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In this paper, the film-solid diffusion model (FSDM) combined with a concentration-dependent surface diffusivity Ds=D0 exp {k(q/qsat)} was presented to describe the kinetics of adsorption of reactive dye from aqueous solution onto activated carbon in a batch reactor. A finite-difference scheme was employed to solve the partial differential equations which govern the entire adsorption process in the batch reactor and the resulting kinetic data was presented in terms of the concentration decay curve. It was found that, for the investigated adsorption system, one set of mass transfer parameters was adequate to describe the adsorption rate at different initial solute concentrations. Compared with the constant surface diffusivity model (CSDM), the concentration-dependent surface diffusivity model (CDSDM) yielded a steeper solid-phase concentration profile due to the concentration dependence of Ds. Parametric sensitivity analysis was also carried out in order to facilitate understanding of the effect of each parameter on the shape of the concentration decay curve. [Copyright &y& Elsevier]

• Platinum nanoenzyme was anchored on BP NSs to ameliorate tumor hypoxia. • Ce6 was covalently linked to BP/Pt NSs to provide enhanced ROS production in the tumor. • Oxygen self-supplied photodynamic and photothermal synergistic therapy was performed towards 4T1 tumor ablation. Tumor hypoxia can cause undesirable barriers for many therapeutic interventions, especially for oxygen-dependent photodynamic therapy (PDT). To ameliorate hypoxia and enhance the cancer therapeutic efficacy, herein, catalase-like platinum (Pt) nanoparticles (NPs) were designed as nanoenzyme to anchor onto the surface of black phosphorus nanosheets (BP NSs), followed by Ce6 conjugation and subsequent PEGylation to obtain BP/Pt-Ce6@PEG NSs. As-prepared BP/Pt-Ce6@PEG NSs could decompose endogenous H 2 O 2 into O 2 in situ to relieve tumor hypoxia, affording enhanced reactive oxygen species (ROS) production. In vitro cytotoxicity studies demonstrated the best therapeutic effect of BP/Pt-Ce6@PEG NSs in comparison to that of BP/Pt NSs or Ce6 alone. In vivo experiments on the 4T1 tumor xenograft mouse model showed that BP/Pt-Ce6@PEG NSs could efficiently alleviate tumor hypoxia and eliminate tumor cells, presenting excellent oxygen self-supplied photodynamic and photothermal synergistic therapy therapeutic efficacy. These results highlight that platinum nanoenzyme functionalization is promising to raise the intratumoral oxygen level to surmount tumor hypoxia for efficient tumor treatment. [ABSTRACT FROM AUTHOR]

• Series of Bi 2 O 3 @CeO 2 hollow microspheres have been fabricated. • Kirkendall effect impels interior Bi 2 O 3 to diffuse outside microspheres. • Crystal phase of Bi 2 O 3 is transformed from α to β. • Bi 2 O 3 @CeO 2 -350 shows the superior visible-light photocatalytic performance. Herein, a two-step hydrothermal synthesis is used to successfully prepare a Bi 2 O 3 microsphere coated with CeO 2 nanosheets on the surface. The resultant core/shell Bi 2 O 3 @CeO 2 microsphere is calcined at different temperatures, yielding a series of Bi 2 O 3 @CeO 2 -t hollow microspheres. It is found that, with the increasing calcination temperature, the Kirkendall effect occurred can impel the interior Bi 2 O 3 to gradually diffuse outward the Bi 2 O 3 @CeO 2 microsphere, meanwhile the crystal structure of Bi 2 O 3 transforms from the metastable tetragonal phase (β) to the stable monoclinic phase (α) at 350 °C. Phase-controllable preparation of the Bi 2 O 3 @CeO 2 -350 composite with the highly active β-Bi 2 O 3 is pursued to obtain the high electron-transfer efficiency between β-Bi 2 O 3 and CeO 2 , thus exhibiting superior photocatalytic performance in the photocatalytic degradation of tetracycline (TC) under visible light irradiation. Therefore, Kirkendall effect can be exploited as a new methodology to effectively improve the photocatalytic performance of heterojunction photocatalysts. [ABSTRACT FROM AUTHOR]

• Ti 3 C 2 T x -PPy/Bi 2 S 3 enabled the voltage window of AZIC-TPB//ZnSO 4 //Zn to 2.1 V. • Ti 3 C 2 T x served as the expansion joint in voltage-window-expansion engineering. • Bi 2 S 3 and PPy offered pseudocapacitance and widened the voltage window laterally. • The energy density of AZIC-TPB//ZnSO 4 //Zn was elevated to 269.09 Wh Kg−1. • DFT calculations revealed the origins of enhanced electrochemical properties. Although increasing the voltage window should be more effective by square rewarding than the specific capacitance for enhancing the energy density of zinc-ion hybrid capacitors (ZIC), the lack of an ideal cathode has hindered its realization. Herein, Ti 3 C 2 T x -PPy/Bi 2 S 3 composite was fabricated through voltage-window-expansion engineering, where Ti 3 C 2 T x layers were covered by a tremella-like network of PPy through hydrogen bonds (-N H···O- and -N H···F-), and then compounded with pseudocapacitive Bi 2 S 3. Due to the redox reactions of Bi 2 S 3 and PPy at low and high potentials, the working voltage window of AZIC-TPB//ZnSO 4 //Zn was elevated up to 2.1 V with low-cost electrolyte ZnSO 4 , exhibiting a high energy density comparable to that of batteries (269.09 Wh Kg−1 with a power density of 1564.73 W Kg−1). Even at a power density of 12947.15 W Kg−1, the energy density of AZIC kept as high as 107 Wh Kg−1, far exceeding the common level. Density functional theory (DFT) calculation demonstrated the obvious electron transfer between Ti 3 C 2 T x and PPy (or Bi 2 S 3) and advanced conductivity, which promoted the redox reaction and facilitate the charge transfer in the electrochemical process. The strategy of voltage-window-expansion engineering here can be further extended to aqueous energy storage devices, offering a viable path to enhancing energy density. [ABSTRACT FROM AUTHOR]

A three dimensional (3D) reduced graphene oxide (rGO)/zeolitic imidazolate framework-67(ZIF-67) aerogel (3D rGO/ZIF-67 aerogel) was prepared via in situ assembly of ZIF-67 polyhedrons on a 3D rGO networks, not only providing multifarious affinity interactions for synergistic promoting the adsorption behavior of organic dyes, but also constructing a holder for ZIF-67 polyhedrons to convenient separation. This porous aerogel displays excellent absorption ability for cationic dyes (crystal violet, CV) and anionic dyes (methyl orange, MO). The maximum adsorption capacities are up to 1714.2 mg·g −1 and 426.3 mg·g −1 for CV and MO, respectively. 3D rGO/ZIF-67 aerogel shows a remarkable promoting of CV adsorption capacity than pure 3D rGO and ZIF-67. The ultrahigh adsorption capability towards cationic CV dyes is mainly driven by π-π interactions and electrostatic interactions between 3D rGO/ZIF-67 aerogel and dye molecules, and synergistic interactions at the interface of 3D rGO and ZIF-67 polyhedrons. The high adsorption capability towards anionic MO dyes is mainly due to the porosity of ZIF-67 polyhedrons and electrostatic attraction between MO and ZIF-67. The multi-component property of 3D rGO/ZIF-67 aerogel shows a great potential application in dye-bearing wastewater treatment. [ABSTRACT FROM AUTHOR]