钙基蒙脱石、天然沸石对废水中Cu^(2+)的吸附研究

Absorption Behavior of Ca-montmorillonite and Natural Zeolite to Cu^(2+) in Wastewater

通过实验研究钙基蒙脱石和天然沸石对水中Cu^(2+)的吸附,探讨了溶液pH值、初始浓度、投加量、温度、时间、粒度等不同因素对去除率影响.结果表明,在酸性条件下,溶液初始pH越高则Cu^(2+)去除率越高;H+相对Cu^(2+)的竞争吸附行为可以使吸附后溶液pH上升,甚至在低浓度的Cu^(2+)溶液中pH上升为碱性.2种矿物对Cu^(2+)的吸附等温线均为L型,表明吸附行为主要是单分子层吸附.在初始浓度10～160mg/L范围内,天然沸石对10mg/LCu^(2+)溶液去除率最优,达96.86%,且优于钙基蒙脱石;而钙基蒙脱石对10～100mg/L溶液去除率达93%以上,对60mg/L溶液去除率最高,达98.21%.天然沸石的投加量越高去除率越高,与其能维持较低的平衡浓度有关,而钙基蒙脱石则存在最佳投加量.

The adsorption characteristics of the Ca-montmorillonite and natural zeolite to Cu^2＋ in water are studied by experiments. The different adsorption effects are compared by the different factors such as pH, ion concentration of the initial solution, dosing quantity, granularity of the adsorbents, temperature and adsorption time. The result is as follows. Under the acidic condition, the removal rate of Cu^2＋ rises with the initial pH increasingly, but the competitive adsorption behavior of H^＋ makes the solution pH increase or even is alkaline in low concentration solution. The adsorption isotherms of both minerals to Cu^2＋ are L type, indicating that their adsorption behavior is mainly single molecular layer adsorption. When the initial concentration varies within 10- 160mg/L, the natural zeolite has the best removal rate of Cu^2＋ with 96.86% in the 10mg/L solution, and is superior to the Ca-montmorillonite. But the Ca-montmorillonite holds the removal rate of more than 93% to the 10- 100mg/L solution, and has the best removal rate with 98.21% in the 60mg/L solution. The removal rises with the dosage of the natural zeolite increasingly, which is related to that the natural zeolite can maintain the lower equilibrium concentration, while the Ca-montmorillonite has the best dosage.