A sustainable colloidal material with sorption and nutrient-supply capabilities for in situ groundwater bioremediation.

Microbial degradation of subsurface organic contaminants is often hindered by the low availability of both contaminants and nutrients, especially phosphorus (P). The use of activated carbon and traditional P fertilizers to overcome these challenges has proved ineffective; therefore, we sought to find an innovative and effective solution. By heating bone meal-derived organic residues in water in a closed reactor, we synthesized nonporous colloids composed of aromatic and aliphatic structures linked to P groups. X-ray absorption near edge spectroscopy analysis revealed that the materials contain mostly bioavailable forms of P (i.e., adsorbed P and magnesium-bearing brushite). The capacity of the materials to adsorb organic contaminants was investigated using benzene and batch isotherm experiments. The adsorption isotherms were fitted to the linearized Freundlich model; isotherm capacity (logKF ) values for the materials ranged between 1.6 and 2.8 μg g-1 . These results indicate that the colloidal materials have a high affinity for organic contaminants. This, coupled with their possession of bioavailable P, should make them effective amendments for in situ groundwater bioremediation. Also, the materials' chemical properties suggest that they are not recalcitrant, implying that they will not become potential contaminants when released into the environment.