摘要
利用改良离心法从好氧颗粒污泥中提取胞外聚合物(EPS),并研究其对重金属废水中Pb2+和Cd2+的吸附行为。结果表明,EPS对Pb2+和Cd2+具有很强的吸附能力,吸附行为符合Langmuir等温式,拟合得到的最大吸附量分别可达534.76和478.47 mg/g。Pb2+和Cd2+在EPS上存在竞争吸附,EPS对Pb2+的吸附选择性更强。Cd2+对EPS吸附Pb2+有一定的抑制作用,但Pb2+的存在对EPS吸附Cd2+具有显著的抑制作用。傅立叶红外光谱(FT-IR)和三维荧光光谱(EEM)测定表明,实验提取的EPS含有大量疏水和亲水性基团,因此可通过络合作用、离子交换、螯合等多种作用与重金属发生强结合。对重金属起主要吸附作用的是存在于EPS蛋白质组分中的—COOH,—NH2,—CH2—,—OH及—C=O官能团。研究表明,EPS吸附Pb2+的主要机理为离子交换和络合作用,而对Cd2+的吸附则主要通过络合作用完成。
As a kind of new biosorbent,aerobic granular sludge which has the advantages of strong adsorption capacity and easily-desorbing property,was paid great attention in the area of heavy metal waste water treatment.In this research,the adsorption behaviors of Pb^2＋ and Cd^2＋ by extracellular polymeric substances（EPS） which extracted from aerobic granular sludge using improved centrifugation methods were studied.The results showed that the adsorption capacity of Pb^2＋ and Cd^2＋ on EPS was considerably large.The experimental results were fit well with the Langmuir iostherms model.The maximum adsorption capacity for Pb^2＋and Cd^2＋by EPS was up to 534.76 mg/g and 478.47 mg/g,respectively.Furthermore,the competitive adsorption experiments presented that EPS exhibited a selective adsorption for Pb^2＋.Specially,there was a minor inhibition for Pb^2＋ adsorption in presences of Cd^2＋,while the adsorption capacity of Cd^2＋ was greatly decreased when Pb^2＋ co-existed in solutions.FT-IR and EEM analysis revealed that EPS was rich in hydrophilic groups and hydrophobic groups,which was benefit to combine heavy metals by complexation,ions exchange and chelation.The adsorption of Pb^2＋ and Cd^2＋ by EPS was mainly attributed to the —COOH,—NH2,—CH,—OH and —C=O groups from protein fractions of them.The main adsorption mechanism of Pb^2＋ by EPS was ion exchange and complexation,while for Cd^2＋ was mainly took effect by complexation.
出处
《北京大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2013年第3期514-522,共9页
Acta Scientiarum Naturalium Universitatis Pekinensis
基金
国家水体污染控制与治理科技重大专项(2009ZX07212-001)资助
