微孔交联淀粉的制备及其对Zn(Ⅱ)的吸附FIRT和XRD分析

FTIR and XRD Analysis of the Preparation and Adsorption for Zn(Ⅱ) of Microporous Crosslinked Starch

以可溶性淀粉做原料,用N,N′—亚甲基双丙烯酰胺交联,过硫酸铵引发聚合得到微孔交联淀粉(MCS),并研究了其对Zn^(2+)的静态吸附行为;用红外光谱仪和X射线衍射仪对MCS及其吸附产物进行了对照分析。结果表明:MCS对Zn^(2+)的吸附符合Freundlich等温方程,吸附量达到2.36 mmol/g;MCS在1536 cm^(-1)处出现酰胺Ⅱ带N-H弯曲振动吸收峰,表明了淀粉与MBAA成功交联;MCS在3445cm^(-1)附近的N—H、O—H伸缩振动偶合而增宽的多重峰在吸附产物中变宽,且向低波数位移,而1536cm^(-1)处的酰胺Ⅱ带N—H弯曲振动吸收峰则移至1543cm^(-1)处,说明在吸附过程中,MCS的酰胺基团上的N、O原子可能与Zn^(2+)发生了配位反应;XRD显示,可溶性淀粉经交联后结晶度降低至6.4%左右,MCS上的酰胺基和—OH与Zn^(2+)形成配位键使MCS的晶形结构被进一步破坏,结晶度约为0.5%左右,已基本处于无序的非晶态。

The Microporous Crosslinked Starch （MCS） were synthesized from soluble starch, using N, N＇--methylenebisacrylamide as the crosslinking agent, APS as the initiator. Adsorption characteristic of MCS for Zn^2＋ was investigated; The product after adsorption was characterized by Fourier transform infrared spectroscopy （FTIR） and X--ray diffraction （XRD）. The results showed that the adsorption characteristic of MCS for Zn^2＋ is adapted to Freundlich adsorption isotherm equation, adsorption amount of Zn^2＋ was 2.36 mmol/g; Absorption peak of bending vibration Amide （ K ）of N--H at the wavenumber of 1536 cm-lecplained that starch and MBAA had been successfully crosslinked; Absorption peak of stretching vibration of N--H,O--H had become broaden in MCS-Zn^2＋, wave number were decreased, absorption peak of bending vibration Amide（ II ） of N--H at the wavenumber of 1536 cm^-1 were enhanced to 1543cm^-1, which illustrated N and O atom had coordinated with Zn^2＋ ; XRD indicated that crystallinity reduced to 6.4% after the soluble starch had been crosslinked, MCS--Zn^2＋ further destroyed the crystallitic structure of MCS, the ture.