Adsorption behavior of carboxymethyl guar gum onto quartz sand

Abstract

Carboxymethyl guar gum (CGG) is a kind of guar gum commonly used in oil fields. A simple method for the determination of the concentration of CGG was proposed. The adsorption capacity of CGG on quartz sand was measured and the maximum adsorption amount of CGG on quartz sand was 4.8 mg g⁻¹ with a 0.5 wt% CGG concentration. X-ray diffraction and scanning electron microscopy results proved that CGG was adsorbed on the surface of the quartz sand, namely by surface adsorption. The Fourier infrared spectroscopy confirmed that the adsorption was conducted via physisorption. The adsorption isotherm fitted with the Langmuir adsorption isotherm well, which indicated that the adsorption was a monolayer adsorption. In summary, the adsorption behavior of CGG on quartz sand is by surface adsorption, physical adsorption and monolayer adsorption. In order to obtain the optimal condition to reduce the adsorption of CGG in formation, the influence factors including pH, temperature, inorganic salt, alcohols and polymers were investigated. The results showed that a decline of the adsorption can be achieved under the conditions of higher pH, higher temperature, and the presence of monovalent cation salts, ethylene glycol and polymers.