Solvent-free preparation of high synthetic yield carbon dots from sodium ligninsulfonate for on-site detection of formaldehyde in the environment

Formaldehyde (FA), as a widespread toxic pollutant in cars, furniture and construction materials, has been implicated in hazardous health effects on the human body. This paper presents a green and large-scale preparation of carbon dots (CDs) using sodium ligninsulfonate and o-phenylenediamine through a solvent-free reaction method. The prepared CDs exhibit a synthetic yield of 43 % and show green fluorescence. In addition, the CDs can be employed as an ideal fluorescent FA probe, exhibiting excellent linearity within the range of 0-50 mu M (R2 = 0.998, limit of detection (LOD) = 79 nM). By taking advantage of the obvious color changes in detection, the droplet detection system is investigated for on-site visual detection of indoor FA gas. This work not only contributes to the efficient utilization of agricultural waste but also represents a significant process in the development of FA on-site detection.