Parametric and adsorption kinetic studies of reactive black 5 removal from textile simulated wastewater using oil palm (Elais guineensis) empty fruit bunch

The potential of using Empty Fruit Bunch (EFB), an agrowaste material, as a low-cost biosorbent for the removal of Reactive Black 5 (RB5) from aqueous solution was investigated in this study. The influences of solution pH, contact time, initial concentration and biosorbent dosage were studied in batch experiments at room temperature. Adsorption equilibrium was achieved after 30 min of agitation. The maximum adsorption uptake of RB5 dye occurred at pH 2, resulting in a rapid adsorption (more than 50% RB5 uptake) for the first 5 min of contact. Lower solution pH values showed better adsorption because the dye molecules tend to adsorb on positively charged adsorbent sites. Furthermore, higher biosorbent dosages increased the dye uptake by up to 90% due to the availability of more active adsorption sites. Both the pseudo-second-order kinetic model and the Langmuir model indicated that monolayer coverage on the adsorbent was dominant and that chemisorption was the rate-determining ste

Photocatalytic degradation of cationic dye simulated wastewater using four radiation sources, UVA, UVB, UVC and solar lamp of identical power output

This study uses photocatalysis, classified under advanced oxidation processes, for the treatment of simulated cationic dye (methylene blue)-contaminated wastewater using TiO2 as the photocatalyst. Three parameters were manipulated throughout this study including the effects of ultraviolet irradiation wavelength (using UV-A, UV-B, UV-C and solar light), the initial dye concentration (2–10 ppm) and the initial pH (4–10), with a total reaction time of 1 h. The shortest wavelength irradiation (UV-C) proved to be the most effective yielding 100% degradation of MB was achieved within 14 min. Increasing the initial dye concentration proved reduced the degradation rate due to the inner photon filtering effect by the dye molecules and as a result of the reduced generation rate of hydroxyl radicals. Since MB is a cationic dye, by increasing the pH of the system, the degradation rate was enhanced requiring just 12 min to achieve complete degradation in the experimental photoreactor. This is due to the electrostatic attraction between the dye molecules and the negatively charged TiO2 particles. Kinetic studies showed that all experiments fulfilled an apparent first-order kinetics at MB concentrations less than 6 pp mmeaning the photocatalytic degradation of MB depended only on its concentration in the solution. Saturation kinetics (zero-order) was observed at MB concentration higher than 6 ppm and a reduction of the initial rate was observed at concentration higher than 10 ppm due the absorption of photon from the dye in solution. From the findings, photocatalysis using TiO2 is able to fully degrade organic compounds like dyes into degradable substance such as carbon dioxide, water and inorganics