Tetracycline capture from aqueous solutions by nanocomposite of MWCNTs reinforced with glutaraldehyde cross-linked poly (vinyl alcohol)/chitosan.

The presence of pharmaceuticals as the emerging contaminates needs novel approaches and new materials to be remediated. This study aimed to develop and apply MWCNTs reinforced with glutaraldehyde cross-linked poly (vinyl alcohol)/chitosan nanocomposite (MWCNTs/CS-PVA/GA NC) for removal of tetracycline (TC) as a model of antibiotics from aqueous solutions. The successful synthesis of NC was supported by techniques of SEM, XRD, TGA, FTIR, and EDX. The prepared NC was then utilized for TC adsorption under the main effective parameters of TC concentration (25-125 mg/L), sonication time (0-8 min), NC dose (1-130 mg), and tempearure (5-45 °C). The process behavior was comparably explored with different methods of central composite design (CCD), artificial neural networks (ANN), and general regression neural network (GRNN). The results showed that under the optimum settings presented by desirability function (DA), in which the respective values for the factors were 125 mg/L, 6.8 min, 130 mg, and 45 °C, the efficiency and adsorption capacity of NC is supposed to be 99.07% and ∼525 mg/g, respectively. From the models studied, although all were able to express the process with satisfactory accuracy, ANN provided the best accuracy and reliability owning to the highest R2 (0.999) and lowest RMSE, ADD, MAE. The kinetics, isotherms, and thermodynamic studies showed that the process is fast (over 4.5 min), chemisorption, heterogeneous with multilayer nature, spontaneous, feasible, and endothermic. In addition, the as prepared NC could be recycled for five times without significant fail in its performance. All in all, the developed MWCNTs/CS-PVA/GA NC can be considered as a promising candidate in dealing with aqueous solutions' pollution with antibiotic.

Effect of ozonation-based disinfection methods on the removal of antibiotic resistant bacteria and resistance genes (ARB/ARGs) in water and wastewater treatment: a systematic review.

Antibiotic resistance is considered a universal health threat of the 21st century which its distribution and even development are mainly mediated by water-based media. Disinfection processes with the conventional methods are still the most promising options to combat such crises in aqueous matrices especially wastewater. Knowing that the extent of effectiveness and quality of disinfection is of great importance, this paper aimed to systematically review and discuss ozonation (as one of the main disinfectants with large scale application) effect on removing antibiotic resistant bacteria (ARB) and antibiotic resistance genes (ARGs) from aqueous solutions, for which no study has been reported. For this, a comprehensive literature survey was performed within the international databases using appropriate keywords which yielded several studies involving different aspects and the effectiveness extent of ozonation on ARB & ARGs. The results showed that no definite conclusion could be drawn about the superiority of ozone alone or in a hybrid form. Mechanism of action was carefully evaluated and discussed although it is still poorly understood. Evaluation of the studies from denaturation and repairment perspectives showed that regrowth cannot be avoided after ozonation, especially for some ARB & ARGs variants. In addition, the comparison of the effectiveness on ARB & ARGs showed that ozonation is more effective for resistant bacteria than their respective genes. The degradation efficiency was found to be mainly influenced by operational parameters of CT (i.e. ozone dose & contact time), solids, alkalinity, pH, and type of pathogens and genes. Moreover, the correlation between ARB & ARGs removal and stressors (such as antibiotic residuals, heavy metals, aromatic matters, microcystins, opportunistic pathogens, etc.) has been reviewed to give the optimal references for further in-depth studies. The future perspectives have also been reported.