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用吸附平衡法研究了不同草酸浓度、体系pH对针铁矿 (G)吸附Cd2 + 的影响与机制以及电解质 (KNO3)浓度对针铁矿、草酸化针铁矿 (G +40 )吸附Cd2 + 的影响差别及原因。结果表明 ,低浓度草酸 (<1mmol·L-1 )促进Cd2 + 的吸附 ;高浓度草酸 (>1mmol·L-1 )抑制Cd2 + 的吸附。已吸附在针铁矿表面的草酸对Cd2 + 吸附的影响与液相中草酸的影响不同 ,这主要与草酸引起的针铁矿表面电荷性质的变化、草酸在固液两相间的分配、草酸与Cd2 + 的配合作用和竞争作用有关。电解质 (KNO3)浓度对针铁矿和草酸化针铁矿吸附Cd2 + 的影响明显不同 ,随KNO3 浓度的提高 ,针铁矿的Cd吸附率由 44 5 %增至 95 %以上 ,而草酸化针铁矿吸附率由 2 9%降至6 2 % ,这主要决定于二者的电荷零点 (PZC)和体系pH变化的不同。
The effects of different concentrations of oxalic acid and system pH on Cd2 + adsorption on goethite (G) and the effect of electrolyte (KNO3) concentration on the adsorption of Cd2 + on goethite and oxalate goethite (G +40) Differences and causes of influence. The results showed that low concentration of oxalic acid (<1 mmol·L-1) promoted Cd2 + adsorption and high concentration of oxalic acid (> 1 mmol·L-1) inhibited Cd2 + adsorption. The effect of oxalic acid adsorbed on the surface of goethite on Cd2 + adsorption is different from that of oxalic acid in liquid phase, which is mainly related to the change of surface charge of goethite induced by oxalic acid, the distribution of oxalic acid between solid and liquid phases, Cd2 + with the role of competition and competition. The effect of KNO3 concentration on the adsorption of Cd2 + by goethite and oxalate goethite is obviously different. With the increase of KNO3 concentration, the Cd adsorption rate of goethite increased from 44 5% to above 95% Iron ore adsorption rate decreased from 29% to 62%, which mainly depends on the difference between the charge zero point (PZC) and the change of system pH.