Evaluation of solution pH and multiwalled carbon nanotubes adsorbent dose effects on removal efficiency of Eriochrome Black T from Saman Noosh Industry waste water

Dyes in industrial wastewater are major pollutants that are difficult to treat due to their complex molecular nature and synthetic origin. EBT is one of azo dyes that has been used in the cosmetics, health and medicine products. Due to its high solubility in aqueous environments and high shelf life, the inseparability of the biological magnification by organic compounds in the environment is a major pollutant in the aquatic environment, especially in the receptive waters. The extensive use of dyes often causes pollution problems in the form of colored wastewater discharged into environmental water bodies. In addition, they create free annular radicals that are highly carcinogenic. EBT being a naphathol azo dye is­ recalcitrant to oxidative biodegradation. Biological treatment would be cost-effective but most dyes are resistant to bacterial degradation and a considerable percentage of these dyes go into the effluent during the dying the process as they are highly soluble in water and cannot be separated by filtration. Therefore developing new methods for their treatment is important. In this study, the effects of major variables governing the efficiency of the process such as, temperature, initial dye concentration, CNTs dosage and pH were investigated. The adsorption kinetic data were analyzed using pseudo-second-order and Freundlich isotherm model. pH=3, and 0.01 g absorbent, absorption capacity rates were 98% for removal of EBT. The results of absorption studies showed that removal rates would increase with decreasing pH and temperature, On the basis of the results, MWCNTs can absorb EBT dye appropriately and efficiency of the process is higher in acidic pH. Multiwalled carbon nanotubes can contribute to environmental pollutant removal, and more pollutant absorption on nanotubes in acidic condition.