Construction of a sensor for the determination of cyanide in industrial effluents: a method based on quartz crystal microbalance

It is the aim of current investigation to develop a method based on quartz crystal microbalance (QCM) system for the detection of cyanide in industrial effluents. A thin layer of nickel was coated on the top of the quartz electrodes. The composite electrode was then used to determine cyanide in solutions. Nickel was reacted with cyanide ions in the presence of oxygen after soaking in cyanide solution. This caused a decrease in electrode mass which is responsible for the frequency shift. sults showed that the corresponding frequency shift was linearly related to the concentration of cyanide ions in solution. Using this method the cyanide ions can be measured in the range of 0–10 ppm. Effect of various factors including solution pH, Ni thickness and the interfering effect of a number of anions and cations was also investigated. No major interference was involved in the performance of the sensor. The lower limit of detection (LLD) of 0.28 ppm obtained for the sensor. A comparative study on the samples of effluent from an electroplating plant revealed no significant difference between ASTM method and the proposed QCM techniques.