以漂白化学热磨机械浆(BCTMP)和针叶木漂白硫酸盐(BKP)为原料,研究阳离子淀粉(CS)单元助留体系、CS/阴离子聚丙烯酰胺(APAM)双元助留体系、轻质碳酸钙(PCC)及烷基烯酮二聚体(AKD)添加对PCC留着率、白水阳离子需求量(CD值)和成纸性能(纸...以漂白化学热磨机械浆(BCTMP)和针叶木漂白硫酸盐(BKP)为原料,研究阳离子淀粉(CS)单元助留体系、CS/阴离子聚丙烯酰胺(APAM)双元助留体系、轻质碳酸钙(PCC)及烷基烯酮二聚体(AKD)添加对PCC留着率、白水阳离子需求量(CD值)和成纸性能(纸页强度、白度和不透明度)的影响。结果表明:CS体系与CS/APAM体系都可提高PCC留着率、降低白水CD值;PCC的添加可以显著提高壁纸原纸不透明度及白度,但当其添加量超过4%时,纸页抗张指数和撕裂指数迅速下降;添加AKD可显著提高纸张的抗水性能。当CS、APAM、PCC和AKD用量分别为0.6%、0.01%、4%和0.6%时,纸页抗张指数、耐破指数和撕裂指数分别为30 N·m·g-1、2.6 k Pa·m2·g-1和15 m N·m2·g-1,Cobb60约为25 g·m-2,纸页白度和不透明度为71%ISO和93.5%,基本符合壁纸原纸的质量要求。展开更多
SUMMARYThe purpose of this study was to evaluate basic density, chemical composition and fiber dimensions of ten Eucalyptus sp wood samples and verify the impact of this set of parameters and their combination on the ...SUMMARYThe purpose of this study was to evaluate basic density, chemical composition and fiber dimensions of ten Eucalyptus sp wood samples and verify the impact of this set of parameters and their combination on the Kraft pulping process yield and on bleached pulp quality. Ten eucalypt woods of different species, with basic densities varying from 365 to 544 kg/m3 and total wood carbohydrate contents varying from 70.0 to 74.5%, were transformed into kraft pulp of kappa number 17-18 and bleached to 90% ISO brightness by the sequence OD(PO)D. Wood basic density showed stronger correlations with fiber dimensions, pulping yield and pulp quality than did chemical composition. Lighter woods resulted in higher yields. However, wood specific consumption was lower for denser woods, even though these demanded more drastic pulping conditions to achieve a given kappa number. The pulp quality results suggest that lower density woods should be directed towards fabrication of refined paper (printing and writing grades) while the denser woods be directed to the sanitary papers segment (tissue grades).展开更多
The present work evaluated the use of photo-Fenton process for the treatment of kraft pulp mill effluent. The photo-Fenton best operating conditions, such as pH, concentration, and H2O2: Fe2+ ratio were evaluated. The...The present work evaluated the use of photo-Fenton process for the treatment of kraft pulp mill effluent. The photo-Fenton best operating conditions, such as pH, concentration, and H2O2: Fe2+ ratio were evaluated. The efficiency of the treatment was measured by COD (chemical oxygen demand) removal. The results showed that the optimum pH for the photo-Fenton process was equal to 3. The increase in H2O2 application resulted in an efficiency increase of the photo-Fenton process, although this was not a directly proportional relation. For most cases, the H2O2: Fe2+ proportion of 100:1 yielded the best results for COD removal. Solar radiation was more efficient than artificial UV to the COD removal. During the treatment the organic matter of the effluent was more oxidized than mineralized, showing a higher removal of COD than BOD (biochemical oxygen demand) and TOC (total organic carbon), respectively. So, photo-Fenton process increased the BOD/ COD ration but decreased the BOD/TOC ratio.展开更多
文摘以漂白化学热磨机械浆(BCTMP)和针叶木漂白硫酸盐(BKP)为原料,研究阳离子淀粉(CS)单元助留体系、CS/阴离子聚丙烯酰胺(APAM)双元助留体系、轻质碳酸钙(PCC)及烷基烯酮二聚体(AKD)添加对PCC留着率、白水阳离子需求量(CD值)和成纸性能(纸页强度、白度和不透明度)的影响。结果表明:CS体系与CS/APAM体系都可提高PCC留着率、降低白水CD值;PCC的添加可以显著提高壁纸原纸不透明度及白度,但当其添加量超过4%时,纸页抗张指数和撕裂指数迅速下降;添加AKD可显著提高纸张的抗水性能。当CS、APAM、PCC和AKD用量分别为0.6%、0.01%、4%和0.6%时,纸页抗张指数、耐破指数和撕裂指数分别为30 N·m·g-1、2.6 k Pa·m2·g-1和15 m N·m2·g-1,Cobb60约为25 g·m-2,纸页白度和不透明度为71%ISO和93.5%,基本符合壁纸原纸的质量要求。
文摘SUMMARYThe purpose of this study was to evaluate basic density, chemical composition and fiber dimensions of ten Eucalyptus sp wood samples and verify the impact of this set of parameters and their combination on the Kraft pulping process yield and on bleached pulp quality. Ten eucalypt woods of different species, with basic densities varying from 365 to 544 kg/m3 and total wood carbohydrate contents varying from 70.0 to 74.5%, were transformed into kraft pulp of kappa number 17-18 and bleached to 90% ISO brightness by the sequence OD(PO)D. Wood basic density showed stronger correlations with fiber dimensions, pulping yield and pulp quality than did chemical composition. Lighter woods resulted in higher yields. However, wood specific consumption was lower for denser woods, even though these demanded more drastic pulping conditions to achieve a given kappa number. The pulp quality results suggest that lower density woods should be directed towards fabrication of refined paper (printing and writing grades) while the denser woods be directed to the sanitary papers segment (tissue grades).
文摘The present work evaluated the use of photo-Fenton process for the treatment of kraft pulp mill effluent. The photo-Fenton best operating conditions, such as pH, concentration, and H2O2: Fe2+ ratio were evaluated. The efficiency of the treatment was measured by COD (chemical oxygen demand) removal. The results showed that the optimum pH for the photo-Fenton process was equal to 3. The increase in H2O2 application resulted in an efficiency increase of the photo-Fenton process, although this was not a directly proportional relation. For most cases, the H2O2: Fe2+ proportion of 100:1 yielded the best results for COD removal. Solar radiation was more efficient than artificial UV to the COD removal. During the treatment the organic matter of the effluent was more oxidized than mineralized, showing a higher removal of COD than BOD (biochemical oxygen demand) and TOC (total organic carbon), respectively. So, photo-Fenton process increased the BOD/ COD ration but decreased the BOD/TOC ratio.
