黄铁矿-卵清蛋白在浮选过程中相互作用的电化学研究

卵清蛋白(OVA),俗称鸡卵清白蛋白,是一种环保、无毒、廉价的表面活性剂。它的分子结构中含有电化学活性巯基。采用循环伏安法、红外光谱和浮选实验研究 OVA 在黄铁矿表面吸附以作为替代抑制剂。在宽的电位范围内和碱性pH值条件下,研究电化学条件对吸附机制和抑制率的作用。当OVA不存在时,可浮性在弱氧化电位条件下达到极大值。超出此电位范围,可浮性会由于生成 Fe 的氢氧化物以及亲水类的硫化物而降低。在整个测试电位范围内OVA?黄铁矿发生相互作用。OVA的抑制效果随着电位从还原电位、弱氧化电位,到黄铁矿的开路电位逐渐增加,这主要是由于OVA分子弱的构象变化以及开路电位下的疏水作用引起的。OVA的抑制率在中等氧化电位下达到极大值,这被称为静电引力。由于 OVA 以金属螯合物形式吸附,在较高的电位下这种高的抑制效果可以几乎一直保持下去。

Electrochemical study of pyrite-ovalbumin interaction in relation to flotation

Ovalbumin （OVA）, chicken egg albumin, is an environmentally friendly, non-toxic, cheap surface active agent. It has electrochemically active sulfhydryl residues in molecular structure. OVA adsorption on pyrite as an alternative depressant was investigated by cyclic voltammetry, FTIR spectroscopy and flotation. Tests were conducted in a wide potential range in alkaline pH to clarify the role of electrochemical condition on the adsorption mechanisms and the rate of depression. In the absence of OVA, the floatability reached its maxima around slightly oxidizing condition. Beyond the range, it decreased presumably due to the formation of Fe-oxyhydroxides together with the hydrophilic S-containing species. OVA-pyrite interaction occurred in the whole examined potential range. Depressing effect of OVA increased gradually from reducing to slightly oxidizing potential, open circuit potential （OCP） of pyrite, mainly due to weak conformational changes in OVA molecules together with the hydrophobic interaction around OCP. The rate of depression reached its maxima at moderately oxidizing potentials, which was referred to electrostatic attraction. This level was almost kept at higher potentials owing to OVA adsorption as metal-chelates.