Recovery of lignocelluloses dissolved in the spent liquors of TMP and CTMP processes via adsorption and flocculation

纸浆和造纸工业在加拿大的整体经济中发挥着重要作用。然而，与化学制浆工艺类似，热机械法（TMP）和化学热机械法（CTMP）制浆工艺近来也面临着严重的危机。解决这些困难的一种方法是发现可以从这些制浆过程的废物中生产的替代增值产品。目前，TMP和CTMP工艺的废液（SL）在废水系统中处理并且未得到充分利用。这些SL含有木质纤维素，可以潜在地用于生产各种增值产品。然而，SL的稀释性质阻碍了通过当前实践的技术生产增值产品。在本研究中，将采用吸附和絮凝工艺分离SL中的木质纤维素。在一组实验中，木质纤维素将被吸附在吸附剂上，例如，活性炭，然后在具有所需性质的溶液中解吸。在另一组实验中，将阳离子聚合物添加到SL中。这些阳离子聚合物和SL的木质纤维素将形成絮凝物，其将从SL中沉淀。本研究的目的是生产木质纤维素/阳离子聚合物复合物（絮凝物），可用作生物燃料或填料（造纸）。或者，无机填料，例如，膨润土将在SL的吸附过程中用作吸附剂，以生产可用作造纸添加剂的半纤维素改性无机填料。这项研究的成果将是从溶解在TMP和CTMP工艺的SL中的木质纤维素生产生物燃料和增值产品的工艺的开发，从而帮助将TMP和CTMP纸浆米尔斯厂转化为森林生物精炼厂。

The pulp and paper industry plays an important role in the overall economy of Canada. However, the thermomechanical (TMP) and chemithermomechanical (CTMP) pulping processes, similar to chemical pulping processes, have recently been faced with substantial crises. One approach to address these difficulties is to discover alternative value-added products that can be produced from the wastes of these pulping processes. Presently, the spent liquors (SLs) of TMP and CTMP processes are treated in the waste water systems and under-utilized. These SLs contain lignocelluloses that can be potentially used for the production of various value-added products. However, the dilute nature of SLs hampers the production of value-added products via the current technology practiced. In the proposed research, the adsorption and flocculation processes will be employed to separate/isolate the lignocelluloses of SLs. In one set of experiments, the lignocelluloses will be adsorbed on adsorbents, e.g., activated carbon, and then desorbed in solutions having desired properties. In another set of experiments, cationic polymers will be added to the SLs. These cationic polymers and the lignocelluloses of SLs will form flocs, which will precipitate from the SLs. The goal of this investigation is to produce lignocelluloses/cationic polymer complexes (flocs) that can be used as biofuels or fillers (in papermaking). Alternatively, inorganic fillers, e.g., bentonite, will be used as adsorbents in the adsorption process of SLs in order to produce hemicelluloses-modified inorganic fillers that can be used as additives in papermaking. The outcome of this research will be the development of processes for producing biofuels and value-added products from the lignocelluloses dissolved in the SLs of TMP and CTMP processes, thus helping convert the TMP and CTMP pulp mills into forest biorefinery plants.