The lignin degradation and its structural change as a result of catalytic steam explosion pretreatment can be considered of great importance for both the subsequent fermentation and the further utilization of the lignin fraction. This work investigated the degradation mechanism and change in the characteristics of lignin during dilute sulphuric-acid catalytic steam explosion (SE) pretreatment and ammonia catalytic steam explosion (AE) pretreatment of corn stalk. For this purpose, two types of lignin samples obtained from the two pretreatments of aqueous products and solid residues were fractionated, and they were then characterized by a series of comprehensive analyses that consisted of gas chromatography-mass spectroscopy (GC-MS), ion chromatography (IC), Fourier transform infrared (FT-IR), Carbon-13 nuclear magnetic resonance ( 13 C NMR), Carbon-Hydrogen two-dimensional heteronuclear single quantum coherence ( 13 C-1 H 2D HSQC), pyrolysis-GC-MS (Py-GC-MS), and field emission scanning electron microscopy (FE-SEM). Overall, the characteristic diversity of the lignin provides useful reference for highvalue applications of lignin.

Acrylic polymer is a superabsorbent for water and widely used in diapers, in which its swelling behavior can be significantly affected by several factors, i.e., the time, temperature, pH, and salt concentration, and thus the product performance in the applications. In this work, the water absorption behavior of acrylic superabsorbent polymers by each of these individual factors was investigated. The results showed that the water absorbency increases with the pH in the range of 2 to ~7 and decreases when the pH continues to increase. However, it decreases with the increases in NaCl concentration in the solution. Moreover, more water can be absorbed by the acrylic polymers at the higher temperature. Based on a previously developed kinetic swelling model and the information from the above investigations, a semiempirical model for predicting the swelling behavior of superabsorbent polymers (SAPs) under different conditions has been developed. Data showed that the model can predict (with a relative error of <4.5%) the amount of water absorbed by acrylic SAPs under different swelling conditions. The model would be very helpful to the practical application in both product design and its performance evaluation.

Cryogels based on microfibrillar cellulose (MFC) and reinforced with chitosan to endow water resistance were loaded with magnetite nanoparticles (MNPs) and characterized by TEM, XRD, and TGA. e MNP-loaded cryogels were tested for heavy metal ion removal from aqueous matrices. e adsorption capacity under equilibrium conditions for Cr(VI), Pd(II), Cd(II), and Zn(II) was measured to be 2755, 2155, 3015, and 4100 mg/g, respectively. e results indicate the potential of the introduced bicomponent cryogels for nanoparticle loading, leading to a remarkably high metal ion sorption capacity.

MFC/NFC aerogel has water sensitivity, and it should be improved in strength in water before application. Chitosan was investigated as a MFC/NFC aerogel reinforcing agent in this paper. The reinforced aerogel showed slightly tighter structure and very good water stability and mechanical strength. FTIR disclosed the chemical bonds formed between chitosan and cellulose. Nanoparticles of silver (Ag-NPs) were loaded using the reinforced aerogel. The excellent Ag-NP monodistribution on the aerogel was expressed by TEM. Both chitosan-reinforced Ag-NPs loaded MFC aerogel and NFC aerogel and expressed great antibacterial activity, though reinforced MFC aerogel exhibited better properties, like higher BET, lighter density, more Ag-NP loading, and better distribution, than NFC aerogel in this research. Chitosan-reinforced MFC aerogel is a good potential substrate for nanoparticle loading and biocomposite making.

In order to reduce production costs, heated explosion gases generated from dilute-sulfuric acid catalytic steam explosion (SE) pretreatment in the pilot production were recovered to provide energy for subsequent steps and to supply heated water (gas condensate water) for the washing steps. However, organic compounds in the explosion gases accumulated in the circulating water during continuous production, which affected subsequent enzymatic hydrolysis steps. The aim of this work was to investigate the major organic components in SE pretreatment gaseous products, their formation mechanism, and their inhibitory effects on the subsequent enzymatic hydrolysis of pretreated corn stalk.