Anion release and uptake kinetics: structural changes of layered 2-dimensional ZnNiHN upon uptake of acetate and chlorinated acetate anions.
X-ray diffraction and UV-vis spectroscopy were used for the investigation of ion exchange reaction kinetics of nitrates with acetate (Ac), chloro acetate (ClAc), dichloro acetate (dClAc) and trichloro acetate (tClAc) anions, using zinc nickel hydroxy nitrate (ZnNiHN) as the exchange precursor. The exchange reactions conducted at 24, 30, 40 and 50°C revealed that rate constants were inversely related to the calculated anion electronic spatial extent (ESE), while a direct relationship between rate constants and the average oxygen charges was observed. Temporal solid phase structural transformations were shown to be affected by the nature of the guest anions. The amount of nitrates released into solution has been shown to decrease as the guest anions became more chlorinated. Use of isoconversional approach revealed that activation energies changed significantly with α during dClAc intercalation than for the other anions. The topotactic intercalation of the guest anions, except dClAc, followed the Avrami-Erofe'ev kinetic model for the entire reaction progress.
Department of Chemistry, Marquette University, PO Box 1881, Milwaukee, WI 53201-1881, United States.
Cleopas
C
Machingauta
Jeanne M
JM
Hossenlopp
D000085:Acetates / Q000737:chemistry*; D000838:Anions; D002713:Chlorine / Q000737:chemistry*; D007700:Kinetics; D015394:Molecular Structure; D033362:Powder Diffraction; D017550:Spectroscopy, Fourier Transform Infrared; D017967:Zinc Compounds / Q000737:chemistry*
D000085:Acetates; D000838:Anions; D017967:Zinc Compounds; D002713:Chlorine
Avrami Erofe’ev; Electronic spatial extent; Isoconversional; Topotactic