Sodium Chlorite Concentration Research Articles

Application of response surface and artificial neural network optimization approaches for exploring methylene blue adsorption using luffa fiber treated with sodium chlorite

Wastewater often laden with colored impurities, presents a substantial environmental contamination risk, necessitating the exploration of effective pollutant removal methods. Clay particles have emerged as promising adsorbents for this purpose. This study delves into the intricacies of methylene blue removal in a dilute environment, utilizing pre-treated luffa fiber with sodium chlorite to eliminate the reactive pigment from aqueous solutions. The adsorption optimization is achieved by applying both response surface methodology (RSM) and an artificial neural network (ANN) architecture. The investigation focuses on four key parameters—sodium chlorite concentration, activation time, temperature, and their combined impact on methylene blue adsorption. Descriptive statistics discern optimal operational conditions for efficiently extracting methylene blue from sewage water solutions. Notably, the ANN models exhibit exceptional optimization accuracy, yielding a remarkable adsorption capacity of 133.58 mg/g. This surpasses the experimental (124.36 mg/g) and RSM (126.97 mg/g) values, indicating a 6.90 % improvement over experimental results and a 4.94 % increase over RSM outcomes. These findings underscore the high efficiency of the adsorption process, positioning it as a promising method for effectively removing ionic anthocyanin contaminants in sewage water treatment.

DELIGNIFICATION PRETREATMENT OF ACANTHOSPERMUM HISPIDUM BIOMASS FOR BIOETHANOL PRODUCTION

Bioethanol from lignocellulosic biomass is environmentally friendly and a renewable source of energy. This study used delignification as a pretreatment process to obtain the optimum conditions for reducing sugar production. The selected delignification parameters, including temperature (oc), time(hours) sodium chlorite concentration (g/dm3) and Volume of acetic acid (cm3). The Optimum conditions for delignification were: 70oc, 6 hr at -0.1 g/ dm3 sodium chlorite concentration and acid-3 cm3 of acetic. The R2 value obtained from the correlation between reducing sugar concentration and time was R2 =0.796 The maximum bioethanol concentration was at 66h and the bioethanol productivity was 0.0304 g/L/h. The result obtain pointed that, the Acanthospermum hispidum can be used for both economic and environmental footprint studies and real world application.

Microcrystalline Cellulose from Jute Fiber: A Bright Prospect for Pharmaceutical Industry

Synthesis of microcrystalline cellulose (MCC) from jute sticks has been studied and reported in this work. The successful removal of lignin and hemi-cellulose has been confirmed through Fourier Transform Infrared (FTIR) spectroscopic technique. X-ray Diffraction (XRD) technique has been used to measure the crystal size and crystallinity index. The FTIR analysis revealed that the acid hydrolysis had an effect on the crystalline of the fibre; however it did not influence the chemical components of the fibres. Pharmaceutical standard tests were done. Higher concentration of sodium chlorite produces minimum particle size and the effective thermal degradation occurs at 340 °C.

Wet processing of agro-residual fibres for potential application in fancy décor items

ABSTRACT This research compares the change of physical and chemical properties of three types of agro-residual (AgR) fibres namely banana plant stem fibre (BSF), pineapple leaf fibre (PALF) and corn husk fibre (CHF) by wet processing steps: scouring, bleaching and dyeing. Bleaching operation was performed using mild sodium chlorite concentration. The percentage of lignin and hemicelluloses were remarkably declined and densities of the fibres were increased. The highest amount of α-cellulose is found 88.7% for bleached BSF, followed by bleached PALF (78.4%) and bleached CHF (70.1%). The morphology changes of the fibres due to bleaching were clearly detected by FTIR spectroscopy. The bleached fibres were dyed with two different types of reactive dyes viz. Reactive Orange 2 R-XF and Reactive Blue F-R by conventional dyeing technique. The absorption of dyes was tested by UV-vis spectroscopy. It was seen that the dye absorption percentage of all types of fibre are not equal. The dye absorption was also diverged in the case of two reactive dyes. Colour fastness properties of dyed fibres were tested under sunlight, wash and reagent spot tests. All the dyed fibres were exhibited excellent colour fastness properties. Reactive Orange 2 R-XF showed better fastness property than Reactive Blue F-R in every investigation.

Synthesis and characterization of microcrystalline cellulose from jute stick

Synthesis of microcrystalline cellulose from jute sticks has been studied and reported in this work. The successful removal of lignin and hemicellulose has been confirmed through Fourier Transform Infra-red spectroscopic technique, whereas WAXD technique has been used to measure the crystal size and crystallinity index. Scanning electron microscopic images depict the porous structure and agglomerate fibrous shape with hierarchical assembly of the microcrystalline cellulose produced. Higher concentration of sodium chlorite produces minimum particle size and the effective thermal degradation occurs at 340 °C. It shows negative zeta potential value, indicating the possible agglomerating tendency of the particles in water medium.

Isolation and characterisation of cellulose from cortex, pith and whole of the Pennisetum purpureum: Effect of sodium hydroxide concentration

In this study, the potential of cellulose isolation from the cortex, pith, and whole of the Pennisetum purpureum stem was explored. The cellulose was extracted using 4, 8, 12, 16, and 20% concentration of alkali followed by 1.7% concentration of sodium chlorite. The cortex and pith of Pennisetum purpureum were separated using a water retting process. The thermogravimetric analysis, Fourier transform infrared spectroscopy, X-ray diffraction, and scanning electron microscopy were used to examine the thermal behaviour, composition, crystallinity, and morphological observation, respectively. The alkali treatment improved the cellulose characteristics due to the reduction of non-cellulosic materials from the cortex and pith of Pennisetum purpureum. From thermogravimetric analysis, the residues of the 8% alkali treatment for the cellulose of cortex, pith and whole of Pennisetum purpureum stems were 51.6, 61.8, and 66.45% respectively of moisture content, cellulose, hemicellulose, and lignin. The lattice transformed from cellulose I to cellulose II with concentrations of alkali treatment that exceeded 8%. Treatment with 8% alkali concentration for cellulose from the cortex produces 76.47% for the crystallinity index, which is a higher value compared to cellulose from the pith of Pennisetum purpureum.

A comparative study of hemicellulose isolation with hot water, alkaline, and delignification methods from tea leaf brewing waste

Tea leaf brewing waste (TLBW) is a waste with high hemicellulose content. It is a valuable waste of the pharmaceutical and cosmetics industry especially the beverage industry. In this study, the extraction of hemicelluloses (HC) from tea leaf brewing waste using three different pretreatment methods were investigated. The isolation yield of the HC was determined depending on pretreatment methods and pretreatment parameters such as the isolation temperature (25–55 °C), alkaline concentration (NaOH, 5–20%), contact time (12–24 h), the oxidative component (H2O2), and the concentration of sodium chlorite (NaCIO2) in the solution (2–10%). It was observed that the yield of isolation of hemicellulose varied between about 1 and 36% on the basis of raw materials depending on the extraction parameters. The experimental results showed that the suitable conditions for isolation of hemicellulose by alkaline pretreatment method were 15% NaOH concentration, 12-h contact time, and 45 °C. As a result of the experiments performed with the most suitable conditions, approximately 96% of the total hemicellulose in the TLBW was isolated. The extraction yield of hemicellulose achieved by the delignification process was found to be lower about 3% compared with the alkaline methods. But, the hemicellulose color achieved by the delignification process was lighter in color than the alkaline method. The results of the FTIR and H-NMR analysis show that the purity of the hemicellulosic fraction, which was obtained using the delignification method, was higher than the alkaline method.

Synthesis of Microcrystalline Cellulose from Carpenter Waste and Its Characterizations

ABSTRACT Carpenter waste has been used as a raw material for synthesizing microcrystalline cellulose through various chemical pre-treatment process sequences. Carpenter waste treated with 10% (w/v) sodium hydroxide followed by various concentration of sodium chlorite (0.5%, 0.7%, and 1.0%) treatment has resulted in substantial loss in weight. The synthesized microcrystalline cellulose has been characterized by different instrumental analysis. FT-IR data showed the successful removal of hemicellulose and lignin from the carpenter waste after various chemical treatments. Wide-angle X-ray diffraction analysis is done to measure the crystallinity index and crystal size of the synthesized microcrystalline cellulose. The microcrystalline cellulose produced under different concentrations of sodium chlorite exhibits crystallinity index in the range of 67.56 to 68.85 and calculated average crystal size within the range of 6.47–6.60 nm. The calculated average particle size of microcrystalline cellulose ranges from 96.42 to 437.83 nm depending on the treatment conditions. Higher concentration of sodium chlorite treatment has led to lowering the particle size. Scanning Electron Microscopic image of microcrystalline cellulose shows curled and soft-flat shaped with rough pits and fibrillated network structure. Field Emission Scanning Electron Microscopic analysis reveals the cylindrical rod-shaped morphology and porous structure of the synthesized microcrystalline cellulose from carpenter waste.

Synthesis and Characterization of Microcrystalline Cellulose from Rice Husk

Rice husk was used as a raw material for synthesizing microcrystalline cellulose (MCC) through mechanical and chemical pre-treatment process. Sodium hydroxide treatment (10%) followed by varying concentration of sodium chlorite (0.5%, 0.7%, 1%) treatment has resulted in substantial weight loss. The synthesized MCC was characterized through different instrumental analyses. ATR-IR spectroscopic analysis showed the successful removal of hemicellulose and lignin. Crystallinity index and crystal size were measured through powder XRD technique and was found to be 64.74% and 6.86 nm, respectively. SEM images indicated the average particle size, shape and porosity of MCC. Higher concentration of sodium chlorite treatment has led to minimum particle size, which is confirmed via DLS technique. The onset of thermal degradation of MCC from rice husk was around 340 °C.

Removal of NOX from diesel engine exhaust by using different chemical absorbent in a lab-scale packed column system

Emissions of NOX from automobile causes various environmental impacts. In order to satisfy the emission norms and standards, it is necessary to reduce the toxic gases from emission. This paper concentrates on designing a packed column and analysis on the selection of an effective absorbent to reduce NOX emission from diesel engines. NOX emission is taken from the exhaust of diesel engine (Kirloskar TV1 Diesel engine). Flue gas inlet to the packed column and the treated gas at the outlet of the packed column are measured using NOX inlet and outlet gas sensors, respectively. Absorbent flow is carried out in a lab-scale packed column experimental setup. Various parameters of the packed column such as liquid: gas ratio, diameter, total height and packing height are determined based on the mathematical modeling. The NOX emission was experimentally measured with various combinations of different absorbents with different flow rate. Based on the experiments, effective absorbents are chosen as NaClO2 and NaOH. Experimental results show chemical absorbent combination with 0.5 M concentration of sodium chlorite and 0.3 M concentration of sodium hydroxide at 80% data acquisition card opening condition is absorbing NOX effectively.

NOx removal in a rotating packed bed: Oxidation and enhanced absorption process optimization

In view of the continuously stringent standard of nitrogen oxides (NOx) emissions, developing new technologies for NOx removal or updating the existing NOx removal system is very urgent. This work introduces a novel technology for NOx removal in an RPB reactor by the combination of oxidation and enhanced absorption. Experimental results show that a rotating packed bed (RPB) reactor, having high gas-liquid mass transfer efficiency, is a more appropriate choice for NOx removal. Then a series system combining firstly a stirred tank reactor (STR) and secondly an RPB reactor, has been developed in order to oxidize more NO to NO2 that is very soluble and enhances the subsequent absorption in the RPB reactor. The higher oxidation degree (~99%) was achieved with a sodium chlorite concentration of 0.10 mol L−1 and a liquid volume of 5.0 L in the STR. An absorbent containing sulfonated cobalt phthalocyanine (CoPcS) was employed in the RPB reactor to meet the demand of very efficient denitrification for a long-term running. Compared to the traditional urea/sodium chlorite composite absorbent in a single RPB system, the total NOx removal efficiency increased by approximately 30% through the absorbent containing CoPcS in a series system under the optimized conditions.

Simultaneous Removal of SO2 and NOX by a Combination of Red Mud and Coal Mine Drainage

Simultaneous removal of sulfur dioxide (SO2) and nitrogen oxides (NOX) is an important research field in air pollution control. The combination application of red mud (RM) with coal mine drainage as absorbent in simultaneous desulfurization and denitrification is an innovative attempt. In this study, a series of bubbling and spray tower tests were conducted to improve desulfurization and denitration abilities. Effects of RM concentration, gas flow, liquid–gas ratio, and SO2 concentration were investigated in the test. Our results indicated that SO2 removal efficiency depends primarily on RM concentration, gas flow, and the liquid–gas ratio. In the denitration test, the denitration characteristics of the absorbent were not consistent with industrial requirements, but denitration ability could be improved by the addition of an oxidant. In addition, influence of interactions between SO2 and NOX was observed, and low concentrations of SO2 could enhance NOX absorption, whereas high SO2 concentrations inhibit NOX absorption. Meanwhile, NOX concentration has a negligible effect on SO2 removal. Under optimized conditions, such as with RM concentration of 12%, gas flow of 40 L/min, liquid–gas ratio of 20 L/m3, absorbent renewal rate of 15%, and a sodium chlorite concentration of 1.9%, desulfurization efficiency is >99.0%, and denitration efficiency ranges from 45.0% to 47.0%. RM and mine water slurry show strong potential as a novel absorbent for the simultaneous removal of SO2 and NOX. This study provides a potential feasible technology for reusing RM and coal mine drainage with low cost instead of conventional method.

Preparation and characterization of lotus fibers from lotus stems

Lotus stems were treated with sodium hydroxide followed by sodium chlorite to prepare lotus fibers. The lotus fibers were characterized by scanning electron microscopy (SEM), Fourier transform infrared spectrometry (FTIR), X-ray diffraction (XRD), and thermogravimetric (TG) analysis. The crystallinity and crystallinity index of lotus fibers are 62.11 and 62.29%, respectively. The content of cellulose in lotus fibers after being purified with sodium chlorite is improved and reaches 69.74%. The moisture regain of lotus fibers was studied and the results show that moisture regain of purified lotus fibers is 6.87%. The influences of concentration of sodium chlorite on tensile strength and breaking elongation of lotus fibers were investigated. The tensile strength and breaking elongation of lotus fibers both decrease as the concentration of sodium chlorite increases. The results are expected to provide valuable guidance for preparing lotus fibers from lotus stems through chemical treatment.

Enhanced bactericidal action of acidified sodium chlorite caused by the saturation of reactants.

Factors affecting the antibacterial action of acidified sodium chlorite (ASC), a widely used disinfectant, have not been determined. This study investigated the significant factors suggesting efficient production method to maximize bactericidal action of ASC. The effects of (i) preparation procedures (total three methods); (ii) initial concentrations of reactants: sodium chlorite (SC) and citric acid (CTA) (up to maximum solubility of each reactant) and (iii) final pH values (3·0 and 2·5) to the bactericidal action of ASC were investigated with a fixed final concentration of SC (10 ppm) using various foodborne pathogens (Escherichia coli O157:H7, Listeria monocytogenes, Salmonella Typhimurium and Staphylococcus aureus). The antimicrobial compounds produced and the bactericidal effects depended on the preparation procedure and the initial concentrations of the reactants. The ASC prepared by premixing highly concentrated reactants (in particular > 40%) followed by dilution (dilution after reaction, DAR) was more effective in inactivating foodborne pathogens, and it produced higher antimicrobial compound (Cl(2) and ClO(2)) yields than the other procedures. A 5-min treatment with ASC, produced using the other procedures, resulted in a reduction of < 3·5 log CFU ml(-1) (Gram positive = 0·18-0·78; Gram negative = 0·03-3·49 log CFU ml(-1)), whereas ASC produced with the DAR procedure using the saturated reactants completely inactivated all of the test pathogens within 5 min without recovery (initial concentration = 6·94-7·08 log CFU ml(-1)). The ASC production with the DAR procedure using the saturated reactants maximizes both the antimicrobial compound yields and bactericidal effects of the ASC solutions. This study will contribute to increase the efficiency of ASC treatments for disinfections reducing the effective SC concentrations for industrial use.

Graft copolymerization of glycidyl methacrylate onto delignified kenaf fibers through pre-irradiation technique

Glycidyl methacrylate grafted kenaf (GMA-g-Kenaf) was prepared by pre-irradiation grafting technique. Kenaf fibers were treated with different concentration of sodium chlorite solution before used as trunk polymer. Treated kenaf fibers were irradiated by electron beam followed by grafting reaction in GMA/water emulsion system. The degree of grafting was determined as a function of absorbed dose, reaction time, reaction temperature and concentration of monomer. The results showed that the lignin content was decreased from 14.3% to as low as 3.3% with the increased of sodium chlorite concentration. This was evidenced by SEM pictures which show the surface of treated kenaf fibers was cleaner and smoother compared to that of untreated one. The degree of grafting increased with the increase of absorbed dose, reaction temperature, reaction time and monomer concentration as well as with decreasing lignin content. Formation of graft copolymer was confirmed with SEM, FTIR analysis. The structural investigation by XRD showed that degree of crystallinity of graft copolymers decreased with the increase in degree of grafting.

Amine salts-activated systems for one-step bleaching of cotton fabrics

In this paper triethanolamine salt-catalyzed sodium chlorite bleaching system was used to bleach plain weave cotton fabric in one step. Different triethanolamine salts, including those derived from organic acids and mineral acids were tried for activating sodium chlorite decomposition during the bleaching reaction. All bleaching trials were carried out keeping fixed sodium chlorite concentration. The concentration of triethanolamine hydrochloride, as an example for the triethanolamine salts was varied to show the effect of the activator concentration on the final fabric degree of whiteness. The optimum triethanolamine hydrochloride concentration, required for activating sodium chlorite decomposition was found to be 10mmol/l and based on that, this concentration was applied for other organic and inorganic triethanolamine salts to show the effect of nature of the activator on the final degree of whiteness. The results showed that salts prepared using mineral acids have activation potential better than those prepared using organic acids.

Sodium chlorite–iodine–methyl acetoacetate oscillatory reaction investigated by UV–vis spectrophotometric method

A new sodium chlorite–iodine–methyl acetoacetate chemical oscillatory reaction was studied using UV–vis spectrophotometric method. The initial concentrations of methyl acetoacetate, sodium chlorite, iodine, sulfuric acid, and the pH value have great influence on the oscillation observed at wavelength of 585 nm. There is a pre-oscillatory or induction period; the amplitude and the number of oscillations are associated with the initial concentration of reactants. The equations for the I3−–starch complex reaction rate changing with reaction time and the initial concentrations in the oscillation stage were obtained. The time of induction period decreases with the initial concentration of methyl acetoacetate or sulfuric acid, and increases with the initial concentration of sodium chlorite. A good linear relationship exists. Oscillatory reaction can be accelerated by increasing temperature. The apparent activation energies in terms of the induction period and the oscillation period were 114.28 and 64.92 kJ/mol, respectively. It may indicate that the two stages have different reaction mechanisms. The reaction of producing enol isomer by keto-enol tautomerism is an important step to constrain the time of induction period.

An effective redox system for bleaching cotton cellulose

An effective sodium chlorite/potassium permanganate bleaching system was used to bleach cotton fabric without severe loss in the fabric's mechanical properties. The bleaching process based on depositing MnIII on the fabric surface followed by treating the fabric with sodium chlorite solution. Parameters governing the bleaching efficiency, like potassium permanganate concentration, sodium chlorite concentration and bleaching bath temperature were studied. The bleached fabrics were fully characterized by measuring their whiteness index, carboxyl and carbonyl contents, percent loss in fabric weight and tensile strength. The obtained results reveal that bleached cotton fabric with satisfactory whiteness index and reasonable tensile strength can be obtained by soaking the fabric, at 50°C in potassium permanganate solution (0.01N), using material to liquor ratio of 1:10. The fabric is then rinsed with distilled water, squeezed and introduced to bleaching bath containing 5g/l sodium chlorite and 1g/l non-ionic wetting agent using a material to liquor ratio of 1:10.

Simple and economic bleaching process for cotton fabric

Cotton fabric was bleached in a simple and economic process using a bleaching system composed of sodium chlorite and hexamethylenetetramine. Different bleaching trials were carried out keeping fixed sodium chlorite concentration and varying other reaction conditions. The obtained results reveal that bleached cotton fabric with satisfactory whiteness index and reasonable tensile strength can be obtained by treating the fabric at 95°C in a bleaching bath containing 5g/l sodium chlorite, 0.02g/l hexamethylenetetramine and 1g/l non-ionic wetting agent using a material to liquor ratio of 1:30. These optimum conditions lead to completion of the bleaching process in a reasonable duration of 2h with minimum evolution of harmful chlorine dioxide gas. Lower concentrations of the activator hexamethylenetetramine were found to prolong the bleaching duration without getting satisfactory whiteness index. Higher concentrations of the activator were found to cause fast sodium chlorite decomposition without imparting bleaching effect to the fabric.

Study on Simultaneous Removal of NOx and SO2 with NaClO2 in a Novel Swirl Wet System

This work attempts to utilize sodium chlorite to clean up NOx and SO2 gases simultaneously from flue gas in a novel swirl scrubber system. Experiments were carried out to evaluate the effects of various operating parameters such as initial SO2 concentration, scrubbing medium pH, sodium chlorite concentration, and liquid and gas volumetric flow rates at 35 °C. In addition, reaction mechanisms of simultaneous denitrification and desulfurization using sodium chlorite in acidic and basic solutions are proposed. Complete oxidation of NO into NO2 occurred using 0.2 M sodium chlorite solution as the scrubbing medium. Complete (100%) SO2 and 81% NOx removal efficiencies were achieved under optimized conditions. The NOx removal increased with decreasing pH. Input SO2 enhanced the NOx absorption. The effect of the SO2 concentration on NOx removal was more intense at higher pH values. Using sodium chlorite as the scrubbing medium in the novel swirl scrubber was found to be quite promising for the simultaneous remova...