Photocatalytic degradation of methylene blue dye from aqueous solution using silver ion-doped TiO₂and its application to the degradation of real textile wastewater

Abstract

Methylene blue dye (MB) was degraded photocatalytically in aqueous solution using Ag(+) doped TiO(2) under UV irradiation. The degradations of the dye using untreated TiO(2) and Ag(+) doped TiO(2) were compared. Ag(+) doped TiO(2) was found to be more efficient. Using Ag(+) doped TiO(2) the filtration process was eliminated, as the particles became more settleable. The effect of various parameters such as catalyst loading, initial dye concentration, depth of solution, degree of adsorption, pH and O(2) on dye degradation was studied. The extent of mineralization was studied by observing the COD removal at different time intervals. The effects of various interfering ions such as Cl(-), NO(3) (-), CO(3) (2-), SO(4) (2-), Ca(2+) and Fe(3+) and electron acceptors such as H(2)O(2), KBrO(3) and (NH(4))(2)S(2)O(8) on the dye degradation was also studied. The degradation kinetics fitted well to Langmuir-Hinshelwood pseudo first order rate law. An aqueous solution of MB (20ppm) degraded by more than 99% after UV irradiation for 180 min with Ag(+) doped TiO(2) (2 g/L) and by more than 95% with untreated TiO(2) (2 g/L)(.) The COD removal was more than 91% with Ag(+)doped TiO(2) and more than 86% with untreated TiO(2) after 240 min. The degradation and COD removal of 5 times diluted textile wastewater was more than 98% and 79% respectively with 1 g/L Ag(+) doped TiO(2) after UV irradiation for 420 min.

Photocatalytic degradation of methyl blue by silver ion-doped titania: Identification of degradation products by GC-MS and IC analysis

“…[29] Aqueous solution of methyl blue (volume: 60 mL, concentration: 50 ppm) was mixed with 1 g L ¡1 micro-TiO 2 in a beaker and stirred in the dark for 30 min to account for adsorption and then irradiated with magnetic stirring up to 120 min by a 15 W lamp emitting UV light of wavelength 254 nm. Samples were withdrawn at 15 min interval and analyzed for decolorization and mineralization after centrifuging.…”

Kinetics and Adsorption Isotherm Studies of Methylene Blue Photodegradation Under UV Irradiation Using reduced Graphene Oxide- TiO2 Nanocomposite in Different Wastewaters Effluents.

“…The elevation of degradation rate with increase of photocatalytic dose may be attributed to greater surface area was available (Sahoo et al, 2012). Furthermore, the results showed low significant difference between the photodegradation effect of three used photocatalyst (Fig.…”

“…After 120 min irradiation time, the rate reached its maximum removal percent (98, 98.9 and 99.3% for 1%, 3% and 5% TiO2@rGO nanocomposites respectively). The results revealed a regular relationship between degradation of MB dye with time increasing which explained on the basis of increasing time more and more light energy falls on the catalyst surfaces which induced formation of photon excited species and enhances the photocatalytic activities (Sahoo et al, 2012).…”

Solar Based Photocatalytic Decolorization of Four Commercial Reactive Dyes Utilizing Bound TiO₂-Fe₃O₄ Nanocomposite

“…The determination of approximate reaction rate constant of each concentration in each dye was determined by simplifying the Langmuir-Hinshelwood kinetics model. Many experiments reported that the photocatalytic decolorization fitted the Langmuir-Hinshelwood model [13,15,[36][37][38].…”

“…The apparent rate constants were determined by using linear regression. First-order kinetics suited for this study [13,15,[36][37][38][40][41][42]. By plotting linear regression of initial concentration versus k' [43][44], the value of k and K from the Langmuir-Hinshelwood model can be determined with the following equation:…”