A feasible approach to dispose of soil washing wastes: adsorptive removal of chlorobenzene compounds in aqueous solutions using humic acid modified with monoolein (HA-M)

Humic acid (HA), one of most ubiquitous natural resources in the world, was modified with monoolein to prepare a novel hydrophobic adsorbent (HA-M) for removal of chlorobenzene compounds (CBs) from aqueous solutions. The influence of pH, temperature, coexisting organics and initial concentration on the adsorption capacity of HA-M for CBs were investigated to obtain the optimum removal efficiency. Furthermore, the adsorption kinetics and isotherms were researched as well as the column adsorption studies to reveal the mechanism for HA-M to adsorb CBs. The experimental results indicated that the HA-M materials exhibit high removal efficiency of CBs (>90%) in a wide range of pH values and temperatures. The adsorption of CBs with HA-M was realized by the hydrophobic interactions between CBs and HA-M. In addition, the HA-M also performed high removal efficiency toward organochlorine pesticides (OCPs) in aqueous solutions. Most important, the excellent adsorbability of the super-hydrophobic HA-M adsorbent could be comparable or fairly good compared with other adsorbents. Consequently, our present investigations provided a facile synthesis route for the highly effective and recyclable hydrophobic adsorbent for the adsorptive removal of CBs and OCPs from aqueous solutions.