Adsorption of nitrate from municipal wastewater by synthesized chitosan/iron/activated carbon of orange peel composite

The target in this perusal was to remove nitrate from municipal effluent by a composite of orange peel activated carbon/chitosan/iron synthesized via sono-chemical method. The chitosan was synthesized from prawn shells via sono-chemical method. Identification of the composite functional groups, the morphology of its surface and pores, and porosity properties were investigated by FTIR, SEM, and BET techniques. The effect of solution pH (1–6), adsorbent amount (0.05–0.15 g), and pollutant concentration (20–100 mg/L) on the nitrate adsorption operation was investigated via the batch process and the optimal operating conditions were determined using the central composite design (CCD). The breakthrough curves of the continuous adsorption process were investigated through Thomas, Yoon-Nelson, and Bohart-Adams patterns. The results offered that the adsorption confirmed the pseudo-second-order kinetics (R² = 1). Also, among the studied isotherms, the Langmuir pattern described well the adsorption of nitrate upon the composite (R² = 0.9999) and the maximum adsorption valence was 263.157 mg/g composite. The optimum pH of nitrate uptake was 2.023. Nitrate uptake was increased by decreasing temperature, indicating that the process was exothermic. Nitrate removal efficiency with composite was estimated to be 99.58%. The equilibrium capacity of the Thomas model in the continuous process is close to the experimental adsorption capacity (q_eq) obtained from the breakthrough curves. In general, it can be said that the composite of orange peel activated carbon/prawn shell chitosan/iron has a good performance in the process of nitrate ion adsorption in a discontinuous (batch) and continuous adsorption process.