Stability,Morphological Transformation,Recrystallization And Flocculability Investigation Of Planar Tridecameric Al₁₃?OH?₂₄?H₂O?₂₄¹⁵⁺

The flocculation morphology plays a decisive role in preparing and applying efficient flocculants.The research on Poly Aluminum Chloride?PAC?was mainly focused on Al₁₃ polymer,because many experiment results indicated that Al₁₃ polymer species were the key component of flocculation.In this thesis,the stability,morphological transformation,recrystallization and flocculation properties of Al₁₃ were studied for the first time.The transformation from P-Al₁₃ to K-Al₁₃ in aqueous solution was associated with temperature,pH and solvent,etc.The transformation was completely inhabited low temperature?below 5??,but was accelerated with increased temperature,thus low temperature was the condition to keep the stability of P-Al₁₃.The transformation trend of K-Al₁₃ presented "volcano",indicating that a higher temperature will promote K-Al₁₃ to develop to Al₃₀.Under the condition of low pH,P-Al₁₃ will not transform to K-Al₁₃ even at high temperature,pH is the main factor affecting the morphological transformation of P-Al₁₃.In addition,due to the organic solvent prevents the further hydrolysis of P-Al₁₃ in the solvent,as a result,P-Al₁₃ will not transform to K-Al₁₃ in organic reagent solution.The recrystallization experiment was conducted under the guidance of the AlCl₃-Al₂O₃-H₂O phase diagram at 25 ?,which conformed P-Al₁₃ crystalline could be recrystallized from the P-Al₁₃ solution aged at high temperature with transformation to K-Al₁₃ or Al₃₀.Due to the maintenance of P-Al₁₃ structure,prepared P-Al₁₃ crystal,P-Al₁₃ solution?0??and freeze dried P-Al₁₃ showed excellent and comparable flocculation property in the terms of floc growth rate,floc size and floc strength,etc.Flocculation dynamic experiments showed that the spontaneous hydrolysis products as-prepared P-Al₁₃ solid and P-Al₁₃ solution?0??flocculation gerenated floc fast,with large particle size,high strength,strong regrowth ability,and forced hydrolysis products K-Al₁₃ and Al₃₀ flocculation dramatically decreased.The stability of P-Al₁₃ is of great significance to develop its flocculation performance.