Main content area

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.