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Because of the large amounts of iron and aluminum in red mud, which is a by-product of the alumina industry, aluminum and iron can be extracted by HCl or H2SO4 to produce inorganic flocculants. However, residues produced by acid leaching pose environmental problems. In this study, a slow-release mineral fertilizer K2MgSi3O8 is prepared at 1,000°C for 2 h by sintering the flocculant by-product based on red mud. The main mineral in the fertilizer is K2MgSi3O8, with an irregular blocky morphology. In distilled water, 0.50 mol/L HCl, and 20 g/L citric acid, the dissolution rates of K2O are 13.13%, 96.36%, and 81.46% and those of MgO are 2.03%, 70.94%, and 66.03%, respectively. Cumulative release values of K2O and MgO are 6.98% and 0.01% on the first day and 56.12% and 1.70% after 28 days, and the slow-release rates satisfy the Chinese standard for slow-release fertilizers. Hence, the mineral fertilizer K2MgSi3O8 based on the by-product of red mud is a potential slow-release fertilizer. [ABSTRACT FROM AUTHOR]

Recycling of iron ore tailings (IOT) which are by‐products of iron ore processing has attracted attention but there have been few studies on their use as fertilizers. In this study, slow‐release silicon fertilizers are prepared from iron tailings by solid‐phase sintering and characterized by X‐ray diffraction (XRD) and scanning electron microscopy (SEM). The solubility results acquired from the optimal sample (Si‐IOT) indicate that the available SiO2 is 20.77% and that of available K2O is 18.43% in 0.50 mol L−1 HCl. For 10 g of Si‐IOT in 200 mL of distilled water at 25°C, the cumulative release of K2O is 4.32% in the first day and 19.4% in 28 days and that of SiO2 is 2.12% in the first day and 16.30% in 28 days. The performance satisfies the Chinese national standard for slow‐release fertilizers and Chinese agricultural standard for silicon fertilizers. The results obtained from Si‐IOT pertaining to release of heavy metals indicate that heavy metals will not affect the quality of the crops and pakchoi growth is improved. Hence, they are potential raw materials for slow‐release silicon fertilizers. © 2017 American Institute of Chemical Engineers Environ Prog, 37: 1011–1019, 2018 [ABSTRACT FROM AUTHOR]

An all-solid-state flexible generator-capacitor polymer composite film converts low-frequency biomechanical energy into stored electric energy. This design, which combines the functionality of a generator with a capacitor, is realized by employing poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) in the simultaneous dual role of piezoelectric generator and polymer matrices of the flexible capacitor. Proper surface modification of the reduced graphene oxide (rGO) fillers in the polymeric matrices is indispensable in achieving the superior energy storage performance of the composite film. The heightened dielectric performance stems from enhanced compatibility of the rGO fillers and PVDF-HFP matrices, and a microcapacitor model properly explains the dielectric behaviors. A device that is easily fabricated using our film allows timely decoupled motion energy harvest and output of the motion-generated electricity. This report opens new design possibilities in the fields of motion sensors, information storage and high-voltage output by accumulating low-frequency random biological motions. [ABSTRACT FROM AUTHOR]

The molecularly selective regulation of molecular fluxes in a biomaterial that delivers multiple chemical species simultaneously is still beyond the reach of materials scientists. A delivery material was developed by means of the layer-by-layer (LbL) technique. This material discriminatively regulates the delivery flux of bioactive small molecules, as represented by a peptide containing the RGD fragment and the chemotherapy drug doxorubicin (DOX). Molecularly selective flux regulations in LbL films are realized through fast, reversible supramolecular interactions between cyclodextrin and its guests. The mechanism underlining the delivery strategy is that supramolecular interactions promote molecular loading and slow down diffusion-dependent release. In a preliminary survey of materials parameters, a maximum difference in cell viability between healthy human bronchial epithelial cells and cancer cells (A549) was realized., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)