Adsorption characteristics of Effluent Organic Matter and Natural Organic Matter by Carbon Based Nanomaterials

Natural Organic Matter (NOM) and Effluent Organic Matter (EfOM) have been regarded as the major membrane foulants in advanced water treatment or wastewater reuse processes. In this study, the adsorption of Suwannee River NOM (SRNOM) and EfOM from a wastewater treatment plant by Carbon-Based Nanomaterials (CBNs) including Single-Wall Carbon Nanotube (SWCNT), Multi-wall Carbon Nanotube (MWCNT) and Expanded Graphite (EG) was investigated to mitigate their membrane fouling potentials. Adsorption of SRNOM and EfOM showed Langmuir type adsorption with constant adsorption enthalpy, regardless of the adsorbents. MWCNT showed the highest adsorption capacity for SRNOM and EfOM, while SWCNT showed the greatest reduction in Soluble Microbial Products (SMP) in EfOM. The UV/Vis spectrophotometry, fluorescence spectrophotometry, and size exclusion chromatography showed that high molecular weight fraction of SRNOM and EfOM was preferentially adsorbed onto ordered CBNs such as SWCNT, MWCNT, and EG. It was also evidenced that SMP adsorptions by SWCNT was significantly higher than those by MWCNT. The results imply that a pretreatment with SWCNT or EG can reduce membrane fouling via adsorption of SMP and high molecular weight organic fractions in EfOM.