Effects of colloidal humic acid on the transport of sulfa antibiotics through a saturated porous medium under different hydrochemical conditions

Colloidal humic acid (HA) acts as a vector that can facilitate the transport of contaminants in groundwater. However, investigations of factors that enhance the transport of sulfa antibiotics when there are colloids present remain incomplete to date. In this study, column experiments were performed under different conditions (particle size, pH, ionic strength, cation valence, colloidal concentration) using 0.25 mg/L sulfamerazine (SM) with or without colloids. The results showed that antibiotics were more easily deposited on the surface of porous media with a diameter of 0.22 mm than 0.45 mm. As the pH increased from 6 to 8, adding colloidal HA increased the maximum breakthrough concentration from 0.94 to 1 for SM. Adding colloidal HA at different NaCl concentrations decreased the maximum C/C0 ratio from 0.97 to 0.92. However, adding colloidal HA changed the C/C0 ratio more when the divalent cation (Ca2+) was present. Overall, increasing the colloidal HA concentration clearly caused the effluent sulfamerazine concentration to increase.

READ-As and GEH sorption materials for the removal of antimony from water

The objective of this work was to verify the sorption properties of granular filter materials (GEH, READ-As) during the process of removing antimony from water. The pilot tests showed that the use of sorption materials could possibly decrease the antimony content in water to the values limited for drinking water (5 μg/L Sb). A more suitable adsorbent for removing antimony was READ-As. At a concentration of antimony in raw water ranging from 21.5 to 31.1 μg/L, a filtration rate of 5.58 m/h, the value of the bed volume of 3,967, and the adsorption capacity of 128.4 μg/g, which was achieved at a breakthrough concentration of 5 μg Sb/L, were determined. The surface characteristics of the sorption materials used through the physical adsorption of nitrogen, mercury porosimetry, X-ray microanalysis, and scanning electron microscopy (SEM) were studied.

A New Laboratory Method for Evaluation of Sulfate Scaling Parameters from Pressure Measurements

Summary Sulfate scaling in offshore waterflood projects, in which sulfate from the injected seawater (SW) reacts with metals from the formation water (FW), forming salt deposit that reduces permeability and well productivity, is a well known phenomenon. Its reliable prediction is based on mathematical models with well-known parameters. Previous research presents methods for laboratory determination of model coefficients using breakthrough concentration during coreflooding. The concentration measurements are complex and cumbersome, while the pressure measurements are simple and require standard laboratory equipment. In the present work, a new laboratory method is developed for determination of the model coefficients from pressure measurements. Several laboratory corefloods have been performed. The tests show that the proposed method is more precise for artificial cores than for the natural reservoir cores. Further development of the method is required to determine parameters of formation damage caused by sulfate scaling for reservoir core samples.