强磁场下NH4Cl水溶液结构的拉曼光谱研究

Study of Raman Spectroscopy on the Structure of NH4Cl Aqueous Solution Under Strong Magnetic Field

迄今为止,国内外存在很多关于强磁场处理对水溶液结构影响的争议,并且关于强磁场对无机盐水溶液结构的研究也相对较少。运用拉曼光谱法,测定了在外加强磁场1.8 T强度下,高纯水与质量分数分别为1%,5%,10%,20%和28%的NH4Cl水溶液在不同磁化时间下的拉曼散射数据,为拉曼光谱法探究强磁场对水溶液结构的影响提供了一个新的可行方式,丰富了拉曼光谱的研究领域。由实验结果可知,随着磁化时间的增加,水分子中氢键的伸缩振动峰值逐渐升高,经过一定的磁化时间后可以达到饱和。高纯水与不同质量分数的NH4Cl水溶液的饱和效应时间均不同。高纯水与质量分数为1%,5%,10%,20%和28%的NH4Cl水溶液峰值饱和时间分别为150,120,120,100,80和80 min。随着NH4Cl水溶液质量分数的增加,达到磁效应饱和的时间呈现减少的趋势。磁场移除后,测定高纯水与不同质量分数NH4Cl水溶液的去磁记忆时间。高纯水与质量分数为1%,5%,10%,20%和28%的NH4Cl水溶液的去磁记忆时间分别为30,40,50,60,80和80 min。随着NH4Cl水溶液质量分数的增加,去磁记忆时间呈现增加的趋势。利用去卷积拟合的方法对磁化2 h后不同质量分数的NH4Cl水溶液进行处理。由去卷积拟合结果可知,质量分数为20%的NH4Cl水溶液比质量分数为10%的NH4Cl水溶液增加了一个N—H峰,该信号峰随着NH4Cl水溶液质量分数的增大逐渐增强。DDAA型氢键结构整体上随磁化时间增加而减少,磁化时间的增加对四面体水结构具有破坏作用。当达到饱和磁化时间后,DDAA型氢键不再发生变化。实验结果表明,通过拉曼光谱法可以得到1.8 T强磁场对NH4Cl水溶液结构的影响规律,为外加强磁场条件下其他无机盐水溶液的研究提供了一定的理论基础。

Numerous controversies are existed at domestic and abroad up to now about the effect of strong magnetic field treatment on the structure of the aqueous solution.However,few pieces of literature have studied the structure of salt solution with the same treatment.Raman spectroscopy was used in this paper to determine the scattering data of high-purity water and NH4Cl aqueous solution with mass fractions of 1%,5%,10%,20% and 28% at a different time under the external strengthened magnetic field of 1.8 T.It provided a feasible method for Raman spectroscopy to investigate the effect of strong magnetic fields on the structure of the aqueous solution,enriching the Raman spectroscopy research field.According to the experimental results,the value of stretching vibrations of hydrogen bonds in water molecules gradually increased with the increased magnetization time.It could reach saturation after a certain magnetization time.The saturation time of high-purity water and NH4Cl aqueous solution with different mass fractions was different.The time of high-purity water and NH4Cl aqueous solution with mass percentages of 1%,5%,10%,20% and 28% was 150,120,120,100,80 and 80 min.The time to reach the saturation of magnetic effect showed a decreasing trend with the increased mass fraction of NH4Cl aqueous solution.The demagnetization memory time of high-purity water and different mass fractions of NH4Cl aqueous solution was measured after the magnetic field was removed.The demagnetization memory time of high-purity water and NH4Cl aqueous solutions with mass fractions of 1%,5%,10%,20%,and 28% was 30,40,50,60,80 and 80 min,respectively.The demagnetization memory time presents an increasing trend with the increased mass fraction of NH4Cl aqueous solution.NH4Cl aqueous solutions with different mass fractions after 2 h of magnetization was processed by deconvolution fitting.According to the deconvolution fitting result,NH4Cl aqueous solution with the mass fraction of 20% increased a peak of N—H compared to NH4Cl aqueous solution with the mass fraction of 10%.The signal peak gradually increased with the increased mass fraction of NH4Cl aqueous solution.The structure of the hydrogen bond of DDAA-type decreased with the increased magnetization time,which had a destructive effect on the tetrahedral structure of water.The hydrogen bond of DDAA-type did not change any more when it reached the saturation magnetization time.The influence of 1.8 T magnetic field on the structure of NH4Cl aqueous solution could be obtained through Raman spectroscopy,which provided a certain theoretical basis for the study of another inorganic salt aqueous solution under the condition of external strengthening magnetic field.