Spent granular activated carbons (sGACs) for drinking water treatments were reused via pulverizing as
low-cost adsorbents for micro-pollutant adsorption from a secondary treated wastewater effluent. The
changes of physicochemical characteristics of the spent carbons in relation to the fresh carbons were
determined and were correlated to the molecular properties of the respective GAC influents (i.e. a surface
water and a groundwater). Pore size distribution analysis showed that the carbon pore volume decreased
over a wider size range due to preloading by surface water, which contains a broader molecular weight
distribution of organic matter in contrast to the groundwater. However, there was still considerable
capacity available on the pulverized sGACs for atrazine adsorption in demineralized water and secondary
effluent, and this was particularly the case for the groundwater spent GAC. However, as compared to the
fresh counterparts, the decreased surface area and the induced surface acidic groups on the pulverized
sGACs contributed both to the lower uptake and the more impeded adsorption kinetic of atrazine in the
demineralized water. Nonetheless, the pulverized sGACs, especially the one preloaded by surface water,
was less susceptible to adsorption competition in the secondary effluent, due to its negatively charged
surface which can repulse the accessibility of the co-present organic matter. This suggests the reusability
of the drinking water spent GACs for micro-pollutant adsorption in the treated wastewater