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整体经济中扮演着重要的角色。然而，类似于化学法制浆的热机械(TMP)制浆和化学热机械(CTMP)制浆工艺最近面临着实质性的危机。解决这些困难的一种方法是寻找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(SLS)都是在废水系统中处理的，并且没有得到充分利用。这些SLS含有可用于生产各种附加值产品的木质纤维素酶。然而，SLS的稀释性质阻碍了通过现有技术生产增值产品。在拟议的研究中，将采用吸附和絮凝过程来分离/分离SLS的木质纤维素酶。在一组实验中，木质纤维素将被吸附在吸附剂上，例如活性碳，然后在具有所需性质的溶液中解吸。在另一组实验中，阳离子聚合物将被添加到SLS中。这些阳离子聚合物和SLS的木质纤维素会形成絮体，并从SLS中沉淀出来。这项研究的目标是生产可用作生物燃料或(造纸)填料的木质纤维素/阳离子聚合物复合体(絮凝体)。或者，在SLS的吸附过程中，将使用膨润土等无机填料作为吸附剂，以生产可用作造纸添加剂的半纤维素改性无机填料。这项研究的结果将是开发从TMP和CTMP工艺的SLS中溶解的木质纤维素生产生物燃料和附加值产品的工艺，从而帮助将TMP和CTMP纸浆厂转变为森林生物精炼厂。

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.