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Residual lignin affects the physical and chemical performance of lignin-containing cellulose nanofibers (LCNFs). In this work, LCNFs were prepared from sugarcane bagasse powder (SBP) through p -toluenesulfonic acid ( p -TsOH) hydrolysis and the subsequent homogenization treatment. By adjusting the concentration of p -TsOH and hydrolysis temperature, LCNFs with lignin content of 4.69–17.53% were obtained, and the effects of lignin content on the chemical structure, crystallinity, size, hydrophobicity and thermal stability of LCNFs were systematically studied. With the increase of lignin content, the diameters and average water contact angles of LCNFs were increased (from 169.65 to 781.56 nm and 39.74–86.16°, respectively), while the crystallinities were decreased. The thermal stabilities of LCNFs were decided both by lignin content and the crystallinity. The by-product lignin nanoparticles (LNPs) with an average diameter of 50–500 nm were generated with LCNFs, further improving the resource utilization value of SBP. This study provides theoretical and experimental basis for the subsequent processing of films with different hydrophobic properties and materials with higher mechanical properties and thermal stability. Graphical abstract

Depolymerizing lignin to produce high-value chemicals has garnered increasing attention. Given the complex structure of real lignin, the cracking efficiency of β-O-4 linkages and the selectivity of depolymerization products are significantly lower than those of lignin model compounds. Meanwhile, the relationship between the structure of lignin and the β-O-4 linkage cracking was ignored. In this work, to well address the issue, three real lignins (corncob lignin (CL), pinus massoniana lignin (PML), and eucalyptus lignin (EL)) were employed to discuss the impacts of special ether bonds in lignin on the β-O-4 linkage cracking in the no-additional-hydrogen catalytic system mediated by a CoNi2@BTC catalyst. The lignin depolymerization results showed that the ether bonding structure in the lignin significantly impacted the cracking of β-O-4 linkages and selectivity of the final products, resulting in a great difference among their intermediates. Notably, the methoxy groups in the real lignin greatly inhibited the further hydrogenation of phenolic compounds, resulting in the accumulation of abundant methoxy-substituted phenolic compounds and a low yield of cycloalkanes (12.37% to 14.06%). To deeply discuss the β-O-4 linkage cracking in the lignin depolymerization, degradation experiments with coexisting ether bond compounds were performed, and the activation energy was employed to quantitatively evaluate the impacts of other ether bonds on the β-O-4 linkage cracking. The results revealed that multiple ether bonds (α-O-4, 4-O-5, and methoxy group) significantly increased the activation energy (from 236% to 373%) of β-O-4 linkages, resulting in the evident decline in the β-O-4 model compound. In addition, the degradation of the methoxy-substituted β-O-4 model compound (GG) demonstrated that the methoxy-substituted aromatic ring products were resistant to further hydrogenation, resulting in the accumulation of methoxy-substituted aromatic ring products in the depolymerization of real lignin. All the findings will provide a novel perspective for the targeted high-value utilization of real lignin in chemical production.

A boron and iron co-doped biochar (B-Fe/biochar) from Masson pine bark was fabricated and used to activate peroxydisulfate (PDS) for the degradation of guaiacol (GL). The roles of the dopants and the contribution of the radical and non-radical oxidations were investigated. The results showed that the doping of boron and iron significantly improved the catalytic activity of the biochar catalyst with a GL removal efficiency of 98.30% within 30 min. The degradation of the GL mainly occurred through the generation of hydroxyl radicals (·OHs) and electron transfer on the biochar surface, and a non-radical degradation pathway dominated by direct electron transfer was proposed. Recycling the B-Fe/biochar showed low metal leaching from the catalyst and satisfactory long-term stability and reusability, providing potential insights into the use of metal and non-metal co-doped biochar catalysts for PDS activation.

Given their considerable solubility in water and potentially high toxicity to human health, organoarsenic compounds have become an emerging contaminant. Herein, a heterogeneous Fenton process mediated by SiO 2 -coated nano zero-valent iron (SiO 2 -nZVI) was employed to simultaneously remove the p -arsanilic acid ( p -ASA, a typical organoarsenic compound) and the released arsenic. The initial pH value significantly influenced on the degradation of p -ASA and at the optimal pH (3.0), p -ASA (10 mg L −1 ) could be completely oxidized to As(V), NH 4 + , and plentiful phenolic compounds such as phenol and p -hydroquinone via the cleavage of C–N and C–As bonds within 60 min in pure water. Meanwhile, although the formed lepidocrocite and magnetite on the surface of SiO 2 -nZVI significantly limited the reutilization, they played a vital role in the adsorption of the released As(V) and the residual arsenic levels in the effluent were as low as 0.031 mg L −1 , meeting both the drinking water standard of the World Health Organization (WHO) and the surface water standard of China (0.05 mg L −1 ). Furthermore, high-level dissolved organic matters (DOM) (> 2 mg C L −1 ) exhibited strong interference with both the oxidation of p -ASA and adsorption of arsenic, but the interference could be eliminated by increasing the SiO 2 -nZVI dosage or adding H 2 O 2 . Importantly, this system could completely remediate p -ASA in a short time and simultaneously avoid the secondary pollution caused by inorganic arsenic, which was significant for the remediation of organoarsenic pollutants in swine wastewater.

Considering the high environmental risk, the remediation of antibiotic pollutants attracted numerous attentions. In this work, a novel photocatalyst, Ce 0.9 Zr 0.1 O 2 /SnIn 4 S 8 , was fabricated by in situ precipitation and hydrothermal method and then applied to the degradation of norfloxacin under the irritation of visible light. The SEM, TEM, XRD, XPS, and electrochemical results clearly showed that the n-type heterojunction between Ce 0.9 Zr 0.1 O 2 and SnIn 4 S 8 was successfully constructed, which greatly reduces the recombination of the photogenic electron and holes, leading to the improvement of photocatalytic performance and stability (recycled over eight times). Besides, the Ce 0.9 Zr 0.1 O 2 /SnIn 4 S 8 composite also exhibited good ability to mineralize norfloxacin. Under the optimal condition (pH 3, 1 g L −1 of 10% Ce 0.9 Zr 0.1 O 2 /SnIn 4 S 8 , and 8 mg L −1 of initial norfloxacin concentration), norfloxacin could be fully and rapidly degraded in 60 min, and completely mineralized in 4 h (99.3 ± 1.7%). LC-QTOF-MS results evidently displayed eight intermediates during norfloxacin degradation. In addition, with the attack of the reactive oxygen species (h + , •OH, and •O 2 − ), norfloxacin could be effectively decomposed via deoxygenation, hydroxylation, and carboxylation reactions. Notably, compared to photodegradation, the photocatalytic process could completely eliminate the norfloxacin from water because it could avoid the accumulation of toxic byproducts.

The extraction of uranium from seawater via membrane adsorption is a promising strategy for ensuring a long-term supply of uranium and the sustainability of nuclear energy. However, this approach has been hindered by the longstanding challenge of identifying sustainable membrane materials. In response, we propose a prototypal hybridization strategy to design a novel series of aminated conjugated microporous polymer (CMPN)@collagen fiber membrane (COLM). These sustainable and low-cost membrane materials allow a rapid and high-affinity kinetic to capture 90% of the uranium in just 30 min from 50 ppm with a high selectivity of Kd > 105 mL·g−1. They also afford a robustly reusable adsorption capacity as high as 345 mg·g−1 that could harvest 1.61 mg·g−1 of uranium in a short 7-day real marine engineering in Fujian Province, even though suffered from very low uranium concentration of 3.29 μg·L−1 and tough influence of salts such as 10.77 g·L−1 of Na+, 1.75 μg·L−1 of VO3−etc. in the rough seas. The structural evidence from both experimental and theoretical studies confirmed the formation of favorable chelating motifs from the amino group on CMPN-COLM, and the intensification by the synergistic effect from the size-sieving action of CMPN and the capillary inflow effect of COLM. [Display omitted] •CMPN-COLM exhibits optimal performance (adsorption capacity = 345 mg⋅g−1).•CMPN-COLM achieves a uranium extraction capacity of 1.61 mg⋅g−1 in seawater.•CMPN-COLM provides over 90 % uranium removal in 30 min in dynamic filtration.•Proven synergistic effect of electrostatic and chemical chelation of CMPN-COLM.

Chitosan (CS) is widely used in the treatment of wastewater containing metal ions. However, the poor stability in acidic aqueous solutions severely limits its application in many practical scenarios. In this work, a CS-based composite nanofiber membrane was prepared by electrospinning using urushiol, a natural biomaterial, as the cross-linking agent. The application of the CS-urushiol (CS-U) membrane in the adsorption and recovery of Cr( ) in wastewater was systematically studied. The CS-U membrane showed great resistance to strongly acidic and oxidative environments, and the adsorption process combined two mechanisms of electrostatic attraction and redox reaction. Due to the nanoscale fibers, porous structure, and strong acid resistance, the CS-U membrane adsorbed Cr( ) rapidly and efficiently in both batch and continuous modes. Moreover, the adsorption capacity and selectivity of the CS-U membrane for Cr( ) could be maximized simultaneously by adjusting the solution pH, promoting the recovery of high-purity Cr

A post-esterification with a high degree of substitution (hDS) mechanical treatment (Pe(hDS)M) approach was used for the production of highly hydrophobic cellulose nanoparticles (CNPs). The process has the advantages of substantially reducing the mechanical energy input for the production of CNPs and avoiding CNP aggregation through drying or solvent exchange. A conventional esterification reaction was carried out using a mixture of acetic anhydride, acetic acid, and concentrated sulfuric acid, but at temperatures of 60–85 °C. The successful hDS esterification of bleached eucalyptus kraft pulp fibers was confirmed by a variety of techniques, such as Fourier transform infrared (FTIR), solid state 13C NMR, X-ray photoelectron spectroscopy (XPS), elemental analyses, and X-ray diffraction (XRD). The CNP morphology and size were examined by atomic force microscopy (AFM) as well as dynamic light scattering. The hydrophobicity of the PeM-CNP was confirmed by the redispersion of freeze-dried CNPs into organic solvents and water contact-angle measurements. Finally, the partial conversion of cellulose I to cellulose II through esterification improved PeM-CNP thermal stability.

A synergistic photocatalytic system based on Fe-based perovskite with persulfate was constructed for alkali lignin (AL) degradation in pulp and paper wastewater. The degradation performance and mechanism on AL were carried out under ambient temperature and pressure, accompanied by visible light irradiation. The results showed that the synergistic photocatalytic system exhibited much better performance on AL degradation than the single catalytic system. The degradation efficiency reached 73.5% under the optimal conditions and was constant at around 65% over the pH range from 2 to 8. A significant escalation of the AL degradation was observed at pH 10, reaching 80.1%. The photogenerated holes, 1 O 2 and SO 4 − ·, generated by the system were involved in the degradation, and the holes played a dominant role. During the degradation process, the efficient promotion of cleavage events in lignin methoxy, β -O-4 bond, and benzene ring was observed. Consequently, the depolymerization process led to the generation of high-value compounds, namely p -hydroxybenzaldehyde and vanillin. Remarkably, the yields of the high-value compounds in the synergistic photocatalytic system were five times larger than those in the control. This study offered a viable method to activate persulfate for alkali lignin degradation and to achieve a mutually beneficial strategy for wastewater treatment and recycling.

The passivation engineering of the hole transport layer in perovskite solar cells (PSCs) has significantly decreased carrier accumulation and open circuit voltage (Voc) loss, as well as energy band mismatching, thus achieving the goal of high-power conversion efficiency. However, most devices incorporating organic/inorganic buffer layers suffer from poor stability and low efficiency. In this article, we have proposed an inorganic buffer layer of Cu2O, which has achieved high efficiency on lower work function metals and various frequently used hole transport layers (HTLs). Once the Cu2O buffer layer was applied to modify the Cu/PTAA interface, the device exhibited a high Voc of 1.20 V, a high FF of 75.92%, and an enhanced PCE of 22.49% versus a Voc of 1.12 V, FF of 69.16%, and PCE of 18.99% from the (PTAA/Cu) n-i-p structure. Our simulation showed that the application of a Cu2O buffer layer improved the interfacial contact and energy alignment, promoting the carrier transportation and reducing the charge accumulation. Furthermore, we optimized the combinations of the thicknesses of the Cu2O, the absorber layer, and PTAA to obtain the best performance for Cu-based perovskite solar cells. Eventually, we explored the effect of the defect density between the HTL/absorber interface and the absorber/ETL interface on the device and recommended the appropriate reference defect density for experimental research. This work provides guidance for improving the experimental efficiency and reducing the cost of perovskite solar cells.