Optimization of the process parameters for the photocatalytic removal of turquoise blue dye in water matrix using AC/NANOTIO2 as catalyst

• Main Author: Mactal, Mary Ann A.
• Format: text
• Language: English
• Published: Animo Repository 2010
• Subjects: Sewage—Purification—Color removal; Environmental Engineering
• Online Access: https://animorepository.dlsu.edu.ph/etd_masteral/6582; https://animorepository.dlsu.edu.ph/cgi/viewcontent.cgi?article=12973&context=etd_masteral
• Institution: De La Salle University

The discharge of textile waste water in the environment creates problems. These waste water are known with its high chemical oxygen demand (COD), strong color, large amount of suspended solids, variable pH, salt content and high temperature. Dyes and auxiliary chemicals used in the textile industry are so much improved to be resistant to environmental influence ad better performance. The objective of this study focused on the optimization of the process parameters for the photocatalytic removal of Turquoise Blue Dye in water matrix and verifying this optimum values using the textile waste water from a textile industry. A 1:10 AC/nanoTiO2 composite catalyst synthesized via sol-gel method was used in this work. Preliminary experiments were conducted to determine the effect of the process parameters by applying one factor at a time while keeping the others constant approach. The range of values as results of these experiments were: 20ppm – 40ppm for initial TBD concentration; 2.0g/L – 2.5g/L for catalyst loading; at pH 3 – 4; and 4hrs – 6hrs for the illumination time. The Response Surface Methodology – Central Composite Design (RSM-CCD) using Design Expert 7.1.6 software was used to design the experiment into 30 runs with varying experimental conditions. Second-order polynomial mathematical model for TBD removal were established. Using ANOVA, F-values of 59.60 and 48.92 and Prob>F less than 0.0500 indicated that the models are significant for %color and %COD removal. Initial TBD concentration (X1), catalyst loading (X2), pH of solution (X3), illumination time (X4), and interaction terms (X1X3, X2X3, X1 2, X2 2, X3 2 and X4 2) are model terms significant to the response (%Color and %COD removal). Thus, models were adequate to predict the decolorization and reduction of COD from TBD by photocatalytic process using AC/nanoTiO2 as catalyst illuminated by visible light. The obtained optimum values of the process variables and the response are 64.9% and 69.7% color and COD removal was achieved respectively for 20ppm TBD, 2.5g/L, pH 3 and at 6 hrs illumination time. These values were used in the treatment of the actual textile waste water of Saffron, Inc. In terms of PCU, the treated waste water was within the range of 50PCU-100PCU and passed the set standard of DENR. Some post characterization test was conducted. SEM images revealed no significant changes in the morphology of the catalyst while EDX reconfirmed the elemental composition of the catalyst. Active phase of the catalyst and the crystallite size were preserved. FTIR result observed shifting of the O-H group vibration towards lower wave number which confirmed the alteration the acidbase character of the used catalyst.