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Background: Carbon black, which has a low utilization rate, is a powdered carbon material produced by incomplete combustion or decomposition of hydrocarbons. Carbon black is used in rubber, coating and ink industries, the product quality will be affected due to its powder structure, and serious environmental pollution will be caused in the stacking process. However, carbon black used as the raw material for the preparation of porous carbon materials with high volatile organic compounds (VOCs) adsorption capacity, which can realize the resource utilization of carbon black and environmental protection. Results: Porous carbon based adsorbents (PCBAs) were prepared by low‐temperature physical pore‐forming and high‐temperature chemical pore‐forming with waste carbon black as raw material and (NH4)2CO3 as pore‐forming agent. The high pore‐forming temperature was beneficial to the pore structure to be formed. The surface morphology of the prepared PCBAs was more wrinkled and loose, and the specific surface area, micropore ratio and graphitization degree showed a volcanic change trend with the increase of pore‐forming temperature. The micropore ratio reached the maximum (81.7%) and the graphitization degree reached the maximum (ID/IG = 1.15) at the pore‐forming temperature of 850 °C. When the pore‐forming temperature was 850 °C, the toluene saturated adsorption capacity of PCBA850 adsorbent was 298.9 mg/g. In addition, the kinetic fitting results show that the adsorption behavior of toluene molecules on the adsorbent is mainly affected by the pore diffusion. Conclusion: Although increasing pore‐forming temperature did not change the surface chemical properties of PCBAs, high temperature pore‐forming could significantly increase the microporosity and surface area of PCBAs. The high microporous ratio and specific surface area can provide more active sites for toluene adsorption, thus improving the toluene adsorption performance of the porous carbon‐based adsorbent. In addition, the PCBA adsorbent prepared at 850 °C can restore the toluene adsorption performance at 120 °C, which provides a possibility for its practical application. © 2022 Society of Chemical Industry (SCI). [ABSTRACT FROM AUTHOR]

Activated carbon adsorbents were prepared by chemical activation with waste Zanthoxylum bungeanum branches as raw materials and H3PO4/H2SO4 as composite activator under different dosages of the auxiliary activator H2SO4. The prepared samples were characterized by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) specific surface area test, Fourier transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). The adsorption/desorption performances of low concentration toluene in the air were evaluated, and its reusability was evaluated by the adsorption/desorption cycle. Adsorption results were fitted using the quasi-first, quasi-second, and Bangham models. The adsorption properties of activated carbon adsorbent for toluene in the air show a "volcanic-type change trend" with the increase of H2SO4 dosage. The toluene adsorption properties of the prepared activated carbon adsorbents from high to low are as follows: BAC02 > BAC05 > BAC01 > BAC10 > BAC00. When the mass fraction of auxiliary activator H2SO4 was 2.0%, the adsorption amount of toluene on the prepared BAC02 activated carbon adsorbent increased by 51%, reaching 511 mg/g. After thermal desorption at 200℃, the adsorption performance of toluene was regenerated. The adsorption process of toluene conforms to the quasi-first-order model and Bangham model. The whole adsorption process can be divided into three stages: outer surface adsorption, intra-channel diffusion, and adsorption equilibrium. The addition amount of H2SO4 significantly affected the specific surface area, pore volume, and pore size distribution of the prepared activated carbon adsorbent. [ABSTRACT FROM AUTHOR]

A heterojunction structure LaVO4/g-C3N4 composite with oxygen defects was successfully prepared. The characterization results show that the recombination of electron–hole pairs could be inhibited by the heterojunction structure. The LaVO4/g-C3N4 composite shows superior photocatalytic water splitting performance for the generation of hydrogen and oxygen under visible light irradiation. Experimental data show that under visible light irradiation, the hydrogen and oxygen evolution rates of the LVOCN1 composite are much higher than those of fresh carbon nitride. Moreover, the photocatalytic activity of LaVO4/g-C3N4 composites could be significantly enhanced by O defects. Mechanism studies display that the possible mechanism of the photocatalytic water splitting reaction is the Z scheme mechanism. [ABSTRACT FROM AUTHOR]