The fixed bed column sorption study for the nitrate removal by a cationic modified inedible pumpkin shell

Abstract

A fixed bed column was applied to remove nitrate ions from an aqueous solution using a cationic modified pumpkin shell as a sorbent. The fixed bed column performances were assessed by varying the influent nitrate concentrations (50 mg dm-3 and 100 mg dm-3) and flow rates (20 cm 3 min-1 and 40 cm 3 min-1) with 13 cm bed height of the sorbent. The obtained results showed that increase of the concentration of the initial nitrate solution affects the increase in the amount of nitrate in the effluent and reduces the breakthrough time. A higher flow rate led to the faster column exhaustion, resulting in the shortened lifespan of the column. In this study, the best nitrate removal was achieved for an initial nitrate solution of 100 mg dm-3 at the flow rate of 20 cm 3 min-1 , when a total nitrate removal of 86% is reached. The relationship between the sorption capacity of this sorbent and the varied parameters was assessed and predicted using two different theoretical breakthrough curve models: the Thomas and Yoon-Nelson models. This study confirmed that the cationic modified pumpkin shell in the fixed bed column has good potential for removing nitrate from aqueous solutions.