摘要
用氨水中和氟铌酸和氟氧铌酸制备的氢氧化铌表面强烈吸附氨,红外光谱分析在1400cm-1处有NH4+的v4(F4)简正振动模式特征峰。热重分析以及在不同温度下热处理的红外光谱分析结果表明,在500℃左右才能将NH3彻底从氢氧化铌表面脱除。因此,用氨中和方法制备氢氧化铌的正确化学表达式为NbOx(OH)y(NH4)x。在室温下用不同浓度的无机酸水溶液处理氢氧化铌后的红外光谱分析结果进一步证实了上述结论。用HNO3水溶液处理氢氧化铌可将NH4+交换下来,得到的氢氧化铌样品在300℃左右失重结束;用H2SO4水溶液处理氢氧化铌也可将NH4+交换下来,但SO42-在其表面发生了微弱的吸附作用,用稀H3PO4水溶液只能将部分NH4+交换下来,但同时PO34-在其表面发生了强烈的吸附作用。
The ammonia can be strongly absorbed on the surface of niobium hydroxide prepared by ammonia neutralization of NbOF2-5 or NbF2-7 complexes.The FTIR analyses shows that there is a characteristic peak at 1400cm-1 which is attributed to the ν4（F4） normal vibration of NH＋4.TG and FTIR analyses show that only at the temperature of 500℃,can ammonium be removed from the surface of niobium hydroxide.Therefore,the correct chemical formula of niobium hydroxide prepared by ammonia neutralization is NbOx（OH）y（NH4）x.The NH＋4 on niobium hydroxide can be exchanged with HNO3 solution,and the weight loss of niobium hydroxide sample is ended at about 300℃.The NH＋4 on niobium hydroxide can also exchanged with H2SO4 solution,however,SO2-4 is weakly absorbed on the surface of niobium hydroxide.Dilute H3PO3 solution can exchange NH＋4 partially,but PO3-4 is strongly absorbed on the surface of niobium hydroxide.
出处
《分析仪器》
CAS
2011年第3期28-32,共5页
Analytical Instrumentation
基金
国家自然基金(20976077)
