Study On The Controllable Preparation And Adsorption Properties Of AlOOH And Al₂O₃ With Special Morphlogy

With the rapid development of industry and the disorder-exploitation,high-grade resources are gradually depleted.The comprehensive utilization of low-grade and complex symbiotic mineral resources has been paid more attention.For example,aluminum contained in laterite nickel ore,it only is agree with the national development strategy to make it into the high-value-added product,but also can improve the utilization efficiency of valuable resources.For instance,AlOOH and Al2O3 have the large specific surface area and strong adsorption capacity,and their morphology control is one of the hotspots of research.Furthermore,the above two have great application prospects in the field of wastewater treatment.In this paper,fabricate AlOOH and Al2O3 adsorbents with special morphology,hollow spherical AlOOH and Al2O3 were synthesized,and adsorption performances were investigated in detail.The research results are listed as following:(1)Employing aluminum sulfate as the raw material and urea as the precipitating agent,the hollow spherical and flower-shaped AlOOH was prepared by hydrothermal method.The influence of the materials ratio,reaction temperature,Al3+concentration,time on the phase structure and micromorphology of the specimens was investigated.The appropriate reaction conditions for preparing hollow spherical AlOOH are as below:Al2(SO4)3/CO(NH2)2 molar ratio of 1:5,reaction temperature of 180 ℃,aluminum sulfate concentration of 0.05 mol·L-1 and reaction time of 12 h.The appropriate reaction conditions for preparing flower-like AlOOH are as below:Al2(SO4)3/CO(NH2)2 molar ratio of 1:5,reaction temperature of 180 ℃,aluminum sulfate concentration of 0.20 mol·L-1 and reaction time of 16 h.(2)Hollow spherical AlOOH and Al2O3 was used to adsorb Congo red and Methyl blue,the adsorption reached equilibrium within 10 min.The adsorption ratios of AlOOH for Congo red and Methyl blue were 98.44%and 94.83%,and the theoretical adsorption capacities were 277.00 and 236.97 mg·g-1,respectively.The adsorption ratios of Al2O3 on Congo red and Methyl blue were 96.64%and 93.42%,and the theoretical adsorption capacities were 492.61 and 450.45 mg·g-1,respectively.The adsorption of Congo red and Methyl blue by hollow spherical AlOOH and Al2O3 followed the Freundlich model,which was a heterogeneous surface adsorption.The adsorption process was endothermic and spontaneous.The adsorption process obeyed the Pseudo-second-order kinetics and the adsorption was mixed controlled by the external membrane diffusion and internal diffusion.(3)Flower-like AlOOH and Al2O3 was adopted to adsorbed Congo red and Methyl blue,the adsorption reached equilibrium within 10 min.The adsorption ratios of AlOOH for Congo red and Methyl blue were 97.38%and 96.16%,and the theoretical adsorption capacities were 149.48 and 198.41 mg·g-1,respectively.The adsorption ratios of Al2O3 on Congo red and Methyl blue were 97.57%and 96.83%,and the theoretical adsorption capacities were 292.40 and 323.62 mg· g-1,respectively.The adsorption of Congo red and Methyl blue by flower-like AlOOH and Al2O3 confirmed the Freundlich model,which was a heterogeneous surface adsorption.The adsorption process was endothermic and spontaneous.The adsorption process followed the Pseudo-second-order kinetics and the adsorption was mixed controlled by the external membrane diffusion and internal diffusion.