Na Xue,Yunpeng Zhang,Zongxu Li,Yangge Zhu,Xuejing Liu,Hao Wang,Yimiao Nie,Long Wang
Fluorite commonly coexists with calcite, whilst the separation of these two minerals is a longstanding challenge due to their closely similar surface properties. In this work, froth flotation was adopted to remove calcite from fluorite with tara gum (TG) innovatively performed as the calcite depressant. Flotation experiment results showed that TG exhibited strong depression performance for calcite in a broad pH range (6–8) in sodium oleate (NaOL) system. Zeta potential results confirmed that TG trended to selectively react on the calcite and prevented the function of NaOL onto calcite surface. X-ray photoelectron spectroscopy (XPS) measurement found that TG chemisorbed onto calcite, while physically adsorbed on the fluorite. Atomic force microscopy (AFM) tests indicated that TG densely adhered onto calcite surface and greatly enhanced its hydrophilicity, whereas it adsorbed weakly on the fluorite surface. Molecular dynamics (MD) simulations further concluded that TG could abundantly adhere to the calcite surface with higher intensity and capacity. Therefore, TG exhibited effective depression impact on calcite and achieved the separation of fluorite from calcite successfully.
Photothermal therapy based on photothermal conversion has received increasing attention due to its non-invasiveness and low side effects. In this study, a 3D-printed biomass photothermal therapy device was prepared for accurate control of photothermal conversion and molecular release. The prepared black phosphorus nanosheets (BPNSs) showed excellent photothermal performance and antibacterial activity. A temperature-regulated sol-gel reversible system was prepared with konjac glucomannan (KGM), tara gum (TG), BPNSs, and manganese dioxide (MnO 2 ) nanoparticles. The sol-gel transition was attributed to the change of interactions of hydrogen bond, and molecular entanglement. Photothermal conversion films with accurate multi-layer and array structures were prepared by 3D printing using the biomass sol-gel conversion system. The photothermal conversion efficiency was regulated by the concentration of BPNSs and MnO 2 . Under infrared radiation (808 nm, 1 W/cm 2 ) for 5 min, the temperatures of hydrogel films with a MnO 2 concentration of 0, 0.5, and 1 % were raised from 25 to 29.3, 61.8, and 90.8 °C, respectively. The accurate temperature distribution induced the controlled release of small active molecules such as epigallocatechin gallate (EGCG) loaded in hydrogels, which was resulted from the changes in the hydrogel structure and the decrease in adsorption energy between polysaccharide and EGCG at high temperatures. This study provides a biomass 3D-printed multifunctional photothermal therapy device and more understanding of the molecular release during photothermal conversion.
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