氧化锰改性的茶叶渣吸附水体中Pb(Ⅱ)

Study on sorption characteristic of tea waste modified by hydrated manganese oxide toward Pb( Ⅱ) in water

将水合氧化锰(HMO)采用原位沉积技术负载于废弃茶叶渣表面,合成了复合材料氧化锰改性的茶叶渣(HMO-TW),研究了HMO-TW对水溶液中常见重金属离子Pb(Ⅱ)的吸附特性,探讨了溶液p H值、共存碱土离子、温度、接触时间、Pb(Ⅱ)初始浓度等因素对Pb(Ⅱ)的吸附效果的影响.结果表明:酸性范围内,Pb(Ⅱ)的去除率随p H升高而增大;在竞争离子Ca(Ⅱ)、Mg(Ⅱ)、Na(Ⅰ)的浓度高于Pb(Ⅱ)20倍时,Pb(Ⅱ)的吸附去除率仅分别下降11%、7%和1%;Pb(Ⅱ)的吸附过程较好的符合Freundlich等温模型,计算的理论最大吸附容量为188.25 mg·g-1.远远高于未经改性茶叶渣的Pb(Ⅱ)吸附量(33.49 mg·g-1);Pb(Ⅱ)的吸附速度较快,250 min内便基本达吸附平衡.所有结果均证实HMO-TW在净化实际铅污染水体中有着较为广阔的应用前景.

Hydrated manganese oxide was impregnated successfully onto tea waste by precipitation to obtain a new sorbent named HMO-TW,and the sorption behaviors of it toward Pb（ Ⅱ） from aqueous solution was evaluated by investigating the influences of pH value, coexisting ion,temperature,contact time and initial concentration of Pb（ Ⅱ）. The experiment results demonstrated that Pb（ Ⅱ） sorption onto HMO-TW was p H-dependent,and the higher pH value was much helpful for Pb（ Ⅱ） removal onto HMO-TW at investigated pH range. The removal efficiency of Pb（ Ⅱ）onto HMO-TW declined only 11%,7% and 1% with the addition of Ca（ Ⅱ）,Mg（ Ⅱ） or Na（ Ⅰ）at 20 times higher than lead concentration. In addition, Pb（ Ⅱ） sorption onto HMO-TW could be described well by Freundlich model,and the calculated maximum sorption capacity by Langmuir equation was 188. 25 mg·g^-1,which was much higher than the unmodified tea waste（ 33. 49 mg·g^-1）,sorption speed of lead was quick and could nearly reach equilibrium within 250 min. All the listed results validated that HMO-TW is a promising sorbent for removal of lead from waters.