1,1-Diarylethanes : Novel Compounds from Alkali Spent Liquors

Abstract

Five 1,1-diarylethanes were detected in three industrial alkali pulping spent liquors. Of these, two were novel compounds. The methylmethine linkages present in these compounds is expected to have formed during pulping. The degraded lignin and residual lignin in the pulp can therefore also be expected to contain methylmethine linkages.     

Purifying acidic waters and using them in a reverse cycle for making zircon refractories

Conclusions It is shown that the use of neutralization followed by cationization of the water gives a high degree of purification for spent acidic liquors and facilitates their use in a reverse cycle while maintaining the desired properties of the goods.Recommendations are given for the use of waste after purification of the liquors.Translated from Ogneupory, No. 5, pp. 20–23, May, 1980.     

SO2-Ethanol-Water (SEW) Pulping: I. Lignin Determination in Pulps and Liquors

Abstract

Quantitative determination of lignin in SO₂-ethanol-water (SEW) pulps and spent liquors is described. The methods developed for conventional sulfite pulping are successfully applied to the SEW process. Linear correlations between Klason/total lignin content and kappa number are found over a wide pulp yield range for spruce, beech, and wheat straw. Lignin content of the spruce spent SEW liquors is determined using either hydrogen peroxide to remove SO₂ and dilution by 3% sulfuric acid or simply by dilution with 0.1M sodium hydroxide. The recommended wavelength is 280 nm. The experimentally found values for the extinction coefficient of dissolved lignin in 3% sulfuric acid and in 0.1M NaOH are 19 and 23 L/(g·cm), respectively. The interference of furanic compounds is eliminated by reduction with sodium borohydride.     

扩散渗析法回收工业酸性废液的研究进展

用阴离子交换膜回收废酸是工业中处理酸性废液行之有效的方法，本文对该过程及过程中所用到的阴离子交换膜(扩散渗析膜)的发展状况进行了初步论述，重点介绍了DF系列阴膜在回收工业酸性废液的应用情况。     

Effect of Sample-Related Sources of Error on the Analysis of Pulp and Paper Mill Process Liquids by Ion Chromatography: Part I—Determination of Sulphur Species

Several factors which could affect the accuracy of measurements of sulphur species by ion chromatography have been identified. Analyses of sulphide, sulphite, sulphate and thiosulphate were conducted on samples of kraft liquors, spent sulphite liquor and newsprint white water. Erroneously high results were observed in the determination of sulphide in kraft white and green liquors, presumably due to shifts in equilibrium between elemental sulphur and polysulphide ions during sample dilution. Another problem was encountered during the analysis of sulphite in kraft liquors. Sulphite concentrations in diluted liquors rose rapidly with increase in time between dilution and injection into the ion chromatograph. Evidence presented in this paper suggests that, in diluted kraft liquors containing polysulphide and/or elemental sulphur, the sulphite concentration increases rapidly, possibly due to hydrolysis of elemental sulphur. Determination of thiosulphate was also subject to positive errors, due to oxidation of sulphide to thiosulphate. The effect of storage conditions on the stability of sulphur species was also determined. Room- temperature storage was the most deleterious for white water samples containing low levels of sulphur ions. Long-term stability in all samples was much improved by refrigeration or freezing. Kraft liquors were very stable even when stored at room temperature. Various recommendations are made to maintain sample integrity and minimize analysis errors.     

聚合氯化铁铝的制备及其对印染废水处理的应用研究

以酸洗废液和氯酸钙粉为原料,采用氧化聚合法制备出聚合氯化铁铝(PFAC)絮凝剂,并用PFAC处理分别处理含有分散蓝106和酸性大红GR的印染废水,考察各因素对去除效果的影响。实验结果表明:染料的去除率主要受PFAC的投加量和初始pH的影响;PFAC处理分散蓝106的能力强于处理酸性大红GR,并且对分散蓝106和酸性大红GR的最佳投加量及温度分别为260 mg/L、20℃,最佳初始pH分别为7、6,对应的最佳去除率分别为98.5%、75.7%,单位质量的PFAC对分散蓝106和酸性大红GR的去除量分别为1.32 mg/mg、0.62 mg/mg。     

Evolution of ozone for the bleaching of paper pulps

Although ozone has been studied seriously as a substitute for chlorine in the bleaching of pulp for paper making since 1949, it has only been since 1992 that ozone has begun to reach its full‐scale commercial potential. In this evolution, ozone has been aided immeasurably by environmental pressures to diminish the discharge of halogenated organics in pulp mill wastewaters. Thanks to the incorporation of ozonation into bleach processes, not only is the creation of halogenated organics minimized (and even eliminated in some cases), but this allows some of the processing liquors to be recovered and volumes of bleach plant effluents to be reduced. As a consequence, this not only decreases the volume of wastewater being discharged to the receiving water bodies, but also increases the potential for the Totally Effluent‐Free (TEF) bleached pulp mill to become a future reality.

Ozone's evolution in this rapidly growing industry is traced, and some characteristics of the 14 full‐scale pulp mills currently using and five additional planning to use ozone for pulp bleaching in various parts of the world will be described.     

Metal mordanting in dyeing with natural colourants

Metal mordanting, or the application of metal salts, is a common method of improving the light fastness in dyeing with natural colourants. This review presents the results from a survey of the literature on metal mordanting to assess what levels of correlation exist between mordant‐induced effects (changes in colour and colour depth) and the changes in light fastness, what is known about the mechanisms of mordant‐induced improvements of light fastness, and how the salt levels used in coloration processes compare with the limits on metal levels in wastewater and on the dyed substrates. No strong interrelationships are found between the mordant‐induced effects and light fastness improvements. Knowledge about mechanisms of mordant effect on light fastness appears, in large part, to be derived from empirical correlations. However, as light fastness is affected by a multitude of factors, the correlations do not always hold true. It is found that residual metal contents in spent dye/mordanting liquors are generally not reported. However, with rough calculations, it is estimated that, with even the lowest reported salt concentrations, the metal contents in spent liquors exceed environmental release limits. The metal contents on dyed substrates are also not generally reported, but similar estimations show that the contents of heavy metal on dyed substrates (when copper and chromium salts are used as mordants) also exceed limits. On the basis of these observations, the authors make suggestions for elements to be included in investigations on furthering the use of natural colourants in textile dyeing.     

Effect of the bio-salt trisodium citrate in the dyeing of cotton

Sodium chloride and trisodium citrate have been studied as exhausting agents for dyeing bleached cotton fabrics with reactive, direct and solubilised vat dyes. The effect of dye concentration, exhausting agent concentration, dyeing time and temperature were studied and the resulting shades obtained by dyeing with trisodium citrate and sodium chloride were compared. Dye uptake values were estimated and found to be higher for trisodium citrate than for sodium chloride. The total dissolved solids content of the spent liquors was lower with trisodium citrate than with sodium chloride.     

Lowering Kraft Black Liquor Viscosity by Ultrafiltration

Abstract

High viscosity is a major factor limiting the percentage total dissolved solids (%TDS) to which kraft black liquor (KBL), a spent pulping liquor, can be concentrated before it is burned to recover its fuel value and its inorganic chemicals. The effect on black liquor viscosity of removing high molecular weight lignin by ultrafiltration of 16% and 24% TDS liquors was studied.

Viscosities of ultrafiltration permeates were reduced relative to feed black liquors. When a permeate was concentrated to higher %TDS levels, its viscosity decreased yet further relative to feed samples evaporated to similar solids levels. Retentate viscosity was very high relative to both feed and permeate.

Ultrafiltration was carried out at 75[ddot]C using polysulfone membranes in a plate-and-frame or hollow fiber system. Flux rates varied greatly depending upon the specific liquor used. Flux was enhanced by increased temperature and increased linear velocity. The membrane molecular weight cutoff (MWCO) typically used was 50,000; increasing MWCO to 100,000 or 200,000 did not enhance flux.     

玉米芯残渣的碱性亚硫酸盐预处理及其反应动力学模型

玉米芯提取木糖后残留了大量富含纤维素和木质素的废弃物。针对玉米芯残渣（corncob residues,CCR）中木质素含量高和半纤维素含量很低的特点,采用碱性亚硫酸盐法进行预处理。研究了预处理pH、液固比、温度、亚硫酸盐用量等条件对纤维素保留率、木质素去除率、底物酶解效率以及预处理液中木质素磺酸钠含量的影响规律。结果表明,当亚硫酸钠用量为10%（质量）、氢氧化钠为5%（质量）、液固比为6：1、160℃预处理1 h时,可去除86.1%的木质素、保留82.4%的纤维素,底物的72 h酶解率达85.1%[酶载量为5 FPU·（g葡聚糖）^-1],预处理液中木质素磺酸钠的收率为31.5 g·（100 g CCR）^-1。为了指导放大试验和工程应用,提出了一个能准确预测底物木质素含量的参数--木质素因子（lignin factor,LF）,在此基础上成功建立了脱木质素反应动力学经验公式以及底物酶解效率的预测方程,预测值与实测值误差在10%之内。     

Chemical composition and physical properties of black liquors and their effects on liquor recovery operation in Brazilian pulp mills

Black liquor is the major by-product and fuel of pulp mills. In this work, effects of black liquor properties on its recovery unit operation are analyzed. Thus, an experimental methodology for characterizing the principal chemical and physical properties of eucalyptus Kraft and bamboo soda black liquors has been developed, including sample collections from six Brazilian mills. Based on results, eucalyptus and bamboo black liquors present higher contents of non-processing elements (NPEs), higher concentration and different molar mass of lignin than those reported by the pine Kraft black liquor. This leads to distinct rheological properties of these liquors. By comparing results obtained for the both liquors, the bamboo and the eucalyptus, the former has the lowest sulfur level, the highest silicon and lignin concentration and, consequently, the highest apparent viscosity.     

13C NMR Characterization of Soda and Soda/Aq Spent Liquor Fractions

Spent liquor fractions from soda and soda/anthraquinone cooks of loblolly pine wood meal were examined by C-13 NMR spectroscopy. The material which precipitated from the liquors at pH 7 as well as that remaining in solution were acetylated and fractionated on a styrene-divinylbenzene gel column. This technique was an attempt to simplify spectral interpretation and to elucidate the distribution of anthracenyl structures within the spent liquor components. The NMR spectra of fractions of the precipitated material revealed that anthracenyl structures chemically bound to lignin increased with decreasing molecular weight (MW), whereas, polysaccharide content decreased markedly with decreasing MW. The NMR spectra of the soluble material had no anthracenyl peaks, but did contain a significant peak at 105 ppm. This is in the same location as a predominant peak observed in C-13 NMR spectra of hardwood lignins, and which has been assigned to C2 and C6 of syringyl structures. However, in the present study the 105 ppm peak has been tentatively assigned to a carbohydrate carbon since it is prominent only in carbohydrate-rich fractions. Also, its aliphatic nature was confirmed by double resonance NMR experiments.     

Dissolution of Lignin in Kraft Pulp by Oxygen Bleaching

Gel permeation chromatography of spent liquors from oxygen bleaching showed that cleavage of covalent linkages in the fiber was a prerequisite for the dissolution of the lignin. The reactions continued in the liquor phase. The cleavage was related to the oxidation of the lignin. With pulps pretreated with nitrogen dioxide an appreciable number of lignin linkages were cleaved also by the direct influence of the hydroxide ions on the nitrated lignin. In the alkaline medium the acidic sites in the fiber and in dissolved lignin fragments are ionized. Donnan-exclusion and an increased fiber swelling promote the transfer of the fragments into the liquor. Hydrophilic groups introduced into the lignin during oxygen bleaching promote the delignification.     

Enhanced PAA bleaching of cotton by incorporating a cationic bleach activator

Peracetic acid is a well-known alternative to hydrogen peroxide as a bleaching agent for cotton. In this study, a novel cationic bleach activator, N -[4-(triethylammoniomethyl)benzoyl]butyrolactam chloride, was used in combination with peracetic acid to investigate the enhancement of cotton bleaching efficiency. The effects of temperature, pH and concentrations of activator and peracetic acid on the bleaching performance were studied using a statistical design of experiment. Adding activator to a peracetic acid bleaching bath improved the resultant whiteness of the substrate and at optimal conditions produced less fibre damage than when peracetic acid was used alone. In addition, the bleaching performance of both peracetic acid and hydrogen peroxide in the presence of activator was compared. In the absence of activator, the peracetic acid performance was considerably superior to a conventional hydrogen peroxide bleach system in which no bleach activator is present. However, addition of activator to the hydrogen peroxide bath increased the whiteness to a level comparable to peracetic acid.     

Terpyridine-manganese complexes: A new class of bleach catalysts for detergent applications

Oxidation catalysis is one approach used to improve the performance of hydrogen peroxide in laundry bleach applications. We introduce herein a new class of bleach catalysts based on the ligand 2,2′∶6′,2″ terpyridine. A set of manganese complexes of substituted terpyridines was investigated with respect to their physicochemical properties and bleach performance. Introduction of electron-donating hydroxy and amine substituents in the 4-position of the individual pyridine rings improves the bleach performance in model experiments with morin (2′,3,4′,5,7-pentahydroxyflavone) in solution as well as on tea-stained cotton fabrics. All the catalysts show excellent bleach performance at 40 and 25°C under European washing conditions. Performance is superior to that of the activator tetraacetyl ethylenediamine (TAED) but depends critically on the substitution pattern. Dye damage caused by the catalysts is similar to that of TAED, proving that catalytic bleach systems with high performance and low damage are indeed feasible. Model experiments revealed that the complexes are highly stable under aqueous alkaline conditions in the presence of hydrogen peroxide. The optimal pH for catalytic activity is about 10. For a catalyst to have a high bleach performance, it must possess a sufficiently low activity to catalyze disproportionation of hydrogen peroxide, which is a major side reaction of catalytic bleach with manganese complexes. All the catalysts showed a similar affinity for the cotton fabric, suggesting that differences in bleach activity of complexes are not caused by differences in the fabric affinity.     

Recovery of vanadium from ash-leaching solutions by solvent extraction

One of the principal problems during vanadium recovery from combustion residues is its purification, mainly from iron and nickel. This can be achieved by selective solvent extraction of V from liquors obtained by ash-leaching. The use of solvents also makes feasible the recovery of V from boiler washing water and leaching ponds. In the present work, leach liquors from two fouling-ashes were extracted at various pH levels with secondary, tertiary and quaternary amines, with di-(2-ethylhexyl) phosphoric acid (DEHPA), and with DEHPA-tributylphosphate mixtures. Various concentrations of the solvents in kerosene were used. Both DEHPA and amines (secondary and tertiary) are good and selective extractants for V leached from ash. However, amines always require V oxidation and partial neutralization of the leach liquors; DEHPA seems more interesting because it does not need any preliminary V reduction nor partial neutralization, provided that ash leaching is carried out with water and not with acid.     

Sugars and Sugar Acids in Lignosulphonate Products

Abstract

The monosaccharide contents of solid lignosulphonate products from spent sulphite liquors were determined by capillary gas chromatography. The predominant monosaccharide was mannose in two softwood calcium bisulphite cases, and xylose in a hardwood calcium bisulphite case. Monosaccharide analysis before and after ultrafiltration of lignosulphonates showed that about 10–25% of the neutral sugars did not pass through the membranes, and presumably remained associated with the lignosulphonates. Chemical “de-sugaring” treatments removed all but traces of the monosaccharides; when hot aqueous sodium hydroxide was used for this purpose, the main products were 3-deoxy carboxylic acids derived from the hexoses.     

Separation and Recovery of Cadmium from Acidic Leach Liquors of Spent Ni-Cd Batteries using Molten Paraffin Wax Solvent Extraction

Separation and recovery of cadmium from sulphate leach liquors of spent Ni-Cd batteries using TBP, HDEHP (D2EHPA), EHEHPA (PC 88A or Ionquest 801 or P507) have been investigated in a laboratory scale. Cadmium can be extracted into paraffin waxes from acidic solutions in the temperature range of 55–75°C using different extractants. The influence of various parameters on extraction and stripping were studied in detail. The feasibility of separation of cadmium from nickel using these extractants and their combination was studied. The mixture extractant of EHEHPA and TBP was found to be the best for the separation of Cd and Ni. A three-stage counter-current extraction simulation test for cadmium extraction was carried out at an A/O phase ratio of 4:1 and pH 2.5. More than 99.97% Cd²⁺ was extracted with the organic phase containing 0.7 mol L^?1 EHEHPA and 0.5 mol L^?1 TBP, while more than 99.97% nickel was left in the raffinate. The cadmium loaded organic phase was stripped with 2 mol L^?1 hydrochloric acid in the stripping stage. The present method can be applied to the separation and recovery of cadmium from acidic leach liquor of spent Ni-Cd batteries or related waste liquor.     

Combustion Properties of Birch (Betula pendula) Black Liquors From Sulfur-Free Pulping

Sulfur-free pulping has an environmental advantage over the traditional kraft process. This article describes the combustion properties of the black liquors produced from silver birch (Betula pendula) sawdust using three different cooking processes: two sulfur-free cooks (soda-anthraquinone and oxygen-alkali), and one reference kraft cook. It also considers the corresponding black liquors from an integrated forest biorefinery, in which a hot-water pretreatment of feedstock was performed prior to pulping. With the same cooking time, the total burning times for the sulfur-free black liquors were higher (15–55%) than those for the conventional kraft black liquors. However, no significant differences were noted between the total burning times for black liquors from pretreated feedstock and those from untreated feedstock. Especially in the case of untreated feedstock, the results showed that the kraft black liquors typically swelled more (25–45%) than the sulfur-free black liquors. It was further observed that the kraft and soda-anthraquinone black liquors from the untreated feedstock swelled more than those from the pretreated feedstock, while the oxygen-alkali black liquors swelled less.