| Three different routes are employed to improve the filtration efficiency of Mg(OH)2granules, which is based on the application of crystallization. Spherical assembly withnanosheets on the surface and hollow microspheres are obtained by utilizing buffer solution toimprove the crystallization of Mg(OH)2. Mg(OH)2 hexagonal platelets are obtained, viahydrothermal treatment of amorphous Mg(OH)2. One-dimensional (1D) Mg(OH)2 whiskersare synthesized on a large scale by utilizing SO42- ions. The high crystallization leads to betterfiltration properties than those of amorphous Mg(OH)2. The improvement of the filtrationefficiency optimizes dynamic manipulation, which offers a significant control over the qualityof Mg(OH)2 products.The chemical bonding theory is used to investigate the fundamental crystallizationbehaviours of magnesium carbonate hydrate crystals Mg5(CO3)4(OH)2·4H2O andMgCO3·3H2O in terms of crystallographic structure, with the aim to guide and control thepractical crystal growth. The ideal morphology of Mg5(CO3)4(OH)2·4H2O and MgCO3·3H2Ocrystals has readily been predicted, by calculating the vertical growth rate of selected planesin terms of the bond number and bond strength. Theoretically, Mg5(CO3)4(OH)2·4H2O crystalexhibits hexagonal plate-shaped characteristics, while MgCO3·3H2O crystal possesses ahexagonal prism morphology. Experimentally, the hexagonal Mg5(CO3)4(OH)2·4H2Omicro-platelets and MgCO3·3H2O micro-prisms with reproducible shape can be obtained by asimple liquid-phase reaction. Theoretical results are in a good agreement with ourexperimental observations. Single crystal growth can be improved by tuning the bondingmodification of constituent atoms or ions, such a process can leave us a great space tokinetically maximize our experimental strategies.1D 5Mg(OH)2·MgSO4·2H2O (512MHSH) materials directed by SO42- ions in aqueoussolution are synthesized on a large scale. The designed experiments show that theconcentration of SO42- ions, pH and the temperature allow us to explain quite well the growthdynamics. The ideal morphology of 512MHSH crystals is predicted from the chemicalbonding theory. Crystallographically, SO42- ions aligned along the b axis of 512MHSHcrystals, play a bridge role to link two adjacent Mg(OH)64- fragments, and thus direct512MHSH to preferentially form 1D structures. Both theoretical and experimental resultsshow that SO42- ions direct the 1D growth of 512MHSH during the transformation from irregular Mg(OH)2 particles to 1D 512MHSH structures. The current work greatly extendspractical application of Mg(OH)2 due to the overcoming of agglomeration.
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