花生壳复合水凝胶的制备及其吸附铅、镉性能

Preparation of peanut shell composite hydrogel and its adsorption properties of lead and cadmium

  • 摘要: 以花生壳(PS)、丙烯酸(AA)为聚合单体,过硫酸钾(APS)为引发剂,N,N-亚甲基双丙烯酰胺(MBA)为交联剂,β-环糊精(β-CD)作为增强材料,通过自由基聚合反应合成花生壳木质纤维素/β-环糊精/丙烯酸复合水凝胶〔PS(H)/β-CD/PAA)〕;研究了PS(H)/β-CD/PAA的表面性质和微观形貌,考察了在不同环境因子条件下PS(H)/β-CD/PAA对Cd2+、Pb2+的吸附行为和吸附机理。结果表明:PS(H)/β-CD/PAA具有多孔网络结构,加入β-CD后制备的复合水凝胶有更好的机械性能;PS(H)/β-CD/PAA合成成本低,并且可以循环使用;PS(H)/β-CD/PAA对Cd2+、Pb2+可在60 min内达到吸附平衡,最大吸附容量分别为115.67、181.71 mg/g,在pH为3~8的较宽范围有良好的效果;PS(H)/β-CD/PAA对Cd2+、Pb2+的吸附过程主要通过离子交换、络合作用或配位作用来进行;此外,PS(H)/β-CD/PAA在处理实际废水时,对Pb2+、Cd2+、Cu2+、Zn2+的去除率分别达76.4%、88.6%、72.9%、31.6%。PS(H)/β-CD/PAA处理水体重金属效果良好,能够充分利用资源、节约成本,可作为一种重金属废水处理的潜在新材料。

     

    Abstract: Peanut shells lignocellulose/β-cyclodextrin/acrylic acid composite hydrogel (PS(H)/β-CD/PAA) was prepared by free radical polymerization, using peanut shells(PS) and acrylic acid(AA) as polymerization monomers, potassium persulfate(APS) as initiator, N,N-methylenebisacrylamide(MBA) as crosslinking agent, β-cyclodextrin(β-CD) as reinforcing material. The surface properties and size morphology of the composite hydrogel adsorbent were characterized. The adsorption behavior and mechanism of PS(H)/β-CD/PAA on Cd2+ and Pb2+ under different environmental factors were investigated. As a result, PS(H)/β-CD/PAA had a porous network structure and positive mechanical properties when β-CD was added. PS(H)/β-CD/PAA presented lower synthesis cost and recyclability. The adsorption of PS(H)/β-CD/PAA on Cd2+ and Pb2+ reached adsorption equilibrium within 60 min and worked effectively in a wide pH range of 3-8. The maximum adsorption capacity of PS(H)/β-CD/PAA composite hydrogel for Cd2+ and Pb2+ was 115.67 and 181.71 mg/g, respectively. The adsorption process of PS(H)/β-CD/PAA on Cd2+ and Pb2+ was mainly carried out through ion exchange, complexation or coordination interaction. In addition, when treating actual wastewater, the removal efficiency of PS(H)/β-CD/PAA on Pb, Cd2+, Cu2+ and Ni2+ was 76.4%, 88.6%, 72.9% and 31.6%, respectively. In a word, PS(H)/β-CD/PAA exhibited good effectiveness in treating heavy metals in water, took full advantage of resources and saved costs, and could serve as a potential new material for heavy metal wastewater treatment.

     

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