改性柚皮粉对水中Cu(Ⅱ)和Zn(Ⅱ)的吸附

基于柚皮中富含纤维素、木质素、多糖等可与重金属发生络合、螯合作用的物质,将农林及生活废弃物柚子皮作为重金属离子的吸附剂。采用经NaOH改性的柚皮粉吸附水中Cu(Ⅱ)和Zn(Ⅱ)。考察了pH、吸附时间、改性柚皮粉用量以及Cu(Ⅱ)和Zn(Ⅱ)初始浓度等因素对吸附的影响,测定了吸附等温线,对等温吸附规律及动力学进行了探讨。结果表明,pH、吸附时间、改性柚皮粉用量、Cu(Ⅱ)和Zn(Ⅱ)初始浓度等因素对吸附效果均有影响。吸附Cu(Ⅱ)的适宜条件为:pH5.4～5.5,吸附时间10min,改性柚皮粉用量0.2g/100mL,Cu(Ⅱ)初始浓度20～80mg/L。在该条件下,Cu(Ⅱ)去除率达95%以上。吸附Zn(Ⅱ)的适宜条件为:pH5.5～5.6,吸附时间60min,改性柚皮粉用量0.4g/100mL,Zn(Ⅱ)初始浓度小于80mg/L。在该条件下,Zn(Ⅱ)去除率达90%以上。等温吸附规律可用Freundlich和Langmuir模式较好地描述,吸附呈单分层形式,吸附性能良好。吸附动力学规律符合准一级、准二级和Elovich动力学模型。

Adsorption of Cu(Ⅱ)and Zn(Ⅱ)Ions onto NaOH-modified Grapefruit Husk Powder

Grapefruit husk which abundantly contains cellulose,lignin and polysaccharide can chelate with heavy metals. Grapefruit husk peel as agricultural and living waste can be used as heavy metal adsorbent. NaOH-modified grapefruit husk powder was used as adsorbent to remove Cu(Ⅱ) and Zn(Ⅱ) ions in aqueous solution. Affecting factors on the adsorption of Cu(Ⅱ) and Zn(Ⅱ) ions from aqueous solution on NaOH-modified grapefruit husk powder including pH,shaking time,NaOH-modified grapefruit husk powder dosage,initial concentration of Cu(Ⅱ) and Zn(Ⅱ) ions were investigated. Adsorption isotherms were determined,isothermal adsorption law and adsorption kinetics was also discussed. Results showed that the factors enumerated above have definite influence on adsorption of Cu(Ⅱ) and Zn(Ⅱ) ions onto NaOH-modified grapefruit husk powder. Suitable conditions for adsorption of Cu(Ⅱ) were as pH 5.4～5.5,shaking time 10min,NaOH-modified grapefruit husk powder dosage 0.2g/100mL and initial concentration of Cu(Ⅱ) 20～80mg/L. Under the suitable conditions,removal rate of Cu(Ⅱ) can reach more than 95%. Suitable conditions for the adsorption of Zn(Ⅱ) were as pH 5.5～5.6,shaking time 60min,NaOH-modified grapefruit husk powder dosage 0.4g/100mL and initial concentration of Zn(Ⅱ) no more than 80mg/L. Under the suitable conditions,removal rate of Zn(Ⅱ) can reach more than 90%. Isothermal adsorption can be described well by Freundlich and Langmuir models. Adsorption appeared monomolecular layer and adsorption performance was favorable,with Cu(Ⅱ) and Zn(Ⅱ) ions easy to be adsorbed. Adsorption kinetics law conformed to pseudo first order model,pseudo second order model and Elovich equation.