Monitoring Cd2+ in oily wastewater using an aptamer-graphene field-effect transistor with a selective wetting surface

Hao Wang; Zhuang Hao; Cong Huang; Feiran Li; Yunlu Pan

doi:10.1039/d2na00416j

Monitoring Cd²⁺ in oily wastewater using an aptamer-graphene field-effect transistor with a selective wetting surface

Nanoscale Adv. 2022 Dec 13;5(5):1416-1424. doi: 10.1039/d2na00416j. eCollection 2023 Feb 28.

Authors

Hao Wang^{1

2}, Zhuang Hao^{1

2}, Cong Huang^{1

2}, Feiran Li^{1

2}, Yunlu Pan^{1

2}

Affiliations

¹ Key Laboratory of Micro-Systems and Micro-Structures Manufacturing of Ministry of Education, Harbin Institute of Technology Harbin 150001 Heilongjiang China yunlupan@hit.edu.cn lifeiran@hit.edu.cn.
² School of Mechatronics Engineering, Harbin Institute of Technology Harbin 150001 Heilongjiang China.

Abstract

The discharge of oily industrial wastewater containing heavy metal ions with the development of industry severely threatens the environment and human health. Therefore, it is of great significance to monitor the concentration of heavy metal ions in oily wastewater quickly and effectively. Here, an integrated Cd²⁺ monitoring system consisting of an aptamer-graphene field-effect transistor (A-GFET), oleophobic/hydrophilic surface and monitoring-alarm circuits was presented for monitoring the Cd²⁺ concentration in oily wastewater. In the system, oil and other impurities in wastewater are isolated by an oleophobic/hydrophilic membrane before detection. The concentration of Cd²⁺ is then detected by a graphene field-effect transistor with a Cd²⁺ aptamer modifying the graphene channel. Finally, the detected signal is collected and processed by signal processing circuits to judge whether the Cd²⁺ concentration exceeds the standard. Experimental results demonstrated that the separation efficiency of the oleophobic/hydrophilic membrane to an oil/water mixture was up to 99.9%, exhibiting a high oil/water separation ability. The A-GFET detecting platform could respond to changes in the Cd²⁺ concentration within 10 min with a limit of detection (LOD) of 0.125 pM. The sensitivity of this detection platform to Cd²⁺ near 1 nM was 7.643 × 10^-2 nM^-1. Compared with control ions (Cr³⁺, Pb²⁺, Mg²⁺, Fe³⁺), this detection platform exhibited a high specificity to Cd²⁺. Moreover, the system could send out a photoacoustic alarm signal when the Cd²⁺ concentration in the monitoring solution exceeds the preset value. Therefore, the system is practical for monitoring the concentration of heavy metal ions in oily wastewater.