Atenolol adsorption onto multi-walled carbon nanotubes modified by NaOCl and ultrasonic treatment; kinetic, isotherm, thermodynamic, and artificial neural network modeling

Abstract

The removal of pharmaceutical pollutants from the aqueous environment is a great environmental concern, mainly due to their diversity, high consumption, and sustainability. In the current study, we aimed to investigate the ability of multi-walled carbon nanotubes (MWCNTs) modified by sodium hypochlorite (NaOCl) and ultrasonic treatment in refining wastewaters contaminated with Atenolol β-blocker drug (ATN). The physical and structural characteristics of the raw MWCNTs and modified MWCNTs (M-MWCNTs) were analyzed using SEM, TEM, Raman spectroscopy, TGA, and FT-IR techniques. The effects of different parameters, including pH, initial concentration, contact time, and temperature were studied and optimized. Subsequently, the adsorption data were analyzed by several kinetic and equilibrium isotherm equations and modeled by artificial neural network (ANN). Highest ATN removal (87.89%) ((q e,exp = 46.03 mg g −1)) occurred on the adsorbent activated within 10 s of ultrasonication time and NaOCl 30%. Moreover, adsorbent modification significantly improved the ATN removal, so that the removal rate on the raw MWCNTs was about 58%, but in the same conditions, M-MWCNTs removed more than 92% of the adsorbate. The adsorption process reached equilibrium after 90 min under the optimized pH of 6. According to ANN modeling, approximately the whole values dispersed around the 45°line, indicating a good compatibility between the trial results and ANNpredicted data. The modification of MWCNTs in proper ultrasonic power via appropriate concentration of NaOCl solution removed many of the impurities and significantly improved the adsorption performance of MWCNTs.

Sensitivity Analysis with the Monte Carlo Method and Prediction of Atenolol Removal Using Modified Multiwalled Carbon Nanotubes Based on the Response Surface Method: Isotherm and Kinetics Studies

“…According to the result obtained in our previous study, the optimum condition was in 30% concentration of NaOCl solution and 15 seconds ultrasonication time. erefore, modification of MWCNTs was carried out with a 30% NaOCl solution and a contact time of 15 seconds with ultrasonic [7]. Several studies showed that MWCNTs modified by the NaOCl solution is an efficient adsorbent for the removal of some contaminants from the aqueous solution [28][29][30][31].…”

“…NaOCl solution of 30% with the balanced chlorine concentration increases the adsorbent porosity, which led to improvement in the removal efficiency. Nevertheless, NaOCl concentration of 60%, the increased chlorine oxidizes carbon nanotubes and, therewith, reduce the electrical conductivity [7]. Ultrasonic modification of the adsorbent has numerous advantages such as increased porosity, shortened length of the nanotubes, high performance, short duration, environmental soundness, and increased specific surface area of CNTs [7].…”

“…e preparation of adsorbent was explained in our last study [7]. e stock solution of 1,000 mg/L of atenolol was made by 100 mg of pure atenolol and deionized water.…”

“…us, this leads to the increasing occurrence of ATN in different water bodies [2] such as surface waters, ground waters, and hospital wastewaters in the last decade [6]. Researches showed ATN concentration in the effluent was about 0.78-6.6 mg/L, whereas the admittable level is 10 ng/L [7]. Studies demonstrate that this compound is resistant to biodegradation and therefore can remain in the matrix for long time [6] and has a toxic effect on aquatic microorganisms and humans [1].…”

Fixed bed adsorption column studies and models for removal of ibuprofen from aqueous solution by strong adsorbent Nano-clay composite

“…Table 7 indicates the value of these parameters for different modes of input concentrations of ibuprofen, bed height and flow rate. Value of A decreased by increasing initial concentration and flow rate and showed an increase by elevating bed height, but the ratio of r was in contrast [46][47][48][49][50]. R 2 in 0.9901 and 0.9980 range indicates that the model is suitable for predicting the breakthrough curve of ibuprofen uptake process as well as is simulated model of Freundlich adsorption kinetic.…”