8-羟基喹啉功能化树脂HQDK-110对Hg2+的吸附性能

8-羟基喹啉对金属离子具有良好的络合性能。研究了一种8-羟基喹啉接枝DK-110的螯合型离子交换树脂HQDK-110对Hg~(2+)的吸附性能,并与DK-110树脂进行比较。考察了不同吸附时间、Hg~(2+)浓度、温度和pH值条件下两种树脂对Hg~(2+)的吸附性能和去除性能。结果表明,HQDK-110和DK-110树脂对Hg~(2+)的适宜吸附p H值为4.5左右。25℃时,HQDK-110和DK-110树脂对Hg~(2+)的吸附容量分别为2.496 mmol/g和2.290 mmol/g。HQDK-110和DK-110对Hg~(2+)的吸附过程更接近于一级动力学方程,其一级吸附动力学常数k1分别为0.009 4 min-1和0.011 8 min-1。吸附过程符合Langmuir等温吸附方程。研究表明,HQDK-110对Hg~(2+)的吸附量和去除率优于DK-110,且树脂的稳定性优于DK-110,湿态树脂比干态树脂具有更好的重复使用性能。

Adsorption properties of 8-hydroxyquinoline functionalized resin HQDK-110 for Hg2+

The paper is inclined to present the results of its studies on determining the adsorptive properties for Hg2+ from the aqueous solution onto a renovated chelating ion-exchange resin known as HQDK-110 and a weak-acid ion exchange resin named DK-110.What is more,the above study has been followed by a comprehensive comparison between the above said two resins in their adsorption performance.Well in contrast,the said HQDK-110 has been prepared by a grafting reaction between DK-110 and 5-cloromethy l-8-hydroquinoline.Apart from that,8-hydroxyquinoline enjoys excellent complex capacity for numerous kinds of metal ions while the extraction efficiency of 8-hydroxyquinoline for the metal ions can be improved by way of grafting 8-hydroxyquinoline onto the insoluble and/or non-meltable macromolecules.It is just due to the aforementioned characteristics that in our experiment,the adsorption properties of Hg2+ have been used to determine the features of the HQDK-110 and DK-110 under the various conditions,such as the adsorption time,the Hg2 + concentration,the temperature,as well as the pH value.In addition,the paper has also made a comparison between the removal rate and repetitive application performance between the two aforementioned kinds of resin.On the other hand,the pH value is also an important factor that has effects on the adsorption of Hg2+ onto the resins with the increase of adsorption,which can be observed with the pH value increase (pH =1.5-6.0).What is more,since the hydrolysis degree also increases at a higher pH value,the optimal adsorption pH has to be fixed at about pH 4.5.Besides,the results gained in our experiment also show that the adsorption of Hg2+ by the resins can be affected by the temperature,too,for higher temperature benefits the adsorption,which implies that the adsorption belongs to an endothermic process.Statistically speaking,the adsorption capacities of Hg2+ on HQDK-110 and DK-110 should be 2.496 mmol/g and 2.290 mmol/g at the temperature of 25 ℃,respectively,when the initial concentration is set up at Hg2+ 0.025 00 mol/L.At the same time,the dynamic adsorption has to be well fit for the pseudo first-order-rate model at the various temperatures,in which the kinetic constant k1 is equal to 0.009 4 min-1 for HQDK -110 and 0.011 8 min-1 for DK-110.Hence,the adsorption process and data also prove to be in conformity with Langmuir isotherm.As a result,the removal rate of HQDK-110 for Hg2+ is higher than that of DK-110.and the wet resin shows better reuse performance than the dry resin does.It is found that chelating ion-exchange resin HQDK-110 has better adsorption for Hg2+ than the ion-exchange resin DK-110,especially,in terms of adsorption capacities and removal rate.Meanwhile,HQDK-110 also shows better particle stability in the process of the repeated application.