Preparation and Process Parameter Optimization of CeO2 Adsorbents by Hydrothermal Method
In response to the issues of high hazard and low safety associated with the preparation of micro/nano adsorbents for pol-lutants using strong bases or highly volatile aqueous ammonia as precipitating agents,this paper combined the hydrothermal method and roasting process to prepare the CeO2 adsorbent by using Ce(NO3)3·6H2O as the cerium source,water as the solvent,and the weakly alkaline organic chemical compound triethanolamine(TEA)as the precipitant.The effects of the process parameters on the physical phase structure and grain size of the final samples were investigated by the gradient design of the hydrothermal reaction temperature(120～200℃)and TEA addition(3～30 mmol).Meanwhile,the adsorption characteristics of the CeO2 adsorbent to-wards the acid orange 7(AO7)azo dye molecules were investigated,and the optimal process parameters for the preparation of CeO2 were screened using the adsorption rate as an indicator.The results showed that when Ce(NO3)3·6H2O was 6 mmol,TEA was 6 mmol,the hydrothermal process condition was 120 ℃-24 h,and the roasting condition was 500 ℃-2 h,the resulting sample was a pure and single CeO2 physical phase,and under these conditions,the CeO2 adsorbent exhibited the highest adsorp-tion efficiency for AO7,reaching up to 99.7％.The research findings provide guidance for establishing green and safe preparation methods for CeO2 adsorbents and their application in purifying azo dye wastewater.
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