办公废纸脱墨中表面活性剂吸附作用研究

目的基于表面活性剂与油墨及废纸纤维之间的交互作用对于浮选脱墨的重要意义,研究办公废纸脱墨中表面活性剂的吸附行为。方法选取十二烷基苯磺酸钠(C12H25Na O4S,SDBS)和全氟辛酸钠(SPFOF15Na O2,SPFO)等2种常用的阴离子表面活性剂,以及疏水性炭黑和亲水性办公室废纸纤维等2种典型物质,通过润湿实验,研究它们在浮选脱墨时的吸附性能。同时,通过在表面活性剂中添加钙,进一步探索钙和表面活性剂的结合作用对炭黑和废纸纤维表面吸附性的影响。结果在不添加钙形成聚集时,随着SDBS或SPFO平衡浓度的增加,炭黑或废纸纸纤维表面的SDBS或SPFO吸附密度将增加,SPFO在废纸纤维和炭黑表面及SDBS在纸纤维表面能形成双分子层吸附,但SDBS在碳黑表面是单层吸附;在表面活性剂溶液中添加钙时,随着钙离子浓度的增加,炭黑表面的SDBS或SPFO吸附均增加,当溶液p H值为9时,纸纤维上SPFO最大吸附密度高于SDBS,在纸纤维上的SPFO吸附存在"钙排斥"效应;炭黑上的SDBS吸附性与p H值无关。结论钙在办公废纸脱墨中是有效的催化剂,可以与阴离子表面活性剂产生协同吸附作用,提高废纸脱墨效果。

Adsorption of the Surfactants in Waste Office Paper Recycling

It is significant for flotation deinking to study the interactions between the surfactants and ink and waste office paper fiber. The adsorption of the surfactants in waste office paper recycling was investigated in this paper. Two common anion surfactants Sodium Dodecylbenzenesulfonate (SDBS) and Sodium Perfluorooctanoate (SPFO) and two typical substances hydrophobic carbon black (ink pigment) and hydrophilic office waste paper fiber were used to study their adsorption performance in flotation deinking. Meanwhile, calcium was added into surfactants to further explore the binding between calcium and surfactants, and its effects on the adsorption to the surface of carbon black and waste paper fiber. The results showed that when no calcium was added, the adsorption density of SDBS or SPFO on the surface of carbon black or paper fiber increased with the rise of SDBS or SPFO equilibrium concentration. And at sufficiently high surfactant concentrations, SPFO adsorbed bilayerly onro both paper fiber and carbon black, and also did SDBS on paper fiber. But SDBS showed monolayer adsorption on the surface of carbon black. When calcium was added to the surfactant solution, the adsorption of SDBS or SPFO on the surface of carbon black increased with the increase of calcium ion concentration. The maximum adsorption density was higher than that of SDBS at pH 9. The adsorption of SPFO on paper fiber showed the calcium rejection effect. The adsorption of SDBS on carbon black had nothing to do with pH value. Calcium was an effective catalyst in deinking of office waste paper, which could produce a synergistic effect with anionic surfactants to improve deinking effect.