磷改性斜发沸石的组成和结构表征

Composition and Structure Characterization of Phosphorus-Modified Clinoptilolite

采用焙烧法、微波法固固相同晶取代反应对斜发沸石骨架进行磷改性 ,并用化学分析、XRD、FT -IR和2 9Si、2 7Al、3 1 PMASNMR等手段对其化学组成和骨架结构进行表征。结果表明 ,通过骨架脱Al或占据晶格空穴 ,P进入沸石骨架形成八面体硅的Si(Oct)—O—P结构及Si端位磷氧基团 ;也可以通过Si、Al、P结构重排形成Al—O—P结构。由于P的进入 ,沸石骨架扭曲 ,矿样结晶度降低 ,主衍射峰位移。但是 ,磷改性并未破坏斜发沸石的基本骨架结构 ,仍属于斜发沸石单斜晶系。由于微波对矿样有较强的穿透能力 ,微波法骨架上P的同晶取代效果优于焙烧法。

The framework of clinoptilolite was modified with solid-solid isomorphous substitution of phosphorus by microwave irradiation and calcination methods. Physicochemical properties of P-modified clinoptilolite (MMZ, WMZ) were characterized by means of chemical analysis, XRD, FT-IR and 29Si, 27Al, 31P MAS NMR spectroscopy. Experimental results showed that in MMZ and WMZ, phosphorus was substituted into the framework by dealumination or by occupying crystal lattice cave, forming the Si(Oct)-O-P structure of octahedron silicon,and the phosphorus-oxygen atom group with Si in the terminal position.The Al-O-P structure could also be formed through structural rearrangement of Si, Al, P. Because of phosphorus substitution into clinoptilolite framework, the crystallinity of P-modified clinoptilolites decreased, the main peaks of XRD and v in as, v ex as were displaced, the framework distorted and the stretching vibration v O P-O of phosphorus-oxgyen atom group yielded in FT-IR of WMZ. But the basic framework structure of clinoptilolites was not destroyed by the phosphorus modification, still maintaining the monoclinic system. For the isomorphous substitution of phosphorus in clinoptilolite, the microwave irradiation method is superior to the calcination method.