran oil is a potential source to produce a non-allergenic, nutritious and safe lecithin, especially when the bleaching process is applied, which can contribute to quality enhancement on an industrial scale.

Study of Chitosan-Stabilized Ti3C2Tx MXene for Ultrasensitive and Interference-Free Detection of Gaseous H2O2.

The development of sensitive, selective, and reliable gaseous hydrogen peroxide (H2O2) sensors operating at room temperature still represents a remaining challenge. In this work, we have investigated and combined the advantageous properties of a two-dimensional Ti3C2Tx MXene material that exhibits a large specific surface area and high surface activity, with favorable conducting and stabilizing properties of chitosan. The MXene-chitosan membrane was deposited on the ferrocyanide-modified screen-printed working carbon electrode, followed by applying poly(acrylic acid) as an electrolyte and accumulation medium for gaseous H2O2. The sensor showed highly sensitive and selective electroanalytical performance for detecting trace concentrations of gaseous H2O2 with a very low detection limit of 4 μg m-3 (4 ppbv), linear response in the studied concentration range of 0.5-30.0 mg m-3, and good reproducibility with an RSD of 1.3%. The applicability of the sensor was demonstrated by point-of-interest detection of gaseous H2O2 during the real hair bleaching process with a 9 and 12% H2O2 solution.

Efficient preparation of high-purity cellulose from moso bamboo by p-toluenesulfonic acid pretreatment

This work proposed a promising biorefinery method for the deconstruction of moso bamboo by using p-toluenesulfonic acid (P-TsOH) pretreatment to product high-purity cellulose (dissolving pulp). The cellulose pulp with high α-cellulose content (82.36 %) was successfully prepared for 60 min at low pretreatment temperature (90 °C) and atmospheric pressure. After the simple bleaching and cold caustic extraction (CCE) processes, the properties of cellulose pulp, such as α-cellulose content, polymerization, ISO brightness, all met the standard of dissolving pulp. In general, the cooking method through P-TsOH pretreatment can shorten the preparation time, which can effectively reduce energy consumption and chemical consumption. Therefore, this work may provide a new perspective for the green preparation of dissolving pulp that can be used to produce lyocell fiber after ash and metal ion treatment.

Extraction and characterization of novel cellulose nanocrystals from Artemisia scoparia straw and their application in hydroxypropyl methyl cellulose (HPMC) films

Abstract This research study reports on the extraction of nanocellulose followed by structural and thermal analysis and application of nanocellulose in hydroxypropyl methyl cellulose (HPMC) nanocomposite films. The cellulose nanocrystals were isolated from Artemisia scoparia straw through an alkaline treatment and bleaching process, followed by sulphuric acid hydrolysis. The HPMC nanocomposite films were prepared by a solution casting method and dried at room temperature. Fourier transform infrared-ray (FTIR) spectroscopy and thermogravimetric analysis (TGA) techniques were used to analyze the structural and thermal properties of the materials, including the cellulosic material, the nanomaterial, and the nanocomposites. The FTIR spectra indicated that the extraction procedure was adequate, demonstrating the removal of lignin and hemicellulose and the preparation of nanocellulose. The TGA results revealed the thermal degradation pattern of the cellulose and showed that the HPMC films had enhanced thermal stability. This research demonstrates that A. scoparia straw has potential for the extraction of cellulosic nanomaterial and a wide range of applications in nanocomposites.

SELULOSA NANOSERAT TANDAN SAWIT SEBAGAI MATRIKS FILM INDIKATOR ALAMI KESEGARAN PANGAN

The food freshness is one trending topic that currently studied to reduce the number of food waste. The development of food freshness film indicator is one technique that can be utilized to resolve the high number of food waste. The objective of this study was to evaluate the ability of cellulose nanofiber film that had been integrated with anthocyanine as the food freshness film indicator. Cellulose nanofiber was obtained from empty fruit bunch of palm oil that had been dried, cut, and milled into fine powder. The initial step of this preparation was bleaching process using NaOCl/NH3 and H2O2/NH3. After bleaching process, cellulose fiber was oxidized using TEMPO/NaOCl/NaBr at pH 10 for 6 h. The TEMPO-oxidized cellulose fiber was then transferred into high pressure-homogenizer for 6-cycles at 800 bar of pressure. The cellulose nanofiber was obtained as hydrated fiber (gel-like) and then combined with anthocyanine obtaining from red cabbage extract, the film was casted on the acrylic plate. The film indicator of cellulose nanofiber was analyzed to determine the characteristic of film, i.e., color stability depending on pH, morphology, mechanical properties, and color response of film on the food freshness. The film of cellulose nanofiber that integrated with anthocyanin extract has the good sensitiveness to test the food freshness at 4oC. The color change produced by this indicator film is quite significant and has a different color at each pH value.

Can Sodium Ascorbate Increase the In Vitro Bond Strength of the Interface between a Composite and Bleached Enamel?

Recently, the use of antioxidants before the bonding of bleached enamel was considered effective for reversing the reduction in the bond strength. This article aimed to assess the influence of different sodium ascorbate (SA) presentations (liquid, gel, and semi-gel) on the composite resin–enamel bond strength after a bleaching protocol. Sound human anterior teeth were collected, cleaned, prepared for a bond strength test, and randomly allocated into groups according to the bonding procedure. Group 1 acted as a control, without bleaching treatment, and without applying an antioxidant agent. In groups 2–6, specimens were bleached using 10% carbamide peroxide. In groups 3, 4 and 5, 10% wt% SA was applied for 10 min as an antioxidant in the form of a liquid, gel, and semi-gel, respectively. In group 6, samples were bleached and immersed in fresh human saliva for 14 days. After the bleaching process, the materials were restored by means of an adhesive system and a resin composite material. The analysis revealed that the differences between the shear bond strength (SBS) between the different groups were statistically significant (p = 0.0469). The highest SBS was achieved for the group where the 10 wt% SA liquid was applied before the bonding procedures. The application of liquid 10 wt% SA might reverse the negative impact that bleaching has on the bond strength of a resin composite and enamel.

Effect of bleaching with different clay on the final composition of post-fermentation corn oil with high content of β-sitosterol

Bleaching of oils is a stage of refining, and for post-fermentation corn oil, it is a novel issue intended to pretreat the corn oil for downstream refining processes. As a result of the completed research, which used a selection of available bleaching clays at 2 g/100g, post-fermentation corn oil with an improved quality was produced. The oil featured a reduced peroxide number and a lower content of carotenoid dyes. The oil after bleaching was found to have increased oxidation stability without any change discovered in the composition of fatty acids. From this research, it was observed that the 5σ-avenasterol levels were reduced, which affected the total phytosterol content and the reduction of oil colour on the Lovibond scale. The colour strength was considerably reduced by the bleaching process, to a level which varied with the specific bleaching clay. The content of the predominant β-sitosterol did not change significantly and remained at 700 mg/100 g. Optimum processing results were achieved by using the Tonsil 4120 AFF bleaching clay with an addition of activated carbon, and using the Supreme 112FF bleaching clay without activated carbon.

Synthesis of cellulose acetate from rice husk cellulose by ultrasound-assisted acetylation

Cellulose acetate is an important product derived from cellulose. Cellulose acetate can be used in a variety of applications including coatings, textile fibers, consumer goods, filtration membranes, composites, laminates, pharmaceutical, and medical items. Rice husk is a lignocellulosic material that contains cellulose and hemicellulose. The aims of this study were to determine the effect of process variables on the cellulose acetate product formation by ultrasound-assisted acetylation using iodine as a catalyst and to characterize the cellulose acetate product. The research was conducted through the delignification, bleaching, acetylation, and characterization processes. The results showed that the optimum yield of cellulose acetate was obtained at the temperature of 60 °C, the reaction time of 50 min, the weight of the catalyst of 10% of cellulose weight, and the ratio of cellulose and acetic anhydride of 1:5 (w/v). The acetylation process using iodine as a catalyst with an ultrasound-assisted method was more effective than the conventional acetylation (acetic acid glacial and sulfuric acid as a catalyst).

Mild Nitric Acid Treatments to Produce Nitrocellulose from Kapok Fiber (Ceiba Pentandra)

Kapok (Ceiba pentandra) is one of the natural fibrous sources with a high content of cellulose. The natural kapok used contains 54.3% of cellulose, 11.3% of hemicellulose, and 19.11% of lignin. Kapok is a potential material to be explored by isolating the fiber, then converting into nitrocellulose. The effect of nitric acid concentration on the nitration process and characterization of material were investigated. Kapok fiber was isolated by delignification and bleaching process. Delignification was done in the presence of 5% (w/v) of NaOH and 30% (v/v) of H2O2 for alkaline and acid hydrothermal treatment, respectively. Kapok was washed until neutral pH and dried in an oven at 100 oC for 4 h to get kapok fiber (CK). For the nitration process, CK 5% (w/w) was added to a solution of 15% (v/v) phosphoric acid and variation of 15%, 20%, and 25% of nitric acid. The mixture was stirred at 10 oC, 300 rpm, for 30 min. The solid CK was separated and poured into hot water for 5 min and continuously washed with demineralized (DI) water and sodium hydrogen carbonate until neutral pH. The nitrocellulose (KN) was produced after the material dried. The smooth surface of fiber and diameter around 14.5-19.1 µm was changed into a plat fiber of 13.3-21.2 µm after hydrothermal treatment. The crystallinity index (CrI) of CK was increased up to 58.17% based on X-Ray Diffraction (XRD) observation. The degree of substitution (DS) was calculated by data spectra of Fourier Transform-Infra Red (FT-IR) analysis of a specific functional group for N-O and C-O stretching vibrations. The DS optimum value was achieved at about 0.885 at concentration of 20% nitric acid (NK20). The synthesis of nitrocellulose kapok fiber-based has potential as a functional material.

Fabrication of Bioethanol via Fermentation from Cellulose of Kepok Banana (Musa Paradisiaca L.) Using Bread's Yeast (Saccharomyces cerevisiae)

Bioethanol has been made by fermentation of the cellulose of Kepok banana stems, where this study went through 3 stages. First-stage isolation of cellulose from Kepok banana prevents using HNO3 and NaNO2, removal of swelling with NaOH and Na2SO3, and bleaching process (bleaching) using NaOCl and H2O2, then functional group analysis was performed with FT-IR. The second stage of cellulose obtained was hydrolysed with 1% HCl for 120 minutes of hydrolysis time. The resulting glucose was analysed by Benedict's reagent and the Luff-Schrool method. The third stage of glucose solution results from fermented hydrolysis using bread yeast (Saccharomyces cerevisiae) with variations in the weight of yeast 5, 6, and 7 grams, and the duration of fermentation is five days. Bioethanol obtained was tested qualitatively using K2CrO7 and H2SO4 reagents and bioethanol characterisation using GC. The study results obtained 10.18% glucose levels, and the highest levels of bioethanol were obtained at 11.27% with 88.53% purity using 7 g of yeast.

Peroxide-Free Bleaching Gel: Effect on the Surface and Mechanical Properties of Nano- and Micro-Hybrid Restorative Composite Materials

This laboratory investigation was designed to test the influence of a novel bleaching formulation based on phthalimidoperoxycaproic acid (PAP) with additives on the surface and mechanical properties of nano- and micro-hybrid restorative composites. Twenty-four bar-shaped and twelve disk-shaped samples from each restorative composite were prepared. The samples from each restorative composite were randomly divided into two groups according to the treatment, i.e., experimental and control. The treated groups went through the bleaching process: by Opalescence Regular or novel PAP+-containing gel (HiSmile™). The treated group underwent a bleaching process for seven consecutive days (a 10-min session of bleaching application every day) before the properties were tested. A paired sample t-test was performed to compare the results between the experimental and the control groups. The level of significance was set at 0.05. The surface roughness of the nanohybrid composite using Opalescence Regular (p &lt; 0.05) was significant. Additionally, a significant difference in nanohardness and elastic modulus between the experimental and the control groups of the microhybrid composite using Opalescence Regular was observed: p = 0.041 and p = 0.023, respectively. While a marked difference in flexural strength was observed in the experimental and control groups using Opalescence Regular, Hismile™ bleaching gel caused a diminutive and insignificant reduction in tested properties (p &gt; 0.05). It was found that Opalescence Regular bleaching gel affects the surface and bulk properties of restorative composite materials, whereas the novel PAP+ formulation has no deleterious effect on either nano- or micro-hybrid restorative composites.

Impact of Toolbox Training on Risk Perceptions in Hazardous Chemical Settings: A Case Study from a Bleach Processing Plant

Impact of Toolbox Training on Risk Perceptions in Hazardous Chemical Settings: A Case Study from a Bleach Processing Plant

Extraction and Characterization of Nanocrystalline Cellulose from Sugar Palm Fibres (Arenga Pinnata)

In this work, cellulose was isolated from sugar palm fibre (Arenga pinnata) and converted into sugar palm fibre nanocrystalline cellulose (NCCs) in the hamlet of Medan Sinembah, Indonesia. Alkalization and bleaching were the stages of the therapy process. The cellulose removed with 30 weight percent concentrated sulfuric acid was then used to isolate NCC. Using Fourier transform infrared spectroscopy (FT-IR), the chemical make-up of sugar palm fibre and NCCs was identified. On the basis of structural analysis, X-ray diffraction (XRD) was used. Scanning electron microscopy (SEM) was used for morphological examination, while transmission electron microscopy (TEM) was used to look into NCCs. The outcomes demonstrated that the extracted cellulose underwent bleaching and alkalization processes, respectively, to eliminate lignin and hemicellulose. The diameters of the sugar palm fibre and NCCs were determined 69.025 µm to 6.07±0.14 nm and, respectively

Bleaching techniques impact on some quality parameters in two different cold‐pressed oils obtained at farm scale

AbstractThe consumption of cold‐pressed oil, such as linseed (Linum usitatissimum L.) and hemp (Cannabis sativa L.) oil has increased recently. In these oils obtained on the farm, a large number of components able to affect oil quality (mainly chlorophylls) are present. Given this, an experiment was conducted with the following aims: (1) to compare different bleaching methods by applying ultrasound waves and earths in cold‐pressed hempseed and linseed oils and (2) to evaluate the effect of different types (acid‐activated and natural) and amount (2% and 4%) of earths with different processing temperatures (60 and 80°C) in hempseed oil, utilizing a bleaching method with earths alone. Regarding the linseed oil, any bleaching methodologies adopted must not include ultrasound treatment, as the high temperatures reached determine high levels of oxidation to the detriment of the oil. Concerning the hemp oil, the natural earths, especially at farm level, should be preferred, because in addition to removing chlorophyll satisfactorily, when used at 4% even at the lowest temperature (60°C), an improvement of the stability and nutritional value (Vit. E) of the oil was observed.Practical applicationsThe use of ultrasound, applied together with bleaching earths, is considered an interesting and efficient bleaching method, in order to remove several pigments able to affect quality of many vegetable oils, with the exception of linseed oil. In fact, the use of ultrasound during the bleaching process determines a high oil temperature (120°C) and this, in an oil such as that of linseed characterized by a very high percentage (&gt; 55%) of α‐linolenic acid, negatively affects the oil stability by the formation of high quantity of primary oxidation products, evidenced by very high peroxide values. In the bleaching activity carried out at farm level in particular, natural earths should be preferred to the acid‐activated ones. The latter, despite demonstrating an effective bleaching efficiency for few specific pigments, could increase the level of free fatty acids, reduce the antioxidant compounds (tocopherols) naturally present, and release undesirable contaminants in the oil.

Jenis dan Konsentrasi Tanah Pengelantang untuk Menurunkan Prekursor Senyawa 3-MCPDE dan GE pada Pemucatan CPO

Refined palm oil contains contaminants such as 3-monochloropropane diol ester (3-MCPDE) and glycidyl ester (GE) which are formed from diacylglycerol (DAG) and chloride (Cl) as precursors during processing. There is a need to control the levels of precursors especially during the bleaching stage using selected bleaching earth (BE). Reducing the number of precursors after the bleaching stage will minimize the formation of 3-MCPDE and GE in bleached palm oil (BPO) for the next refinery stage. The research consisted of three stages: (1) characterization of raw materials consisting of CPO, BE types 1, 2, 3, 4, and 5; (2) study on the effect of BE type; and (3) study on the concentration effect of selected BE for reducing DAG and Cl by chemical analysis of oil quality. The results showed that degummed palm oil (DPO) contained DAG of 6.70%, free fatty acid 5.66%, carotene 424.31 mg/kg, P 20.30 mg/kg, and Fe &lt;0.021 mg/kg. The five types of BE have different physicochemical properties on which the effect will be seen on BPO. The second stage results showed that BE-4 was selected as the most potential BE. Using BE-4 of 2.5% was proven to reduce total Cl as 3-MCPDE precursors in the resulted BPO sample. The Cl level decreased to 3.05 mg/kg with the largest decrease percentage of 55.80% compared to DPO sample. BE-4 concentration of 2.5% has been able to withstand and prevent the increase of DAG as a precursor to GE contaminants during bleaching process.&#x0D; &#x0D; Keywords: 3-monokloropropanadiol ester, chloride, diacylglycerol, glycidyl ester, palm oil

Microbial xylanase aided biobleaching effect on multiple components of lignocelluloses biomass based pulp and paper: a review

Abstract Due to discharge of hazardous organochlorine compounds and absorbable organic halogen compounds in the effluent, the pulp and paper industries are trying to alter the bleaching process to limit the use of chlorine compounds and comply with regulatory, environmental, and market demands. With progress in biotechnology, enzyme technologies can effectively pre-treat lignocellulosic biomass in the pulp and paper making process. Usually, these enzymatic processes reduce the environmental impact of traditional pulp and paper-making processes, lower the overall production cost, and enhance product quality. Microbial xylanases are the potential bio-bleaching candidate due to their renewable, mild operating, highly specific, and eco-friendly nature. Xylanase enhances the efficacy of the bleaching process by breaking the β-1, 4-glycosidic backbone of the re-precipitated xylan network and removing the trapped lignin from the pulp fibers. Xylanolytic action positively influences the kappa number, hexenuronic acid, chromophore compounds release, pulp crystallinity, morphology and many other attributes of pulp. The present review comprehensively highlights the microbial xylanolytic system, its mechanism, and its application in pulp bioleaching. With the recent development, the paper delineates the xylanase-aided bleaching effects on pulp, paper, and effluent attributes aimed to reduce bleaching chemical use, AOX formation, and energy use in the pulp refining process.

The Effects of Office Bleaching Techniques on Nanoceramic Composite Resin

Objective: The aim was to evaluate the effect of activated bleaching agents on the nanoceramic composite resins based on microhardness and surface roughness measurements. Methods: Opalescence Boost (Ultradent Products, USA) and Whiteness HP Blue Calcium (FGM Dental Products, Brazil) bleaching agents and a nanoceramic composite resin Ceram.X® SphereTEC™ One (DENTSPLY, Germany) were used in the study. Fifty composite samples in disc form (8x2mm) were prepared. The samples were polished with discs (Sof-Lex, 3M Dental Products, St.Paul, USA) and incubated in the dark in distilled water. Samples were divided into 5 main groups (n=10). Control group (C), Opalescence Boost/ without light (OB), Opalescence Boost/ with light (OBL), Whiteness HP Blue/ without light (WB), and Whiteness HP Blue/ with light (WBL). Surface roughness (Ra) and Vickers microhardness (VHN) measurements were conducted after the bleaching process. Statistical analyses were performed using the Kruskal Wallis – H test and the Mann Whitney – U test; a p value of &lt; 0.05 was considered statistically significant. Result: The VHN was significantly different among groups in terms of the application of bleaching agents and light (p = 0.008). The Ra was not significantly different among groups with respect to the application of bleaching agents or lighting conditions (p = 0.144). Conclusion: Within the conditions of this study, after bleaching procedure the microhardness values of the nanoceramic composite increased, however bleaching did not show any effect on surface roughness.