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Graphical abstract Highlights • The honeycomb carbon materials were prepared by using carbon hollow spheres. • The specific surface area of HCM is 1436.21 m2/g. • The maximum amount of Cr adsorbed by HCM is 332.53 mg/g. • HCM has good reusability performance. Abstract Hollow carbon spheres (HCSs) were prepared by a hydrothermal synthetic method using glucose as the raw material, and a honeycomb carbon material (HCM) was prepared by modifying these HCSs. The materials were characterized by SEM, TEM, BET, Raman spectroscopy, XPS, XRD, and elemental analysis. A large number of pores were observed in the HCM by SEM and TEM, and the specific surface area of the material, as determined by BET testing, was 1436.21 m2/g. The adsorption properties of the HCM were tested by a batch adsorption method. The maximum adsorption capacity of the HCM for Cr(VI) was 332.53 mg/g, and the performance was better than that of a similar materials. The kinetic thermodynamics and intraparticle diffusion models were fit, and it was found that the adsorption of Cr(VI) onto the honeycomb carbon was a spontaneous endothermic process. The regenerative adsorption experiments showed that the material had good regenerative abilities. [ABSTRACT FROM AUTHOR]

• Modified xylan with good amphiphilicity was obtained under mild reaction conditions by hydroxypropylsulfonation. • HSX exhibited a satisfactory dispersion efficiency of MWCNTs in water. • The aerogels were prepared by freeze-casting technology which reveals excellent mechanical performance. • The aerogel is utilized to construct a pressure sensor, which exhibit high sensitivity (S = 2.17 kPa−1) and impressive responsiveness. Currently, aerogels are promising for wearable pressure sensors due to their superior flexibility and high sensitivity. However, uniform dispersion of conductive solid filler is a critical step in the preparation process. Herein, xylan with good amphiphilicity was obtained by hydroxypropylsulfonation under mild reaction conditions, which is accepted as a dispersant for multi-walled carbon nanotubes (MWCNTs) in water. The hydroxypropylsulfonated xylan (HSX) exhibited a satisfactory dispersion efficiency reached to 97.8 %. After standing for 20 days, there are still 76 % of MWCNTs stabilized in the dispersion. Then, the ultralight, flexible and superstable anisotropic aerogels were prepared by freeze-casting technology. The obtained aerogel reveals excellent mechanical performance, with a great compressibility (undergoing a strain of 70 %) and elasticity (91.8 % height retention after 100 cycles at a strain of 20 %). As a proof of concept, the HSX/MWCNTs aerogel is utilized to construct a pressure sensor, which exhibit high sensitivity (S = 2.17 kPa−1) and impressive responsiveness to human motions. This work demonstrates a promising flexible electronic material for wearable electronics, electronic skin, and human motion monitoring. [ABSTRACT FROM AUTHOR]

• The respective maximum CE and H 2 selectivity of 95.34% and 0.99 were achieved. • The dependence of gasification efficiency on reaction temperature was apparent. • Bond-making of functional group was observed at a high feedstock concentration. • The disorderly conversion between organic matters triggered a low CE. • The improvement method on gasification performance was proposed. The clean and efficient utilization of biomass waste for hydrogen production conforms to social development in the future. In this work, hydrogen production from supercritical water gasification (SCWG) of fir bark (FB) was investigated systematically at various reaction temperatures (500–750 °C), feedstock concentrations (5 wt%–15 wt%), and retention time (0–40 min). The gaseous, liquid, and solid products were analyzed to master the gasification mechanism. The results demonstrated the maximum CE and H 2 selectivity of 95.34% and 0.99 were obtained at 700 °C-5 wt%-40 min. Reaction temperature was positively related to the gasification efficiency, and the effects of feedstock concentration and retention time were related to the reaction temperature. Increasing feedstock concentration contributed to the cyclisation and Diels-Alder reaction, with a cohesive aromatic structure. A benign conversion resulted in the enhancement of gasification efficiency with prolonging retention time in the high temperature SCWG. The vital reason for low gasification efficiency was due to the disorderly interconversions between organic matters. [ABSTRACT FROM AUTHOR]

• The synergistic influences of US and PS are reviewed. • Operational factors influencing the removal efficiency are discussed and summarized. • Reaction mechanisms of sono-activated persulfate oxidation are evaluated and outlined. • Knowledge gaps and research needs of sono-activated persulfate are proposed. Persulfate (PS) has attracted great attention as an alternative to H 2 O 2 for advanced oxidation processes in recent years. Among various activation techniques, ultrasound (US) activation acts as an emerging method and has gained increasing interest especially in recent years. The combination of US and PS is a promising alternative for organic wastewater treatment. In this review, the synergistic effects of US and PS were investigated based on wide applications. The degradation efficiency is easily influenced by the reaction factors, including ultrasonic power and frequency, pH, temperature, PS concentration, and coexisting inorganic anions etc. These factors were summarized and analyzed to give the optimal references for further in-depth studies. Moreover, the decomposing mechanisms are outlined in terms of molecular structures due to the one-sidedness of reactive radical analysis. In the end, the concluding remarks and perspectives are made for future study on US-PS technologies. This review can provide an overview for the systematic understanding of the mechanisms and synergistic effects of US and PS combination. [ABSTRACT FROM AUTHOR]