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The adsorption mechanism of Cr(VI) onto different α-Fe2O3 crystal facets is chemisorption process through outer surface of doubly and triply coordinated hydroxyl groups.<br><br>Display Omitted<br>• 3D hierarchical α-Fe2O3 nanoparticles with different planes predominantly exposed were synthesized. • The Cr(VI) removal ability reach to 34.4 mg/g by flower-like α-Fe2O3 particles with (0 0 1) plane exposed. • The coordination between Cr(VI) and special doubly coordinated hydroxyl groups plays important role for adsorption.<br>Two kinds of 3D hierarchical α-Fe2O3 nanoparticles, flower-like structure with the (0 0 1) plane predominantly exposed on petals and urchin-like structure with nanorods grown along [0 0 1] direction, have been synthesized under the influence of glycerol by a facile hydrothermal method. It is proposed that the Fe(III)-glycerol micro-reaction units that selectively adsorb to (0 0 1) or other planes result in different morphologies. The adsorption of Cr(VI) from aqueous solution onto these α-Fe2O3 nanoparticles showed that the removal efficiency up to 98.5% and 88.8% in 25 mg/L Cr(VI) solution, and the adsorption capacity reaches to 34.4 mg/g and 26.0 mg/g without pH adjustment. The adsorption kinetic is well described by the pseudo-second-order model and the Cr(VI) adsorption on the adsorbent agrees well with the Langmuir model. Lower surface areas and more excellent adsorption property associates with the chemisorption of Cr(VI) onto α-Fe2O3 (0 0 1), which is achieved by coordination between Cr(VI) and doubly or triply coordinated hydroxyl groups on α-Fe2O3 surface.
"The ancient art of Tibetan medicine is a veritable treasure in the world annals of medical science. Tibetan medicine evolved over ages, as the Tibetan people accumulated experience struggling against the conditions of the snow plateau, emerging as a unique realm of medicine with a distinct understanding of physiology and pathology and its own methods of diagnosis, treatment and medication. The abundant medicinal herbs that grow on the plateau are the active ingredients in the special medicines Tibetans use to treat patients, which in turn is a precious cultural legacy that is now being passed on to the world. Known for its traditional therapies, Tibetan medicine is remarkably effective and beneficial, and has made great contributions to the overall health of humankind"--Container.