Antibiotics adsorption from aqueous solutions using carbon nanotubes: a systematic review

Over the past few years, antibiotics are considered as an emerging environmental and health challenges due to their genotoxic and mutagenic effects and persistence in natural ecosystems. Adsorption materials are widely used for water purification. Among them carbon nanotubes (CNTs) have attracted the attention of many researchers for removing water contaminants, especially antibiotics. CNTs have many advantages such as lower cost, and energy, less chemical mass and impact on the environment, large surface area and, greater chemical reactivity that make them suitable materials for water and wastewater treatment. Therefore, this review discussed the environmental and health impacts of antibiotics, the physical and chemical characteristics of CNTs, as well as parameters that influenced the efficiency of antibiotics removal using CNTs. Based on this review nanotubes in different forms of a walled nanotubes, double-walled, multi-walled and in combination are used. Most studies investigated the application of CNTs to remove antibiotics in the modified form or by other factors assistant that make them superior than other adsorbents for antibiotics removal. Review results also showed the maximum removal (100%) related to Metronidazole by multi-walled carbon nanotubes and contact time = 60 min, pH = 7, temperature = 30 +/- 2 degrees C and adsorbent dosage 0.1 g/L and ionic strength 0.2 NaCl. Also comparison of adsorption capacity showed the highest absorption capacity related to MWCNTS (1100 mg/g for Cephalexin). Adsorption isotherms study showed the best fitness relate to the Langmuir isotherm (R-2= 0.999) and higher adsorption reaction rate in the nanotubes is because of better adsorption in the intermediate levels of CNTs.