Polypyrrole-modified mushroom residue activated carbon for sulfate and nitrate removal from water: Adsorption performance and mechanism

A new type of adsorption material, polypyrrole-modified mushroom residue activated carbon (Ppy-MRAC), was prepared by compounding MR in agricultural waste and Ppy using a dipping method. A characterization analysis indicated that Ppy-MRAC is a mesoporous material, containing functional groups such as hydroxyl (OH) and coordinated chloride (Cl-) ions. The efficacy of Ppy-MRAC for removing sulfate (SO42-) and nitrate (NO3) from water was studied. The experimental results showed that the adsorption of SO42- and NO3 by Ppy-MRAC followed the Langmuir and pseudo-second-order kinetic models, with maximum adsorption capacities of 40.00 and 51.55 mg/g, respectively. The removal rates of 500 mg/L SO42- at 35 degrees C and 50 mg/L NO3 at 15 degrees C were 31.53% and 82.65%, respectively. A thermodynamic analysis revealed adsorption of SO42- and NO3 via spontaneous endothermic and exothermic reactions, respectively. The adsorption mechanisms were mainly electrostatic attraction, ion exchange, and hydrogen bond. The Ppy-MRAC could be regenerated six times after being eluted by NaOH. Low-cost Ppy-MRAC had a high removal rate for inorganic salts in simulated wastewater, and strong environmental and economic benefits.

Automated summary

A study was conducted on the removal of sulfate and nitrate from water using a polypyrrole-modified mushroom residue activated carbon material. The results showed high adsorption capacities and removal rates, as well as the ability for multiple regeneration.