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古尔胶属多糖类,目前广泛应用于制药、化妆品、纺织、食品及矿业等工业领域。其中一个重要的用途就是在浮选镍矿和铂矿中作为脉石矿物滑石的抑制剂。然而,古尔胶在固体表面上的吸附机理还不是很清楚。本文应用光谱方法及相关技术对古尔胶在固液界面上的吸附进行了研究。研究结果表明,溶液条件,如pH和离子强度等对古尔胶在滑石上的吸附量没有显著的影响,从而确定了静电力不是吸附过程中的决定性因素。动电研究表明,古尔胶降低了滑石表面的负的Zeta电位值,但并不改变电荷符号。没有观察到古尔胶从矿物表面上解吸下来的现象,这说明这种聚合物牢固地键合在固体表面上。用芘和丹磺酰作探针剂的荧光光谱法研究了疏水缔合在古尔胶吸附中所起的作用。试验结果表明,经古尔胶作用后在滑石-液相界面上没有形成疏水区域。能破坏氢键的尿素降低古尔胶在滑石上的吸附量的幅度与降低古尔胶在氧化铝上的吸附量的幅度相近,而在古尔胶吸附于氧化铝表面过程中氢键起主要作用。综上所述,古尔胶吸附在滑石上的主要动力是氢键,而不是静电力或疏水作用。
Gul gum is a polysaccharide, is currently widely used in pharmaceutical, cosmetics, textiles, food and mining and other industrial fields. One of the important uses is the use of talc as a gangue-mineral inhibitor in flotation of nickel and platinum. However, the mechanism by which Gul gum adsorbs on solid surfaces is not well understood. In this paper, spectroscopic methods and related techniques were used to study the adsorption of guer gum on the solid-liquid interface. The results show that the solution conditions, such as pH and ionic strength, have no significant effect on the adsorption amount of guer gum on talc, and thus determine the electrostatic force is not the decisive factor in the adsorption process. Electrokinetic studies have shown that gul gum reduces the negative Zeta potential of the talc surface but does not change the charge sign. No evidence of the desorption of gul gum from the mineral surface was observed, indicating that the polymer is firmly bound to the solid surface. Fluorescence spectra of pyrene and dansyl as probes were used to investigate the role of hydrophobic association in the adsorption of guer gum. The experimental results show that no hydrophobic region is formed on the talc-liquid interface after the Gul gum effect. The extent to which the urea that destroys the hydrogen bond reduces the amount of adsorbed on the talc by the guer gum is similar to that of the decrease of the amount of the guer gum adsorbed on the alumina whereas the degree of hydrogen bond in the adsorption of the guar gum on the alumina surface is mainly effect. In summary, Gul gum adsorption on talc in the main driving force is hydrogen bonding, rather than electrostatic or hydrophobic effect.