[Study of infrared spectra of polyaluminum ferric chloride].
Mid-IR spectra of polyaluminum ferric chloride (PAFC) with different Al/Fe molar ratio were studied by Fourier transform infrared spectroscopy. Some vibration bands were assigned. In the range of Al/Fe molar ratio < 3:7 and > 6:4, the delta bending vibration frequencies at 850-880 cm-1 of [formula: see text] and 930-970 cm-1 of [formula: see text] in PAFC vs Al/Fe molar ratio are linearly relalional. It shows that Fe(III) and Al(III) were taken place each other in [formula: see text] and [formula: see text], and these were the evidences for the presence of [formula: see text]. When Al/Fe molar ratio was close, [formula: see text] and [formula: see text] Al bulk bending vibration bands at 680 cm-1 and 625 cm-1 respectively became an overlapped and broad band at 640 cm-1. Correspondingly, the [formula: see text] and [formula: see text] delta bending vibration bands were weak markedly or even disappear. And these were the evidences for the presence of co-aggragation of Fe(III) and Al(III) hydroxyl polymers (Aluminous ferrihydrite). Intensity and frequency change of H-OH delta vibrations bands at 1,610-1,630 cm-1 vs Al/Fe molar ratio show: the amounts of coordinating water in Al-Fe hydroxyl co-aggragation compounds of PAFC are the highest and no longer change, as well as, the force of banding of coordinating water with center atoms is increasing when Al/Fe molar ratio > 6:4. These suggested that there are species structural Al-Fe hydroxyl co-aggragatin compounds and this is one of the causes that stability of PAFC solution can be keeped for a long time.
Zhang
Xin-hua
XH
Guizhou Administrative Bureau of Prison, Guiyang 550002, China.
Zhou
Li-yun
LY
Tang
Min
M
D000535:Aluminum / Q000737:chemistry*; D017607:Aluminum Compounds / Q000737:chemistry*; D002712:Chlorides; D005290:Ferric Compounds / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry; D015394:Molecular Structure; D011108:Polymers; D017550:Spectroscopy, Fourier Transform Infrared
D017607:Aluminum Compounds; D002712:Chlorides; D005290:Ferric Compounds; D011108:Polymers; D017665:Hydroxyl Radical; D000535:Aluminum; C024555:ferric chloride