摘要
镉离子是水体、土壤中的一类重要污染物,主要来源于采矿、冶金、电镀等工业排放的废水,必须经严格处理后才能排放。为此,研究了碳纳米管对水中镉离子的吸附去除性能,首先将碳纳米管在浓硝酸中于140℃回流1h进行纯化;然后在一组100mL碘量瓶中,分别加入25mL50mg/L的镉离子溶液,再分别加入一定量的碳纳米管,进行静态吸附试验,测定镉离子的去除率。结果表明:纯化的碳纳米管对水中镉离子的去除效果明显高于未纯化的碳纳米管,在25mL50mg/L的镉离子溶液中当其用量为4g/L时,纯化的碳纳米管对水中镉离子的吸附去除率达到93.6%;纯化的碳纳米管对水中镉离子的吸附在60min达到平衡;溶液pH值对水中镉离子的去除有一定的影响,在中性和弱碱性条件下的去除率大于酸性。平衡吸附量qe与平衡质量浓度ρe之间的关系符合Freundlich和Langmuir等温吸附方程所描述的规律。
As one of the major pollutants in soil and water,Cd2+ is mainly originated from industrial effluent of mining,metallurgy and electroplating,and must be removed before discharging of the wastewater.Thus the adsorption of Cd2+ in wastewater by carbon nanotubes(CNS)was studied.The as-received CNS were firstly purified by refluxing in concentrated nitric acid at 140 ℃ for 1 h.Then static adsorption experiments were carried out by adding 25 mL of aqueous solution with 50 mg/L Cd2+ into a series of iodine measuring flask,for determination of the removal efficiency of Cd2+.Results showed that the purified CNS had much better removing efficiency for Cd2+ than that the as-received ones.Namely,when the dose of the purified CNS was kept as 4 g/L,the Cd2+ in the wastewater containing 50 mg/L Cd2+ were adsorbed up to a rate of about 93.6%,and the adsorption of Cd2+ reached equilibration around a duration of 60 min.Moreover,the adsorption of Cd2+ depended on acidity of the aqueous solution.Namely,slightly stronger adsorption was reached in neutral and weakly alkaline solution than in acidic solution.And the relationship between adsorbing capacity(qe)and equilibrium mass concentration(ρe)was found to be in accordance with the isothermal adsorption equations of Freundlich and Langmuir.
出处
《材料保护》
CAS
CSCD
北大核心
2008年第9期14-16,共3页
Materials Protection
基金
辽宁省教育厅基金资助基目(No.05L367)
关键词
镉离子
吸附
碳纳米管
纯化
等温线
Cd2+
adsorption
carbon nanotubes
purification
isotherm
