有机皂土的双硫腙修饰及其对水中铅离子的吸附行为

The adsorption behavior of the organobentonite (CTMAB-bentonite) modified with dithizone for lead ion in water was investigated.A sort of cheap sorbent was prepared through modifying organobentonite with dithizone and was characterized with FT-IR.By means of flame atomic absorption spectrometry (FAAS), the adsorption situation and mechanism were studied.The results showed that after treating bentonite with cetyl trimethyl ammonium bromide (CTMAB),dithizone could be immobilized on the bentonite firmly.The lead ion in water could be adsorbed quantitatively on the organobentonite modified with dithizone, and the adsorbed quantity was affected by pH value of medium, temperature and time.The adsorption behavior followed a Langmuir adsorption isotherm and a pseudo-second-order kinetic model.The enthalpy change of the adsorption process was 58.432 kJ·mol-1,and Gibbs free energy change was negative at different temperatures.The reaction of adsorption was an spontaneous, endothermal process.

1-(2-吡啶偶氮)-2-萘酚修饰有机皂土吸附富集火焰原子吸收光谱法测定水中铅

采用十六烷基三甲基溴化铵(CTMAB)对皂土进行改性,用1-(2-吡啶偶氮)-2-萘酚(PAN)对其表面进行修饰,得到了新型粉体吸附材料PAN-OBNTN,对其结构及其对水中铅离子的吸附性能进行了研究。结果表明:当介质的pH为6时,振荡吸附45 min吸附达到平衡,最大吸附容量为5.7 mg·g^(-1)。吸附在PAN修饰有机皂土上的铅离子可用10 g·L^(-1)EDTA溶液5 mL完全洗脱回收,在此洗脱液中用火焰原子吸收光谱法测定其中痕量铅的含量。本方法的富集倍数为10,检出限(3S/N)为8.3μg·L^(-1)。在铅的初始浓度为0.2 mg·L^(-1)的条件按方法测定,所得测定值的相对标准偏差(n=6)为4.3%。用于自来水和河水中痕量铅的吸附富集测定,加标回收率在93.8%～101.0%之间。

双硫腙修饰有机皂土吸附富集-原子吸收光谱法测定水中痕量镉

采用静态浸渍法，将双硫腙修饰于用十六烷基三甲基溴化铵（CTMAB）改性的皂土表面，制备了双硫腙修饰有机皂土，对其结构及其对水中镉离子的吸附性能进行了研究，确立了双硫腙修饰有机皂土对镉离子的吸附和洗脱条件，建立了双硫腙修饰有机皂土吸附富集-火焰原子吸收光谱法测定水中镉的新方法。结果表明，经CTMAB改性后，双硫腙可牢固地负载于皂土上，当介质的pH值为4～8时，双硫腙修饰有机皂土对水中镉离子具有很强的吸附能力，其吸附容量可达1．428mg／g。经富集10倍后，该法检出限为0．16μg／L。应用于管网水和河水中镉的测定，加标回收率为92．8％～104．0％，并与石墨炉原子吸收光谱法测定值一致。