PAHs (naphthalene) removal from stormwater runoff by organoclay amended pervious concrete

Stormwater runoff increasingly induces contaminants to the groundwater to imperil the sustainable development of human society. Pavement can be considered as the first line of defense for contaminant removal of the stormwater runoff. The organic contaminant delivered by the stormwater runoff from the impervious pavement surface, especially the cancerogenic polycyclic aromatic hydrocarbons (PAHs), would inevitably pollute the groundwater system by cumulative effect. To assist PAHs removal, a multi-functional green pervious concrete (MGPC) was proposed in this study. The PAHs remediation function can be realized by introducing organoclay to the conventional pervious concrete. The isothermal batch sorption test was conducted to quantify the sorption capacity of the organoclay modified cement paste, and the breakthrough column test was performed to investigate the transport mechanism and retardation behavior of naphthalene, a typical 2-ring PAH in MGPC. The compressive strength test and the hydraulic conductivity test have also been used to evaluate the effect of using organoclay on the mechanical and hydraulic properties of the MGPC. The results indicated that compared to conventional pervious concrete, the developed MGPC with a small addition of organoclay could substantially remove PAHs contaminants and it also has much stronger adsorption and retardation capacity than the conventional pervious concrete. The research also found that using small amount of organoclay would not adversely affect the compressive strength and hydraulic conductivity of the concrete. Therefore, the developed MGPC has a great potential to be used as a pavement material with the stormwater purification function. (C) 2018 Elsevier Ltd. All rights reserved.