Agglomeration, adsorption and polymerization of hydrolysate components

Abstract

Biomass utilization has been drawn attention of governments and industries, as it is renewable resource. Pulp and paper industry depend on woody biomass utilization system to get multiple products. However, it is also featured by large energy consumption and low efficiency of using raw material. It is crucial to integrate biorefinery concept into pulp mill to create a long-term sustainable pathway. This research work trends to investigate the performance of autohydrolysis of spruce wood at various parameters such as temperature, residence time, liquid to solid ratio. The performance of self-aggregation of hydrolysates with different conditions and deposition of hydrolysates on stainless steel surface were also studied. The hydrostats were characterized by gel permeation chromatography (GPC), nuclear magnetic resonance (NMR) spectroscopy, zeta potential analyzer, scanning electron microscopy (SEM), particle charge detector, quartz crystal microbalance with dissipation (QCM-D), dynamic light scattering (DLS). It was noticed that the hydrolysate with higher hydrophilicity and surface tension possessed higher affinity for adsorption of its lignocelluloses on stainless steel. The image analysis and QCM results revealed that the formation of agglomerates in hydrolysate and their deposition on stainless steel surface. The results of this thesis provided insights into the fundamental knowledge on the autohydrolysis, selfassembly behavior of hydrolysates which have great influence for producing lignocellulose-based coproducts. In this thesis, the hydrolysates generated via autohydrolysis of spruce wood chips were directly used as feedstock for producing coagulant. In-situ polymerization of acrylamide (AM) and lignocellulose (LC) of hydrolysates in an aqueous solution in the presence of K2S2O8 as an initiator was successfully conducted, and the reaction was optimized to generate LC-AM with the highest molecular weight and charge density. In order to confirm the grafting of acrylamide on LC NMR spectroscopy confirmed the grafting of acrylamide on LC. Other properties of product were characterized by elemental analyzer, zeta potential analyzer, gel permeation chromatography (GPC) and particle charge detector (PCD). The applications of the resultant copolymer as a coagulant in dye suspensions were systematically assessed. LC-AM was combined with cationic polyacrylamide and anionic polyacrylamide in dual-coagulant systems. These results confirmed that the dual system of LC-AM and APAM led to a similar dye removal as the singular system of APAM, which was due to the multibranch structure of LC-AM favoring bridging. In addition to its reliable dye removal efficiency, other advantages of LC-AM were its biodegradable, environmentally friendly, and inexpensive production costs compared with other oil-based coagulants used in industry.