THE USE OF PIEZOELECTRIC SYSTEMS WITH MOLECULAR PRINTS FOR FORMALDEHYDE DETERMINATION IN WASTE WATER OF WOOD PROCESSING PLANTS

The development of methods for controlling formaldehyde content in wastewater, ensuring high accuracy, ease of use, rapidity and efficiency is an urgent problem of the woodworking industry. This article discusses a method for determining the content of formaldehyde and its concentrations in water using piezoelectric sensor systems with molecular imprinting polymers, which make it possible to form three-dimensional complementary voids for the templates of the molecules being detected during polymerization and their subsequent removal. Piezoelectric sensor with molecular imprints of formaldehyde molecules for the express determination of its concentration in solution has been obtained. A grading graph with a linear relationship has been built. The coefficient of determination (R2) was determined to be 0.9815. Unknown concentrations of formaldehyde in solutions were found by the "added-found" method. For sensory determination of unknown concentrations in solution, the standard deviation (Sr,%) is less than 7%. Thus, it has been established that piezoelectric sensors modified with molecularly imprinted polymers allow highly accurate determination of the concentration of unknown pollutants in wastewater of woodworking enterprises. They are economically beneficial, regenerated with further deposition of a polymer with other imprints on their surface

Hydrothermal synthesis of nitrogen-doped carbon quantum dots from lignin for formaldehyde determination

A hydrothermal method for synthesis of lignin-based N-doped carbon quantum dots (NCQDs) proposes a mechanism for rapid reaction of NCQDs with formaldehyde to generate Schiff bases, which leads to enhanced FL emission and the observed blue shift.

Smartphone-Based Microfluidic Colorimetric Sensor for Gaseous Formaldehyde Determination with High Sensitivity and Selectivity

Formaldehyde is one of the most dangerous air pollutants, which can cause sick building syndrome. Thus, it is very crucial to precisely determine formaldehyde with a low cost and simple operation. In this paper, a smartphone-based microfluidic colorimetric sensor is devised for gaseous formaldehyde determination with high sensitivity and selectivity. Specifically, a novel microfluidic chip is proposed based on the 4-aminohydrazine-5-mercapto-1,2,4-triazole (AHMT) method to determine formaldehyde; the chip consists of two reagent reservoirs, one reaction reservoir and a mixing column. In this design to prevent the fluid from flowing out while letting the gas molecule in, a hydrophobic porous poly tetra fluoroethylene (PTFE) membrane is put on the top of the reaction reservoir. Using the microfluidic chip sensor, a smartphone-based formaldehyde determination system is developed, which makes the measuring process automated and simple. As per the experiment results, the limit-of-detection (LOD) of the system is as low as 0.01 ppm, which is much lower than the maximum exposure concentration (0.08 ppm) recommended by the World Health Organization (WHO). Moreover, the sensor is hardly affected by acetaldehyde, volatile organic compounds (VOCs) or acidic-alkaline, which shows great selectivity. Finally, the performance of the proposed sensor is verified by using it for the determination of formaldehyde in a newly decorated house.