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A facile eco-friendly hydrothermal route (180°C, 12.0h) has been developed for the first time to the uniform hierarchical porous MgBO2(OH) microspheres without the aid of any organic additive, surfactant or template, by using the abundant MgCl2·6H2O, H3BO3and NaOH as the raw materials. The as-obtained porous microspheres exhibit a specific surface area of 94.752mg·g−1, pore volume of 0.814cm3·g−1, and ca. 84.0% of which have a diameter of 2.25–3.40μm. The thermal decomposition of the porous MgBO2(OH) microspheres (650°C, 2.5°C·min−1) leads to the porous Mg2B2O5microspheres with well-retained morphology. When utilized as the adsorbents for the removal of CR from mimic waste water, the present porous MgBO2(OH) microspheres exhibit satisfactory adsorption capacity, with the maximum adsorption capacity qmof 309.1mg·g−1, much higher than that derived from most of the referenced adsorbents. This opens a new window for the facile green hydrothermal synthesis of the hierarchical porous MgBO2(OH) microspheres, and extends the potential application of the 3D hierarchical porous metal borates as high-efficiency adsorbents for organic dyes removal.

Heteropolyacid nanoparticles (NPs) were supported on Cs-modified three-dimensionally ordered macroporous (3DOM) SiO2and used as the catalyst for the oxidation of methacrolein (MAL) to methacrylic acid (MAA). Hydrothermal treatment and incipient wetness impregnation were employed respectively for the Cs-modification. It was found that hydrothermal Cs-modification of 3DOM SiO2promoted the dispersion of the supported heteropolyacid, which showed an average particle size of 5.2 nm, much smaller than that (17.6 nm) on the Cs-modified 3DOM SiO2prepared by incipient wetness impregnation. The effects of hydrothermal treatment on the structure and catalytic performance of the catalyst were investigated. Results showed that the ion exchange between Cs+and the surface silanol groups on 3DOM SiO2was promoted with the increase of the hydrothermal temperature. Meanwhile, Cs-modification helped the heteropolyacid to retain intact Keggin structure, inhibiting the formation of MoO3. Highly dispersed heteropolyacid NPs with enhanced structural stability exhibited excellent selectivity to MAA in the oxidation of MAL.

Water contamination caused by hazardous organic dyes has drawn considerable attention, among all of the techniques released, adsorption has been widely used, which however to a large degree is dependent on the development of high efficiency adsorbents. Waste biomass based porous carbon is becoming the new star class of adsorbents, and thus contribute more to the sustainable development of the society. In this work, for the first time to the best of our knowledge, abundant waste fallen Platanus orientalisleaves are employed as the raw material for hierarchical activated porous carbon (APC) microspheres viaa mild hydrothermal carbonization (210 °C, 12.0 h) followed by one-step calcination (750 °C, 1.0 h). The APC microspheres exhibit a specific surface area of 1355.53 m2·g−1and abundant functional groups such as OH and CO. Furthermore, the APC microspheres are used as the adsorbents for removal of RhB and MO, with the maximum adsorption capabilities of 557.06 mg·g−1and 327.49 mg·g−1, respectively, higher than those of the most porous carbon originated from biomass. The adsorption rates rapidly approach to 98.2% (RhB) and 95.4% (MO) within 10 min. The adsorption data can be well fitted by Langmuir isotherm model and the pseudo-second-order kinetic model, meanwhile the intra-particle diffusion and Boyd models simultaneously indicate that the diffusion within the pores is the main rate-limiting step. Besides, the APC microspheres also demonstrate good recyclability, and may also be applied to other areas such as heterogeneous catalysis and energy storage.