Rapid and efficient ultrasonic assisted adsorption of PNP onto LDH-GO-CNTs: ANFIS, GRNN and RSM modeling, optimization, isotherm, kinetic, and thermodynamic study

In this work, the original, inexpensive, efficient and biodegradable nanocomposite (Mg/Co/Al/LDH - GO - MWCNT) was fabricated and characterized by the analyses of SEM, EDX, TEM, XRD, RAMAN, TGA, and BET and then used as adsorbent for removal of Para Nitrophenol (PNP) from aqueous solutions. In addition, the GRNN, ANFIS and RSM based on the CCD experiments were developed to predication the Para Nitrophenol removal. The aforementioned approaches determined the impacts of adsorbent mass, PNP concentration, pH, temperature, and sonication time. In addition, the preference of mentioned approaches was judged in terms of different statistical criteria including RMSE, MSE, MAE, AAD, SSE, SAE, ARE, HYBRID, MPSD, chi(2) and R-2 and the best algorithm was proposed for the process studied. Furthermore, comprehensive kinetic, isotherm, thermodynamic, the effect of interfering ions, reusability cycles and optimization (by GA and DF) studies were investigated to understand the behaviour and adsorption mechanism of PNP on the surface of Mg/Co/Al/LDH-GO-MWCNT nanocomposite. The results proposed that the optimum values to attain a maximum PNP removal (94.77%) were Mg/Co/Al/LDH-GO-MWCNT dose 10.00 mg, pH 5.35, temperature 50.15 degrees C, PNP initial concentration 16.22 mg L-1, and sonication time 13.36 min with DF about 0.94. The equilibrium data pointed out excellent fit to the Langmuir isotherm model with maximum monolayer adsorption capacity of 769.23 mg/g at 25 degrees C and pH 5.35. Dubinin-Radushkevich isotherm model based on mean sorption energy determine high contribution of chemisorption (9.280 kJ/mol) on removal process. Moreover, diffusion-chemisorption kinetic model delivered a better correlation for the experimental data in comparison to the pseudo-first-order kinetic model and intraparticle diffusion mechanism. High removal efficiency (96%) of PNP in only 13.36 min, along with an excellent capacity (823.33 mg/g) that has ever been reported and reusability (seven times), turns the nanocomposite to a very promising option in adsorption of PNP. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

In this study, a novel nanocomposite material was synthesized and used as an adsorbent for removing Para Nitrophenol from aqueous solutions. Various models were developed to predict the removal efficiency, and the optimal operating conditions were determined. The nanocomposite exhibited excellent adsorption performance, making it a promising option for PNP removal.