蒙脱石中Cu2+的吸附态研究

对在ＰＨ≤４．５、痕量浓度条件下吸附了Ｃu＾２＋的蒙脱石的Ｘ射线衍射（ＸＲＤ）进 行了研究。该蒙脱石的ｄ（００１）由原始蒙脱石的１．４７９ｎｍ变为１．５２３ｎｍ,说明水合铜离子置换了蒙脱石的层间阳离子;在该蒙脱石的ＥＰＲ谱中记录到了ｇ＝２．０７、ｇ ＝２．１４精细结构线和ｇ为约２．７～２．２超精细结构线三组有关Ｃu＾２＋ 的信号,说明其中的Ｃu＾２＋有三种不同的结构状态。同时,该蒙脱石热处理产物的ＥＰ

State of Cu2+ adsorbed by montmorillonite

XRD result of montmorillonite adsorbing Cu~(2+) shows its d(001) value is 1. 523 um which is different from that of the original sample with d(001 ) of 1. 479 um, suggesting that the inter-canons of montmorillonite have been replaced by hydrated copper ions. In the EPR spectra of montmorillonite adsorbing Cu~(2+), there are three signals relating with Cu~(2+). They are respectively located at g = 2. 07, g = 2. 14 which are fine lines and g ca. 2. 2 - 2. 7 which is supper fine line. It is proposed that there is three different structural state of Cu~(2+). EPR study of the thermal products of these montmorillonites shows that g = 2. 14 signal relates with hydrated copper ions existing in the interlayer of montmorillonites and g = 2. 07 signal relates with Cu~(2+) occupying the ditrigonal cavities of Si-O sheet. And, the supper fine line of g ca. 2. 2 - 2. 7 suggests Cu~(2+) migrating into octahedral vaeancies. It can be concluded that there is two adsorption styles of montmorillonite to Cu~(2+): exchangeable adsorption and special adsorption.