A surface-modified nano-scale black carbon(MBC)was used as a sorbent for Cu2+ and Cd2+ in single or binary system.The adsorption-desorption characteristics and stability were investigated in terms of adsorption kinetics,isotherms and desorption isotherms of Cu2+ and Cd2+ on the MBC.Batch experiments showed that the adsorption reaction of Cu2+and Cd2+on the MBC was divided into a rapid and a slow process.The adsorption quantities of Cu2+ or Cd2+ on the MBC were more than 90% of maximum within 30 min.The adsorption isotherms of Cu2+ and Cd2+ on the MBC were fitted with both the Langmuir and Freundlich equations.The maximal adsorption quantities of Cu2+ and Cd2+ on the MBC from the Langmuir equation were 417 and 245 mmol/kg,respectively,which showed that the adsorption quantity of Cu2+ was higher than Cd2+ on the MBC.The n values from the Freundlich equation were 2.56 and 3.85,respectively,and exhibited preferential adsorption.The desorption percentages of Cu2+ or Cd2+ from the MBC increased with the increase of the adsorption capacities.The desorption percentages of Cu2+ and Cd2+ were 1.45% -20.20% and 2.67% -31.40% ,respectively,and the adsorption stability of Cu2+ on the MBC was better than that of Cd2+.The two metal ions exhibited competition absorption on the MBC,and the maximum adsorption capacity of Cu2+ or Cd2+ on the MBC both decreased with the increase of the competing ion concentration.It can be concluded that the MBC hadhigher adsorption properties for the metal ions,and could be applied in the purification of wastewater containing such metal ions and the passivation of heavy metals in contaminated soils.%通过Cu2+或Cd2+单体系和Cu2+-Cd2+复合体系中Cu2+或Cd2+的吸附-解吸试验,研究了改性纳米黑碳( MBC)对Cu2+和Cd2+的吸附特性和吸附稳定性.结果表明:Cu2+和Cd2+在MBC上的吸附可以分为快、慢2个阶段,30 min达到饱和吸附量的90％以上.Cu2+和Cd2+在MBC上的吸附等温线均能用Langmuir方程和Freundlich方程拟合.Cu2+和Cd2+在MBC上的最大吸附量分别为417和245 mmol/kg,n值分别为2.56和3.85.MBC对Cu2+和Cd2+是优惠吸附,且对Cu2+的吸附能力大于Cd2+.吸附在MBC上的Cu2+和Cd2+的解吸率均随着吸附量的增加而增大,Cu2+在MBC上的解吸率为1.45％ ～ 20.20％,Cd2+为2.67％ ～31.40％.Cu2+和Cd2+在MBC上存在着竞争吸附,其最大吸附量均随着竞争离子浓度的增加而降低.MBC对Cu2+吸附量和吸附稳定性均大于Cd2+.MBC对重金属有强的吸附作用,可探索其在含重金属废水处理和重金属污染土壤钝化修复中的应用.
展开▼
