Bleached Effluent Research Articles

New method for isolating β-sitosterol from bleaching effluent of sulphite pulp mill

β-sitosterol (BS) is a phytosterol with wide potential in cosmeceutical, biomedical and food applications. In acid sulphite pulp cooking, BS and its derivatives are considered an underutilized natural source of bioactive compounds, which are adsorbed on the resulting pulp or dispersed in the spent liquor. In this work, a new method for the isolation of BS from alkaline extract (AE) of unbleached sulphite pulp purification stage is proposed. BS was recovered by two-step acidification of AE up to pH 3 under pre-selected conditions, followed by fractionation of the formed precipitate with water-miscible organic solvents, having obtained best results (>90% of BS purity; yield of 70–210 mg/dm3 of AE) with methanol fractionation followed by BS crystallization induced via addition of water (ca. 10% vol.). When ethanol was used instead, BS was detected in low amounts in the isolate, being fatty acid sterol esters and fatty acid glycerides the major components, as revealed from analyses by wet chemistry coupled with gas chromatography-mass spectrometry and thin layer chromatography (TLC). The method is adaptable for large-scale industrial production of BS and may represent an important source of sterol-based products.

A Comprehensive Review on Pulp and Paper Industries Wastewater Treatment Advances

The pulp and paper industry generates vast amounts of wastewater, and its character heavily depends on various factors (raw material, the undertaken process, the final product, etc.). The wastewater from this sector, which originates from several sources in each mill and are mostly combined, is polluting and hazardous. This paper presents a state-of-the-art review of the physical, chemical, biological, and advanced hybrid treatment techniques, concerning their effectiveness in removing specific pollutants, namely, chemical oxygen demand, lignin, color, and adsorbable organo-halogens. Throughout the manuscript, at the end of each section, a conclusive comparison has been presented and the proper method is introduced. Furthermore, numeric data regarding the effectiveness of each technique toward each pollutant are gathered from the literature and are available in the Supporting Information of the paper. Biological treatment processes using anaerobic–aerobic treatment mostly cure organic biodegradable contaminants (75–90% COD removal). Moreover, biological treatment using a consortium of microorganisms can potentially increase color removal efficiency (from 65 to 97%). Hybrid treatment is also among the candidates for color removal. To treat complex matters (lignin and AOX), physical and chemical treatments have shown promising performance, but they are generally expensive and impractical to treat huge amounts of wastewater. For the treatment of high molecular weight contaminants (lignin) advanced oxidation processes (AOPs), including ozonation and Fenton-based treatment, have shown great performance (90–99%); however, they are limited due to their maintenance and operation costs. To overcome these challenges, source separation of the wastewater streams in the pulp and paper industry is recommended. AOPs or membrane technologies or hybrid processes are suggested for the bleaching effluent (80% AOX removal), which is relatively low in amount, and a combination of conventional treatment processes would be preferred to treat wastewater streams that are more biodegradable. The biological performance can also be enhanced using granular activated carbon on the sequence. Finally, for treating black liquor, adsorption processes have proven to be the prime candidate.

Synergy of adsorption-photocatalysis and enriched surface oxygen vacancies over lignin-biochar/Bi2MoO6 nanocomposites for organic pollutant removal and bamboo ECF bleaching effluent treatment

LC/Bi 2 MoO 6 composites were successfully fabricated and applied to the effective degradation of methylene blue (MB) under visible light illumination. The composition, morphology and photoelectrochemical properties of prepared samples were characterized by various techniques. EPR analysis reveals that the density of surface oxygen vacancies was enhanced after lignin-biochar addition. Under optimal conditions, the degradation efficiency of MB over LC/Bi 2 MoO 6 was 95.34 % at 1 h under visible light irradiation, and the reaction rate constant ( k ) was 18.96 folds higher than that of pristine Bi 2 MoO 6 . The enhanced photocatalytic performance of LC/Bi 2 MoO 6 was due to the synergistic effect between adsorption-photocatalysis and enriched surface oxygen vacancies, which greatly promotes the separation of photogenerated charge carriers. Moreover, the MB degradation removal with LC/Bi 2 MoO 6 decreased by 3.84 % at 1 h under visible light irradiation after four cycles, illustrating excellent stability and reusability in the photocatalytic recycling process. Notably, the bandgap of Bi 2 MoO 6 decreased from 2.66 eV to 2.26 eV with the addition of lignin-biochar. Radical capture experiment and ESR characterization demonstrate that •OH radicals were the main active radical in the photocatalytic process, which increases the radical concentration during the combination of lignin-biochar. Furthermore, the LC/Bi 2 MoO 6 composites were also applied to the degradation of bamboo ECF bleaching effluent, with a higher COD Cr and AOX removal of 75.72 % and 69.64 %, respectively. Herein, this work provides a novel insight for constructing economic and efficient photocatalysts for wastewater remediation and biomass utilization. • A novel LC/Bi 2 MoO 6 composites with enriched oxygen vacancies was prepared. • LC/Bi 2 MoO 6 composites exhibits superior adsorption and visible-light photocatalytic activity for MB and bamboo ECF bleaching effluent degradation. • The photocatalytic mechanism of LC/Bi 2 MoO 6 was proposed.

Determination of kinetic constants on thermophilic aerobic wastewater treatment of Kraft bleaching cellulose effluent

Recalcitrant compounds found in pulp and paper mill effluents, which are usually generated at high temperatures, have shown the potential for thermophilic treatment. Using bleached kraft pulp mill effluents, this study aims to evaluate the acclimation conditions of mesophilic aerobic sludge to thermophilic conditions and determine the kinetic parameters. Two feeding strategies were used for this purpose: in the first approach, the first reactor R1 was fed with bleached kraft pulp effluent, while in the second strategy the reactor R2 was fed with easily biodegradable synthetic effluent and then the gradual substitution for bleached effluent was performed after sludge acclimation to a thermophilic environment. Both reactors were operated in batch at 55ºC. The second strategy has a slight advantage in COD (chemical oxygen demand) degradation and a considerable higher biomass production. The kinetic parameters (KS, µmax, Y, Kd) for both approaches were obtained using the Monod model. Those values indicated that the approach used for reactor R2 provided higher reaction speed.

Effects of the Preferential Oxidation of Phenolic Lignin Using Chlorine Dioxide on Pulp Bleaching Efficiency.

Chlorine dioxide is widely used for pulp bleaching because of its high delignification selectivity. However, efficient and clean chlorine dioxide bleaching is limited by the complexity of the lignin structure. Herein, the oxidation reactions of phenolic (vanillyl alcohol) and non-phenolic (veratryl alcohol) lignin model species were modulated using chlorine dioxide. The effects of chlorine dioxide concentration, reaction temperature, and reaction time on the consumption rate of the model species were also investigated. The optimal consumption rate for the phenolic species was obtained at a chlorine dioxide concentration of 30 mmol·L-1, a reaction temperature of 40 °C, and a reaction time of 10 min, resulting in the consumption of 96.3% of vanillyl alcohol. Its consumption remained essentially unchanged compared with that of traditional chlorine dioxide oxidation. However, the consumption rate of veratryl alcohol was significantly reduced from 78.0% to 17.3%. Additionally, the production of chlorobenzene via the chlorine dioxide oxidation of veratryl alcohol was inhibited. The structural changes in lignin before and after different treatments were analyzed. The overall structure of lignin remained stable during the optimization of the chlorine dioxide oxidation treatment. The signal intensities of several phenolic units were reduced. The effects of the selective oxidation of lignin by chlorine dioxide on the pulp properties were analyzed. Pulp viscosity significantly increased owing to the preferential oxidation of phenolic lignin by chlorine dioxide. The pollution load of bleached effluent was considerably reduced at similar pulp brightness levels. This study provides a new approach to chlorine dioxide bleaching. An efficient and clean bleaching process of the pulp was developed.

Effect of sub lethal concentrations of textile bleaching effluent in the total protein content in the fish, Cyprinus carpio

Proteins can be expected to be involved in the compensatory mechanism of stressed organisms. Toxic effect of treated textile bleaching effluent on the fish Cyprinus carpiowas assessed. Alteration in the protein content in muscle, liver, gill and intestine was determined after exposure to sublethal concentrations of the effluent for a period of 28 days. Data showed that total protein content was decreased in all test tissues compared to control. Results indicated the toxic nature of the effluent.

Alteration of lipid content in the fresh water carp, Cyprinus carpio under the toxic stress of industrial effluent

Contamination of aquatic ecosystems by industrial effluents causes harmful effects on health, growth, survival of aquatic animals like fishes which serves as a useful model for assessing the effect of chemicals mixed in the aquatic environment. Present study investigated the effect of sub-lethal concentrations (1.5%, 2 and 2.5%) of the treated textile bleaching effluent on the total lipid content in muscle, gill, liver and intestine of Cyprinus carpioafter exposure to 28 days. A significant decrement in total lipid content suggested that lipid might have utilized for the energy demand under the condition of stress.

EFFECT OF RECYCLING OF ELEMENTAL CHLORINE FREE BLEACHING EFFLUENT TREATED BY ELECTROCOAGULATION ON PAPER PROPERTIES

This study aimed to determine the effect of recycling elemental chlorine free (ECF) bleaching effluent (D0EpD1 and OD0EpD1) after treatment through electrocoagulation under optimum conditions on paper properties. The effect of pH, current density, time and dose of electrolyte on the reduction of chemical oxygen demand (COD) and color was studied. Maximum decrease in COD and color was found under optimum conditions (i.e., pH 7, treatment time of 30 min, current density of 29.16 mA/cm2, and 1 g/L NaCl). Under these optimum conditions, the reduction in COD and color was of 79.9% and 99.10%, respectively. The reduction in the strength properties of paper, caused by recycling, was found to be insignificant, but a decline of 2.11% for D0EpD1 and of 1.43% for OD0EpD1 in brightness was found. Using the electrocoagulation method to treat the bleaching effluent can prove to have valuable potential towards wastewater utilization, pollution control, and sustainable development of the industry.

Eco-friendly bleaching of sugarcane bagasse with crude xylanase and pectinase enzymes to reduce the bleaching effluent toxicity.

Bio-bleaching effect on bagasse pulp using xylano-pectinolytic enzymes produced by a bacterial species was studied in order to evaluate the potential of these enzymes in paper industry. In this study, action of enzymes was maximum with xylanase/pectinase dose 7/1.75 IU/g, pulp consistency 1:12.5 g/L, pH 8.5, temperature 50° C and 180 min of treatment time. Under the optimized bio-bleaching conditions, removal of reducing sugars (6.15±0.05 mg/L), brightness (16.08%), whiteness (25.54%) and release of chromophores (hydrophobic and phenolic compounds and lignin impurities) were maximum, along with decrease in kappa number (26.28%), and yellowness (27.88%) values were obtained. Improvement in the various physical properties like breaking length (10.28%), burst index (29.55%), tear index (5.02%), double fold (14.89%), Gurley porosity (15%) and viscosity (8.6%), along with the reduction of chlorine dioxide dose by 27%, was also observed. There is also reduction in COD and BOD values of bio-bleached effluents by 27.62% and 20.52%, respectively. This is the first report on bio-bleaching of bagasse pulp using xylano-pectinolytic enzymes.

H2O2 bleaching in mixed triploid poplar and acacia woodchips high-yield pulping process with substitution of 50 wt% NaOH by MgO and its kinetics study

In the present work, the H2O2 bleaching with the substitution of 50 wt% NaOH by MgO as the alkali source in the high-consistency (HC) retention stage of mixed triploid poplar (Populus tomentosa Carr.) and acacia (Acacia confusa Merr.) woodchips P-RC APMP (preconditioning followed by refiner chemical treatment, alkaline peroxide mechanical pulp) was conducted. Meanwhile, the related bleaching reaction kinetics was well established. The obtained high-yield pulp presented a higher bleaching yield, improved bulk, favorable brightness and physical properties in comparison with the obtained pulp using 100 % NaOH as the alkali source. Most importantly, the chemical oxygen demand (COD) of the bleaching effluent was greatly decreased. The established bleaching kinetic equation is as following: dwdt=K[H2O2]3.63[NaOH]1.08[MgO]0.57[Na2SiO3]0.05w−1.89K= A·e–E/RT where the activation energy E =57.2 kJ/mol. It demonstrates that the bleaching reaction rate greatly depends on the concentration of primary bleaching reagents. The magnitude of the dependent extent is [H2O2] > [NaOH] > [MgO] > [Na2SiO3]. The rapid rise of the pulp brightness increment occurred in the first 35 min in the bleaching reaction.

Bleaching of Jute-Cotton blend fabric with Peracetic acid for deep dyeing

The purpose of this study was to introduce sustainable bleaching of jute-cotton blend (Juton) fabric with Peracetic acid instead of conventional peroxide bleaching agents for the deep dyeing process. Juton was bleached with peracetic acid by varying the process conditions including temperature, pH, treatment time,concentration and the dyeing properties, fastness properties were investigated in a comparative manner. In addition, the physical properties of treated fabrics such as tensile strength, elongation, weight loss and the chemical changes of bleached fabrics were evaluated by using FT-IR. The morphological surface changes of bleached fabric were confirmed by SEM. Peracetic acid and hydrogen peroxide bleaching effluents were analyzed by measuring BOD, COD, TDS and DO values. The highest color strength was obtained at 70̊C,using neutral pH (7), concentration 20 mg/L in 80 min treatment time based on peracetic acid bleaching agent for Juton fabric. Peracetic acid bleaching of Juton fabric was found to be higher tensile strength and elongation than H2O2 bleaching. Peracetic acid bleaching effluent exhibited lower BOD, COD, TDS and higher DO than hydrogen peroxide bleaching effluent. Moreover, peracetic acid bleaching provided higher fastness to washing,light and rubbing than hydrogen peroxide bleaching.

Effects of point source discharges on common bully (Gobiomorphus cotidianus) along the Waikato River, New Zealand

ABSTRACT The common bully (Gobiomorphus cotidianus) was used as a bioindicator to assess the impacts of geothermal, bleached kraft mill effluent (BKME), sewage, and thermal discharges in the Waikato River, Northern New Zealand. A range of morphological and physiological parameters were measured to assess fitness in fish sampled upstream and downstream from these point sources. Isotopic signatures gave evidence that fish were resident at sites and showed a gradient corresponding to site-specific sources of carbon and nitrogen along the river. There were changes in the size range and age structure of the populations but, no physiological responses were detected. Limited impacts were observed on common bully health at individual discharge sites, or downstream where the river showed gradual deterioration in water quality, particularly nutrient enrichment, and increased turbidity. Despite the gradual deterioration in water quality no concomitant cumulative impacts were observed in common bully. Responses were largely local in nature, responding to point-source discharges. Population responses at the geothermal and BKME discharge sites warrant further study to investigate possible effects on fish recruitment.

Biobleaching: An eco-friendly approach to reduce chemical consumption and pollutants generation

Abstract The pulp and paper industry is known to be a large contributor to environmental pollution due to the huge consumption of chemicals and energy. Several chemicals including H2SO4, Cl2, ClO2, NaOH, and H2O2 are used during the bleaching process. These chemicals react with lignin and carbohydrates to generate a substantial amount of pollutants in bleach effluents. Environmental pressure has compelled the pulp and paper industry to reduce pollutant generation from the bleaching section. Enzymes have emerged as simple, economical, and eco-friendly alternatives for bleaching of pulp. The pretreatment of pulp with enzymes is termed as biobleaching or pre-bleaching. Different microbial enzymes such as xylanases, pectinases, laccases, manganese peroxidases (MnP), and lignin peroxidases are used for biobleaching. Xylanases depolymerize the hemicelluloses precipitated on pulp fiber surfaces and improves the efficiency of bleaching chemicals. Xylanase treatment also increases the pulp fibrillation and reduces the beating time of the pulp. Pectinases hydrolyze pectin available in the pulp fibers and improve the papermaking process. Laccase treatment is found more effective along with mediator molecules (as a laccase-mediator system). Biobleaching of pulp results in the superior quality of pulp along with lower consumption of chlorine-based chemicals and lower generation of adsorbable organic halidesadsorbable organic halides (AOX. An enzyme pretreatment reduces the kappa number of pulp and improves ISO brightness significantly. Better physical strength properties and pulp viscosity have also been observed during biobleaching of pulp.

Improvement in the absorbency of ozone bleached cotton fabric by the addition of surfactant

The combined effect of surfactants with ozone bleaching process on the quality of cotton fabric was examined in this paper. The concentration of surfactants was varied between 0.01- 0.5 g/l in order to evaluate its effect on CIE whiteness, absorbency and strength of cotton fabric bleached by ozone. The maximum improvement in absorbency (1.07 s) and whiteness (WCIE 66.53) was achieved in the presence of anionic surfactant (0.01 g/l) at optimized experimental conditions. The strength properties of cotton fabric bleached by ozone in the presence of surfactant were also improved. Pollution load of ozone bleaching effluent even after adding surfactant was far less than conventional bleaching effluent. Statistically it was confirmed that surfactant addition significantly improved the whiteness and absorbency of ozone bleached cotton fabric.

Effect of introducing ozone in elemental chlorine free bleaching of pulp on generation of chlorophenolic compounds

Abstract Effect of using ozone before elemental chlorine free (ECF) bleaching of oxygen delignified wheat straw pulp produced following soda-anthraquinone pulping on bleaching effluent and pulp properties was studied. The effluent generated during bleaching of pulp contains high amount of adsorbable organic halogens (AOX), chemical oxygen demand (COD), biochemical oxygen demand (BOD) and highly toxic chlorophenolic compounds. This study is aimed to utilise green chemistry approach during bleaching of one of the abundantly used agro residue wheat straw for improving the quality of bleaching effluent and pulp properties. Introducing ozone stage before ECF bleaching resulted in significant reduction of chloriphenolic compounds like chlorocatechols by 48.9 %, chloroguaiacols by 33.3 %, chlorovanillins by 28.4 % and chlorophenols by 26.7 % in the effluent compared to those of control. Incorporation of ozone before ECF bleaching BOD, COD, AOX and colour were reduced by 40.0 %, 41.1 %, 46.7 % and 57.8 %, respectively, as compared to control. Optical properties like brightness and whiteness of the pulp bleached using ozone were also improved by 2.5 units and 4.0 units, respectively as compared to that with control.

Reducing the formation of adsorbable organic halides using an ammonium thiosulfate chlorine dioxide bleaching process

Reducing the formation of adsorbable organic halides during chlorine dioxide bleaching (the first stage chlorine dioxide bleaching, D0) is necessary to obtain clean bleaching processes. A new bleaching agent, ammonium thiosulfate (AT), was investigated to determine its potential for reducing the amount of adsorbable organic halides (AOX). Upon investigating the optimal reaction conditions for an effective reduction in AOX, the authors determined that adding 0.20% of AT 10 min after the beginning of the bleaching reaction, while maintaining a pH of 4 and a temperature of 70°C, yielded the best results. Under these conditions, AOX formation decreased by 22.0%. The bleaching effluent after the addition of AT was analyzed via gas chromatography-mass spectrometry, which showed an inhibited production rate of chlorobenzene and chlorophenol, which are both highly toxic and difficult-to-degrade compounds. Therefore, AT not only reduces AOX formation during the bleaching process, but also minimizes the difficulty of treating bleaching effluent. The results of this study provided a new, clean method for reducing AOX formation during chlorine dioxide bleaching.

Simple and Easily Applicable Method for Reducing Freshwater Consumption in Dyeing of Wool Fabric

ABSTRACT Textile wet processing is one of the most water-consuming industries. The deficiency of soft water in some parts of the world urged the researchers to exert effort toward minimization of water consumption during textile wet processes. In this work, we bleach wool fabrics by hydrogen peroxide, followed by utilization of the discharged bleaching bath (DBB) in dyeing of wool with acid, reactive, and basic dyes. The residual H2O2 in the bleaching bath was decomposed into water and oxygen by adding low concentrations of potassium iodide (KI). Results of this investigation clarify that treatment of the DBB with KI is mandatory to make the bath appropriate for wool dyeing. The dyeability of wool toward the said dyes in KI-treated DBB is significantly higher than that upon dyeing with tap water. The fastness properties of the dyed fabric to washing, perspiration, and light were assessed. The turbidity, pH, total dissolved salts (TDS), total suspended salts (TSS), biological oxygen demand (BOD), and chemical oxygen demand (COD) of the bleaching effluent were assessed. Solubility of bleached/dyed wool fabrics in alkali and urea-bisulfite solutions assures the modification of some disulfide bonds along wool keratin macromolecules into cystine oxides/cysteic acid residues, and consequently the dyeability was enhanced.

Biomimic-Inspired and Recyclable Nanogel for Contamination Removal from Water and the Application in Treating Bleaching Effluents

A recyclable and high-efficiency nanoscale adsorbent is prepared from sustainable resources in this study. Inspired by the amino acid and phenolic hydroxyl group in reed root acting as active sites...

The Treatment of Absorbable Organic Halogens and Organic Compounds in Simulated Bleaching Effluents Through the Response Surface Methodology Optimized Fenton System

In this study, the effects of four main factors on the removal of absorbable organic halogens were evaluated by response surface methodology, and the changes of absorbable organic halogens components were characterized by gas chromatography-mass spectrometer during the Fenton reaction. The high regression coefficient (R2 = 0.9028) and the low coefficient of variation (7.45%) indicated that the model was accurate in predicting the experimental results. The optimized pH, Fe2+ concentration, molar ratio of H2O2/Fe2+ and reaction time were respectively 3.4, 16.3 mM, 22.5 and 1.2 h. Consequently, 93.8% of absorbable organic halogens were removed under the optimized condition. The initial pH is the most important factor impacting the absorbable organic halogens removal. Furthermore, gas chromatography-mass spectrometer revealed that 25 out of 28 organic compounds including 7 absorbable organic halogens were thoroughly removed. Conclusively, Fenton reaction can effectively remove absorbable organic halogens from the simulated bleaching effluent.

Graphene oxide modified waste newspaper for removal of heavy metal ions and its application in industrial wastewater

Waste newspapers as absorbents to remove contaminant are limit to the extracting fibers from the newspaper at present, which lead to a complicated preparation and a difficult separation at the end of adsorption. In this study, we reported a simple, effective and renewable adsorption material assembled with waste newspaper and graphene oxide (GO). The adsorption and durability of the GO/paper have been evaluated using heavy metal ions solution and industrial effluent from the bleaching plant of paper industry, and the adsorption isotherm and kinetics are also valuated. The results indicate that the maximum adsorption capacities of GO/paper are 75.41 mg/g, 29.04 mg/g and 31.35 mg/g for Pb2+, Ni2+, and Cd2+, respectively, and the regeneration efficiency of the adsorbent to each ion is reduced by less than 10% within three testing cycles. Moreover, the GO/paper has a superior performance of removing the residual lignin and Chemical Oxygen Demand of the bleaching effluent, the adsorption of which are 64.4 mg/g and 225.7 mg/g, respectively. All these results highlight that the GO/paper as an environment-friendly, renewable and low-cost material possess an excellent adsorption capacity for both heavy metal ions and industrial wastewater.