Considering the protocol of "zero-alkaline waste disposal" for green and arsenic-free environment, lanthanum (La3+)-based MOF-like complex materials were designed, and the complex materials have been employed as adsorbent for AsO43- adsorption from water. The sucrose-derived porous carbon (SPC)@La-oxalate complex was prepared by a simple one-pot coprecipitation method at room temperature, where oxalate has been used as an organic ligand, and the carbonaceous biomass has been used as a doping material that is naturally a carboxylate-rich functional group derived from a sucrose biomass. In addition to SPC@La-oxalate, bare-SPC, La(OH)3, and SPC@La(OH)3 were also prepared via simple base-addition conventional methods, and their performances in AsO43- removal were compared. The FTIR peak at 848 cm-1 confirmed the presence of AsO43- on the SPC@La-oxalate complex after adsorption of 1 mM AsO43-. The high resolution X-ray photoelectron spectrum for the AsO43- adsorbed SPC@La-oxalate showed a peak at EB[As 3d] = 45.2 eV, which could be attributed to As5+. The EXAFS of the As K-edge revealed that there are two distinct atomic shells, As-O with the distance of 1.68 Å and As-La with the distance of 3.32 Å, indicating the formation of monodentate complex of La with AsO43-. Additionally, an electrostatic interaction and hydrogen bonding are also possible adsorption mechanism in acidic conditions. The SPC@La-oxalate complex adsorbent showed excellent dearsenate behavior of 1.093 mmol/g, and the maximum AsO43- removal was maintained in a wide pH range from 3 to 8. Sorption kinetic data were the best expressed by a pseudo-second-order rate equation, and the maximum adsorption capacity was 1.858 mmol/g based on Langmuir monolayer adsorption. Compared with previous reports, SPC@La-oxalate adsorbent could be easily prepared, and the uptake amounts for AsO43- were enriched. Reusability of the material after six cycles is yet another advantage to the present adsorbent. This work will help to facilitate the research on novel complex adsorbents for the removal of AsO43- from water.
!!!All Science Journal Classification (ASJC) codes
- 化学 (全般)