Adsorption of nitrate and nitrite anion by modified maize stalks from aqueous solutions.

The newly developed aminated maize stalk (AMS) was prepared by a chemical process using charred maize stalk (CMS). The AMS was used for the removal of nitrate and nitrite ions from aqueous media. The effects of initial anion concentration, contact time, and pH were studied by the batch method. The prepared adsorbent was characterized by FT-IR, XRD, FE-SEM , and elemental analysis. The concentration of the nitrate and nitrite solution before and after was determined with the help of a UV-Vis spectrophotometer. The maximum adsorption capacities were found to be 294.11 mg/g for nitrate and 232.55 mg/g for nitrite, respectively, at pH 5 for both ions attaining equilibrium within 60 min. The BET surface area of AMS was found to be 25.3 m 2 /g with a pore volume of 0.02cc/g. The pseudo-second-order kinetics model fit well, and the adsorption data supported the Langmuir isotherm. The findings revealed that AMS has a high capability for removing nitrate (NO 3 - ) and nitrite (NO 2 - ) ions from their aqueous solutions.