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In this study, a novel approach is to apply polyaspartic acid (PASP) as an eco-friendly regulator for the flotation of coking coal, which is different from the conventional use of oil collectors only. Flotation trails showed that adding PASP contributes to a two-way improvement in the yield and ash content of clean coal. SEM-EDS observations directly revealed that adding PASP significantly reduces the coating of high-ash fine slimes on the surface of low-ash coal particles. Contact angle detections and zeta potential analysis presented that the preferential adsorption of PASP hardly affects the adsorption of sodium oleate (NaOL) on the surface of low-ash coal particles but significantly weakens the adsorption of NaOL on the surface of high-ash fine slimes, leading to a remarkably hydrophobic difference. Particle interaction energy calculations verified that adding PASP enlarges the energy barrier between low-ash coal particle and high-ash fine slime. Hence, it can be arrived that the preferential adsorption of PASP affects the adsorption of NaOL on the surface of high-ash fine slime, widens the hydrophobic difference, enlarges the energy barrier between low-ash coal particle and high-ash fine slime, reduces the high-ash fine slime coating, therefore leading to a better flotation performance of lean coal. [ABSTRACT FROM AUTHOR]

A new design strategy was proposed to improve the mechanical performance of double network (DN) hydrogels by introducing polyhydroxy compounds into the DN structure and form a physically linked double network through the interaction of hydrogen bonding. Herein, agar/poly(acrylic acid)/hydroxyethyl cellulose composite hydrogels could be prepared by a simple one-pot method. The resulting hydrogels exhibit highly mechanical properties and excellent recoverability, which have potential applications in biomedical fields. [ABSTRACT FROM AUTHOR]

Abstract\nHIGHLIGHTSHigh-ash fine slime has an adverse effect on coal flotation. In this study, the roles of sodium silicate (SS) and sodium carbonate (SC) in the facilitating effect on lean coal flotation (a type of coking coal) were studied when sodium oleate (NaOL) was used as a collector through flotation tests, Scanning Electron Microscope-Energy Dispersive Spectroscopy (SEM-EDS) observations, turbidity measurements, and particle interaction energy calculations. The flotation tests found that SS has a stronger capacity than SC for the improvement of flotation performance of lean coal. Moreover, SEM-EDS observations and turbidity measurements showed that SS presents a stronger weakening effect for the coating of high-ash fine slime on the surface of low-ash coal particles than SC. Furthermore, the particle interaction energy calculations verified that the increase in the energy barrier for the attachment between low-ash coal particle and high-ash fine slime caused by SS is larger than SC, providing theoretical supports for the experiments. Compared to kerosene as a collector, based on the similar ash content, the yield of clean coal increases greatly with the synergistic effect of SS and NaOL. In summary, SS is an appropriate dispersant for lean coal flotation in sodium oleate system.Effects of sodium silicate and sodium carbonate on the flotation of lean coal were studied.Sodium silicate presents a better ash reduction effect than sodium carbonate.Sodium silicate presents a stronger reduction effect of slime coating than sodium carbonate.Sodium silicate greatly increases the energy barrier for the attachment between coal particle and slime.Sodium silicate is an appropriate dispersant for the flotation of lean coal. [ABSTRACT FROM AUTHOR]