ELECTROCOAGULATION FOR TREATMENT OF PETROCHEMICAL WASTE WATER

Abstract

Petrochemical waste water is characterized by a high COD (chemical oxygen demand) and other toxic substances. In the present work, the treatment of PTA (purified terephthalic acid) for synthetic and actual waste water was executed by electrochemical (EC) technique using stainless steel (SS) as electrode material in a batch reactor. A fully factorial central composite design (CCD) with four different parameters specifically pH: 5.30 - 10.40, current density (A/m2): 31.25 - 156.25, reaction time (min): 30 - 240, interelectrode distance (cm): 0.5 -2.5, which are denoted by symbol A, B, C and D. All these parameters at five different levels were performed to optimize the aspect for higher % COD removal. Here the operational parameters were varied in order to obtain different % COD removal. The optimum % COD removal was 70.86% for synthetic and 66.72% for actual waste water as a set of 30 runs were performed for both the type of waste waters. ANOVA showed a high coefficient of determination for Chemical oxygen demand (COD) (R2 = 0.9537) and (R2 = 0.9474) for synthetic and actual between the experimental values. By the regression model the %COD removal were investigated. A complete physico-chemical scrutiny for residue (scum, sludge) and electrodes (before and after the process) were performed. XRD (diffraction) was done to reflect upon the structure of sludge particles. SEM was performed in order to confirm the change in structure of electrode before and after the process along with the scum and sludge. Finally TGA (thermo gravimetric analysis), DTA (differential thermal analysis) and DTG (differential thermal gravimeter) was performed.