Studying the Efficiency of Treatment Model Mixtures of Petroleum Products with the Modified Sorbent Made of Ash-and-Slag During Dynamic Sorption

Experimental studies on the dynamic sorption of model mixtures containing petroleum products were performed. The subject of the study was the modified sorbent from the ash-and-slag wastes accumulated in the ash dump of the Novocherkassk State District Power Plant (SDPP) (Russia, Novocherkassk, Rostov Region), obtained using the method of ash removal. The quantity of the sorbent for each model solution was fixed at 5.0 g. The model solutions in the amount of 1 dm3 were passed through a column filled with the modified sorbent at constant filtration rate w = const with filtrate takeout of 0.1 dm3/min. The pH value of the solution, which is advisable for extracting petroleum products, was determined experimentally. For this purpose, the model solutions, containing 100 mg/dm3 of petroleum products with pH = 1.65, 4.01, 6.86, 8.12, 9.18, and 11.34, were prepared. The optimum pH value of the solution was considered pH = 7.5. The content of petroleum products in the filtrate in all experiments was determined using IR spectrometry. The working range of water pollution with petroleum products was determined on a series of model solutions containing petroleum products in the range between 0.5 and 10 mg/dm3 with the increment of 0.5, between 10 and 100 mg/dm3 with the increment of 10, and between 100 and 1,000 mg/dm3 with the increment of 100. The maximum extraction of petroleum products from the solution was 88.23%. The applicability of the Henry’s law to the range of petroleum products concentrations in the filtrate of 50 mg/dm3 was confirmed. The adsorption equilibrium constant (Henry’s law constant) was determined experimentally. The effect of the natural freshwater matrix on the degree of petroleum products extraction was studied; no significant effect on petroleum products sorption was found. A conclusion was made that the sorbent can ensure the efficiency of water purifying from petroleum products of no less than 85% in the range of pollution between 5 and 300 mg/dm3