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Adsorption is one of the most significant approaches for treatment of wastewater. An adsorbent with high mechanical strength, good renewability, and high efficiency is expected for practical applications. In this paper, a cationic xylan-based aerogel composed of xylan, polyvinyl alcohol, and agarose was fabricated to adsorb pectin, which is a typical anionic trash substance in the papermaking white water. The freeze-drying method was used to prepare the aerogel. A cationic xylan-based aerogel with high mechanical strength (34.676 MPa at 50% strain) was obtained. FT-IR results illustrated that the hydrogen bonds between three components contributed to the formation of aerogels. The addition of cationic xylan led to a slight decrease of crystallinity and thermostability of the aerogels. The maximum adsorption capacity of anionic pectin was 19.52 mg/g. Moreover, the aerogels maintained a high pectin-adsorption capacity after five recycles. This new cationic xylan-based aerogel offers potential possibilities for the development of value-added hemicellulose-based materials and the purification of papermaking white water in practical applications.

As a green and sustainable packaging material, industrial sack paper has gained increased attention in recent years due to the public's heightened environmental awareness. Practical applications for industrial packaging sack paper demands that the paper possess high physical strength properties. In this study, silicon dioxide (SiO2) nanoparticles in conjunction with poly(diallyldimethylammonium chloride) (PDADMAC) were applied to improve the physical strength of sack paper. The results showed that the physical strength properties of the sack paper increased with the addition of the SiO2 nanoparticles and PDADMAC, while the air permeability of the paper also remained high. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM) were used to characterize the sack paper with the SiO2 nanoparticle filler. [ABSTRACT FROM AUTHOR]

The reactivity of rayon-grade dissolving pulp is an important parameter in the subsequent production of viscose fiber. It can determine the processability and the quality of the viscose fiber. This study focused on improving the reactivity of kraft-based rayon-grade dissolving pulp through a mechanical treatment with mechanical refining, which could induce more fiber ends and channels or reactive sites via fiber cutting and fibrillation. Results showed that the Fock reactivity of a softwood kraft-based dissolving pulp increased from 54.4% to 68.4%, and the viscose filterability improved from 3743 s to 11 s when the beating degree of dissolving pulp was increased from 9 ºSR to 16 ºSR. Such a treatment also led to increases in the fines content, pore diameter, water retention value, and specific surface area while decreasing the fiber length. Meanwhile, it was beneficial that the intrinsic viscosity of dissolving pulp fiber was almost unaffected by the beating treatment. [ABSTRACT FROM AUTHOR]

In the production of paper, especially when using mechanical pulp or recovered wood-containing paper, a large amount of dissolved and colloidal substances (DCS), mainly composed of hemicelluloses, extractives, lignans, and lignin-related substances, are released from the pulp and dissolved or dispersed into the process water. The accumulation of DCS during the papermaking operations due to the closure of process water systems gives rise to various detrimental impacts on the papermaking process and the resulting paper products. Thus it is indispensible to remove or control the DCS in order to overcome or alleviate their negative influences. This review emphasizes recent advances in control of DCS by physical, chemical, and biological methods. The widely used fixatives such as aluminum sulfate, poly-(aluminum chloride), polyamines, polyvinyl amine, and highly cationic starch, as well as their functional effectiveness, mechanism, influencing factors, and influences on paper products are considered. Simultaneously, biological treatments including fungal treatment and enzymatic treatments with lipase, pectinase, laccase, and immobilized enzymes, are also assessed in detail. DCS control has been an important way to improve the runnability of paper machines and the quality of wood-containing paper and recycled paper products. Advances in DCS control are likely to create additional benefits to the papermaking industry in the coming years. [ABSTRACT FROM AUTHOR]