半碳化离子交换纤维的研究

本文对半碳化离子交换纤维(SCSIEF)的制备条件、反应机理和产物结构以及对金属离子的交换吸附行为进行了研究。将天然纤维经半碳化处理后,分别用浓 H_2SO_4、浓 HNO_3、HSO_3Cl 氧化或磺化处理,可制得具有较高交换容量的 SCSIEF。实验结果表明:SCSIEF 的最高交换容量可达9.16meq/g,最佳制备条件为半碳化温度300—400℃,磺化温度90—100℃,反应时间90min。这种 SCSIEF 对稀土金属离子 La~(3+1)过渡金属离子 Cu~(2+)、Co~(2+)、Ni~(2+)、Hg~(2+)、Cd~(2+)有较好的交换吸附性能。特别对贵重金属离子 Ag~+、Au~(3+)有优异的交换吸附能力。

SEMI-CARBONIZED ION EXCHANGE FIBER

Using the semi-carbonized fiber as a raw material,which is obtained by usingnatural fiber to be impregnated with diluted NaOH and NH_4H_2PO_4 solution res-pectively in pure nitrogen,through the following reactions respectively,the ionex-change fiber(SCSIEF)can be obtained:① sulfonation reaction with concentratedH_2SO_4 by using V_2O_5 and Na_2SO_4 as catalysts;② oxidization with concentratedHNO_3;③ preoxidation with concentrated HHO_3 at room temperature and then sul-fonating with concentrated H_2SO_4;④ sulfonating with diluted solution of chlorosul-furic acid(HSO_3Cl)in dichloroethane solvent.The experiemental results show thatSCSIEF,which was prepared through the reaction ③,possesses the highest ion ex-change capacity(IEC)9.16meq/g,and that the IEC of SCSIEF obtained through the reaction ① can reach 7.58-8.42 meq/g,however,that obtained through the reaction ④ isthe lowest.The temperature of semi-carbonization,the temperature and time of sulfo-nating reaction influence significantly upon the IEC of SCSIEF.The optimal semi-car-bonization temperature is in the range of 300 to 400℃,If over that,the IEC rapidlydecreases.When temperature of sulfonation reaction is in the range of 90 to 100℃,the IEC of SCSIEF increases speedly with the increasing of reaction temperature.Theoptimal reaction time is 90 minutes.The results of investigation of absorption behavi-ours of SCSIEF indicates the orders of absorption amounts of SCSIEF towards La~(+3)are Ha~+ -SCSIEF>NH_4~+ SCSIEF>H~+ SCSIEF.The SCSIEF are also a good absorbenttowards transition metal ion such as Cd~(+2),Hg~(+2)and precious metal ions such as Ag~(+1)and Au~(+3).