Experimental investigations of dynamic sorption of diesel from contaminated water

Surface wastewater pollution due to accidental runoff or release of oil or its products is a longstanding and common environmental problem. The aim of the study was to investigate the impact of concentrations of oil products (diesel) and suspended solids, the sorbent type, the water flow rate and the interfering factors (chlorides) on the dynamic sorption of diesel and to test regeneration of polypropylene after its use for sorption. The sorbents used for study included common wheat straw (Triticum aestivum), polypropylene and sorbents modified with hydrogen peroxide solution. Standard methods were used for the determination of the investigated parameters and an in-house procedure employing a gas chromatograph was used for the determination of diesel concentration. The following factors that impact the sorption of diesel were investigated during the study: diesel concentration, concentration of suspended solids; type of sorbent (common wheat straw (Triticum aestivum), wheat straw modified with hydrogen peroxide, and polypropylene), water flow rate; and influence of the interfering factors (chlorides). Filtration speed in the range of investigated speeds does not affect the efficiency of diesel removal. Removal efficiency does not depend on the concentration of diesel before the sorbent reaches its maximum sorption capacity. Filling containing 50% of polypropylene and 50% of wheat straw was used for the study. It was found that polypropylene and wheat straw do not remove chlorides and suspended solids from solution. The study found that the solution of hydrogen peroxide boosts the hydrophobic properties of common wheat straw, but does not affect the sorption of diesel. The recommended number of regenerations of polypropylene should be limited to two.