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Investigating PPCP Removal from Wastewater by Powdered Activated Carbon/Ultrafiltration
- Rodriguez, Elena, Campinas, Margarida, Acero, Juan Luis, Rosa, Maria João
- Water, air, and soil pollution 2016 v.227 no.6 pp. 177
- activated carbon, adsorption, deet, electrostatic interactions, hydrophobicity, ions, organic matter, personal care products, porous media, ultrafiltration, wastewater
- Powdered activated carbon/ultrafiltration (PAC/UF) hybrid process was investigated for removing from wastewater five pharmaceutical and personal care products (PPCPs): 1-H-benzotriazole, DEET, chlorophene, 3-methylindole and nortriptyline-HCl. Adsorption, UF and PAC/UF experiments were performed, focusing on PPCP adsorption as a function of PPCP characteristics and organic matter (EfOM) competition. Two water matrices and two fine-particle PACs were studied, differing on EfOM nature and concentration and on PAC microporosity. Neutral PPCP uptake by the positively charged, meso- and microporous PACs followed PPCP hydrophobicity expressed by log Kₒw. The uptake of the positively charged nortriptyline exceeded the expected from log D due to its high aromaticity and the background ions, which partially shielded PAC-nortriptyline electrostatic repulsions. Adsorption capacity depended on PPCP hydrophobicity whereas the kinetics further depended on PPCP charge. Hydrophobic EfOM was preferentially adsorbed and a stronger competitor, particularly for PPCPs with logKₒw < 2.6. The highly microporous PAC better adsorbed these PPCPs and the hydrophobic EfOM, and it attenuated the EfOM competition. For all waters, PAC had no effect on UF-flux, and it significantly improved PPCP and EfOM removal by PAC/UF over standalone PAC and UF. For all conditions and microcontaminants, PPCP uptake exhibited a sigmoid curve with logKₒw, with a turning point at 2.2–2.6. In real applications, meso- and highly microporous PACs are recommended, and the dose should target the PPCPs with log Kₒw < 2.6.