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Hydrotropic pretreatment using sodium xylene sulfonate (SXS) could remove lignin and xylan from corn stover to enhance enzymatic saccharification. Peracetic acid (PAA) treatment prior to the hydrotropic process [so-called modified hydrotropic pretreatment (MHP)] could double the delignification efficiency and remarkably increase glucan conversion. After pretreatment, samples were treated by PFI refining for comparison. With the supplement of PFI refining before enzymatic hydrolysis of the MHP-treated corn stover, 87.6% of the glucan yield could be achieved and the corresponding xylan yield was 43.7%. In addition, the pretreated corn stover was analyzed by Fourier transform infrared spectroscopy (FTIR), X-ray diffractometer (XRD), and scanning electron microscopy (SEM). The lignin precipitate from the spend liquor was also investigated by FTIR. The cleavage of the lignin structure could be observed from FTIR results. The crystallinity index (CrI) of corn stover after MHP was increased according to XRD analysis, while the reduction of total CrI of cellulose between pretreatment samples was analyzed by FTIR. SEM analysis demonstrated that PAA treatment affected the morphology of corn stover fiber by generating pores and allowing for better contact of the enzyme to polysaccharides.

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In this work, dilute alkaline and alkaline peroxide pretreatments were conducted in comparison with hydrotropic pretreatment to improve the delignification of bagasse prior to enzymatic hydrolysis. The surface chemical composition of bagasse after pretreatments was investigated by X-ray photoelectron spectroscopy (XPS) and time-of-flight secondary ion mass spectrometry (ToF-SIMS). The surface distribution of lignin and extractives on the bagasse fiber was significantly changed by dilute alkaline, alkaline peroxide, and hydrotropic pretreatments. Hydrotropic pretreatment typically showed, other than the decrease of surface coverage by lignin and extractives, dramatic removal of xylan, thereby leading to more cellulose exposed on the fiber surface after pretreatment. Fiber morphology after pretreatments was more favorable for enzyme hydrolysis as well. However, the hydrotropic treatment had clear advantages because the enzymatic hydrolysis yields of glucan and xylan of pretreated bagasse were 83.9 and 14.3%, respectively.

Paper-based electrodes are of special interest for the industry due to their degradability, low cost, ion accessibility, and flexibility. However, the poor dispersibility and stability of loading conductive fillers, for example, carbon nanotubes (CNTs), limit their applications. In this study, bacterial cellulose (BC) was embedded within the cellulosic fiber matrix to prepare a paper substrate with a dual fiber matrix structure. BC with its unique nanoporous surface structure assisted the adsorbing, dispersing, and stabilizing of CNTs; cellulosic fibers reduced the cost, enhanced the ion accessibility, and improved the rigidity of the material. The prepared paper electrodes exhibited a high conductivity up to 5.9 × 10 −1 S/cm and an extraordinary durability under high bending strain; it can be rolled into a 2 mm radius 800 times while maintaining the conductivity almost constant. The paper electrode had a gravimetric capacitance up to 77.5 F/g, which remained more than 98% after 15,000 charge/discharge cycles. This study suggests that this paper electrode has potential applications in supercapacitors with high performance and durability.