D201树脂吸附富马酸的工艺条件优化

Optimization of adsorption conditions for fumaric acid by D201 resin

离子交换树脂因具有吸附率高、选择性高等优点常被用于有机酸的原位分离。本文首先筛选了对富马酸具有较高吸附能力的D201树脂作为吸附树脂,然后进一步探究了pH和温度的影响。结果发现:D201树脂对富马酸离子形式的吸附能力从大到小顺序为HFA^(-)、FA^(2-)、H_(2)FA;且HFA^(-)吸附到树脂上仅占据一个吸附位点,FA^(2-)可能占据两个吸附位点,吸附位点利用率降低;分子形式的H_(2)FA通过疏水相互作用被吸附到树脂骨架上;吸附过程属于吸热反应(ΔH>0),升温有助于吸附。对解吸条件进行了优化,最佳的解吸条件是NaCl为解吸剂,解吸浓度1 mol/L,解吸体积10 mL,解吸时间20 min,此条件下解吸率达到89.6%。通过重复实验证明了D201树脂具有较高的重复利用率。最终证明了D201树脂可以被用于富马酸的分离,为进一步的原位回收奠定了基础。

Ion exchange resins with high adsorption capacity and high selectivity are usually used to separate of organic acids.Firstly,the D201 resin with high adsorption capacityfor fumaric acid was selected.The pretreatment method of resin,pH and temperatureare studied to determine the influenceon its adsorption capacity.The results show the adsorption ability of D201 resin for three fumarate ion forms was as follows:HFA->FA^(2-)>H_(2)FA.HFA^(-) was adsorbed on the resin by one-site-occupancy adsorption,but FA 2-is adsorbed by two-site-occupancy adsorption which decreased the utilization rate of adsorption sites.H_(2)FA could not be adsorbed on the adsorption sites of D201 resin but it had the hydrophobic interactions with resin matrix.The adsorption process was an endothermic reaction and increasing the temperature was beneficial to this process.At the same time,the desorption conditions were optimized and the desorption rate reached 89.6%when 10 mL 1 mol/L NaCl was used as stripping agent to treat resin 20 min.D201 resin could be reused for eight times.The results prove that D201 resin can be used for the separation of fumaric acid,for in situ recovery of fumaric acid.