pyrocatechol removal from aqueous solutions by using azolla filiculoides

background pyrocatechol or 1, 2-dihydroxybenzene, or 2-hydroxyphenol is considered as apriority pollutant since it is harmful to organisms at low concentrations, and has been classified as hazardous pollutants. objectives the objective of this study was to examine whether azolla filiculoides, is able to remove pyrocatechol from aqueous solutions. materials and methods this study is an experimental research. in this study, the aquatic fern azolla with different biomass (0.3, 0.6, 0.9, 1.2 g) has been cultured in solutionwhichwas contained 5, 10, 25, and 50 ppm pyrocatechol. each exam repeated twice. samples were collected every 2 days from all of containers. the analytical determination of pyrocatechol was performed by using dr4000 spectrophotometer by analyzing the color resulting with the wavelength of 600nm. results the results showed that azolla has high ability to remove pyrocatechol from aqueous solutions. the pyrocatechol removal was 60-90%. the removal efficiency wasincreasing with decreasing pyrocatechol concentration, and increasing biomass amount, and vice versa. the removal efficiency was more than 90% when pyrocatechol concentration was 5 ppm, and amount of biomass was 0.9 gr. conclusions it is concluded that azolla is able to accumulate and remove pyrocatechol from the aqueous solutions. since conventional methods of pyrocatechol removal need high cost and energy, phytoremediation by azolla as a natural treatment system can decrease those issues, and it can be a useful and beneficial method for theremoval of pyrocatechol.