Application of Layered Double Hydroxide Membranes as Phosphate-Sensitive Electrodes

作者：Tafesse Fikru^*; Enemchukwu Martin

来源：Phosphorus, Sulfur, and Silicon and the Related Elements, 2015, 190(1): 36-44.

DOI：10.1080/10426507.2014.919294

• aluminium phosphate
• adsorption
• Layered double hydroxides (LDH)
• interference
• chemisorption
• phosphate-sensitive electrode

Highly selective and sensitive phosphate sensors have been fabricated by constructing a solid membrane disk comprising variable mixtures of aluminum powder (Al), aluminum phosphate (AlPO4), and powdered copper (Cu). Both binary and ternary electrode systems were produced. The ternary membranes exhibit greater selectivity over a wide range of concentrations. The ternary electrode with the composition 25% AlPO4, 25% Cu, and 50% Al was selected as our preferred electrode. The ternary membrane electrodes exhibited linear potential response in the concentration range of 1.0x10(-1) to 1.0x10(-6)molL(-1). The mechanism for the selectivity of phosphates by the electrodes includes adsorption, absorption, and ion-exchange processes. An understanding of these processes reveals that the composition of the membrane material and its molecular structural framework are all important. The layered double hydroxides which form within the interstitial layers of the phosphate selective membranes contribute to the selectivity of the ions.

• 出版日期2015-1-2