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lckk

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[求助] 阿尔法-三氧化二铁纳米颗粒的表面电性是怎样的

请教下阿尔法-三氧化二铁的表面电性是正或负呢，这个和什么有关系，如何调控

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1楼2013-01-26 11:04:19

已阅回复此楼关注TA 给TA发消息送TA红花 TA的回帖

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3楼: Originally posted by lckk at 2013-01-26 18:42:08
请问带正负电与PH值的关系是怎样的呢...

在这篇文献Colloids and Surfaces A: Physicochemical and
Engineering Aspects 提到了 The polyanionic organic complexants like humic acids canmod-
ify the surface charge properties ofmagnetite entirely or in a certain
degree depending on their amount present in the systems. Since the
trace amount of HA (0.08mmolHA/g magnetite) only neutralizes
the positive charges of magnetite at pH lower than its PZC ∼8, and
so it promotes the aggregation between the particles having both
positive sites and negative humate patches on the surface [5]. This
patch-wise surface charge heterogeneity ruins the colloidal stabil-
ity of oxide dispersions considerably [26]. However, the presence
of larger HA amount (1.64mmol/g roughly two times higher than
the adsorption saturation of HA in Fig. 1, left) leads to the complete
surface coverage causing a sign reversal of particle charge and over-
charging of nanoparticles. High negative electrophoreticmobilities
were detected over a wide range of pH from 3 to 10 proving the
enhanced electrostatic stabilization due to the coating layer of HA.