title: Investigation of the efficiency of a tubular continuous-flow photoreactor with supported titanium dioxide nanoparticles in the removal of 4-nitrophenol: operational parameters, kinetics analysis and mineralization studies.
abstract: In this study, to investigate the application of heterogeneous photocatalysis in the removal of organic contaminants from aqueous media a novel tubular continuous-flow photoreactor with supported TiO2-P25 on glass plates was designed and constructed. The photoreactor comprises six quartz tubes and a UV lamp which was placed in the center of the quartz tubes. 4-nitrophenol (4-NP) as a most refractory pollutant was chosen as a probe pollutant to examine the photoreactor efficiency for environmental cleaning applications. Results of experiments show that the removal efficiency of 4-NP in this photoreactor is a function of photoreactor length, gas and liquid flow rates and 4-NP initial concentration. Kinetics analysis indicates that degradation of 4-NP in continuous-mode can be modeled with the Langmuir-Hinshelwood (L-H) model (k(L-H) = 1.5 mg L(-1) min(-1), K(ads) = 0.11 mg(-1) L). A design equation was obtained with a combination of L-H modified equation and tubular reactor design equation. This equation can be used for estimation of 4-NP concentration in different photoreactor lengths under various operational parameters. Mineralization study was followed through total organic carbon (TOC) analysis and measurement of nitrite and nitrate as final degradation products.
authors: Department of Chemistry, Faculty of Science, Tabriz Branch, Islamic Azad University, Tabriz, Iran. behnajady@iaut.ac.ir
authors: Mohammad A
authors: MA
authors: Behnajady
authors: Sadegh
authors: S
authors: Amirmohammadi-Sorkhabi
authors: Nasser
authors: N
authors: Modirshahla
authors: Mohammad
authors: M
authors: Shokri
mesh_terms: D002244:Carbon / Q000737:chemistry; D007700:Kinetics; D053758:Nanoparticles / Q000737:chemistry*; D009566:Nitrates / Q000737:chemistry; D009573:Nitrites / Q000737:chemistry; D009596:Nitrophenols / Q000737:chemistry / Q000302:isolation & purification*; D010084:Oxidation-Reduction; D014025:Titanium / Q000737:chemistry*; D014874:Water Pollutants, Chemical / Q000737:chemistry / Q000302:isolation & purification*; D014876:Water Pollution / Q000517:prevention & control*; D018508:Water Purification / Q000295:instrumentation / Q000379:methods*
chemical_list: D009566:Nitrates; D009573:Nitrites; D009596:Nitrophenols; D014874:Water Pollutants, Chemical; C009495:titanium dioxide; D002244:Carbon; D014025:Titanium; C024836:4-nitrophenol