Extraction of triazine herbicides by polyhydroxyl-polyurethane foam in environmental samples

In this work, a new type of sorbent (polyhydroxyl-polyurethane foam or PPF) was synthesized by using water hydrolysis of polyurethanediazonium chloride salt. PPF was characterized using different tools (infrared spectra, elemental analysis, scanning electron microscopy and thermogravimetric analysis). It was tested for the extraction of atrazine, prometryn and terbutryn herbicides from environmental samples. The batch technique was conducted to evaluate the effects of initial pH, contact time, temperature, volume of sample and initial concentration of triazine herbicides on the removal of the herbicides from the aqueous solution. The extraction of the herbicides was accomplished in a period ranging from 5-15 min. The experimental data of the sorption was fitted by pseudo-first and pseudo-second-order kinetic mathematical equations and better followed the pseudo-second-order kinetics (R(2) ≈ 0.966). The equilibrium process was accurately described by the Freundlich isotherm model; the average Freundlich constant (1/n) value was 0.68, which was attributed to the heterogeneous surface structure of the PPF. The average capacity of the conventional polyurethane foam material was 0.34 mmol/g for herbicides. The study shows that PPF has the potential to be applied as an efficient sorbent for the extraction of herbicides from real matrix samples.