Using waste to treat waste:Red mud induced hierarchical porousγ-AlOOH andγ-Al_(2)O_(3) microspheres as superior Pd support for catalytic reduction of 4-nitrophenol

摘要

Toward the imperative treatment of the industrial wastewater containing 4-nitrophenol(4-NP)and industrial solid waste red mud(RM),an innovative approach of“Using waste to treat waste”is developed.Valuable element Al is leached from the RM first,the resultant NaAlO_(2) solution is hydrothermally converted toγ-AlOOH hierarchical porous microspheres(RMγ-AlOOH HPMSs,average diameter:2.0μm,SBET:77.81 m^(2) g^(-1),pore volume:0.38 cm^(3) g^(-1))in the presence of urea.The subsequent mild thermal conversion results inγ-Al_(2)O_(3) hierarchical porous microspheres(RMγ-Al_(2)O_(3) HPMSs).Both of the RMγ-AlOOH and RMγ-Al_(2)O_(3) HPMSs are employed as the Pd catalyst support for the catalytic reduction of 4-NP.Particularly,the as-obtained composite Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) exhibit excellent catalytic activities with superior knor as 8204.5 and 4831.4 s^(-1) g^(-1),respectively,significantly higher than that of most Pd based catalysts.Moreover,the excellent catalytic stability and durability of the Pd/RMγ-AlOOH and Pd/RMγ-Al_(2)O_(3) within 10 successive cycles of reduction enable the present industrial solid waste RM inducedγ-AlOOH andγ-Al_(2)O_(3) HPMSs as great promising Pd catalyst support for the reduction of the industrial wastewater containing 4-NP.