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Nanomaterials have excellent adsorption performance due to nano-effect and have been widely used in many fields. The adsorption performance of nanomaterials depends on their adsorption thermodynamics and kinetics. Here, the thermodynamic and kinetic equations of adsorption for spherical nanoparticles are first derived in theory. The mechanisms and regularities of influences of nano-effect on thermodynamics and kinetics, using nano-CdS adsorption of methylene blue as a probe, were investigated. The results show that there are significant influences of nano-effect (i.e., interface area effect and interface tension effect) on the thermodynamics and kinetics of nanoparticle adsorption. When the particle radius is larger and beyond the nanometer scale (∼100 nm), the nano-effect can be neglected. When the radius of the nanoparticle is within 10–50 nm, the nano-effect of adsorption is mainly the interface area effect. When the radius is less than 10 nm, the influences of both the interface area effect and the interface tension effect on adsorption thermodynamics and kinetics become more significant. The theoretic equations and experimental insights in the present work could provide a significant basis and reference for improving and perfecting the adsorption theory involving nanomaterials and provide guidelines for the explanations of adsorption mechanisms as well as the selection of adsorbents. [ABSTRACT FROM AUTHOR]

2D tin sulfide with adjustable dual crystal plane and band gap was synthesized by one-step hydrothermal method and applied for effective photodegradation of organic pollutants. The as-synthesized SnS2 showed a peony flower-like structure composed of 2D nanosheets. UV-vis spectra showed that the introduction of N can extend the light absorption range to the visible region. Compared with pristine SnS2, the as-prepared SnS2 exhibited better photodegradation performance for rhodamine B removal under simulated sunlight irradiation; after 120 min, the removal rate could reach 94.5%. Transient photocurrent, photoluminescence, and UV-vis spectra show that this superior photocatalytic performance is due to the effective separation of photo induced carriers and the enhancement of light absorption. According to the active free radical capture experiments, a possible mechanism was proposed, which explained the reason for the enhancement of photocatalytic ability. The results show that SnS2 is a highly effective and metal-free photocatalyst for the removal of pollutants from wastewater. Our research provides a novel idea for the synthesis of SnS2 materials with effective removal of environmental pollutants. [ABSTRACT FROM AUTHOR]

Rapid and effective detection of potent volatile organic compounds (VOCs) at low operating temperatures is of great significance to keep humans safe from these environmental pollutants. In this work, we show the facile synthesis of two-dimensional (2D) and three-dimensional (3D)-laminated SnO2 nanomaterials that are decorated with reduced graphene oxide (rGO) and their efficient chemosensing properties for the potent VOC triethylamine (TEA). The as-prepared hybrid material (rGO/SnO2) possesses p-n-type heterojunction and mesoporous structures that are composed of self-assembled SnO2 nanoparticles. The heterojunction between rGO and SnO2 in this hybrid material can be tuned by varying the relative amount of rGO in it. Because of its 3D/2D structures and p-n heterojunction, the material exhibits better carrier mobility, electron transfer, activation energy, and mass diffusion for chemosensing processes than pristine SnO2. It also shows excellent chemosensing properties for TEA, with high response and selectivity at low operating temperatures, while remaining stable and operational for 13 days. Its detection limit for TEA, for example, can reach as low as 358 ppb. These attributes make this material a promising TEA chemosensor for practical applications. [ABSTRACT FROM AUTHOR]