Experimental Study of 4-Nonylphenol Removal from Aquatic Solutions Using Graphene Oxide Chitosan Aerogel Beads

Abstract

4-Nonylphenol (4-NP) as one of the most abundant and toxic alkylphenols is the most effective of endocrine disruptive compounds. It is produced in high quantities and then enters the aquatic environment via discharge of sewage treatment effluents. Therefore, its removal from surface water and municipal wastewater effluents is more commonly considered. This study has been done with the aim of the investigation of the grapheneoxide chitosan aerogel beads’ performance for removal of 4-NP from aquatic solutions. In this regard, the characteristics of the synthesized nano-adsorbent have been investigated by SEM, TEM, FTIR, BET and pHpzc techniques. Then, batch adsorption experiments have been done to determine the adsorption behavior. In this method, the effect of some parameters such as adsorbent dosage, 4-NP concentration, pH, contact time, and temperature was evaluated with the aim of determining optimum conditions. The results show that the adsorption efficiency could reach 100% in 10 min at neutral pH with 1.5 mg/L of 4-NP concentration and 0.8 g/L of the adsorbent. The achieved results were compared with different kinetic and isotherm models, which found that the 4-NP adsorption by the synthesized nano-adsorbent are explained by the Pseudo-Second-Order kinetic (R2=0.9992) and Dubinin-Radushkevich isotherm (R2=0.9988) models with the adsorbents’ maximum capacity of 70.97 mg/g. Thermodynamic investigations indicated that the adsorption process was spontaneous and feasible (-ΔG), endothermic (+ΔH), and reversible (+ΔS).

Keywords

• 4-nonylphenol
• graphene oxide
• chitosan
• aerogel
• adsorption
• thermodynamic