title: Thermal-pressure-mediated hydrolysis of Reactive Blue 19 dye.
abstract: The thermal-pressure-mediated hydrolysis rates and the degradation kinetics of environmentally persistent Reactive Blue (RB) 19 dye were studied. The dye decomposition was studied at 40-120 degrees C, pH 2-10, and atmospheric pressure range of 1-2 atm. The intermediates and end products formed during the degradation were identified using gas chromatography/mass spectrometry and a possible degradation pathway of RB 19 was proposed. The stability of the dye in aqueous solution was influenced by changes in pH. At pH 4, half-life was 2247.5 min at 40 degrees C and it reduced to 339.4 min when the temperature was increased to 120 degrees C. Acidic conditions were more conducive to enhance hydrolysis rate than basic ones as the decomposition was optimum at pH 4. The kinetic studies indicated that the rate of hydrolysis apparently followed first order reaction. A linear relationship was observed between hydrolysis rate of RB 19 dye and increasing temperatures and pressures. Overall, 23% dye decomposition occurred in 120 minutes at pH 4, 120 degrees C and pressure of 2 atm. Along with thermal-pressure, a combination of techniques like physico-chemical, biological, enzymatic etc. may be more suitable choice for the effective treatment of RB19 dye.
authors.affiliation: Department of Environmental Sciences, COMSATS Institute of Information Technology, Abbottabad 22060, Pakistan.
authors.forename: Maria
authors.initials: M
authors.lastname: Siddique
authors.forename: Robina
authors.initials: R
authors.lastname: Farooq
authors.forename: Abda
authors.initials: A
authors.lastname: Khalid
authors.forename: Ather
authors.initials: A
authors.lastname: Farooq
authors.forename: Qaisar
authors.initials: Q
authors.lastname: Mahmood
authors.forename: Umar
authors.initials: U
authors.lastname: Farooq
authors.forename: Iftikhar Ahmad
authors.initials: IA
authors.lastname: Raja
authors.forename: Saleem Farooq
authors.initials: SF
authors.lastname: Shaukat
mesh_terms: D000880:Anthraquinones / Q000737:chemistry*; D006358:Hot Temperature; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007700:Kinetics; D011312:Pressure; D014873:Water Pollutants / Q000737:chemistry*
chemical_list: D000880:Anthraquinones; D014873:Water Pollutants; C024758:Remazol Brilliant Blue R