No abstract

a b s t r a c tIn the present research work, it found that the Electrocoagulation Process (EC) could be effectively utilized for the purification of tri-dye (Yellow 145, Reactive Red 195, and Blue 222) from wastewater of the textile industry located in Karachi. In order to purify the sample from the said dyes,the impacts of operational parameters namely pH, electrolysis time, amount of electrolyte and voltage were monitored on color and COD (chemical oxygen demand) removals potency using central composite design (CCD). As a result of this, the electrolysis time and amount of electrolyte showed a greater influence on color and COD removals than pH and voltage. The R 2 (regression coefficient) values of the effluent was observed from 87% to 98% by ANOVA (Analysis of Variance). Subsequently, the kinetic reaction was also determined in the discharge of industry. Simultaneously, The Fourier transform infrared (FTIR) analysis was performed to identify the presence of functional groups of the dyes contaminated in the sample. Afterwards, the inverse relation was observed between the concentration of NaCl and the specific electrical energy consumption (SEEC). Consequently, the sludge formation of tri-dyes was obtained from sample and then calculated. By this, the industrial effluent was filtered from three harmful dyes that can be very dangerous for human as well as aquatic life. Moreover, it is cost effective technique too because its operating cost is US$ 1.360/L. Hence, this method may be used as a purifier for effluents of textile industries.

The adsorption of Malachite Green (MG) dye was well studied and elucidated from the liquid phase using reduced Graphene Oxide (rGO) nano-adsorbent. The desired levels of the factors were determined to be the amount of adsorbent of 0.2 g/L, pH of 8.5, the concentration of the dye as 100 mg/L and the sonication time of 50 min by Central Composite Design (CCD). The removal of the dye was found to be 95% at the optimum levels of the variables. Furthermore, the removal of the dye was higher at the higher values of the amount of adsorbent and pH. Langmuir and Temkin models were observed significant for rGO-MG dye system. The values of Gibb's free energy, the entropy and the enthalpy were found to be -10.502 KJ/mol, 34.314 KJ/mol and 0.147 KJ/mol.K, respectively. The kinetic data were also found well fitted to pseudo second order kinetics model for the said system. Afterwards, the cost of the process was found to be US$0.654/dm3. Therefore, the adsorption process effectively removed the dye from the simulated aqueous phase using rGO nano-adsorbent.