Core-Shell Structured Cobalt Sulfide/C. I. Pigment Yellow 53 Photocatalysts with Abundant Sulfur Vacancies for Efficient Photocatalytic Co-Production of Xylonic Acid and CO.

Photocatalytic biorefinery has been gaining increasing attention as a promising method for utilizing biomass and solar energy, yet it still faces the key challenge of designing stable, efficient, and cost-effective photocatalysts. In this study, cobalt sulfide/ C. I. Pigment Yellow 53 composite photocatalysts (CoS/PY53-CSx) with a core-shell structure, which has abundant sulfur (S) vacancies, are developed using a simple hydrothermal method. The CoS nanocage with S vacancies not only offers numerous active sites but also enhances the light-trapping performance of PY53. Moreover, the internal electric field within the core-shell CoS/PY53-CSx further enhances charge separation/transfer efficiency while reducing electron transfer resistance, thereby boosting photocatalytic activity. Remarkably, 75.2% of xylonic acid and 22.8 µmol of CO from xylose are obtained using CoS/PY53-CS0.1 in an air atmosphere. Recycling experiments demonstrate that CoS/PY53-CS0.1 exhibits excellent recyclability due to the strong bonding force between the core and shell. In addition, electron spin resonance characterization combined with poisoning experiments suggests that h+ and ·O2 - serve as the main oxidation active species during this system. This work presents a simple and cost-effective method for efficient photocatalytic biorefinery.

Comparative study of different sewage sludge incineration treatments based on environmental and economic life cycle assessment.

Incineration is one of the most widely used treatments in the field of sewage sludge disposal. However, the choice of sewage sludge incineration process is still controversial. In this study, the comparative life cycle assessment of sewage sludge incineration processes, including the mono-incineration, co-incineration in coal-fired power plants and co-incineration in municipal solid waste (MSW) incineration plants, was carried out from the perspective of environment, carbon footprint and economy. The environmental assessment results show that terrestrial ecotoxicity, freshwater ecotoxicity, marine ecotoxicity, human carcinogenic toxicity and human non-carcinogenic toxicity are the most significant environmental impacts. And the environmental performance of co-incineration in coal-fired power plants is the best. Moreover, the environmental impact is most sensitive to the dehydrant, electricity and fly ash chelating agent. Co-incineration in MSW incineration plants has the lowest carbon emissions, with only 70.50% and 82% of the carbon emissions from mono-incineration and co-incineration in coal-fired power plants, respectively. Furthermore, sewage sludge mono-incineration has the highest disposal costs because of the higher depreciation and solid waste disposal costs. The comprehensive evaluation results reveal that the optimization should focus on the selection of dehydrant and fly ash chelating agent, as well as the improvement of the equipment efficiency.

Three-Dimensional Hierarchical Seaweed-Derived Carbonaceous Network with Designed g-C3N4 Nanosheets: Preparation and Mechanism Insight for 4-Nitrophenol Photoreduction.

The development of g-C3N4-based photocatalysts with abundant active sites is of great significance for photocatalytic reactions. Herein, a smart and robust strategy was presented to fabricate three-dimensional (3D) g-C3N4 nanosheet-coated alginate-based hierarchical porous carbon (g-C3N4@HPC), including coating melamine on calcium alginate (CA) hydrogel beads, freeze-drying hydrogel beads as well as pyrolysis at high temperatures. The resulting photocatalyst possessed a significantly high surface area and a large amount of interconnected macropores compared with porous carbon without the melamine coating. The unique structural features could effectively inhibit the curling and agglomeration of g-C3N4 nanosheets, provide abundant photocatalytic active sites, and promote mass diffusion. Therefore, the g-C3N4@HPC composite exhibited remarkable photocatalytic activity and outstanding stability toward the photoreduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) by NaBH4 under natural sunlight and simulated visible-light irradiation (λ > 420 nm) using a 300 W xenon lamp. Moreover, the mechanism toward the photocatalytic reaction was extensively studied by quenching experiments and electron spin resonance (ESR) experiments. The results showed that active hydrogen species were able to be achieved by following a dual-channel pathway in the NaBH4 system, which included photocatalytic reduction of H+ ions and photocatalytic oxidation of BH4- ions. This work not only opens up a new way to design efficient photocatalysts for various reactions but also provides a reference for an in-depth study of the photoreduction mechanism.

Integrated preparation of functional lignin nanoparticles and levulinic acid directly from the pre-hydrolysis liquor of poplar wood.

The pre-hydrolysis liquor (PHL) produced during pulp dissolution and biomass refining is mainly composed of hemicellulose and lignin, and it is a potential source for production of value-added materials and platform chemicals; however, their utilization has been a serious challenge. In this study, we proposed a green and simple strategy to simultaneously prepare size-controlled functional lignin nanoparticles (LNPs) and levulinic acid (LA) from PHL as the raw material. The as-prepared LNPs exhibited remarkable stability thanks to the presence of saccharides with abundant oxygen-containing groups and surface charges, which prevented aggregation and maintained long-term storage stability. Trace amounts of the LNPs (≤ 0.2 wt%) could stabilize various Pickering emulsions, even with oil-to-water ratios as high as 5:5 (v/v). Subsequently, the remaining PHL was directly used to produce LA without adding a catalyst; under optimal conditions (160 °C and 1 h), the yield of LA was 56.3 % based on the dry saccharide content in the raw PHL. More importantly, p-toluenesulfonic acid (p-TsOH), the only reactive reagent used during the entire preparation process, including the two preparation steps of the LNPs and LA, was reusable, and the recovery rate was >70 % after five cycles. Overall, this green and simple strategy effectively and comprehensively utilized the PHL and showed potential for producing biobased nanomaterials and platform chemicals.

Chitosan-amidated lignin aerogel beads efficiently loaded with lanthanum hydroxide for phosphate removal from aqueous solutions.

Developing phosphorus removal adsorbents with high adsorption performance and excellent structural stability remains a challenge. Herein, a chitosan (CS) - amidated lignin (AL) gel-bead adsorbent with high efficiency in immobilizing lanthanum hydroxide (La(OH)3) was fabricated via an in situ precipitation and freeze-drying strategy (abbreviated as La@ALCSx). The abundant hydroxyl and amino groups in CS promoted excellent loading of La(OH)3 on the surface and inside of the adsorbent. The introduction of lignin enhanced the structural stability of the beads along with the mass transfer efficiency. Owing to the porous structure and high La utilization, the adsorption capacity of La@ALCS2 reached 130.52 mg P g-1. Intra-sphere complexation of La(OH)3 with phosphate resulted in high adsorption selectivity of La@ALCS2. Moreover, the millimeter-sized of La@ALCS2 has favourable recoverability and maintains high adsorption performance after five adsorption-desorption cycles. Characterization analysis indicated that electrostatic attraction and ligand exchange were the main adsorption mechanisms. The excellent phosphorus removal efficiency, separation efficiency and recyclability of La@ALCSx provide a viable solution for the remediation of phosphate contaminated waters.

Construction of biodegradable superhydrophilic/underwater superoleophobic materials with CNF (cellulose nanofiber) fence-like attached on the surface for efficient oil/water emulsion separation.

Superhydrophilic/underwater superoleophobic materials for the separation of oil-water emulsions by filtration have received much attention in order to solve the pollution problem of oil-water emulsion. In this paper, a fence-like structure on the surface of CNF/KGM (Konjac Glucomannan) materials by a simple method using CNF instead of metal nanowires was successfully developed based on the hydrogen bonding of KGM and CNF. The resulted organic CNF/KGM materials surface has outstanding superhydrophilic (WCA = 0°) in air and superoleophobicity (OCA≥151°) in water, which could separate oil-water mixtures with high separation efficiency above 99.14 % under the pressure of the emulsion itself. The material shows good mechanical properties because of the addition of CNF and has outstanding anti-fouling property and reusability. More importantly, the material can be completely biodegraded after buried in soil for 4 weeks since both of KGM and CNF are organic substances. Therefore, it may have a broad application prospect in the separation of oil-water emulsion because of its outstanding separation properties, simply preparation method and biodegradability.

Performance optimization and comparison of vertical motion-based triboelectric nanogenerators.

The vertical motion configuration is a common design in triboelectric nanogenerators (TENGs) for energy harvesting; however, the performance optimization and comparison are still vague between various vertical motion-based structures. In this paper, time-averaged power density is defined as a metric to compare the power output performances of vertically structured TENGs, including contact mode and freestanding mode. To ensure comparisons under the same circumstances, a novel sandwich-structured dielectric layer was designed to maintain a stable and consistent surface charge density, with an extra rotating triboelectric nanogenerator working as a charge pump. We also investigated the impact of parasitic capacitance, which is a primary source of error in theoretical optimization. The freestanding TENG (FTENG) with a single dielectric layer demonstrates superior power performance, even when accounting for the influence of parasitic capacitance. This work provides valuable insights and guidelines for the design of high-performance mechanical energy harvesting devices.

Preparation of strong and tough conductive hydrogel based on Grafting, Fe3+-Catechol complexations and salting out for triboelectric nanogenerators.

The development of a strong and tough conductive hydrogel capable of meeting the strict requirements of the electrode of a hydrogel-based triboelectric nanogenerator (H-TENG) remains an enormous challenge. Herein, a robust conductive polyvinyl alcohol (PVA) hydrogel is designed via a three-step method: (1) grafting with 3,4-dihydroxy benzaldehyde, (2) metal complexation using ferric chloride (FeCl3) and (3) salting-out using sodium citrate. The hydrogel contains robust crystalline PVA domains and reversible/high-density non-covalent interactions, such as hydrogen bonding, π-π interactions and Fe3+-catechol complexations. Benefiting from the crystalline domains, the hydrogel can resist external forces to the hydrogel network; meanwhile, the reversible/high-density of non-covalent interactions can impart gradual and persistent energy dissipation during deformation. The hydrogel possesses multiple cross-linked networks, with 6.47 MPa tensile stress, 1000 % strain, 35.24 MJ/m3 toughness and 37.59 kJ/m2 fracture energy. Furthermore, the inter-connected porous hydrogel has an ideal structure for ionic-conducing channels. The hydrogel is assembled into an H-TENG, which can generate open circuit voltage of âˆ¼ 150 V, short-circuit current of âˆ¼ 3.0 µA, with superb damage immunity. Subsequently, road traffic monitoring systems are innovatively developed and demonstrated by using the H-TENG. This study provides a novel strategy to prepare superiorly strong and tough hydrogels that can meet the high demand for H-TENGs.

Efficient removal of phosphate from aqueous media using magnetic bimetallic lanthanum­iron-modified sulfonylmethylated lignin biochar.

The use of lignin carbon as an adsorbent for the adsorption of phosphates from wastewater is a promising technology. However, most lignin carbon-based adsorbents still suffer from low adsorption efficiency and poor selectivity. Herein, a novel FeLaO3-modified sulfomethylated lignin (SL) biochar adsorbent (FLO@CSL) was prepared for phosphate removal. The development of this adsorbent took into consideration the strong affinity of lanthanum (La) and iron (Fe) (hydro) oxides for phosphate and the excellent carrier properties of lignin-based biochar. As the core of FLO@CSL, FeLaO3 active sites are highly dispersed on the surface of SL biochar. Besides, doping of Fe(III) not only imparts magnetic properties to FLO@CSL, thereby effectively improving the separation efficiency of the adsorbent, but also enhances the phosphate adsorption performance. Performance studies revealed that FLO@CSL exhibits remarkable adsorption selectivity and substantial phosphate-adsorption capacity. Notably, the maximum adsorption capacity was found to be 137.14 mg P g-1. Phosphate adsorption on the FLO@CSL surfaces proceeds via chemisorption in a single layer, and ligand exchange plays an important role in determining the adsorption behaviour. Because of its exceptional selectivity, remarkable adsorption capacity and outstanding magnetic separation efficiency, FLO@CSL is a highly promising adsorbent material for effectively treating phosphates in wastewater.

Efficient extraction of uranium from seawater by reticular polyamidoxime-functionalized oriented holocellulose bundles.

A novel multi-layered reticular polyamidoxime (PAO)-functionalized holocellulose bundles (ML-r-PAO@HB) with abundant oriented micro-channels and high mechanical strength was created via a facile solvent-exchange strategy and used for the first time to capture uranium from seawater. Due to the hydrophobic interaction of PAO chains induced by the solvent-exchange, multi-layered reticular PAO was successfully self-assembled onto the oriented micro-channels of the HB, which greatly improved the accessibility to the adsorption sites by increasing the exposed surface of PAO. The ML-r-PAO@HB exhibited high uptake capacity (851.42 mg g-1 PAO) and excellent adsorptive selectivity for U(VI) ions. After exposure to 500-L natural seawater for 28 days, an ultra-high uranium extraction capacity (9.74 mg g-1 PAO) was achieved by ML-r-PAO@HB. The N and O atoms in the -C(NH2)N-OH group were the main coordination sites for U(VI) uptake. These wonderful performances render the ML-r-PAO@HB highly desirable for the large-scale uranium extraction from seawater.

Hierarchical build-up of vertically oriented lignin-based aerogel for photothermally assisted uranium uptake and recovery from acidic wastewater.

Developing the lignin-based functional materials for uranium uptake is extremely attractive, but challenging due to the complex structure, poor solubility and reactivity of lignin. Herein, a novel phosphorylated lignin (LP)/sodium alginate/ carboxylated carbon nanotube (CCNT) composite aerogel (LP@AC) with vertically oriented lamellar configuration was created for efficient uranium uptake from acidic wastewater. The successful phosphorylation of lignin by a facile solvent-free mechanochemical method achieved more than six-times enhancement in U(VI) uptake capacity of lignin. While, the incorporation of CCNT not only increased the specific surface area of LP@AC, but also improved its mechanical strength as a reinforcing phase. More importantly, the synergies between LP and CCNT components endowed LP@AC with an excellent photothermal performance, resulting in a local heat environment on LP@AC and further boosting the U(VI) uptake. Consequently, the light irradiated LP@AC exhibited an ultrahigh U(VI) uptake capacity (1308.87 mg g-1), 61.26% higher than that under dark condition, excellent adsorptive selectivity and reusability. After exposure to 10 L of simulated wastewater, above 98.21% of U(VI) ions could be rapidly captured by LP@AC under light irradiation, revealing the tremendous feasibility in industrial application. The electrostatic attraction and coordination interaction were considered as the main mechanism for U(VI) uptake.

In-situ exsolution of Fe-Ni alloy catalysts for H2 and carbon nanotube production from microwave plasma-initiated decomposition of plastic wastes.

The management of plastic wastes has become an urgent issue due to the overconsumption of single-use plastic products. As a promising avenue for plastic waste valorization, chemical recycling by converting plastics into value-added products has attracted tremendous attention. In this paper, the Fe-Ni alloy catalysts via in-situ exsolution were employed for the straightforward microwave plasma-initiated decomposition of plastic wastes for high yield H2 and carbon nanotubes. The partial substitution of Fe by Ni promoted in-situ exsolution of alloy nanoparticles homogeneously. Specifically, characterization results showed that the introduction of Ni modulated metal-support interaction, which further affected the crystalline phase, nanoparticle size and oxygen vacancies. The exsolved Fe-Ni alloy catalyst exhibited the highest catalytic activity, over which 96 % hydrogen of plastic wastes rapidly evolved out in the form of gas products accompanied with high-purity carbon nanotubes. The H2 yield was 415 mmol·g-1Hplastic, which exhibited an over 2 times improvement versus the supported catalyst. Moreover, the successive cycle test displayed the potential for converting plastic wastes into H2-rich fuels and high-quality CNTs continuously. Generally, the in-situ exsolution strategy of Fe-Ni alloy catalysts contributed to the sustainable and high-efficient recycling of plastic wastes into H2-rich gas products and carbon nanotubes under microwave plasma.

Simultaneous photocatalytic biomass conversion and CO2 reduction over high crystalline oxygen-doped carbon nitride.

Simultaneous photocatalytic biorefinery and CO2 reduction to co-produce fuels and high value-added chemicals have recently attracted significant attention; however, comprehensive studies are still lacking. Herein, we report the preparation of highly crystalline oxygen-doped carbon nitride nanotubes (O-CNNTs-x) using an ammonium fluoride-assisted hydrothermal/calcination strategy. The hollow structure, high crystallinity, and O incorporation endowed the O-CNNTs-x with photocatalytic activity by considerably improving optical absorption and modulating the charge carrier motion. The lactic acid yield and CO evolution rate over O-CNNTs-2.0 reached 82.08% and 67.95 µmol g-1 h-1, which are 1.57- and 7.37-fold times higher than those of CN, respectively. Moreover, ·OH plays a key role in the oxidation half-reaction. This study offers a facile approach for fabricating highly crystalline element-doped CN with a customizable morphology and electronic properties and demonstrates the viability of co-photocatalytic CO2 reduction and biomass selective oxidation.

Unraveling the capture mechanism of gaseous As2O3 over H-ZSM-5 zeolite from coal-fired flue gas: Experimental and theoretical insights.

Gaseous As2O3 discharged from coal-fired power plants results in severe detriments to the ecological environment. It is of great urgency to develop highly efficient As2O3 capture technology for reducing atmospheric arsenic contamination. Utilizing solid sorbents for gaseous As2O3 capture is a promising treatment for As2O3 capture. The zeolite of H-ZSM-5 was applied for As2O3 capture at high temperatures of 500-900 °C. Special attention was paid to clarifying its capture mechanism and identifying the influence of flue gas components via density functional theory (DFT) calculations and ab initio molecular dynamics (AIMD) simulations. Results revealed that due to high thermal stability with large specific areas, H-ZSM-5 demonstrated excellent arsenic capture at 500-900 °C. The captured arsenic consisted of As3+ and As5+ speciations, ascribed to As2O3 adsorption and oxidation. Moreover, As3+ and As5+ compounds were both through physisorption or chemisorption at 500-600 °C while dominant chemisorption at 700-900 °C. In particular, As3+ compounds were much more steadily fixed in products at all operating temperatures. Combining the characterization analysis and DFT calculations, it further verified that both Si-OH-Al groups and external Al species of H-ZSM-5 could chemisorb As2O3, and the latter exhibited much stronger affinities via orbital hybridization and electron transfer. The introduced O2 could facilitate As2O3 oxidation and fixation in H-ZSM-5, especially at a lower concentration of 2%. Additionally, H-ZSM-5 possessed great acid gas resistance for As2O3 capture under the concentration of NO or SO2 less than 500 ppm. AIMD simulations further identified that compared to NO and SO2, As2O3 was far more competitive and occupied the active sites of the Si-OH-Al groups and external Al species of H-ZSM-5. Overall, it demonstrated that H-ZSM-5 is a promising sorbent for As2O3 capture from coal-fired flue gas.

High-efficiency capture and removal of phosphate from wastewater by 3D hierarchical functional biomass-derived carbon aerogel.

The development of functional biomass-based carbon aerogels (CAs) with excellent mechanical flexibility and ultra-high phosphate capture capacity is crucial for capture and recovery of phosphate from waste water. Herein, a functional biomass-derived CA (MgO@SL/CMC CA) with an ordered wave-shaped layered structure and excellent compressibility was fabricated with the aim of creating a material with efficient phosphate capture performance. The incorporation of sulfonomethylated lignin (SL) significantly improves the mechanical flexibility of MgO@SL/CMC CA. Numerous MgO nano-particles (NPs), which act as principal adsorption sites, were uniformly anchored on the MgO@SL/CMC CA. The prepared MgO@SL/CMC CA with high Mg content (20.34 wt%) exhibited an ultra-high phosphate capture capacity (218.51 mg P g-1 for adsorbent or 644.58 mg P g-1 for MgO), excellent adsorptive selectivity for phosphate and a wide pH range of application (2-8). Notably, more than 81.95% of the phosphate capture capacity was retained after six cyclic adsorption-desorption tests. A considerable effective treatment volume (468 BV) of actual wastewater (1.7 mg P L-1) could be achieved by the MgO@SL/CMC CA in the fixed-bed adsorption column. Research into the adsorption mechanism reveals that monolayer chemisorption of phosphate occurs on the MgO@SL/CMC CA through a ligand exchange process. The combination of favorable flexibility, green raw materials and superior phosphate capture performance endows MgO@SL/CMC CA with great application potential in the practical treatment of wastewater.

Rural Farmers' Cognition and Climate Change Adaptation Impact on Cash Crop Productivity: Evidence from a Recent Study.

The world faces a once-in-a-century transformation due to the COVID-19 pandemic, adversely affecting farmers' employment, production practices, and livelihood resilience. Meanwhile, climate change (CC) is a crucial issue limiting agricultural production worldwide. Farmers' lives, severely affected by extreme weather conditions, are resulting in the reduced production of major economic crops. The CC has drastically influenced the major agricultural sectors of Pakistan, leading to a significant decline in farmers' living standards and the overall economy. Climate-smart and eco-friendly agricultural practices can mitigate greenhouse gas emissions and ameliorate agricultural productivity under extreme environmental conditions. This paper highlights farmers' autonomous CC adaptation strategies and their influence on cash crop (maize for this study) yield under prevailing circumstances. The current study used a simultaneous equation model to examine the different adaptation impacts on adapters and non-adapters. The survey results of 498 maize farmers in rural Pakistan revealed that growers were aware of the recent CC and had taken adequate adaptive measures to acclimatize to CC. Farmers' arable land area, awareness level, and information accessibility to CC are the most crucial factors that impart a significant role in their adaptation judgments. However, most growers have inadequate adaptation strategies, including improved irrigation and the utilization of extensive fertilizers and pesticides. Using a simultaneous equation model of endogenous switching regression, the study found that farmers not adapted to CC were negatively affecting maize productivity. Therefore, this study suggests that policymakers pay attention to the countermeasures farmers have not taken to mitigate the impact of CC. In addition, policymakers should deliver appropriate adaptation strategies to assist growers in coping with climate-related natural hazards and ensure farmers' livelihood security, rural revitalization, and sustainable agricultural development.

Does Adoption of Honeybee Pollination Promote the Economic Value of Kiwifruit Farmers? Evidence from China.

Honeybee pollination plays a significant role in sustaining the balance and biodiversity of sustainable rural development, agricultural production, and environments. However, little research has been carried out on the agricultural and economic benefits of pollination, especially for small farmers. This study investigated the adoption of honeybee pollination and its impact on farmers' economic value using primary data from 186 kiwifruit farmers in three major producing districts, such as Pujiang, Cangxi, and Dujiangyan, in the Sichuan province of China. This study was conducted in two different steps: first, we used a bivariate probit model to estimate factors influencing honeybee pollination and artificial pollination adoption; second, we further used the Dynamic Research Assessment Management (DREAM) approach to analyze the influence of the adopted honeybee pollination economic impact. The results showed that: (1) growers with higher social capital, proxied by political affiliation, are more aware of quality-oriented products, and older growers tend to choose less labor-intensive pollination technology; (2) with the increase in labor costs, more kiwifruit growers would choose honeybee pollination, and more educated growers, measured by the number of training certificates, are more likely to adopt honeybee pollination; (3) the lack of awareness and access to commercial pollinating swarms hinders the adoption of honeybee pollination; (4) in addition to the economic benefit to producers, honey pollination also brings an even larger consumer surplus. This study suggests some policy recommendations for promoting bee pollination in China: raising farmers' awareness and understanding of bee pollination through training, promoting supply and demand in the pollination market, and optimizing the external environment through product standardization and certification.

Removed heavy metal ions from wastewater reuse for chemiluminescence: Successive application of lignin-based composite hydrogels.

The novel sulfomethylated lignin-grafted-polyacrylic acid (SL-g-PAA) hydrogel was fabricated in this work via a facile and green synthetic strategy for the efficient removal of heavy metal ions from wastewater, and then successively reused for chemiluminescence (CL). The sulfomethylation of lignin was first performed to improve its water solubility and introduce numerous active sites for adsorption of heavy metal ions. The as-synthesized SL-g-PAA hydrogel with high content of lignin exhibited the highly efficient and rapid removal of various metal ions from simulated wastewater. More importantly, the spent hydrogel (M2+@SL-g-PAA) after adsorption was reused for the first time to develop a new CL system by an ingenious strategy, in which these metal ions adsorbed on M2+@SL-g-PAA act as heterogeneous catalytic sites to catalyze the CL reaction between N-(4-aminobutyl)-N-ethylisoluminol (ABEI) and H2O2. The resultant CL system displayed high CL intensity and long duration time, which could be observed by naked eye in the dark and lasted for > 24 h. The combination of facile fabrication process, renewable raw materials, and ingenious strategy for successive application in adsorption and CL endows this lignin-based composite hydrogel with a great potential for application in wastewater treatment, biological imaging and cold light sources.

Efficient removal of residual lignin from eucalyptus pulp via high-concentration chlorine dioxide treatment and its effect on the properties of residual solids.

In fact, effectively removing lignin from pulp fibers facilitates the conversion and utilization of cellulose. In this study, the residual lignin in eucalyptus pulp was separated using a high concentration of chlorine dioxide. The effects of chlorine dioxide dosage, temperature, and time on lignin removal were investigated. The optimal conditions are chlorine dioxide dosage 5.0%, reaction temperature 40 °C, and reaction time 30 min. The lignin removal yield is 88.21%. The removal yields of cellulose and hemicellulose are 2.28 and 17.00%, respectively. The treated eucalyptus pulp has higher fiber crystallinity and thermal stability. The carbon content on the fiber surface is significantly reduced. The results show that lignin is removed by efficient oxidation, and the degradation of carbohydrates is inhibited using high concentrations of chlorine dioxide at low temperatures and short reaction times. This provides theoretical support for high value conversion of cellulose.

Highly selective separation of eucalyptus hemicellulose by salicylic acid treatment with both aromatic and hydroxy acids.

Aromatic and hydroxyl acid treatments demonstrate their respective characteristics for the separation of lignocellulosic biomass. In this study, the effect of salicylic acid (SA-A) treatment on the separation of eucalyptus components with both aromatic and hydroxyl acid properties was analyzed. The optimal conditions were SA-A concentration 9.0%, reaction temperature 140 °C and time 75 min. The separation yield of xylose was 85.93%. The separation of cellulose and lignin was inhibited by SA-A treatment in contrast to the separation by glycolic acid and p-toluenesulfonic acid treatment. Moreover, SA-A treatment resulted in a larger fiber crystallinity index and higher thermal stability. The SA-A-treated samples contained lignin that was rich in ß-O-4 and hydroxyl groups. The degradation and condensation of lignin was inhibited. The selectivity of aromatic acids for separating hemicellulose and protecting the lignin structure using hydroxy acids was demonstrated. Thus, new and efficient organic acid treatments can be developed.