Review of Recent Progress in Wastewater Treatment Using Carbon Nanotubes

Background: Clean and clear water is an essential element in our life. Finding new and innovative approaches to purify water is a critical topic in research and development. Carbon nanotubes are promising adsorbent for many stable organic compounds. The ability of wastewater treatment using carbon nanotubes was studied in this review article. Methods: Adsorption mechanism was discussed based on several research studies. Kinetics and thermodynamics of sorption were reviewed using carbon nanotubes. This review has discussed the approach of removing dyes and heavy metal ions from wastewater using nanomaterials as adsorbent. Furthermore, the paper provides several essential parameters involved in the adsorption mechanism of carbon nanotubes for wastewater applications. Results: The results of this review show that carbon nanotubes are an advantageous source of the adsorbent for wastewater applications. High thermal and chemical stability make carbon nanotubes more attractive for the wastewater treatment application. It is observed that both kinetics and equilibrium studies are essential to understand the adsorption phenomena. The adsorption rate constant is considered an important factor to study the adsorption. Conclusion: Nanomaterials in the adsorption process make the process more effortless compared to other types of adsorbents. Carbon nanotubes have several properties that help in surface modification, which make them an effective and environmentally friendly material for wastewater treatment.

Thermodynamic investigation of disperse dyes sorption on polyester fibers

The thermodynamics of sorption during the dyeing process of raw polyester fibers with disperse dye was studied in this article. Dyeing of fibers is carried out by a discontinuous batch process, according to standard procedures with varying of the initial dye concentration and the dyeing temperature. Several of the accepted models for calculation of thermodynamic parameters were used which define and clarify the sorption of disperse dyes on polyester fibers. High functionality of variables for the calculation of basic thermodynamic parameters was determined, which confirmed the validity of the results. Depending on the method of calculation , the change of free energy during the dyeing of the polyester was negative (-10-40 kJ·mol-1), which corresponds to the spontaneous and mainly the physical process of sorption. A positive value for the change in enthalpy during dyeing (1.1×10-2-2.9×10 1 kJ·mol-1) reflects the endothermic nature of the interactions, and a relatively lower value characterizes the physisorption phenomenon. A positive value for the change in entropy (1.1×10-4-1.5×10-1 kJ·mol-1 ·K-1) confirms that it is a physical sorption.