功能化多壁碳纳米管负载铁离子改性双极膜的制备与表征

分别用未功能化的多壁碳纳米管(MWCNTs)、羟基化多壁碳纳米管(MWCNTs-OH)、羧基化多壁碳纳米管(MWCNTs-COOH)、磺酸基化多壁碳纳米管(MWCNTs-SO3H)改性羧甲基纤维素钠(CMC)-聚乙烯醇(PVA)/壳聚糖(CS)-聚乙烯醇双极膜(BPM)的阳离子交换膜层。采用力学性能分析、接触角测定、电流密度-槽电压曲线等对改性前后双极膜的性能进行表征,并测定了改性前后双极膜中Fe~(3+)的流失量。结果表明,经功能化多壁碳纳米管改性后,双极膜的亲水性和力学性能得到了显著提高。功能化多壁碳纳米管和Fe~(3+)对催化中间界面层水解离有协同作用,大大提高了中间界面层水解离效率,降低了双极膜的膜阻抗和槽电压。此外,改性后双极膜中Fe~(3+)的流失量有了明显的下降,从而保持了双极膜结构和催化水解离性能的稳定性。

Preparation and Characterization of Bipolar Membranes Modified by Functionalized Multiwalled Carbon Nanotubes Loaded with Fe3 +

The cationic exchange layers of the carboxymethyl cellulose (CMC)-polyvinyl alcohol (PVA) /chitosan (CS)-polyvinyl alcohol bipolar membranes (BPM) using glutaraldehyde as crosslinker and ferric chloride as modifier,were modified by multi-walled carbon nanotubes (MWCNTs),hydroxylated multi-walled carbon nanotubes (MWCNTs-OH),carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) and sulfonated multi-walled carbon nanotubes (MWCNTs-SO3H),respectively.The mechanical properties,contact angle and electric current density-cell voltage curve as well as the Fe3+ loss amount of the CMC-PVA/CS-PVA BPMs before and after modification were compared.The experimental results show that after modification by functionalized multi-walled carbon nanotubes,both the hydrophilicity and mechanical properties of the bipolar membrane are significantly improved.The functionalized multi-walled carbon nanotubes and Fe3 + have a synergistic effect on promoting water splitting in the intermediate layer,thus the water splitting efficiency is greatly improved,and the membrane impedance and cell voltage of bipolar membrane are reduced.In addition,functionalized multi-walled carbon nanotubes existed in the bipolar membrane are beneficial for retention rate of Fe3 + in BPMs during electrolysis,and then to maintain the stability of the structure and catalytic performance for water splitting of the BPMs.