The direct use of spent liquor from pulping and papermaking engineering, which is abundant in active organic matter, can avoid resource wastage and environmental pollution. In this study, the effects of soaking solution and filtrate from steam-exploded rice straw on seed germination and the early development of cabbage were investigated. The results have shown that soaking solution and filtrate stimulated early cabbage growth at low concentrations. Optimal germination potential and the rate of soaking solution-treated cabbage seeds increased by 8% and 5%, respectively; meanwhile, that of the filtrate-treated cabbage seeds increased by 11% and 5%, respectively. Promotion of root growth by steam-exploded rice straw spent liquor was expressed in lateral root multiplication. The fresh weight of cabbage seedlings treated with the soaking solution/filtrate increased by more than 50% and the dry weight over 20%. Comparatively, the stimulation of filtrate on seed germination and early development of cabbage is superior to that of the soaking solution. Steam-exploded rice straw spent liquor is rich in bioactive lignin and oligosaccharides, which makes it a promising biostimulant for promoting crop growth.

The refining performances of mixed poplar and eucalypt woodchips (mixture ratio 6:4) were investigated at medium and high pulp consistency via chemi-mechanical pulping (CMP). The specific refining energy consumption (SEC), fiber fraction proportion, and Canadian standard freeness (CSF) were determined to evaluate the effects of pulp consistency and NaOH dosage on the refining performances of mixed poplar and eucalypt woodchips. While the dosage of NaOH for impregnation was maintained constant, the SEC and shive content increased with increasing pulp consistency. Different fractions obtained from the Bauer-McNett classifier showed that higher pulp consistency could be expected to yield more long fibers and shive in the stock. Upon increasing the NaOH dosage, the shive content and SEC reduced significantly. When the NaOH dosage was increased to 6%, the results indicated that it was difficult to reduce the shive content to less than 1% at high pulp consistencies (25%~35%), whereas 0.18% shive fraction could be achieved at a medium pulp consistency (15%).

Nanocellulose, a kind of cellulose with nanometer sizes, has drawn great interest in the pulp and paper industry due to its unique structure and excellent performance. It can be divided into five categories: nanocrystalline cellulose (NCC), nanofibrillated cellulose (NFC), bacterial cellulose (BC), electrospun cellulose nanofibers (ESC), and precipitation regenerated cellulose nanofibers (PRC). In this paper, we reviewed the industrialization progress of nanocellulose in China. Furthermore, we proposed that efficient and environmentally friendly preparation methods and high value utilization would be the focus of nanocellulose development.

Nanofibrous media with both high particle interception efficiency and robust air permeability has broad technological applications in areas including individual protection, industrial security, and environmental governance. However, producing such filtration media has proven to be extremely challenging. Here we reported an approach to preparing and fabricating a polyvinylidene fluoride (PVDF) nanofiber composite filter medium composed of 2D PVDF nanofiber nets and a stable substrate via one-step electrospinning for effective air filtration. PVDF nanofibers are obtained by adjusting the electrospinning process. With the combined properties of ultrasmall diameter, high porosity, and a bonded scaffold, the resulting PVDF nanofiber composite filter medium exhibits a robust high filtration efficiency of 99.901% (equivalent to an F9 rating) for 0.4 mm particles and a long service life (a large dust holding capacity of 36 g/m²) for ultrafine airborne particles based on the sieving principle and surface filtration behavior. The successful synthesis of PVDF nanofibers medium would not only make it a promising candidate for air filtration, but also provide new insights into the design and development of composite nanofiber structures for various applications.

Cellulose nanocrystals (CNCs) of rod-like shape were prepared from degreased cotton using sulfuric acid hydrolysis. The obtained CNC suspension was neutralized using a sodium hydroxide solution to remove the residual sulfuric acid and improve the thermal stability of the CNC particles. Then, poly(ethylene oxide) (PEO) was employed to modify the nanocrystals through entanglement and physical adsorption. The goal was to further improve the thermal stability and weaken the hydrophilicity of CNCs. Original and modified CNCs were dosed into a polylactic acid (PLA) matrix to prepare nanocomposites using a hot compression process.Resultsof the thermogravimetric analysis showed that the initial thermal decomposition temperature of the modified CNCs showed a 120℃ improvement compared to the original CNCs. That is, the thermal stability of the modified CNCs improved because of their shielding and wrapping by a PEO layer on their surface.Resultsfrom scanning electron microscopy and ultraviolet-visible spectrophotometry showed that the compatibility of the modified CNCs with organic PLA improved, which was attributed to the compatibility of the PEO chains adsorbed on the surface of the CNCs. Finally, the results of tensile tests indicated a significant improvement in terms of breaking strength and elongation at the break point.

Lignin is the main by-product of pulp and papermaking and is not effectively utilized. Conversion of industrial lignins into value-added materials is beneficial for the effective utilization of resources as well as for environmental protection. Because of their adsorptivity, slow-release property, biocompatibility, and biodegradability, lignin and its derivatives find potential applications as eco-friendly slow/controlled release materials in agricultural fields. This report reviews the recent research advances in lignin-based slow/controlled release fertilizers and pesticides.

In this study, a straightforward, one-step wet-end formation process was employed to prepare cellulose/graphene conductive paper for antistatic packing materials. Cationic polyacrylamide was introduced into the cellulose/graphene slurry to improve the graphene loading on the surfaces of the cellulose fibers. The effect of the super calender process on the properties of the cellulose/graphene conductive paper was investigated. When 55 wt% graphene was added, the volume resistivity of the cellulose/graphene conductive paper was 94.70 Ω·cm, decreasing to 35.46 Ω·cm after the super calender process. The cellulose/graphene conductive paper possessed excellent anti-static ability and could be used as an anti-static material.

By dividing the rewinding process of a three-roll rewinder into three zones, mathematical equations were formulated and diagrams were drawn to determine the structure factors of the rewinder, such as the diameters and spatial distribution of the rewinding rolls. The qualitative and quantitative analysis results show that the roll gap of the first two rewinding rolls and the angle between the line that connects the center points of the first two rewinding rolls and the vertical line play an important role in determining the ideal log diameter, which is related to the production capacity of the rewinder. Additionally, the ideal roll gap has a significant effect on the spatial distribution of the three rewinding rolls, the rewinding dead zone, and the rewinding quality of the log, which should be taken into full consideration when designing and improving rewinders to enhance production efficiency and satisfy ultra-high quality requirements.

The effects of adding pulping black liquor and other additives to coal-water slurry (CWS) on the sulfur-fixing performance of the resultant mixture (pulping black liquor coal-water slurry) were evaluated. The experimental results demonstrated that the ash content of the black liquor coalwater slurry decreased as the addition of pulping black liquor in the mixture increased. Nevertheless, the addition amount should be appropriately selected to ensure that the black liquor coal-water slurry had a moderate calorific value. Addition of black liquor improved the combustion performance of CWS by lowering the ignition point and stabilizing the combustion process; moreover, the sulfur-fixation ratio after combustion increased by 12 to 16 percentage points than that of CWS, and the content of high-melting-point salt in the ash from CWS after adding black liquor was low. The sulfur-fixing ratio of CWS after adding a sulfur-fixing agent was effectively increased by 25 to 30 percenatge points, but with compromise of the fluidity and stability of the CWS; thus, the addition amount of a sulfur-fixing agent should be optimized.

Despite its biodegradability, adequate cohesive strength and comparatively low cost, the use of cooked starch as a paper coating binder is limited due to its high viscosity and serious negative impact on the gloss. Starch-based bio-latex with size in the nanometer or sub-micrometer range has been developed recently to overcome these shortcomings. In this study, ultrafine starch particle(UFSP) was prepared by mechanical milling using a DYNO mill in combination with light chemical pretreatment. Model coating colors containing different dosages of UFSP were applied to base paper and the properties of the coated papers were evaluated. The results showed that the UFSP was disc-shaped with a median particle diameter of 167 nm. Water retention capacity of the coating colors was improved considerably with the addition of UFSP, i.e., the water retention value decreased by nearly 40% when styrene-butadiene latex was replaced by UFSP at a dosage of 3 pph(per hundred parts of pigment). The high shear rate viscosities of the coating colors containing no more than 2 pph of USFP were similar to that of the control coating color at shear strain rate higher than 2000 s^-1. The properties and performances of the coated papers were comparable to the control coated paper with single synthesized latex binder. The gloss and the print gloss of paper samples with or without USFP were 59.7% and 58.2%, 79.0% and 78.8%, respectively. Surface strength of paper samples with or without USFP were 0.96 and 0.90 m/s, respectively, while the ink absorptivity values were 34% and 33%. This study demonstrates a promising approach to obtain submicrometer sized starch for paper coating.