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Performance of dissolved organic matter removal from membrane bioreactor effluent by magnetic powdered activated carbon

Ittisupornrat, Suda, Phihusut, Doungkamon, Kitkaew, Duangta, Sangkarak, Sirirat, Phetrak, Athit
Journal of environmental management 2019 v.248 pp. 109314
activated carbon, adsorbents, adsorption, coatings, dissolved organic matter, humic acids, iron oxides, kinetics, magnetism, membrane bioreactors, molecular weight, pH, particle size, sorption isotherms, surface area
Magnetic powdered activated carbon (Mag-PAC) was successfully developed and applied as an adsorbent for dissolved organic matter (DOM) removal from the effluent of a membrane bioreactor (MBR) using batch experiments. The results show that a coating of iron oxide particles is consistently distributed on the surface of powdered activated carbon (PAC), resulting in a decrease in the specific surface area and in the pH at the point of zero charge, even though the particle sizes of Mag-PAC and PAC were similar. A Mag-PAC dosage of 4 g/L exhibited efficient and fast DOM adsorption with a relatively short contact time of 5 min. The iron oxide coating on the surface of PAC may play an important role in the DOM removal efficiency. Temkin isotherm and pseudo-second order kinetic models well described the DOM adsorption, suggesting that the adsorption of DOM onto Mag-PAC could be mainly governed by a chemisorption mechanism. Humic acid- and fulvic acid-like compounds and aromatic DOM with molecular weights (MWs) between 2610 Da and 3030 Da were efficiently removed by Mag-PAC, whereas aromatic DOM with an MW of 1760 Da was poorly removed. Our results demonstrate that the application of Mag-PAC for DOM adsorption is attractive and yields benefits as a posttreatment system for MBR effluent due to its efficient and fast DOM adsorption.