改性甘蔗渣对Pb~(2+)、Cd~(2+)的吸附行为研究

为提高废弃甘蔗渣对重金属离子Cd2+和Pb2+的吸附能力,文章采用简单的方法制备了乙二胺四乙酸二酐(EDTAD)修饰的甘蔗渣。经FTIR分析,有大量的羰基修饰在了甘蔗渣的表面,为其吸附重金属离子提供了更多的活性位点。实验结果表明:经过修饰后的甘蔗渣对Cd2+和Pb2+的吸附量分别为46.46 mg/g、119.36 mg/g,是未修饰的3.69和12.31倍,且均能在20 min内达到最大吸附量并保持平衡,其吸附符合Langmuir等温吸附模型,且吸附过程遵循二级动力学模型。在pH 4~7范围内,修饰SCB对Cd2+和Pb2+具有较高的吸附能力。除此之外,在Cd2+、Pb2+、Cu2+和Zn2+共存的情况下,修饰SCB对Pb2+仍能保持较高的吸附量。修饰后的甘蔗渣对Cd2+和Pb2+的吸附能力有了显著提高,且具有一定的抗干扰能力,有望应用于实际工业废水处理。

Modified Sugarcane Bagasse for Adsorption of Pb2+ and Cd2+

EDTAD modified sugarcane bagasse(SCB) was prepared to improve its adsorption capacity for heavy metal ion such as Cd2+ and Pb2+.FTIR spectrometer demonstrated that a large number of carboxyl groups(-COO-) were introduced on the surface of SCB which could provide more active sites for adsorption of heavy metal ions.Experimental results showed that the adsorption capacities of the modified SCB for Cd2+ and Pb2+ were 46.46 mg/g and 119.36 mg/g respectively,which were 3.69 and 12.31 times than the unmodified ones.The metal adsorption data were fitted well with the Langmuir isotherms and the adsorption process for Cd2+ and Pb2+ obey the pseudo-second-order kinetics.It also displayed consistently high levels of metal uptake over pH range from 4 to 7.Under the condition of co-ion of Cd2+,Pb2+,Cu2+ and Zn2+,high adsorption capacity of the modified SCB for Pb2+ was still retained,which indicated that the modified biosorbent may have great potentials for application in wastewater treatment.