Review—Graphene-Based Water Quality Sensors

Abstract

Water is fundamental to most aspects of human civilization and terrestrial life in general. The problem of deteriorating water quality is very real, but often hard to quantify for lack of data. Hence the development of water quality sensors has become an urgently important area of research. Here we summarize an emerging class of water quality sensors based on field effect or chemiresistive geometries, which work completely in the solid state and can operate without reference electrodes. Such devices are candidates for continuous online monitoring applications of surface, ground, drinking, process, and wastewater streams. Single layer and few layer graphenes are suitable materials for the sensing channels in these devices due to their chemical and mechanical robustness and favorable electronic properties. While single layer graphene devices are more sensitive, few layer graphene sensors are easier to manufacture at a lower cost and offer a wider dynamic range. Detection of pH, disinfectants, mercury, lead, chromium, arsenic, potassium, calcium, some anions, as well as organic and biological species has all been demonstrated at the proof of concept stage, with much more work in progress. One can anticipate the commercial availability of such devices in the near future.

Influence of the Electrolyte Salt Concentration on DNA Detection with Graphene Transistors

“…In interfacial sensing with GFETs, the conductance is mainly influenced by two concurrent mechanisms: Local gating by charged molecules in the vicinity of graphene that perturb the EDL and locally change the gate capacitance, and electron transfer, which may oppose the former effect, giving rise to opposite Dirac point shift directions [ 29 ]. In our experiment with pH, the non-modified graphene surface was in direct contact with the solution, with pH ranging from 3 to 9, which resulted in a shift toward lower voltage with increasing pH ( Figure 3 c).…”

Structure, Properties, and Electrochemical Sensing Applications of Graphene‐Based Materials

“…[140,141] Some of these electrochemical devices combined with high-standard materials, such as graphene and its derivatives, present great potential for environmental applications. [1,133] Herein, we emphasize several studies that have described the environmental applications of graphene, GO, and rGO for monitoring water quality [142] and detecting food colorants, toxic substances, [143] and hazardous ions. [137,144] These studies have emphasized the importance of the electronic/structural characteristics of graphene and its derivatives for the improvement of the electroanalytical figures.…”

Graphene field-effect transistors as bioanalytical sensors: design, operation and performance

“…nucleic acids, proteins, metabolites, drugs, etc.). Such biosensors have numerous applications in a variety of areas including biomedicine, [1][2][3] environmental monitoring 4,5 and public health. 6,7 Analyte detection and transduction into signal can be mediated by different mechanisms, including optical, electrochemical, electrical or mechanical.…”