改性棕榈纤维活性炭对活性染料的吸附性能

Adsorption kinetics of reactive dye onto modified palm fiber activated carbon

为探究棕榈纤维在处理印染废水中的应用,将氧化镁(MgO)通过共沉淀-灼烧氧化法负载于棕榈纤维活性炭,利用场发射扫描电子显微镜(FE-SEM)、傅里叶转换红外光谱FT-IR、真密度测定法证实了棕榈纤维活性炭孔道及表面存在MgO。通过静态吸附实验,考察了改性前后棕榈纤维活性炭对活性艳红X-3B染料的吸附性能,对不同染料初始浓度下MgO改性棕榈纤维活性炭(MgO/PAC)对染料的吸附动力学以及在不同pH值下对染料的吸附性能进行了研究。结果表明:MgO改性可显著提高棕榈纤维活性炭的吸附性;当n(镁)∶n(碳)=2.5∶1时,改性棕榈活性炭对染料活性艳红X-3B的吸附量提高约8倍;MgO改性棕榈纤维活性炭对活性艳红X-3B的吸附符合伪二级动力学模型,颗粒内扩散不是吸附过程的唯一速率控制步骤,整个吸附过程是由多种动力学吸附机制共同作用的结果。

The palm fiber was carbonized and then modified by MgO in precipitation-burning oxidation method for dealing with dyeing wastewater. The presence of MgO on the surface of the modified palm fiber activated carbon （MgO/PAC） was confirmed by scanning electron microscopy （SEM）, FT-IR spectroscopy and the true density method. The adsorptive capacity for Reactive Brilliant Red X-3B of the palm fiber activated carbon before and after modification was tested by static absorption experiments. The adsorption kinetics of dyes onto MgO modified plam fiber activated carbon was investigated by varying dye initial concentrations and pH values. The MgO modification significantly improves the adsorption capacity of palm fiber activated carbon ; and when the ratio of MgO to carbon is 2.5： 1, the adsorption of Reactive Brilliant Red X-3B onto the MgO modified palm fiber activated carbon was increased by a factor of about 8, it followed the pseudo second-order kinetic model. The whole absorptive process was not only controlled by the intra-particle diffusion but also by extra-particle diffusion process.