Acidification of prehydrolysis liquor and spent liquor of neutral sulfite semichemical pulping process

AbstractAcidification has been commercialized for producing kraft lignin from black liquor of kraft pulping process. This work intended to evaluate the effectiveness of acidification in extracting lignocelluloses from the spent liquor of neutral sulfite semichemical pulping (NSSC) process and from prehydrolysis liquor (PHL) of kraft-based dissolving pulp production process. The results showed that the NSSC and PHL spent liquors had some lignin-carbohydrate complexes (LCC), and that the square weighted counts of particles with a chord length of 50–150μm in the spent liquors were significantly increased as pH dropped to 1.5. Interestingly, the acidification reduced the lignosulfonate/lignin content of NSSC and PHL by 13% or 20%, while dropped their oligosugars content by 75% and 38%, respectively. On a dry basis, the precipitates had more carbon, hydrogen and a high heating value of 18–22MJ/kg, but less oxygen, than spent liquors. The precipitates of PHL could be used as fuel

IMPACT OF FURFURAL ON THE SUGAR ANALYSIS OF PRE-HYDROLYSIS LIQUOR OF KRAFT-BASED DISSOLVING PULP PRODUCTION PROCESS USING THE HPAEC TECHNIQUE

High performance anion-exchange chromatography with pulse ampero-metric detector (HPAEC-PAD) is a reliable method to systematically determine the sugar contents in pulp and paper waste streams, including bleaching and extraction liquors. We used the same method to determine the sugar content of industrially produced pre-hydrolysis liquor (PHL) from a kraft-based dissolving pulp production process. The analysis showed that the traditional method cannot be applied for sugar analysis, and an improvement on the method was required. In fact, the presence of furfural in the PHL sample was the reason for the required modification. It was noted that the removal of furfural via evaporation could improve the reliability of the HPAEC technique for sugar assessments. If the concentration of furfural was higher than 0.045% (wt.) in the PHL, the error introduced in the sugar analysis was profound. Also, the industrially produced PHL contained more furfural than the laboratory produced PHL under the same hydrolysis conditions. Consequently, the concentration of furfural in the PHL should be taken into account for sugar analysis using the HPAEC technique

Predicting future cardiovascular disease. Do we need the oral glucose tolerance test?

WSTĘP. Celem badania było porównanie przydatności doustnego testu tolerancji glukozy (OGTT, oral glucose tolerance test) z wieloczynnikowymi modelami, uwzględniającymi powszechnie dostępne dane kliniczne do przewidywania wystąpienia w przyszłości chorób układu sercowo-naczyniowego (CVD, cardiovascular disease). MATERIAŁ I METODY. Ze spisu ludności w San Antonio losowo wybrano 2662 osoby pochodzenia latynoskiego i 1595 osób rasy białej pochodzenia nielatynoskiego, w wieku 25–64 lat, niechorujących na CVD i cukrzycę w chwili rozpoczęcia badania. Na początku badania zebrano od osób zakwalifikowanych dokładny wywiad medyczny, informacje na temat palenia tytoniu oraz zbadano ich wskaźnik masy ciała (BMI, body mass index), ciśnienie tętnicze, glikemię i insulinemię na czczo i 2 godziny po posiłku, stężenie triglicerydów oraz stężenie cholesterolu całkowitego, frakcji LDL i HDL na czczo. Choroba układu sercowo-naczyniowego pojawiła się u 88 osób pochodzenia latynoskiego i 71 osób pochodzenia nielatynoskiego w czasie 7-8-letniej obserwacji. Stworzono model krokowej, wieloczynnikowej analizy regresji logistycznej w celu przewidywania występowania CVD. Pola pod krzywą operacyjno-charakterystyczną (ROC, receiver operator chracteristic) użyto do oceny mocy przewidywania tych modeli. WYNIKI. Pole powierzchni pod wykresem ROC glikemii w 2. godzinie testu obciążenia glukozą było nieznacznie, nieznamiennie większe niż pod wykresem glikemii na czczo, oba jednak były słabym wskaźnikiem wystąpienia CVD. Pole pod wykresem ROC dla modeli wieloczynnikowych, uwzględniających łatwo dostępne dane kliniczne inne niż glikemia 2 godziny po obciążeniu glukozą, były znacznie i znamiennie większe niż pod krzywymi ROC glikemii. Uwzględnienie OGTT w tych modelach nie zwiększyło ich wartości predykcyjnych. WNIOSKI. Osoby z wysokim ryzykiem wystąpienia CVD można skuteczniej rozpoznać za pomocą prostych modeli predykcyjnych niż na podstawie wyniku OGTT. Uwzględnienie tego ostatniego w modelach prawdopodobnie nieznacznie, jeżeli w ogóle, zwiększa ich siłę predykcyjną.INTRODUCTION. Our objective was to compare the performance of oral glucose tolerance tests (OGTTs) and multivariate models incorporating commonly available clinical variables in their ability to predict future cardiovascular disease (CVD). MATERIAL AND METHODS. We randomly selected 2662 Mexican-Americans and 1595 non-Hispanic whites, 25–64 years of age, who were free of both CVD and known diabetes at baseline from several San Antonio census tracts. Medical history, cigarette smoking history, BMI, blood pressure, fasting and 2-h plasma glucose and serum insulin levels, triglyceride level, and fasting serum total, LDL, and HDL cholesterol levels were obtained at baseline. CVD developed in 88 Mexican-Americans and 71 non-Hispanic whites after 7–8 years of follow-up. Stepwise multiple logistic regression models were developed to predict incident CVD. The areas under receiver operator characteristic (ROC) curves were used to assess the predictive power of these models. RESULTS. The area under the 2-h glucose ROC curve was modestly but not significantly greater than under the fasting glucose curve, but both were relatively weak predictors of CVD. The areas under the ROC curves for the multivariate models incorporating readily available clinical variables other than 2-h glucose were substantially and significantly greater than under the glucose ROC curves. Addition of 2-h glucose to these models did not improve their predicting power. CONCLUSIONS. Better identification of individuals at high risk for CVD can be achieved with simple predicting models than with OGTTs, and the addition of the latter adds little if anything to the predictive power of the model

Synthetic and lignin-based surfactants: Challenges and opportunities

Surface active agents (surfactants) are chemicals that can accumulate at the surface of a liquid, or interface between two phases with the role of changing the surface tension of the interface. Depending on their structures, they have many applications in industries, such as the petroleum, mining, pulping and textiles, wherein they are utilized as detergents, wetting agents, emulsifiers, foaming agents and dispersants. Most of commonly used surfactants are oil-based chemicals. However, using environmentally friendly feedstocks to produce surfactant is desirable to lessen the environmental impact of surfactant production and use in industry. Lignin is an attractive candidate for this purpose as it is inexpensive and readily available. Lignin and lignin derivatives, such as lignosulfonates, can be chemically modified to produce surfactants with different chemical and physical properties, which makes them suitable for a wide variety of applications. The lignin types and the processes performed for lignin production affect the properties of generated lignin significantly, which in turn influence the reactivity and the efficiency of the reaction for surfactant generation. In this review, the characteristics and applications of oil-based surfactants, and the efforts to produce lignin-based surfactants are reviewed. As oil-based surfactants with altered properties are available in the market, several different pathways can be followed for producing lignin-based surfactants. The advantages and disadvantages of using lignin-based surfactants are also discussed. Keywords: Lignin, Surfactant, Lignosulfonate, Biorefining, Organic material

Using Sulfobutylated and Sulfomethylated Lignin as Dispersant for Kaolin Suspension

Kraft lignin is an abundant natural resource, but it is underutilized. In this study, sulfoalkylated lignin derivatives with similar charge densities but with different alkyl chain length were produced via sulfobutylation and sulfomethylation reactions. The contact angle studies revealed that sulfobutylated lignin (SBL) with longer alkyl chains had a higher hydrophobicity than sulfomethylated lignin (SML) did. The adsorption behavior of sulfoalkylated lignins was studied using a Quartz crystal microbalance with dissipation (QCM-D) on Al2O3 coated surface as representative of positively charged sites of kaolin particles. The results of adsorption studies showed that SBL deposited more greatly than SML did on the Al2O3 surface, and it generated a thicker but less viscoelastic adlayer on the surface. The adlayer thickness and configuration of molecules on the surface were also related to the zeta potential and stabilization performance of the polymers in the kaolin suspension system. The results also confirmed that both lignin derivatives were very effective in dispersing kaolin particles at neutral pH, and their effectiveness was hampered under alkaline or acidic pH

Cationic Lignin Polymers as Flocculant for Municipal Wastewater

The radical polymerization of acid-washed and unwashed softwood kraft lignin with [2-(methacryloyloxy) ethyl] trimethylammonium chloride (METAC) was attempted to investigate the production of lignin-based flocculants for simulated wastewater. The incorporation of METAC onto lignin resulted in a cationic charge density (2.3–3.3 meq/g), increased water solubility (89–96% in neutral pH), and increased molecular weight (70,000–210,000 g/mol) of lignin. The lignin–METAC polymers generated from acid-washed lignin had higher molecular weights than those generated from unwashed lignin. The lignin–METAC polymers showed lower resistance to thermal decomposition than unmodified lignin due to the inclusion of PolyMETAC. The unmodified acid-washed lignin samples did not significantly affect the COD of the wastewater, while the unmodified unwashed lignin samples contributed to the COD, implying that unmodified lignin was not suitable for wastewater treatment. The flocculation of wastewater with lignin–METAC led to the chemical oxygen demand (COD) reduction of 17–23% and total organic carbon (TOC) drop of 51–60%. The lignin–METAC polymer with the highest molecular weight (produced from acid-washed lignin) reached the highest COD removal, while lignin–METAC polymer with the highest charge density (produced from unwashed lignin) reached the highest TOC removal. Focused beam reflectance measurement (FBRM) studies revealed that the lignin–METAC polymer produced from acid-washed lignin with a high molecular weight generated larger and more flocs in wastewater than the lignin–METAC polymer produced from unwashed lignin. The comparison of theoretical and experimental dosages required for neutralizing the charges of wastewater demonstrated that charge neutralization was the main flocculation mechanism, although a bridging mechanism was also involved for component removals from wastewater. The use of 1 mg/L of alum along with 65 mg/L lignin–METAC in a dual coagulation–flocculation system led to higher average phosphorous (42%) and COD (44%) removals than the singular flocculation system only using 65 mg/L of lignin–METAC (with phosphorous removals of 3.4% and COD removals of 18.7%). However, lignin–METAC flocculant slightly increased the ammonia–nitrogen content in both singular flocculation and dual coagulation–flocculation systems due to the residual ammonia content of lignin–METAC. The coagulation–flocculation system determined that the use of lignin–METAC (65 mg/L) could reduce the alum dosage significantly while maintaining a similar organic content reduction of 44% for wastewater