Thermally activated powders of leaves, stems or barks and their ashes of Calotropis Zygantia, Azadiracta Indica and Eichhornia, are found to have affinity towards nitrites at low pH values. The sorption properties of these sorbents have been explored for extracting nitrites from polluted waters by optimizing the physicochemical parameters such as pH, time of equilibration and sorption concentration. The sorption concentration needed for the maximum extraction of nitrite at optimum pH: 2 is less for bark powders and ashes than for leaves powders in the case of Calotropis Zygantia and Azadiracta indica but in the case of bio-materials derived from Eichhornia, the optimum sorption concentration remains the same. The optimum time of equilibration is found to be less with powders of stems or ashes of leaves than with raw powders of leaves for Azadiracta Indica and Eichornia but in the case of materials related to Calotropis Zygantia, the time remains the same. More than 80% removal of Nitrite is noted with bio-sorbents at optimum experimental conditions. Five fold excess of common ions present in natural waters has less effect on the % of extraction of Nitrite at optimum conditions of extraction. The methodologies developed are tested with the real polluted water samples and are found to be remarkably successful.