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Dairy wastewater is one of the most pollutant resulting from food industry, which is mainly composed of complex substances such as organic compounds, mineral compounds, chlorides, sulfides, fats and oils. The presence of high organic loading in dairy wastewater causes negative effects on the environment. In this research, magnetic polyaniline with strontium-titanium trioxide was applied as an environmentally friendly, low-cost and efficient Nano adsorbent to reduce polyphenols from dairy wastewater. The synthesized nanocomposite shows a high absorption capacity compared to polyphenols. This feature can be attributed to van der Waals interaction (π-π and electrostatic interactions), n-π interaction, and hydrogen bonding of the adsorbent with the analyte. Polyaniline causes hydrogen and π-π interaction with polyphenols due to the presence of functional groups containing nitrogen and backbone of π-conjugated electrons. Also, the existence of metal orbitals in SrTiO3 enables the formation of Lewis acid base with polyphenols. SrTiO3 nanoparticles give outstanding physical properties, high thermal and chemical stability, acceptable specific surface area to the nanocomposite, which causes a synergistic effect with the unique properties of polyaniline. Finally, due to the presence of magnetic nanoparticles and with the help of an external magnet, time is saved in the separation step. Also, in this article, factors affecting the absorption of polyphenols such as solution pH, adsorbent amount, contact time, concentration and temperature were investigated. The results showed that MPANI@SrTiO3 shows high efficiency by removing 89.41% of polyphenols (under optimal conditions, pH 5, adsorbent amount 20 mg, time 150 minutes at room temperature and salt percentage 0.01(w/v% ). Validity of the proposed method was checked using adsorption isotherm and kinetic models. According to the data, the adsorption kinetics of polyphenols on the MPANI@SrTiO3 adsorbent corresponded to the semi-first-order, and the experimental equilibrium of the Langmuir model was matched with the maximum adsorption capacity of the single layer of 67.11 mg/g. Also, the thermodynamic parameters ΔG° (kJ/mol), ΔH° (kJ/mol) and ΔS° (kJ/mol K) were obtained as -19.8, -60.61 and -0.17, respectively, as a result of the nature of adsorption It corresponds to the exothermic mechanism and physical absorption. |
