Mg-doped CaCO_(3)nanoarchitectures assembled by(441)high-index facets for efficient trace removal of Pb(Ⅱ)  

作　　者：Yu Yan Yu-Bo Cui Qing-Yan Wang Zhong-Xuan Che Tong Liu An-Ran Li Wei Zhou 

机构地区：[1]School of Chemistry,Beijing Advanced Innovation Center for Biomedical Engineering,Beihang University,Beijing,100191,China

出　　处：《Rare Metals》2023年第2期525-535,共11页稀有金属（英文版）

基　　金：financially supported by the National Natural Science Foundation of China(Nos.51438011,51102005);the Academic Excellence Foundation of BUAA for Ph.D.students。

摘　　要：Removal of trace heavy metal ions puts high demands on designing adsorbents with favorable surfaces.Crystal-plane engineering can provide controllable adsorption energy between surficial planes and adsorbents.Herein,we have creatively synthesized Mg-doped CaCO_(3)nanoarchitectures assembled by layered sheets(Mg-CaCO_(3)LSs)with high-index facets of(441)through a facile wet chemical process.Adsorption tests reveal that the layer-bylayer assembled sample exhibits a maximum Pb(II)adsorption capacity of 1961.9 mg·g^(-1),agreeing with the monolayer-adsorption Langmuir model.At an initial Pb(II)ion concentration of 20 mg·L^(-1),the adsorption can achieve a high removal rate near 99.0%within 1 min,and the adsorption kinetics follows a chemisorption pseudo-second-order model.Interestingly,the Mg-CaCO_(3)LSs show much-improved adsorption properties towards low-concentration Pb(II)ions,which could reduce the concentration from 1 mg·L^(-1)to~2.9μg·L^(-1)in 3 h(within 30 min decrease to less than 10μg·L^(-1),meeting drinking water standard from WHO).For comparison,the commercial CaCO_(3)and collected CaCO_(3)scale show much lower adsorption values with Pb(Ⅱ)ion residual concentration of~935.0 and~944.9μg·L^(-1)in 3 h,respectively.Xray diffraction(XRD),energy dispersive spectroscopy(EDS),and inductively coupled plasma(ICP)characterizations on the Mg-CaCO_(3)LSs before and after adsorbing Pb(Ⅱ)confirm that the high removal performance could be ascribed to fast metal ion exchange and excellent physical adsorption contributed by high-index planes.The density functional theory(DFT)calculations also confirm that the much-enhanced adsorption kinetics benefits from the optimal adsorption of the(441)planes.This work will provide a feasible route to design highefficient low-cost adsorbents through crystal-plane engineering.

关 键 词：High-index plane Calcium carbonate High adsorption energy Trace Pb(Ⅱ)removal 

分 类 号：X703[环境科学与工程—环境工程] TQ424[化学工程]