Abstract:

Co²⁺-Ni²⁺-Fe³⁺--LDHs (layered double hydroxides, LDHs) materials were synthesized by using trisodium citrate (TSC) assisted homogeneous precipitation technology. The influences of TSC amount on the basal spacing and morphology of the obtained materials were investigated by changing TSC amount from 0.6 mmol/L to 3.0 mmol/L. Then the deintercalation of carbonate ions from a Co²⁺-Ni²⁺-Fe³⁺--LDHs materials with different basal spacing and shape morphology were investigated by socking in a NaCl-HCl mixed solution. The results indicated that LDHs with basal spacing of 0.776 nm and well-defined hexagonal shapes was obtained when TSC optimized amount was between 0.6-1.0 mmol/L, exhibiting a good anion exchange property. Thus a series of materials intercalated by, , , and CH₃(CH₂)₁₁anions were obtained. When TSC amount was up to 1.5 mmol/L, a new layered structure of LDHs with basal spacings of 0.770 nm and 0.691 nm was observed with rose-like morphology consisting of reunion hexagonal shapes, decreasing its anion exchange property. When TSC amount was further increased to 3.0 mmol/L, the layered structure of LDHs with a basal spacing of 0.681 nm was observed with ball-shaped like morphology consisting of reunion hexagonal shapes, leading to its anion exchange property disappear.

Key words: Co2+-Ni2+-Fe3+ LDHs, trisodium citrate, ion exchange reaction, morphology